Vitamins in animals

G. B. Shinde
(M.V.Sc., IV Sem)
Dept. of Animal
Nutrition.
CoVAS, Udgir, (MS)

VITAMINS
Definition-Vitamins are defined as a group of complex
organic compounds present in minute amounts in
natural foodstuffs that are essential to normal
metabolism and lack of which in the diet causes
deficiency diseases.
1911-The term “vitamine” was first used by the Polish
biochemist Funk to describe an accessory food factor.
1913-McCollum and Davis discovered fat-soluble A in
butter that was associated with growth.

3
Water Soluble Vitamins Fat Soluble Vitamins
1) Thiamin
2) Pyrodoxin
3) Biotin
4) Riboflavin
5) Pantothanic acid
6) Nicotinic acid
7) Vit. B12
8) Folic acid.
9) Vitamin C
(Ascorbic acid)
1) Vitamin A
2) Vitamin D
3) Vitamin E
4) Vitamin K
Vitamin like compound
1) Lipoic acid
2) Chollin
3) Meso-inositel
4) Ubiquinone

Differences fat soluble water soluble vitamins
Names A,D,E,K Vitamin C
B Vitamins
Solubility Soluble in fats and organic
solvents
Water soluble
Digestion and absorption Requires fat and bile Easily absorbed in intestine
Excretion Via faeces Via Urine
Storage Stored in the body in fat
depots and in liver
Not stored in body except
Vitamin B12
Toxicity An overdosage can lead to
toxicity
Usually not toxic as it is
readily excreted when given
in excess
Composition only of carbon, hydrogen,
and oxygen
whereas some of the water-
soluble vitamins also contain
nitrogen, sulfur, or cobalt.
DIFFERENCES BETWEEN FAT SOLUBLE AND WATER SOLUBLE VITAMINS
4

Vitamin Synonym
Vitamin A1 Retinol, Retinal,
Retinoic Acid
Vitamin A2 Dehydroretinol
Vitamin D2 Ergocalciferol
Vitamin D3 Cholecalciferol
Vitamin E Tocopherol,
tocotrienols
Vitamin K1 Phylloquinone
Vitamin K2 Menaquinone
Vitamin K3 Menadionea
Vitamin Synonym
Vitamin B1 Thiamin
Vitamin B2 Riboflavin
Vitamin B3 Niacin, Vitamin PP
Vitamin B5 Pantothenic acid
Vitamin B6 Pyridoxol, pyridoxal,
pyridoxamine
Vitamin B8 Biotin, Vitamin H
Vitamin B9 Folic acid, Folacin, folate,
Vitamin M, Vitamin Bc
Vitamin B12 Cobalamin,
Cyanocobalamin
Vitamin C Ascorbic acid 5

Fat Soluble Vitamins
History
1900s, McCollum and Davis described “fat-soluble A,” a
factor isolated from animal fats
1919-Steenbock- suggested that carotene was the
source of the vitamin A.
1939-Wagner and coworkers suggested in that the
conversion of β-carotene into vitamin A occurs within the
intestinal mucosa.
1930 to 1931-Karrer and coworkers proposed the exact
structural formulas for vitamin A and β-carotene.
1947-Isler and coworkers synthesized the first pure
vitamin A.
7

In plant present as provitamin-carotenoids.
It is nearly colorless, fat-soluble, long-chain, unsaturated
alcohol with five double bonds.
 Animal present as vitamin A (retinol).
The vitamin is a pale yellow crystalline solid, insoluble in
water but soluble in fat and various fat solvents. It is readily
destroyed by oxidation on exposure to air and light.
8

Fig.Nutritionally important retinoids and major metabolites. The conventional
numbering system for retinoids is shown for all-trans-retinol, the parent
molecule of the retinoid family. 9

Fig. Nutritionally important carotenoids. (a) Lycopene, a nonprovitamin A carotene; (b) alltrans-bb0-
carotene; arrows indicate sites of cleavage by b-carotene monooxygenase, BCO, and BCO-2;(c)
all-trans (a,b0) carotene; (d) lutein, a nonprovitamin A xanthophyll; (e) b-cryptoxanthin. 10

All-trans-retinal
is the immediate product of the central cleavage of b-carotene as well as an
intermediate in the oxidative metabolism of retinol to all transretinoic acid.
All-trans-retinoic acid
is the most bioactive form of vitamin A.
When fed to vitamin A-deficient animals,
retinoic acid restores growth and tissue
differentiation and prevents mortality, indicating
that this form alone, or metabolites made from
it, is able to support nearly all of the functions
attributed to vitamin A.
A notable exception is vision, which is not
restored by retinoic acid because retinoic acid
cannot be reduced to retinal in vivo.
11

Carotenoids- At least 600 naturally occurring carotenoids are known, but only a few of
these are precursors of the vitamin.
One mol of carotene yields two molecules of Vit A.
 α-carotene,
 β−carotene,
 γ-carotene,
 cryptoxanthine.
Highest Vitamin A activity
Most biologically active form.
Main source of vitamin A in diet.
Twice as potent as the other isomers
Vitamin A1-
-Retinol (Alcohol),
-Retinal (Aldehyde),
-Retinoic acid(Acid).
Vitamin A2- Dehydroretinol
-It contains an additional double bond in the β−ionone ring.
-Liver oils of marine fish-less than 10% of the total vitamin A content.
-Biological activity-40 to50% that of Vit A1.
12

Digestion
Vitamin A in animal products and carotenoids are released from proteins by
the action of pepsin in the stomach and proteolytic enzymes in the small
intestine. (Ong, 1993; Ross, 1993).
In the duodenum, bile salts break up fatty globules of carotenoids and retinyl
esters to smaller lipid congregates, which can be more easily digested by
pancreatic lipase, retinyl ester hydrolase, and cholesteryl ester hydrolase.
β−carotene
In
the intestinal mucosa
two molecules of
retinal
retinol
However,extensive evidence exists also for
random (eccentric) cleavage, resulting in
retinoic acid and retinal, with a
preponderance of apocarotenals formed as
intermediates (Wolf, 1995).
15,15 dioxygenase
Retinaldehyde
reductase
Absorption
13

The cleavage enzyme has been found in many vertebrates
but is not present in the cat or mink.
Therefore, these species cannot utilize carotene as a source
of vitamin A.
In some species, such as the rat, pig, goat, sheep,rabbit,
buffalo, and dog, almost all of the carotene is cleaved in the
intestine.
In humans, cattle, horses, and carp, significant amounts of
carotene can be absorbed.
Absorbed carotene can be stored in the liver and fatty
tissues.
Hence, these latter animals have yellow body and milk fat,
whereas animals that do not absorb carotene have white fat.
No absorption occours in Stomach
Main site of lipid absorption is Mucosa of Proximal jejunum.
14

In mucosal cells of Int., retinol is re-esterified
Palmitate ester
incorporated into the chylomicra of the mucosa
secreted into the lymph
transported through the lymphatic system with a LPL
deposited Liver (hepatocytes and stellate and parenchymal
cells)
Intestine Liver
Retinyl ester hydrolase by pancreas
16

Liver Target
Tissue
Retinol is readily transferred to the egg in birds, but the transfer of retinol across
the placenta is marginal, and mammals are born with very low liver stores of
vitamin A. Uterine RBP has been identified in the pig uterus, with the function of
delivering retinol to the fetus (Clawitter et al., 1990). 17

Excretion
Derivatives of vitamin A with an intact carbon chain are generally excreted in
feces, whereas acidic chain-shortened products tend to be excreted in urine
(Olson, 1991).
Liver normally contains about 90% of total-body vitamin A.
The remainder is stored in the kidneys, lungs, adrenals, and blood,
with small amounts also found in other organs and tissues.
A large quantity of vitamin A is stored in the kidney as well as the liver
in cats and dogs.
This high level of vitamin A in the kidney is unique to cats and dogs.
Grass-fed cattle have large stores of carotene in their body fat, which
is evidenced by a deep yellow color
18

1. Vision
2. Maintenance of Normal Epithelium
3. Bone Development
Vision
19

Blood
II cis-Retinol
Rhodopsin
Trans-Retinal +Scotopsin
II cis-Retinal
II cis-Retinal=
Prosthetic group
Trans-Retinol
Blood and Epithelium
Esterase
Retinyl Esters
Retinal
Alcohol
Dehydrogenase
(NADH)
NADPH
H+
Retinal Isomerase
Palmitic, Stearic,
Oleic)
Fig. Vitamin A and its role in the Chemical Reactions involved in vision.
scotopsin
20

Retina of eye
Rods Cones
Dim light
Bright light
Rhodopsin Iodopsin
Cis isomers of retinol
Vision
21

II-Cis isomer of Retinol
oxidation
Retinal
(aldehyde)
In absence
of light
II cis isomer of
retinol
ε amino group of Lysin
in OPSIN
Rhodopsin {VISUAL PURPLE}
22

In presence
of light
All trans form
Cis retnaldehyde
Released from Opsin
Transmission of impulse up the Optic nerv
23

Synthesis of glycoprotein to maintain integrity of epithelial cell
Required for maintenance of epithelial cells, which form protective linings on
many of the body’s organs
Vitamin A penetrates lipoprotein membranes and, at optimum levels, may act
as a cross-linkage agent between the lipid and protein, thus stabilizing the
membrane (Scott et al., 1982).
Vitamin A is necessary for normal vision in animals and humans,
maintenance of healthy epithelial or surface tissues, and normal bone
development.
Bone Development
Through control exercised over the
activity of osteoclasts of the epithelial
cartilage.
Release of protease, cathepsin from
the lysosomes, which act on the
muco-protein of the bone cartilage
releasing protein and
mucoployschride derivatives. 24

Vitamin A deficiency affects immune function, particularly the antibody
response to T-cell–dependent antigens
(Ross, 1992).
Vitamin A deficiency causes decreased phagocytic activity in macrophages and
neutrophils.
Several studies in animal modelshave shown that the intestinal IgA response is
impaired by vitamin A deficiency
(Davis and Sell, 1989; Wiedermann et al., 1993; Stephensen et al., 1996).
Reproduction
Normal levels of vitamin A are required for sperm production.
Normal reproductive cycles in females require adequate availability of vitamin A.
25

Animal Purpose or Class Requirement
(IU/kg)
Reference
Dairy cattle Growing 2,200 NRC (1989a)
Lactating cows and bulls 3,200 NRC (1989a)
Calf milk replacer 3,800 NRC (1989a)
Goat All classes 5,000 Morand-Fehr
(1981)
Cat Gestation 6,000 NRC (1986)
Dog Growing 3,336 NRC (1985a)
Chicken Leghorn, 0–18 weeks 1,500 NRC (1994)
Laying (100-g intake) 2,000 NRC (1994)
Broilers 1,500 NRC (1994)

Bitot's spots- Mild vitamin A deficiency may result in changes in the conjunctiva
(corner of the eye)
EFFECT ON REPRODUCTION:-
•Deficiency of vitamin A can lead to infertility or sterility in male
•Deficiency of vitamin A can lead to vaginitis, abnormal oestrous cycle, early
embryonic mortality, abortion and defective formation of foetus in females.
•EFFECT ON CEREBROSPINAL FLUID PRESSURE:
One of the initial effects of vitamin A deficiency is elevated cerebrospinal fluid
(CSF) pressure.
The mechanism whereby the increase in CSF pressure is brought by thickened
duramater leading to under absorption of CSF.
EFFECT ON BONE FORMATION- vitamin A can lead to developmental bone
deformities.
EFFECT ON IMMUNE SYSTEM-
Vitamin A is commonly known as the anti-infective vitamin, because it is
required for normal functioning of the immune system.
The skin and mucosal cells (cells that line the airways, digestive tract, and
urinary tract) function as a barrier and form the body's first line of defense
against infection.
27

ANTI-INFECTIVE VITAMIN –
Vitamin A is involved in the formation and protection of epithelial cells.
Damage to epithelial cells can cause easy entry of pathogenic microbes leading
to infection.
So infection of gastrointestinal tract, respiratory tract, urogenital tract and skin
is common in Vitamin A deficiency.
As vitamin A helps to prevent these infections it is called anti infective vitamin.
CONGENITAL BLINDNESS-
Vitamin A is needed for bone formation.
If vitamin A is deficient optic foramen is not formed properly.
Small size optic foramen leads to the constriction of optic nerve.
Permanent damage to the nerve can lead to permanent blindness.
XEROPHTHALMIA (DRY EYE)-
Xerophthalmia is characterized by changes in the cells of the cornea that
ultimately result in corneal opacity, keratinization of the cornea, corneal ulcers,
scarring, and blindness.
28

Deficiency Symptoms
Night blindness
Xeropthalmia
Keratinization of epithelium
Reproductive performance
Nervous lesions
Retinoic acid :unable to fullfill
The function of Vit a in vision
And reproduction although it
Maintain normal growth.
29

Fig. Vitamin A-deficient calf. Note the emaciated appearance and evidence of
diarrhea. The calf also shows excessive lacrimation and nasal discharge
characteristic of vitamin A deficiency. 30

 Dry condition of cornea
and conjuctiva,cloudiness
and ulceration
 Softning of cornea
 Thickned cornea
 Bitot spot (human)
 White foamy patches on
white portion of eye
31

 Occulonasal discharge
 Conjuctivitis
 Sticking of eyelids
 Presence of cheesy partical in eye and
nasal sinus
 Swelling of face
Egg production
and hatchability
decreased
•Poor hatchabilitylili
•Poor feather development
•Fall in egg production
•Retarded growth
32

Fig. Advanced stage of anasarca in hindquarters of vitamin A-deficient steer. 33

Fig. Vitamin A-deficient calf shows incoordination and weakness. 34

Fig. Typical appearance of a vitamin A-deficient lamb. Note the extreme
weakness and swayed back. This was followed by the inability to stand. 35

Fig. Vitamin A deficiency in growing pigs: (A) partial paralysis and seborrhea, (B)
initial stage of spasm, (C) lordosis and weakness of hind legs.
A
B
C
36

 Keratinization
of epithelium
 Respiratory
trouble-cold and
sinus inf
 GIT disorder-
Diarrhoea
 Genitourinary-
kidney and
bladder stone.
 Deposition of
urate –on
heart,pericardium,
liver and spleen
 Nervous lesion
 Skeletal growth
retarded but
nervous tissue
and brain
grows-there is
pressure on
nervous tissue-
increased CSF
 SEVERE ATAXIA
37

 Skin
 :Shaggy
appearance
Hyperkeratini
satin
Bran like
scales-
Ptiyriasis
Horse-hooves
manifest
vertical
cracks
Congenital
malformatn
 Anopthalmus
 Micropthalmus
 Anasarca,Palat
oschisis(Cleft
palat,Hare lip)
 Malformed
limb.
38

Decline in sexual maturity.
Decreased no.of
spermatozoa
Decrease in motility
Failure of spermatogenesis
Degeneration of germinal
epithelium and
seminiferous tubule.
Oestrus is disturbed
Abortion or birth of dead ,weak or
abnormal offspring
Thickning of vaginal epithelium
Retension of placenta.
39

Deficiency Symptoms
Ataxia in chicks Retarded growth in poult
40

Ricket and Osteomalacia
Pain in bone due to calcification
Soreness of corners of mouth and
coarseness of hair
Exostoses in various places
In human-Persistant chronic
headache
Distorted vision.
41

Antioxidant
Stabilisation on cellular membrane
Vitamin C
Antioxidant for hepatic vitamin A storage
Enfluence on hepatic synthesis of Ascorbic acid.
Vitamin E
B1, B2 , B3 , B5 , B6 Show synergistic effect
42

 Vit E-Being fat soluble ,may
compete with vittamin A for
absorption Supress PGE2
Enhance PGE1 synthesisVitamin E
Vitamin A Enhance PGE2 synthesis
Vitamin D Absorption and retention
of Calcium
Vitamin A Cause bone resorptnm
decalcification
43

Involved in regulation of vit A
Adequate amt are required for the mobilization Of Vitamin A
from liver
Involved in maintaining plasma RBP
Specific transport
Zinc
Selenium
Synergistic(antioxidant)
Antagonistic
Iodine In the form of T4
Synergistic
Antagonistic
44

ADH-Increase mobilization of
vitamin A from liver
Thyroxin-……………..
Estogen……………
45

Vitamin A (Retinol) (IU/g)Content of Feeds
Whale liver oil 400,000 Barracuda liver oil 12,000
Swordfish liver oil 250,000 Dogfish liver oil 12,000
Halibut liver oil 240,000 Seal liver oil 10,000
Herring liver oil 211,000 Cod liver oil 4,000
Tuna liver oil 150,000 Sardine body oil 750
Shark liver oil 150,000 Pilchard body oil 500
Bonito liver oil 120,000 Menhaden body
oil
340
White sea bass liver oil 50,000 Butter 35
Eggs 10 Cheese 14
Milk 1.5
Sources: Adapted from Scott et al. (1982) and Maynard et al. (1979). 46

Fresh green legumes and grasses, immature (wet basis) 33–88
Dehydrated alfalfa meal, fresh, dehydrated without field curing, very
bright green
242–297
Dehydrated alfalfa meal after considerable time in storage, bright green 110–154
Alfalfa leaf meal, bright green 120–176
Legume hays, including alfalfa, very quickly cured with minimum sun
exposure, bright green, leafy
77–88
Legume hays, including alfalfa, good green color, leafy 40–59
Legume hays, including alfalfa, partly bleached, moderate amount of
green color
20–31
Legume hays, including alfalfa, badly bleached, or discolored, traces of
green color
9–18
Non-legume hays, including timothy, cereal, and prairie hays, well cured,
good green color
20–31
Non-legume hays, average quality, bleached, some green color 9–18
Legume silage (wet basis) 11–44
Corn and sorghum silages, medium to good green color (wet basis 4–22
Grains, mill feeds, protein concentrates, and by-product concentrates,
except yellow corn and its by-products
0.02–0.44 47

History
Chemical Structure & Properties
1919-Sir Edward Mellanby was able to experimentally produce rickets in puppies by
feeding synthetic diets
-He further showed that rickets could be prevented by the addition of cod-
liver oil or butterfat to the feed.
1922- McCollum showed that the antirachitic factor in cod-liver oil could survive
both aeration and heating to 1000C for 14 h whereas the activity of vitamin A was
destroyed by this treatment. McCollum named the new substance vitamin D
Dietary source of vitamin D-steroid, ergosterol
Occurs as colourless crystals.
Insoluble in water.
Readily soluble in alcohol and other organic solvents.
Less soluble in vegetable oils.
Destroyed by overtreatment wit uv light and by peroxidation in the
presence of rancidifying polyunsaturated fatty acids.
Sunshine Vitamin
49

Ergocalciferol (C₂₈H₄₄O)
In plant present as Vitamin D2 (Ergocalciferol).
Ergocalciferol is derived from a common plant steroid, ergosterol,
and is the usual dietary source of vitamin D.
Three double bonds
melting point-121⁰C
Molecular weight-384.65
Insoluble in H₂O
Soluble in benzene, chloroform, ethanol, and acetone.
Unstable in light
Will undergo oxidation if exposed to air at 24⁰C for 72 h.
Stored at 0⁰c.
Cholecalciferol (C₂₇H₄₄O)
In animal present as Vitamin D3 (Cholecalciferol). Precursor is 7-
ehydrocholesterol
Four double bonds
melting point-121⁰C
Insoluble in H₂O
Soluble in benzene, chloroform, ethanol, and acetone.
Unstable in light
Will undergo oxidation if exposed to air at 24⁰C for 72 h.
Stored at 0⁰c.
Chemical Properties
50

Provitamin Trivial
Name
Vitamin D
Produced
upon
Irradiation
Empirical Formula
(Complete Steroid)
Side Chain
Structure
Ergosterol D2 C28H44O
7-dehydrocholesterol D3 C27H44O
22,23-
dihydroergosterol
D4 C28H46O
7-dehydrositosterol D5 C29H48O
7-dehydrostigmasterol D6 C29H46O
7-dehydrocampesterol D7 C28H46O
52

Absorption
Cholecalciferol is absorbed from the intestinal tract primarily in the
duodenum.
It is poorly absorbed in the absence of bile, the secretion of which is
limited in young chicks.
Highest concentration found in the- intestinal wall, liver, kidneys,
spleen, gall bladder and serum.
While concentration in muscle, bone, pancreases and skin are low,
these tissue account for large proportion of the stored vitamin D.
Vitamin D₃ absorption is enhanced by certain organic acids,
especially lactic acid.
However, the effect of organic acid in improving calcium absoption
may be independent of Vitamin D.
Half life of Vitamin D₃-25days in birds while that of 25(OH)D₃ is
closer to 20 days and the half life of 24,25(OH) ₂D₃ is only around
2days 53

Principal stores are liver ,blood.
Kidneys, lungs to the lesser extent.
In pigs, the amount of vitamin in blood is several
fold higher than that in the liver.
Excretion of absorbed vitamin D and its metabolites
occurs primarily in feces with the aid of bile salts.
Very little vitamin D appears in urine.
Ohnuma et al. (1980)
Storage, Excretion

To elevate Ca and P levels in the plasma necessary to support normal body
functions.
There is also some evidence that Vitamin D₃ may play a regulatory role in
immune cell function.
(Reinhardt and Hustmyer,1987)
There is possible use of Vitamin D analogues, is to bring about cell
differentiation of mylocytic- type leukemias
(DeLuca, 1988).
Vitamin D₃ brings about an elevation of plasma Ca
and P by stimulating specific pump mechanisms in the intestine, bone,
and kidney thus maintaining blood levels of ca and p, from these body
reserves.
The active form of vitamin D, 1,25-(OH)2D, functions as a steroid hormone.
The hormone is produced by an endocrine gland, circulated in blood bound
to a carrier protein (DBP), and transported to target tissues.
Vitamin D has also been reported to influence magnesium (Mg) absorption as
well as Ca and P balance
(Miller et al., 1965).
Intestinal Effects- It is well known that vitamin D stimulates active transport
of Ca and P across intestinal epithelium. 57

Bone Effects-
Vitamin D plays roles both in the mineralization of bone as well as
demineralization or mobilization of bone mineral. 1,25-(OH)2D is one of the
factors controlling the balance between bone formation and resorption.
In young animals during bone formation, minerals are deposited on the
matrix. This is accompanied by an invasion of blood vessels that gives rise
to trabecular bone. This process causes bones to elongate. During vitamin D
deficiency, this organic matrix fails to mineralize, causing rickets in the
young and osteomalacia in adults.
Another role of vitamin D has been proposed in addition to its involvement
in bone; namely, in the biosynthesis of collagen in preparation for
mineralization. (Gonnerman et al., 1976).
Kidney Effects-
There is evidence that vitamin D functions in the distal renal tubules to
improve Ca reabsorption and is mediated by calbindin.
(Bronner and Stein, 1995).
1,25-(OH)2D3 functions in improving renal reabsorption of Ca.
(Sutton and Dirks, 1978).
58

Other Vitamin D Functions-
Vitamin D has also been shown to be required for chick embryonic
development.
1,25-(OH)2D is also essential for the transport of eggshell Ca to the
embryo across the chorioallantoic membrane
(Elaroussi et al., 1994).
In the pancreas, 1,25-(OH)2D is essential for normal insulin
secretion.
More than 50 genes have been reported to be transcriptionally
regulated by 1,25-(OH)2D.
(Hannah and Norman, 1994).
The actions of 1,25-(OH)2D3 are recognized as being involved in
regulation of the growth and differentiation of a variety of cell types,
including those of hematopoietic and immune systems.
(Lemire, 1992).
A deficiency of vitamin D may promote prostate cancer.
(Skowronski et al., 1995).
59

Deficiency
Rickets- generally characterized by a decreased concentration of
Ca and P in the organic matrices of cartilage and bone.
Osteomalacia- is characterized by a decreased concentration of
Ca and P in the bone matrix
Osteoporosis-is defined as a decrease in the amount of bone,
leading to fractures after minimal trauma.
vitamin D deficiency occurs in animals includes the following
characteristics
1. Failure of Ca salt deposition in the cartilage matrix.
2. Failure of cartilage cells to mature, leading to their
accumulation rather than destruction.
3. Compression of the proliferating cartilage cells.
4. Elongation, swelling, and degeneration of
proliferative cartilage.
5. Abnormal pattern of invasion of cartilage by
capillaries.
(Kramer and Gribetz, 1971)

Calves developed severe rickets while receiving ration deficient in vitamin D,
and kept away from sunlight. (A: Courtesy of W. Krauss, Ohio Agriculture
Experiment Station. B: Courtesy of Michigan Agriculture Experiment Station,
NRC, 1958.)
Fig. A Fig. B
Fig. Pig with advanced
rickets caused by lack of
vitamin D.
61

62
Vitamin D deficiency (rickets) . Note the ungainly manner of balancing the body
and initial swelling of the hock joint.

There is enlargement at ends of bones from deposition of
excess cartilage, giving the characteristic “beading” effect
along the sternum where ribs attach
(NRC,1989a, 1996).
An early report of rickets in Scotland referred to the
condition as “bent leg,” which occurred in ram lambs 7 to
12 months of age.
(Elliot and Crichton, 1926).
Severe rickets in kittens resulted in enlarged
costochondral junctions (“rachitic rosary”), with
disorganization in new bone formation and excessive
osteoid
(NRC, 1986).

Dogs-receiving toxic concentrations of vitamin D exhibited anorexia, polyuria,
bloody diarrhea, polydipsia, prostration, and excessive calcification of the lungs
(Morgan, 1947)
In poultry, excess vitamin D elevates 1,25-(OH)2D with hypercalcemia and soft
tissue mineralization.
(NRC, 1994).
Harrington and Page (1983) compared toxicity of D2 to D3 in horses. Signs of
toxicity included weight loss, hypercalcemia, hyperphosphatemia, and
cardiovascular calcinosis.
A condition known as “humpy-back,” in which clinical symptoms reminiscent of
calcinosis occur, may be caused by sheep grazing the fruits of S. esuriale in Australia.
In Jamaica, “Manchester wasting disease” and in Hawaii, “Naalehu disease” are
conditions seen in cattle that are virtually identical to enteque seco in relation to
clinical and pathological signs.
(Wasserman, 1975; Arnold and Fincham, 1997).
64

Fig. Vitamin D toxicity (enteque seco) in Argentina: (A) Cow that had consumed
the shrub Solanum malacoxylon; (B) Calcium deposits in soft tissue. (Courtesy
of Bernardo Jorge Carrillo, CICV, INTA, Castelar, Argentina.)
Fig. A Fig. B
65

Animal Dietary
Requirement
Exposure Time
< 60 days > 60 days
Chicken 200 40,000 2,800
Horse 400 2,200
Sheep 275 25,000 2,200
Swine 220 33,000 2,200
Source: Modified from NRC (1987). 66

(IU/kg)
Reference
Dairy cattle Milk replacer 300 NRC (1989a)
Lactating cows 1,000 NRC (1989a)
Growing bulls 300 NRC (1989a)
Goat All classes 1,400 Morand-Fehr (1981)
Cat Gestation 500 NRC (1986)
Dog Growing 22 IU NRC (1985a)
Chicken Leghorn, 0–18 weeks 200 NRC (1994)
Laying (100-g intake) 300 NRC (1994)
Broilers(0–8 weeks) 200 NRC (1994)
67

Vitamin D (Ergocalciferol )(D2) IU/100 g Concentrations in Various Foods and
Feedstuffs
Food or Feedstuff Red clover, fresh 4.7
Alfalfa pasture 4.6 Red clover, sun
cured
192
Alfalfa hay, sun cured 142 Sorghum grain 2.6
Alfalfa silage 12 Sorghum silage 66
Alfalfa wilted silage 60 Corn silage 13
Birdsfoot trefoil hay, sun
cured
142 Molasses, sugar
beet
58
Barley straw 60
Cocoa shell meal, sun
dried
3,500
Sources: Adapted from Scott et al. (1982) and Maynard et al. (1979). 68

Vitamin D (Cholecalciferol D3) IU/100 g Concentrations in Various Foods and
Feedstuffs
Blue fin tuna liver oil 4,000,000 Milk, cow’s whole
(winter)
1
Cod liver oil meal 4,000 Sardine, entire
body oil
8,000
Cod liver oil 10,000 Swordfish liver oil 1,000,000
Eggs 100
Halibut liver oil 120,000
Herring, entire body oil 10,000
Menhaden, entire body
oil
5,000
Milk, cow’s whole
(summer)
4
Sources: Adapted from NRC (1982b) and Scott et al. (1982).
69

History
1922-Discovered by Evans and Bishop
1936: Evans et al, Isolated α-tocopherol
1960s: Vitamin E deficiency was described in children with fat
malabsorption syndromes.
1980s: Major symptom of vitamin E deficiency in Human was a
peripheral neuropathy.
Greek -‘‘tokos’’ (offspring) and ‘‘pherein’’ (to bear) with an ‘‘ol’’ to
indicate that it was an alcohol
Tocopherols and Tocotrienols is closely related to Vitamin E
Eight forms of vitamin E
Tocopherols(Saturated )- α, β, γ, and δ.
Tocotrienols(Unsaturated )- α, β, γ, and δ.
α- tocopherols -most biologically active
-yellow oil i.e. insoluble in water
-soluble in organic solvents.
-tocopherol > potent than b > g > d
Tocotrienols (trienols)
unsaturated side chains
only  has significant biological activity
Synthetic-α tocopheryl acetate.

Fig. Vitamin E structures are shown. The methyl groups on the chromanol head
determine whether the molecule is a-, b- or g-, or d-, while the tail determines
whether the molecule is a tocopherol or a tocotrienol. 72

Tocopherols-extremely resistant to heat but are easily
oxidized, destroyed by peroxides, ozone
Resistant to acids (anaerobic) and bases
Vitamin E is a potent peroxyl radical scavenger and
especially protects PUFA within phospholipids of
biological membranes and in plasma lipoproteins.
73

Vitamin E absorption is related to fat digestion and is facilitated by
bile and pancreatic lipase .
(Sitrin et al., 1987).
Most vitamin E is absorbed as the alcohol
Absorption and
Transport
Vitamin E is stored throughout all body tissues; major deposits are
in adipose tissue, liver, and muscle, with highest storage in the
liver..
The major route of excretion of ingested vitamin E is fecal
elimination.
Usually less than 1% of orally ingested vitamin E is excreted in the
urine. 74

Placental and Mammary Transfer
Vitamin E does not cross the placenta in any appreciable
amounts; however, it is concentrated in colostrum (Van Saun et
al., 1989). With respect to neonatal ruminants (Hidiroglou et al.,
1969; Van Saun et al.,1989) and baby pigs (Mahan, 1991).
The importance of providing colostrum rich in vitamin E is quite
apparent, as both calves and lambs are born with low levels of
the vitamin
(Nockels, 1991; Njeru et al., 1994a).
Low blood vitamin E may lead to diminished disease resistance
and immune response in the neonate
(Nockels, 1991).

a-Tocopherol decreased the release of proinflammatory cytokines and
chemokines (IL-8 and plasminogen activator inhibitor-1 [PAI-1]).
(Singh et al.,2005).
Vitamin E has been shown to be essential for integrity and optimum
function of the reproductive, muscular, circulatory, nervous, and
immune systems.
(Hoekstra, 1975; Sheffy and Schultz, 1979; Bendich,1987; McDowell et
al., 1996).
Vitamin E as a Biological Antioxidant
One of the most important functions is its role as an intercellular and
intracellular antioxidant.
Vitamin E is part of the body’s intracellular defense against the adverse
effects of reactive oxygen and free radicals that initiate oxidation of
unsaturated phospholipids (Chow, 1979) and critical sulfhydryl groups
(Brownlee et al., 1977). 76

Semen quality of boars was improved with Se and vitamin E
supplementation, with vitamin E playing a role in maintaining sperm
integrity in combination with Se
(Marin-Guzman et al., 1989).
Membrane Structure and Prostaglandin Synthesis
α-Tocopherol may be involved in the formation of structural components
of biological membranes, thus exerting a unique influence on
architecture of membrane phospholipids
(Ullrey, 1981).
It is reported that α-tocopherol stimulated the incorporation of 14C from
linoleic acid into arachidonic acid in fibroblast phospholipids.
Also, it was found that α-tocopherol exerted a pronounced stimulatory
influence on formation of prostaglandin E from arachidonic acid, while a
chemical antioxidant had no effect.
77

Vitamin E is an inhibitor of platelet aggregation in pigs.
(McIntosh et al., 1985),
May play a role by inhibiting peroxidation of arachidonic acid, which
is required for formation of prostaglandins involved in platelet
aggregation
(Panganamala and Cornwell, 1982; Machlin,1991).
Disease Resistance
Both in vitro and in vivo studies showed that the antioxidant vitamins
generally enhance different aspects of cellular and noncellular
(humoral) immunity.
One function of vitamin C is that this vitamin can regenerate the
reduced form of α-tocopherol, perhaps accounting for observed
sparing effects of these vitamins .
(Jacob, 1995; Tanaka et al., 1997).
78

Both vitamin E and Se may help these cells to survive the toxic products
that are produced in order to effectively kill ingested bacteria.
(Badwey and Karnovsky, 1980).
Vitamin E has been implicated in stimulation of serum antibody
synthesis, particularly IgG antibodies.
(Tengerdy, 1980).
Vitamin E deficiency allows a normally benign virus to cause disease .
(Beck et al., 1994).
Selenium or vitamin E deficiency leads to a change in viral phenotype,
such that an avirulent strain of a virus becomes virulent and a virulent
strain becomes more virulent.
(Beck, 1997).
79

Relationship to Toxic Elements or Substances
Both vitamin E and Se provide protection against toxicity with three
classes of heavy metals
(Whanger, 1981).
Vitamin E can be effective against other toxic substances. For
example, treatment with vitamin E gave protection to weanling pigs
against monensin-induced skeletal muscle damage .
(Van Vleet et al.,1987).
Relationship with Selenium in Tissue Protection
Vitamin E prevents fatty acid hydroperoxide formation, sulfur amino
acids are precursors of glutathione peroxidase, and Se is a component
of glutathione peroxidase.
(Smith et al., 1974).
In diets severely deficient in Se, vitamin E does not prevent or cure
exudative diathesis, whereas addition of as little as 0.05 ppm Se
completely prevents this disease.
(Scott, 1980).
80

1. Normal phosphorylation reactions, especially of high-energy
2. phosphate compounds, such as creatine phosphate and adenosine
triphosphate
3. A role in synthesis of vitamin C and ubiquinone
4. Role in sulfur amino acid metabolism.
Scott et al. (1982)
A deficiency of vitamin E interferes with conversion of vitamin B12 to its
coenzyme 5′-deoxyadenosylcobalamin and concomitantly metabolism
of methylmalonyl-CoA to succinyl-CoA.
Pappu et al. (1978)
In rats, vitamin E deficiency has been reported to inhibit vitamin D metabolism
in the liver and kidneys with the formation of active metabolites and decreases
in the concentration of the hormone-receptor complexes in the target tissue.
Liver vitamin D hydroxylase activity decreased by 39%, 25-OHD3 1-hydroxylase
activity in the kidneys by 22%, and 24-hydroxylase activity by 52%
(Sergeev et al., 1990).
81

(IU/kg)
Reference
Dairy cattle Milk replacer 40 NRC (1989a)
Lactating cows 25 NRC (1989a)
Growing bulls 100 NRC (1989a)
Goat All classes 100 Morand-Fehr (1981)
Cat Gestation 30 NRC (1986)
Dog Growing 22 NRC (1985a)
Chicken Leghorn, 0–6weeks 10 NRC (1994)
Leghorn, 6-18weeks 5
Laying (100-g intake) 5 NRC (1994)
Broilers(0–8 weeks) 10 NRC (1994)
REQUIREMENTS

DEFICIENCY
Nutritional myopathy / white muscle disease / stiff lamb disease
/ mulberry heart disease / exudative diathesis / crazy chick
disease
The most frequent and the most important manifestation of
Selenium deficiency in farm animals is muscle degeneration
(myopathy).
Nutritional myopathy , also known as muscular dystrophy,
frequently occurs in cattle, particularly calves.
The myopathy primarily affects the skeletal muscles and the
affected animals have weak leg muscles, a condition
manifested by difficulty in standing and, after standing, a
trembling and staggering gait.

Eventually, the animals are unable to rise and weakness of the
neck muscles prevents them from raising their heads.
A popular descriptive name for this condition is white muscle
disease.
The heart muscle may also be affected and death may result.
Nutritional myopathy also occurs in lambs, with similar
symptoms to those of calves. The condition is frequently
referred to as stiff lamb disease.

Vitamin E deficiency in the chick. Note prostrated chick with retracted head.

Fig. Vitamin E-selenium deficiency in cattle is manifested as white muscle
disease or necrosis of the gastrocnemius muscle; chalky white streaks are
evident in the belly of the muscle 86

Chicks:-
 In nutritional myopathy the main muscles affected are the
pectorals although the leg muscles also may be involved.
 Nutritional encephalomalacia or crazy chick disease is a
condition in which the chick is unable to walk or stand, and is
accompanied by hemorrhages and necrosis of brain cells.
 Exudative diathesis is a vascular disease of chicks
characterized by a generalized oedema of the subcutaneous fatty
tissues, associated with an abnormal permeability of the capillary
walls.
 Both selenium and vitamin E appear to be involved in nutrition
myopathy and in exudative diathesis but selenium does not seem
to be important in nutritional encephalomacia.

In pigs, the two main diseases associated with vitamin E and
selenium deficiency are myopathy and cardiac disease.
The pigs demonstrate an uncoordinated staggering gait, or
are unable to rise.
The pigs heart muscle is more commonly affected.
Sudden cardiac failure occurs and on post-mortem
examination the lesions of the cardiac muscles are seen
as pale patches or white streaks. This condition is
commonly known as mulberry heart disease.

Fig. Vitamin E-selenium deficiency is seen as flexion of the hock and fetlock
joints as a result of decreased support by the gastrocnemius muscle, which is
severely affected by myodegeneration 89

Hypervitaminosis E studies in rats, chicks, and humans indicate
maximum tolerable levels in the range of 1,000 to 2,000 IU/kg of diet
(NRC, 1987).
In chickens, the effects of vitamin E toxicity are depressed growth
rate, reduced hematocrit, reticulocytosis, increased prothrombin time
(corrected by injecting vitamin K), and reduced calcium and
phosphorus in dry, fat-free bone ash
(NRC, 1987).
90

Tocopherols in Selected Feedstuffs (ppm)
Source: Modified from Ullrey (1981).
Feedstuff α β γ δ
Barley 4 3 0.5 0.1
Corn 6 ---- 38 Trace
Oats 7 2 3 ---
Rye 8 9 -- 0.8
Wheat 10 9 ---- 0.8
Corn oil 112 50 602 18
Cottonseed oil 389 --- 387 ---
Wheat germ oil 1,330 710 260 271
Palm oil 256 ---- 316 70
Safflower oil 387 --- 174 40
Soybean oil 101 ---- 593 264
NATURAL SOURCES

History
1935- Discovered by Henrik Dam
Vitamin K extracted from plant- Phylloquinone (Vitamin K1) .
Synthesised by intestinal bacteria- Menaquinones (Vitamin K2).
Synthetic-Menadione (Vitamin K3).
Vitamin K is a golden yellow viscous oil.
Vitamin K1 is slowly degraded by atmospheric oxygen but fairly rapidly
destroyed by light.
stable to heat, destroyed by sunlight & alkali.
melting points 35ºC to 60ºC
 Phylloquinone.Synonym
93

Fig. Structures of some compounds with vitamin K activity. 94

Dicumarol.
By feeding sulfonamides (in monogastric species) at levels
sufficient to inhibit intestinal synthesis of vitamin k.
Mycotoxins, toxic substances produced by molds, are also
antagonists causing vitamin k deficiency.
In cattle, vitamin k1 is much more potent than vitamin k3 as an
antidote to dicumarol.
(Goplen and Bell 1967)
95

Fig. Oral anticoagulants that antagonize vitamin K action. 96

Fig. Other vitamin K antagonists 97

Absorption and Transfer
Absorption of vitamin K depends on its incorporation into mixed micelles, and
optimal formation of these micellar structures requires the presence of both
bile and pancreatic juice.
Storage and Excretion
Vitamin K -stored liver.
Excreted in the urine.
The lymphatic system is the major route of transport of absorbed phylloquinone
from the intestine in mammals but by portal circulation in birds, fishes, and
reptiles.
(Shearer et al. 1970)
98

The vitamin is required for the synthesis of the active form of
prothrombin (factor II) and other plasma clotting factors (VII, IX, and X).
These four blood-clotting proteins are synthesized in the liver in inactive
precursor forms (zymogens) and then converted to biologically active
proteins by the action of vitamin K
(Suttie and Jackson,
1977).
Blood Coagulation
99

Fig. Scheme involving blood clotting. The vitamin K-dependent factors
(synthesis of each is inhibited by dicumarol) include factor IX, Christmas factor;
factor X, Stuart-Prower factor; factor VII, proconvertin; and factor II,
prothrombin.
10
0

The metabolic function of vitamin K is as the coenzyme in the
carboxylation of protein-incorporated glutamate residues to yield γ-
carboxyglutamate thus converting inactive precursor proteins to
biological activity.
Carboxylation allows prothrombin and the other procoagulant
proteins to participate in a specific protein-calcium-phospholipid
interaction that is necessary for their biological role
(Suttie andJackson, 1977).
Calcium binding proteins

The major clinical sign of vitamin K deficiency in all species is impairment of
blood coagulation.
Sweet clover poisoning / hemorrhagic sweet clover disease
Dicumarols are produced by molds, particularly those that attack sweet
clover hay, thus giving rise to the term sweet clover disease.
During the process of spoiling, harmless natural coumarins in sweet clover
are converted to dicumarol (bis-hydroxycoumarin), and when toxic hay or
silage is consumed by animals, hypoprothrombinemia results, presumably
because dicumarol combines with the proenzyme to prevent formation of the
active enzyme required for the synthesis of prothrombin. It probably also
interferes with synthesis of factor VII and other coagulation factors.
In an experiment with calves, dicumarol poisoning was produced by feeding
naturally spoiled, sweet clover hay that contained a minimum of 90 mg
dicumarol per kilogram of hay.
(Alstad et al., 1985).102

Poultry
Generalized hemorrhage due to severe vitamin K deficiency in a young chick.
103

Hemorrhagic blemishes in the muscle of a chicken fed a diet deficient in
vitamin K. (Courtesy of M.L. Scott, Cornell University.) 104

Rabbits
When a vitamin K-deficient diet was fed to pregnant rabbits, the result was
placental hemorrhage and abortion of young
(NRC, 1977).
Dogs
Vitamin K deficiency has been demonstrated in adult dogs following diversion
of bile from the intestine by means of a cholecystonephrostomy .
(NRC, 1985a).
One study found that although blood clotting was impaired and there was a
reduction in bone γ-carboxyglutamic acid concentration, vitamin K deficiency
did not functionally impair skeletal metabolism of laying hens and their
progeny
(Lavelle et al., 1994).
105

Toxic effects of the vitamin K family are manifested mainly as hematological and
circulatory disorders.
Dosages of 2 to 8 mg/kg body weight were reported to be lethal in horses,
resulting in renal colic, hematuria, azotemia, and electrolyte abnormalities
consistent with acute renal failure.
(Rebhun et al., 1984).
oral ingestion of large amounts of vitamin K1 (25g/kg body weight) produced no
fatalities, whereas menadione had an LD50 (in mice) equal to 500 mg/kg of diet
(Molitor and Robinson,1940).
TOXICITY

(as fed basis)
Sources: From NRC (1982b) and Marks (1975).
Feedstuff Vitamin K
Level (ppm)
Feedstuff Vitamin
K Level
(ppm)
Barley, grain 0.2 Peas 0.1–0.3
Alfalfa hay, sun cured 19.4 Potatoes 0.8
Alfalfa meal, dehydrated
(20% protein)
14.2 Sorghum, grain 0.2
Cabbage (green) 4.0 Spinach 6.0
Carrots 0.1 Tomatoes 4.0
Corn, grain 0.2 Liver (cattle) 1–2
Eggs 0.2 Liver (swine) 4–8
Fish meal, herring
(mechanically extracted)
2.2 Meat (lean) 1–2
Soybean, protein concentrate
(70.0% protein)
0.0
108

Vitamin B 1
Water Soluble Vitamins
(C12H17N4OSCl)

History
Synonym
Thiamine, Aneurin ,Thiamin
Thiamin is considered to be the oldest vitamin with the
deficiency disease beri beri .the early history of thiamin can
be found in sebrell and harris (1973) and loosely (1988).
Beriberi was recognised in china as early as 2600 BC.
In the 1890 eijkman, a dutch investigator, produced a
paralysis in chickens fed boiled polished rice he called the
condition “ polyneuritis” and observed the clinical sign were
similar to Beriberi symptom in humans.
It consists of a molecule of-
-Pyrimidine
-Thiazole linked by a methylene bridge & it contains both
nitrogen and sulfur atoms.
It is isolated in pure form as the white thiamin hydrochloride.
It soluble in water.
Insoluble in fat solvents.
It is very sensitive to alkali.
Thiamin hydrochloride is more hygroscopic (takes up moisture).

• Thiamine chloride hydrochloride (the name is
often shortened to thiamine hydrochloride) is a
• Colorless
• Crystalline
• Hygroscopic
• Highly water-soluble substance
• They have a characteristic pungent odour.
Antagonists
Thiamin-degrading enzymes (thiaminases).
The synthetic compounds pyrithiamine, oxythiamine, and amprolium
(coccidiostat) are structurally similar antagonists, and their mode of
action is competitive inhibition with iologically inactive compounds,
thus interfering with thiamin at different points in metabolism.

• Heat-stable thiamin antagonists occur in a number of
plants (e.g.,ferns and tea); these include polyphenols
(e.g., caffeic acid and tannicacid), which oxidize the
thiazole ring to yield the nonabsorbable thiamin
disulfide.

Digestion
Adenosine triphosphate (ATP) provides the diphosphate moiety
for the synthesis of thiamine diphosphate from free thiamine by
the action of thiamine pyrophosphokinase.
Thiamine diphosphate can be metabolized either by
dephosphorylation to form thiamine monophosphate, catalyzed
by thiamine pyrophosphatase, or by further phosphorylation to
give thiamine triphosphate, catalyzed by thiamine diphosphate–
ATP phosphoryltransferase.
To a limited extent, free thiamine can be converted to thiamine
monophosphate by an intestinal membrane alkaline
phosphatase, in the presence of phosphate donors
Absorption
Absorption occurs in the small intestine, particularly in the
jejunum
Horse-cecum.
Ruminants- Rumen 11
3

Absorbed thiamin is transported via the portal vein to the liver with a carrier
plasma protein, thiamin-binding protein .
(Rose, 1990).
This binding protein is hormonally regulated (e.g., corticosteroid hormones)
and is associated with thiamin transport into and out of the cell.
In animal tissues, thiamin occurs mostly as phosphate esters.
The principal storage organs are the liver and kidney; however, approximatel
one-half of total thiamin is present in muscle.
(Tanphaichair, 1976)
Thiamin is one of the most poorly stored vitamins. Mammals can exhaust
their body stores within 1 to 2 weeks
(Ensminger et al., 1983).
Absorbed thiamin is excreted in both urine and feces, with small quantities
excreted in sweat 11
4

FUNCTIONS
Decarboxylation of α-Keto Acids and Transketolase Reactions
Thiamine diphosphate is a coenzyme involved in oxidative ecarboxylation of
pyruvate to acetyl coenzyme A. and of alpha ketoglutarate to succinyl COA
in TCA cycle.
Other Functions
Thiamin has a vital role in nerve function
Possible mechanisms of action of thiamin in nervous
tissue include the following
115

1. Thiamin is involved in the synthesis of acetylcholine, which
transmits neural Impulses
2. Thiamin participates in the passive transport of sodium of excitable
membranes, which is important for the transmission of impulses at
the membrane of ganglionic cells
3. The reduction in the activity of transketolase in the pentose
phosphate pathway that follows thiamin deficiency reduces the
synthesis of fatty acids and the metabolism of energy in the
nervous system.
(Muralt, 1962; Cooper et al., 1963)
Thiamin has been shown to have a role in insulin biosynthesis.
Isolated pancreatic islets from thiamin-deficient rats secreted less
insulin than those from controls
(Rathanaswami and Sundaresan, 1991).
116

Fig. Sheep with thiamin deficiency. Characteristics of the condition are head
bent backward (opisthotonos), cramp-like muscle contractions, disturbance of
balance, and aggressiveness.
11
7

Occurs sporadically in cattle, sheep, and goats.
The term PEM refers to a laminar softening or degeneration of brain gray matter
(Brent and Bartley, 1984).
The condition affects mainly calves and young cattle between 4 months to2 years
old, and lambs and kid between 2 and 7 months old.
The condition is characterized by circling, head pressing, and convulsions, and in
severe cases, the animal collapses within 12 to 72 hours after onset of the
disease.
High-sulfur diets are associated with thiamin deficiency and PEM
(Gould, 1998). Gould et al. (1991)
Polioencephalomalacia (PEM)

A B
Fig. (A and B). An animal with polioencephalomalacia, a disease of thiamin
deficiency. Feedlot cattle suffering from this condition show dullness and
sometimes blindness, with a series of nervous disorders such as circling, head
pressing, and convulsions. Six to eight hours after thiamin injection, the same
animal was able to stand
11
9

Fig. With continued thiamin treatment, in 3 to 5 days, the
animal returned to almost normal, with slight brain
damage.
12
0

Wasting disease (secadera)
Fig. Wasting disease (secadera) of cattle in the llanos of Colombia. The disease
is characterized by emaciation in spite of the availability of good-quality forage.
Secadera has been reported as thiamin deficiency because it has been alleviated
with thiamin injections.
12
1

Fig. Polyneuritis in a thiamin-deficient chick. Muscle paralysis causes extended
legs and retraction of the head
Polyneuritis(star gazing posture)
122

Fig. Enlarged heart on right is due to thiamin deficiency. Heart on left is
from a similar pig fed the same diet plus thiamin. 123

Chastek Paralysis
The disease occurs in mink and foxes and is induced by feeding these
animals certain types of raw fish.
In foxes, clinical signs include anorexia and abnormal gait, followed by
severe ataxia, inability to stand, hyperesthesia, constant moaning, and
convulsions
(Long and Shaw, 1943)
RABBITS
Rabbits fed a thiamin-free diet, along with a thiamin antagonist
(neopyrithiamin), developed ataxia, flaccid paralysis, convulsions, and coma,
followed by death
(Reid et al., 1963; NRC, 1977).
Humans
Swelling of the legs, with pitting in ankle region, marks beginning of so-
called wet beriberi.
124

CROCODILES
Disease conditions were noted in 4 of 11 clutches of crocodile hatchlings.
Sudden loss of righting reflex was the outstanding feature of the disease.
(Jubb, 1992)
Fig. A 2-month-old saltwater crocodile hatchling with suspected thiamin
deficiency, floating on its side in shallow water. The listless appearance and open
jaws are also characteristic of the disease 125

Thiamin in large amounts is not toxic, and usually the same is
true of parenteral doses.
Dietary intakes of thiamin up to 1,000 times the requirement are
apparently safe for most animal species
(NRC, 1987).
Lethal doses with intravenous injection were 125, 250, 300, and
350 mg/kg body weight for mice, rats, rabbits, and dogs,
respectively
(Gubler, 1991).

Sources: Modified from Bräunlich and Zintzen (1976), Marks (1975), and Scott et al. (1982
Feedstuff mg/kg Feedstuff mg/kg
Alfalfa meal 3.9 Linseed meal, expeller
extracted
5.1
Barley grain, dried 5.7 Rice, bran 23.0
Beans 6.0 Sorghum grain 3.9
Brewer’s grains, dried 0.8 Sugarcane molasses 1.2
Brewer’s yeast, dried 95.2 Wheat bran 8.0
Coconut meal, dried 0.8 Wheat grain 5.5
Corn (maize), yellow grain 3.5 Blood meal, dried 0.2
Corn (maize), germ meal 10.9 Eggs, whole 3.4
Corn (maize), dried gluten
meal
2.1 Milk, cow’s 0.4
Cottonseed meal, solvent
extracted
6.4 Fish meal, with solubles 2.0
Distiller’s dried solubles 6.8 Sesame meal 10.0
NATURAL SOURCES

History
 1915-it was known that a water soluble factor or factor promoted
growthand prevented beriberi in rats.
 1933-Kuhn (Germany) suggested that this growth factor for rats be given
the name flavin
 Pure crystalline flavin compounds were found to contain ribose, and thus,
the name riboflavin became popular.
It consists of a a dimethylisoalloxazine nucleus combined with the
alcohol of ribose as a side chain.
It exists in three forms:-free riboflavin
-coenzyme derivatives FMN (Riboflavin 5 phosphate)
-FAD.
Riboflavin is an odorless, bitter orange-yellow compound that melts at
2800C.
Its empirical formula is - C
17
H
20
N
4
O
6 ,with an elemental analysis of
carbon 54.25%, hydrogen 5.36%, and nitrogen 14.89%.
Synonym  Riboflavin.
130

Riboflavin is only slightly soluble in water but readily soluble in dilute basic
or strong acidic solutions.
Very little is lost in cooking.
Loss in milk during pasteurization
131

Fig. Structural formulas of riboflavin and the two coenzymes derived from
riboflavin, FMN and FAD. FMN is formed from riboflavin by the addition in the
50 position of a phosphate group derived from adenosine triphosphate. FAD is
formed from FMN after combination with a second molecule of adenosine
triphosphate.
13
3

Metabolic pathway of conversion of riboflavin into FMN, FAD, and covalently
bound flavin, together with its control by thyroid hormones.
(Rivlin, R.S., 1970.)
13
4

Digestion, Absorption and Transport
Transport association with albumin and some globulins
FAD
Enters the blood
FMN/ free vitamin
free the vitamin enters mucosal cells of the small
intestine.
Phosphorylated forms (FAD, FMN)
hydrolyzed by phosphatases
Phosphorylated flavokinase
135

Riboflavin is found in feeds as FAD, FMN, and free riboflavin.
Liver-the major site of storage, contains about one-third of the total body
flavins.
The liver, kidney, and heart have the richest concentrations.
136

Riboflavin is required as part of many enzymes essential to
utilization of carbohydrates, fat, and protein.
More than 100 enzymes are known to bind FAD or FMN in animal
and microbial systems.
It is a constituent of flavoproteins, Flavin mononucleotide and
Flavin adenine dinucleotide.
They are involved in amino acid and carbohydrate metabolism.
In sows riboflavin is necessary to maintain normal oestrous activity
and prevent premature parturition.

Fig. (A) Riboflavin deficiency in a pig that received no dietary riboflavin.
Note the rough hair coat, poor growth, and dermatitis. (B) Pig that received
adequate riboflavin.
A B

Fig. Riboflavin deficiency. (A) All of the pigs in this litter were born dead; some
were in the process of resorption. A few had edema and enlargement of front
legs as a result of gelatinous edema. (B) Pigs from a litter in which gelatinous
edema was more pronounced.
A B
13
9

Seven of the ten pigs farrowed were born dead, and the other three were dead
within 48 hours. The sow received a riboflavin-deficient diet for a shorter
period than the sows farrowing the other two litters.
14
0

Fig. Curled-toe paralysis in a riboflavin- deficient chick
14
1

142
Riboflavin deficiency in a young chick. Note the position of the hocks, with the
toes curled inward.

Fig. Riboflavin deficiency in chicks. (A) The chick at left was fed a corn-soybean
meal diet without supplemental riboflavin; it exhibited the predominant
type of paralysis observed at the zero level of riboflavin supplementation.
Both chicks are female. (B) Same as in (A), but the chicks are male.
14
3

Fig. Riboflavin deficiency in turkeys at 21 days of age. (A) The turkey at left was
fed a corn-soybean basal diet without supplemental riboflavin. (B) Severe
leg paralysis and poor feathering in a turkey poultry fed the riboflavin deficient
diet.
14
4

Riboflavin-deficient dogs exhibit low growth rates, anemia, and
corneal lesions
(NRC, 1985a).
Cats deficient in the vitamin develop cataracts, fatty livers, testicular
hypoplasia, and alopecia with epidermal atrophy
(NRC, 1986).
Corneal vascularization and ulceration, cataract formation, anemia,
myelin degeneration of sciatic nerves and spinal cord, fatty liver,
congenital abnormalities, and metabolic abnormalities of
hepatocytes may occur.
(NRC, 1995).
145

Fig. Riboflavin deficiency in the rat, exhibited by (A) generalized dermatitis,
growth failure, and marked keratitis of the cornea. (B) After 1 month of
treatment with riboflavin, growth resumed, and ocular and skin lesions
practically disappeared.
14
6

After 2 months of treatment, the rat showed no signs of deficiency.
14
7

Fig. Riboflavin deficiency in foxes. After 7 weeks on a riboflavin deficient
diet, the 12-week-old blue fox at right showed depigmentation, shedding of
fur, and dermatitis. The littermate at left was fed a diet supplemented with
riboflavin.
14
8

Feedstuff (ppm, dry
basis)
Feedstuff (ppm, dry
basis)
Alfalfa meal sun cured 13.4 Linseed meal, expeller
extracted
3.2
Barley grain 1.8 Rice, bran 23.0
Alfalfa leaves, sun cured 23.1 Sorghum grain 1.4
Brewer’s grains, dried 1.6 Sugarcane molasses 3.8
Chicken, broilers (whole) 15.6 Wheat bran 4.6
Citrus pulp 2.7 Wheat grain 1.6
Corn (maize), yellow grain 1.4 Blood meal 2.2
Copra meal (coconut) 3.7 Eggs, whole 3.0
Corn (maize), dried gluten
meal
1.8 Milk 20.5
extracted
5.3 Soybean meal, solvent
extracted
3.2
Clover hay, ladino (sun cured) 17.2 Sesame meal 10.0
Bean, navy (seed) 2.0
NATURAL SOURCES
Source: NRC (1982b).

History
Synonym Vitamin PP, Niacin, Nicotinic acid, Nicotinamide.
1914-Funk isolated nicotinic acid from rice polishing.
Older term replace Nicotinic Acid & nicotinamide to niacin & niacinamide
Its empirical formula is - C6H5O2N.
Niacin is pyridine-3-caboxylic acid.
Two forms-nicotinic acid and nicotinamide (niacinamide).
Both are white, odorless, crystalline solids soluble in water and
alcohol.
They are very resistant to heat, air, light, and alkaline conditions
and thus are stable in foods.
Nicotinic acid is a white crystalline solid, stable in air at normal
room temperature.
152

Nicotinic acid readily forms salts with metals such as aluminum,
calcium, copper, and sodium.
When in acid solution, niacin readily forms quaternary
ammonium compounds, such as nicotinic acid hydrochloride,
which is soluble in water.
When in a basic solution, nicotinic acid readily forms carboxylic
acid salts.
It is moderately soluble in water and alcohol, but insoluble in
ether.
In contrast to nicotinic acid, nicotinamide is highly soluble in
water, and is soluble in ether, characteristics that allow separation
of the two vitamers.
Niacin Coenzymes
The biologically active forms of niacin compounds are the NAD and
NADP coenzymes.
The oxidized and reduced forms of the coenzymes are designated
NAD+ or NADP+ and NADH or NADPH, respectively.

Fig. Chemical structures of niacin compounds. (a) Nicotinic acid, (b)
nicotinamide, (c) NAD+, (d) NADP+, and (e) site of reduction.
15
4

Pathways of Synthesis
Although plants and most microorganisms can synthesize the pyridine ring of
NAD de novo from aspartic acid and dihydroxyacetone phosphate, animals do
not have this ability.
Nicotinic acid, nicotinamide, pyridine nucleotides, and tryptophan represent
the dietary sources for the pyridine ring structure in mammals.
Animals may also practice coprophagy to take advantage of colonic synthesis of
niacin by icroflora. Ruminants receive an ample supply of niacin from foregut
bacteria
155

Fig.Pathways of NADþ synthesis in mammals. Reactions 5, 6, 8, and 9 comprise the Preiss–
Handler pathway whereas reactions 10 and 11 form the Dietrich pathway. The following
enzymes correspond to the numbered reactions: 1, tryptophan 2,3-dioxygenase (hepatic) or
indoleamine 2,3-
dioxygenase (extrahepatic), which start the five-step conversion to ACMS and nine-step
catabolism of tryptophan to acetyl CoA; 2, ACMS decarboxylase (ACMSD); 3, spontaneous
chemical reaction; 4, quinolinic acid phosphoribosyltransferase; 5, NAMN
adenylyltransferase (enzymes 5 and 11 may be identical proteins); 6, NAD synthetase; 7,
NAD glycohydrolases, various ADP-ribosylation reactions; 8, nicotinamide deamidase; 9,
nicotinic acid hosphoribosyltransferase; 10, nicotinamide phosphoribosyltransferase; 11,
NMN adenylyltransferase.
1. 3-acetyl pyridine .
2. pyridine sulfonic acid.
Antagonists
157

METABOLISM
Niacin in foods occurs mostly in its coenzyme forms, which are hydrolyzed
during digestion, yielding nicotinamide, which seems to be absorbed without
further hydrolysis in the gastrointestinal tract.
In the gut, mucosa nicotinic acid is converted to nicotinamide
(Stein et al., 1994).
Nicotinamide is the primary circulating form of the vitamin and is converted
into its coenzyme forms in the tissues.
Excretion
Urine is the primary pathway of excretion of absorbed niacin and its
metabolites.
The principal excretory product in humans, dogs, rats, and pigs is the
methylated metabolite N′-methylnicotinamide or one of two oxidation products
of this compound, 4-pyridone or 6-pyridone of N′-methylnicotinamide.
On the other hand, in herbivores niacin does not seem to be metabolized by
methylation, but large amounts are excreted unchanged.
In the chicken, however, nicotinic acid is conjugated with ornithine as either α-
or δ-nicotinyl ornithine or dinicotinyl ornithine. 158

FUNCTIONS
The major function of niacin is in the coenzyme forms of nicotinamide, NAD and
NADP.
They are especially important in the metabolic reactions that furnish energy to the
animal.
Important metabolic reactions catalyzed by NAD and NADP are summarized
below:
1. Carbohydrate metabolism—(a) glycolysis (anaerobic oxidation of glucose) and
(b) the Krebs cycle.
2. Lipid metabolism—(a) glycerol synthesis and breakdown, (b) fatty
3. acid oxidation and synthesis, and (c) steroid synthesis.
4. Protein metabolism—(a) degradation and synthesis of amino acids and (b)
oxidation of carbon chains via the Krebs cycle.
5. Photosynthesis.
6. Rhodopsin synthesis

NADþ=NADH
redox exchanges
Numerous NAD-
dependent enzymes
throughout oxidative
metabolism
NADH and
oxidized
metabolites,
e.g., TCA cycle
intermediates
1. Transfer of
electrons from
macronutrient
substrates to
the ETC, ATP
production
2. Numerous
oxidative
reactions are
enabled by the
high ratio of
NADþ:NADH
16
0

NADPþ=NADPH
redox
exchanges
Numerous NADP-
dependent
enzymes involved
in reductive
metabolism
NADPþ and
reduced
metabolites, e.g.,
fatty acid
Biosynthetic
metabolism, oxidant
defense
Numerous reductive
reactions are
enabled by the high
ratio of
NADPH:NADPþ,
which is maintained
by the pentose
phosphate pathway
Poly(ADP-
ribosyl)ation
reactions
Up to 18 different
PARP enzymes,
mainly nuclear and
DNA associated
Poly(ADP-ribose)
covalently bound
to proteins, free
polymer resulting
from catabolism
Diverse functions,
but many related
to DNA
metabolism and
genomic stability
Polyanionic nature
controls protein
function
High-affinity polymer
binding by other
proteins
16
1

Mono(ADP-
ribosyl)ation
reactions
Numerous
poorly
characterized
transferases
Mono(ADP-ribose)
covalently bound to
proteins, many of
which are G-
proteins
Diverse and poorly
characterized
Cyclic ADP-
ribose and
NAADP
formation
ADP-ribosyl
cyclases, which
also have the
potential to
form NAADP
Cyclic ADP-ribose
NAADP
Control of intracellular
calcium levels, and
thereby control of
almost all cellular
signaling events
SIR2=SIRT1
deacetylation
reactions
SIR2 (rats)
SIRT1
(humans)
Deacetylated
proteins, including
histones, p53
O-Acetyl-ADP-
ribose
Control of p53
function and
chromatin structure,
central to life
extension through
caloric restriction
16
2

Niacin deficiency is characterized by severe metabolic disorders
in the skin and digestive organs.

Fig. Leg disorders in niacin-deficient
broiler chicks. The bird on the left, with
bowed legs, was fed a corn-soybean meal
diet without Supplemental niacin.
Fig. Intestine from niacin-deficient
pig shows thickened and
hemorrhagic mucous membrane
and denuded areas.
16
4

Dogs & Cats
Blacktongue (Canine Pellagra).
There is severe cheilosis, glossitis, and gingivitis. Necrotic patches and
ulcers may be seen on the oral mucosa, and there is a foul odor.
There is bloody diarrhea, inflammation, and hemorrhagic necrosis of
the duodenum and jejunum, with shortening and clubbing of villi and
inflammation
and degeneration of the mucosa of the large intestine.
Foxes & Mink
Foxes fed a niacin-deficient diet exhibited anorexia, weight
loss, and typical blacktongue, characterized by severe
inflammation of the gums and fiery redness of the lips,
tongue, and gums
(NRC, 1982a).
16
5

Fig. 8.7 Niacin-deficient dog with blacktongue exhibits drooling of thick, ropy
saliva.
16
6

Fig. Niacin deficiency in turkey poults. (A and B) The birds on the left side,
which were fed a corn-soybean meal without supplemental niacin, showed
Perosis like signs. © Comparison of the legs of the poultry in B.
16
7

Feedstuff (mg/kg,
dry basis)
Feedstuff (mg/kg, dry
basis)
Alfalfa meal sun cured 42 Linseed meal, expeller
extracted
37
Barley grain 94 Rice, bran 23.0
Alfalfa leaves, sun cured 53 Sorghum grain 1.4
Brewer’s grains 47 Sugarcane molasses 3.8
Chicken, broilers (whole) 230 Wheat bran 268
Citrus pulp 23 Wheat grain 64
Corn , yellow grain 55 Blood meal 34
Copra meal (coconut) 28 Eggs, whole 3.0
Corn , gluten meal 55 Milk, cattle 269
extracted
48 Soybean meal, solvent
extracted
31
Clover hay, ladino (sun cured) 11 Soybean seed 24
NATURAL SOURCES

TOXICITY
Limited research indicates that nicotinic acid and nicotinamide are toxic at
dietary intakes greater than about 350 mg/kg of body weight per day
(NRC, 1987).
In dogs, oral administration of 2 g of nicotinic acid per day (133 to 145 mg/kg of
body weight) produced bloody feces in a few dogs, followed by convulsions and
death
(NRC, 1987).
170

History
Synonym Pantothenic acid, antidermatitis vitamin
Greek word pantos, meaning “found everywhere.”
discovered by Roger J. Williams in 1919.
Pantothenic acid deficiency was first described in the chick as a
pellagra-like dermatitis by Norris and Ringrose in 1930.
Pantothenic acid is found in two enzymes -coenzyme A,
-acyl carrier protein.
Pantothenic acid is an amide consisting of pantoic acid joined to β-alanine.
It metabolically active form- panthenol
It is viscous, pale yellow oil readily soluble in water and ethyl acetate.
The oil is extremely hygroscopic and is easily destroyed by acids, bases, and
heat.
Maximum heat stability occurs at pH 5.5 to 7.0.
Pantothenic acid is optically active (characteristic of rotating a polarized
light).
17
2

• Calcium pantothenate, the form used in commerce,
crystallizes as white needles from methanol and is
reasonably stable to light and air.
• Feeding chickens on high intakes of copper results in
reduced formation of coenzyme A, by increasing the
oxidation of cysteine to cystine, and also by the
formation of copper-cysteine and copper-glutathione
complexes, which render the amino acid unavailable
for coenzyme A synthesis
(Latymer and Coates, 1981).

Fig. Structural components of coenzyme A.
17
4

Fig. Pathway for the biosynthesis of pantothenic acid found in plants, bacteria
(including archaea), and eubacteria.
17
5

Antagonist
• The most common antagonist of pantothenic acid is ω-
methyl-pantothenic acid, which has been used to
produce a deficiency of the vitamin in humans
(Hodges et al., 1958).
• Other antivitamins include pantoyltaurine,
phenylpantothenate hydroxycobalamine (c-lactam)
(analog of vitamin B12), and antimetabolites of the
vitamin containing alkyl or aryl ureido and carbamate
components in the amide part of the molecule.
(Fox, 1991; Brass, 1993).
176

Pantothenic acid
Pantothenate
Coenzyme A 4′-phosphopantetheine
Free Forms Bound Forms
Pantetheinase
17
7

Fig. Coenzyme A metabolism and importance of pantothenic acid kinase.
17
8

Pantothenic acid, its salt, and the alcohol are absorbed primarily in the
jejunum by a specific transport system that is saturable and sodium ion
dependent
(Fenstermacher and Rose, 1986).
After absorption, pantothenic acid is transported to various tissues in the
plasma, from which it is taken up by most cells via another active-transport
Process.
Within all tissues pantothenic acid is converted to coenzyme A and other
compounds in which the vitamin is a functional group
(Sauberlich,1985).
17
9

Urinary excretion represents the major route of body loss of absorbed
pantothenic acid, with prompt excretion when taken in excess.
Most pantothenic acid is excreted as the free vitamin, but some species
(e.g., dog) excrete it as β-glucuronide
(Taylor et al., 1972).
An appreciable quantity of pantothenic acid (approximately 15% of daily
intake) is oxidized completely and is excreted across the lungs as CO2
(Combs, 1992).
180

Animals and humans do not appear to have the ability to store
appreciable amounts of pantothenic acid, with organs such as the
liver and kidney having the highest concentrations.
Most pantothenic acid in blood exists in red blood cells as coenzyme
A; serum contains no coenzyme A but does contain free pantothenic
acid.
18
1

FUNCTIONS
Pantothenic acid is a constituent of coenzyme A, which is the
important coenzyme of acyl transfer.
It is also a structural component of acyl carrier protein, which is
involved, in the cytoplasmic synthesis of fatty acids.

Enzyme Pantothenate
Derivative
Reactant Product Site
Pyruvic
dehydrogenase
CoA Pyruvate Acetyl-CoA Mitochondria
α-
Ketoglutarate
dehydrogenase
CoA α-
Ketoglutarate
Succinyl-CoA Mitochondria
Fatty acid
oxidase
CoA Palmitate Acetyl-CoA Mitochondria
Fatty acid
synthetase
Acyl carrier
protein
Acetyl-CoA,
Malonyl-CoA
Palmitate Microsomes
Propionyl-CoA
carboxylase
CoA Propionyl-
CoA, carbon
dioxide
Methylmalonyl
- CoA
Microsomes
Acyl-CoA
synthetase
Phosphopant
hetheine
Succinyl-CoA,
GDP + P1
Succinate, GTP
+ CoA
Mitochondria
Selected Biochemical Reactions Catalyzed by Coenzyme A
Source: Modified from Olson (1990).
18
3

Functions of CoA and Acyl Carrier Protein
Function Importance
Carbohydrate-related citric acid cycle
transfer reactions
Oxidative metabolism
Acetylation of sugars (e.g., N-
acetylglucosamine)
Production of carbohydrates important to
cell structure
Lipid-related
Phospholipid biosynthesis Cell membrane formation and structure
Isoprenoid biosynthesis Cholesterol and bile salt production
Steroid biosynthesis Steroid hormone production
Fatty acid elongation Ability to modify cell membrane fluidity
Acyl (fatty acid) and triacyl glyceride
synthesis
Energy storage
Protein-related
Protein acetylation Altered protein conformation; activation of
certain hormones and enzymes, e.g.,
adrenocorticotropin transcriptional
regulation, e.g., acetylation of histone
Protein acylation (e.g., myristic and palmitic
acid, and prenyl moiety additions)
Compartmentalization and activation of
hormones and transcription factors 18
4

DEFICIENCY
Species Symptoms
Chicken Dermatitis around beak, feet, and eyes; poor feathering; spinal cord
myelin degeneration; involution of the thymus; fatty degeneration of
the liver
Fish Anorectic behavior; listlessness; fused gill lamellae; reproductive
failure
Rat Dermatitis; loss of hair color (achromotrichia). with alopecia;
hemorrhagic necrosis of the adrenals; duodenal ulcer; spastic gait;
anemia; leukopenia; impaired antibody production; gonadal atrophy
with infertility
Dog Anorexia; diarrhea; acute encephalopathy; coma; hypoglycemia;
leukocytosis; hyperammonemia; hyperlactemia; hepatic steatosis;
mitochondrial enlargement
Pig Dermatitis; hair loss; diarrhea with impaired sodium, potassium, and
glucose absorption; lachrymation; ulcerative colitis; spinal cord and
peripheral nerve lesions with spastic gait

Fig. Goose-stepping pig with pantothenic acid deficiency.
18
6

Fig. Pantothenic acid deficiency. (A) Locomotor incoordination
(goosestepping).(B) An affected pig often falls sideways or, with its back legs
A B
18
7

Fig. A. Pantothenic acid deficiency in a turkey with dermatitis on lower beak and at angle
of mouth (lower turkey). Sticky exudate that formed on the eyelid resulted in encrustation
and caused swollen eyelids to remain stuck together. Normal turkey above is the control.
Fig. B. Pantothenic acid deficiency in a chick, with dermatitis around beak
A B
18
8

Feedstuff (mg/kg,
dry basis)
basis)
extracted
16.3
Barley grain 9.1 Rice, bran 25.0
Alfalfa leaves, sun cured 32.4 Sorghum grain 12.5
Brewer’s grains 8.9 Sugarcane molasses 50.3
Rice, grain 9.1 Wheat bran 33.5
Citrus pulp 14.3 Wheat grain 11.4
Corn , yellow grain 6.6 Blood meal 2.6
Corn , gluten meal 11.2 Milk, cattle 38.6
extracted
extracted
18.2
Clover hay, ladino (sun cured) 1.1 Soybean seed 17.3
NATURAL SOURCES

History
Synonym Pyridoxol, Pyridoxal, Pyridoxamine
1934-Gyorgy first recognized Vitamin B6 as a distinct Vitamin.
Kuhn and coworkers-the structure of the vitamin was first
explained.
It refers to a group of three compounds:-
1.Pyridoxol/Pyridoxine(Alcohol),
2.Pyridoxal (Aldehyde).
3.Pyridoxamine.(Amine).
Two additional forms coenzyme-1.Pyridoxal phosphate (PLP)
2.Pyridoxamine phosphate.
In plant-pyridoxine
In animal-pyridoxal and pyridoxamine.
It can be destroyed by heat, alkali and exposure to light, especially
in neutral or alkaline media is highly destructive.
Vitamin B6 are colorless crystals soluble in water.
Synthetic- Pyridoxine hydrochloride
19
2

Antagonist
1. The anDeoxypyridoxine is a powerful antagonist to
vitamin B6
2. Isoniazid is a strong inhibitor of pyridoxal kinase and
results in anemia in humans, probably by inhibiting
the synthesis of δ-aminolevulinic acid and thus of
heme.
3. Isonicotinic acid hydrazide (isoniazid)
4. Cycloserine
5. Penicillamine
6. tihypertensive drugs thiosemicarbizide and
hydralazine have also been shown to interfere with
vitamin B6 usage.
193

Digestion, Absorption, and Transport
Vitamin B6 is absorbed mainly in the jejunum, but also in the
ileum, by passive diffusion.
Both niacin (as the NADP-dependent enzyme) and riboflavin (as
the flavoprotein pyridoxamine phosphate oxidase) are important
for conversion of vitamin B6 forms and phosphorylation reactions
(Wada andSnell, 1961; Kodentsova et al., 1993).
Vitamin B6 is found in the blood largely as PLP, most of which is
derived from the liver after metabolism by hepatic flavoenzymes.
Only small quantities of vitamin B6 are stored in the body
Reports of PLP content of glycogen phosphorylase suggest that
90% or more of the vitamin B6 present in muscle might be present
in this single enzyme
(Merrill and Burnhan, 1990).
Excreted through urine

Function
More than 60 enzymes are already known to depend on vitamin
B6 coenzymes.
Pyridoxal phosphate functions in practically all reactions involved
in amino acid metabolism, including transamination
aminotransferase), decarboxylation,deamination, and
desulfhydration, and in the cleavage or synthesis of amino acids.

Vitamin B6 is involved in many additional reactions, particularly those
involving proteins. The vitamin participates in the following functions
(Bräunlich, 1974; Marks, 1975; LeKlem, 1991)
1. Deaminases—for serine, threonine, and cystathionine.
2. Desulfhydrases and transulfhyurases—interconversion and metabolism
of sulfur-containing amino acids.
3. Synthesis of niacin from tryptophan—hydroxykynurenine is not
converted to hydroxyanthranilic acid but rather to xanthurenic acid
because of lack of the B6-dependent enzyme kynureninase
4. Formation of δ-aminolevulinic acid from succinyl-CoA and glycine, the
first step in porphyrin synthesis.
5. Conversion of linoleic to arachidonic acid in the metabolism of essential
fatty acids (this function is controversial).
6. Glycogen phosphorylase catalyzes glycogen breakdown to glucose l-
phosphate. Pyridoxal phosphate does not appear to be a coenzyme for
this enzyme but rather affects the enzyme’s conformation.
7. Synthesis of epinephrine and norepinephrine from either phenylalanine
or tyrosine—both norepinephrine and epinephrine are involved in
carbohydrate metabolism as well as in other body reactions.
19
6

8. Racemases—PLP-dependent racemases enable certain microorganisms to
utilize D-amino acids. Racemases have not yet been detected in mammalian
tissues.
9. Transmethylation by methionine.
10. Incorporation of iron in hemoglobin synthesis.
11. Amino acid transport—all three known amino acid transport systems—(a)
neutral amino acids and histidine, (b) basic amino acids, and (c) proline and
hydroxyproline—appear to require PLP.
12. Formation of antibodies—B6 deficiency results in inhibition of the synthesis
of globulins, which carry antibodies.
19
7

 Affects the animal's growth rate.
 Convulsions may also occur, possibly because a reduction in the activity of
glutamic acid decarboxylase results in an accumulation of glutamic acid.
 In addition, pigs exhibit a reduced appetite and may develop anemia.
 Chicks on a deficient diet show jerky movements, while in adult birds
hatchability and egg production are adversely affected.
Fig. A 6-week-old B6-deficient pig weighing only 3.6 kg.
19
8

Fig. This pig is having an epileptic-like seizure while receiving a diet low in vitamin B6.
19
9

Fig. Goose-stepping pig with pantothenic acid deficiency
20
0

20
1Pyridoxine deficiency. Note loss of control of the legs and the head retraction

Fig. Vitamin B6-deficient poult (about 4 weeks old) on left and a normal
poult on right.
20
2

basis)
basis)
extracted
6.1
Barley grain 7.3 Rice, polished 0.4
Bean, navy (seed) 0.3 Sorghum grain 5.0
Brewer’s grains 0.8 Sugarcane molasses 5.7
Rice, grain 5 Wheat bran 9.6
Crab meal 7.2 Wheat grain 5.6
Corn , yellow grain 5.3 Blood meal 4.8
Corn , gluten meal 8.8 Milk, cattle 4.5
extracted
extracted
6.7
Peanut meal, solvent
extracted
6.9 Oat, grain 2.8
NATURAL SOURCES

History
Synonym Biotin, Vitamin H
Biotin was the name given to a substance isolated from egg yolk by
Kogl and Tonnis in 1936 that was necessary for yeast growth
The term vitamin H was chosen by György because the factor protected
the haut, the German word for skin..
The structure of biotin includes- sulfur atom in its ring (like thiamin) and
a transverse bond across the ring.
It is a monocarboxylic acid with sulfur as a thioether linkage.
The empirical formula for biotin is C11H18O3S
It contains three asymmetric carbonations and therefore eight different
isomers are possible.
Of these isomers only one contains vitamin activity, d-biotin.
The stereoisomer l-biotin is inactive.
Melting point- 232-2330C.
It soluble in dilute alkali and hot water and practically insoluble in fats and
organic solvents
It is destroyed by nitrous acid, other strong acids, strong bases, and
formaldehyde and is inactivated by rancid fats and choline
20
6

Mild oxidation converts biotin to sulfoxide, and
Strong agents result in sulfur replacement by
oxygen, resulting in oxybiotin and desthiobiotin.
strong oxidation converts it to sulfone.
METABOLISM
Biotin exists in natural materials in both bound
and free forms, with much of the bound biotin
apparently not available to animal species.
Naturally occurring biotin is found partly in the
free state (fruit, milk, vegetables) and partly in a
form bound to protein in animal tissues, plant
seeds, and yeast.

The few studies conducted in animals on biotin metabolism
revealed that biotin is absorbed as the intact molecule in the first
third to half of the small intestine
(Bonjour, 1991).
Biotin appears to circulate in the bloodstream both free and
bound to a serum glycoprotein, which also has biotinidase activity,
catalyzing the hydrolysis of biocytin.
All cells contain some biotin, with larger quantities in the liver and
kidneys.
Absorption

FUNCTIONS
Biotin is an essential coenzyme in carbohydrate, fat, and protein
metabolism. It is involved in conversion of carbohydrate to protein
and vice- versa as well as conversion of protein and carbohydrate
to fat.
Biotin also plays an important role in maintaining normal blood
glucose levels from metabolism of protein and fat when dietary
intake of carbohydrate is low.
Biotin functions as a carboxyl carrier in four carboxylase enzymes:
pyruvate carboxylase, acetyl CoA carboxylase, propionyl CoA
carboxylase, and 3-methylcrotonyl CoA carboxylase.
Specific biotin-dependent reactions in carbohydrate metabolism are
the following:
•Carboxylation of pyruvic acid to oxaloacetic acid.
•Conversion of malic acid to pyruvic acid.
•Interconversion of succinic acid and propionic acid.
•Conversion of oxalosuccinic acid to α-ketoglutaric acid.

In protein metabolism, biotin enzymes are important in protein
synthesis, amino acid deamination, purine synthesis, and nucleic
acid metabolism.
Biotin is required for transcarboxylation in degradation ofvarious
amino acids.

DEFICIENCY
Fig. The two middle pigs are biotin deficient. Note the hair loss and dermatitis.

Fig. Biotin-deficient pigs. Note transverse cracking of the soles and the tops of
the hooves.

Fig. Perosis (bone deformities) as a result of biotin deficiency. Chicks showed perosis as
early as 17 days of age, with rigid limb joints that resulted in a stilted walk.

Fig. Normal (left) and biotin-deficient (right) Broad-Breasted Bronze male turkeys at 3
weeks of age.

Fig. A Severe foot-pad lesions in the growing turkey as a result of biotin deficiency. Less
A B

Fig. 11.8 Hoof condition of a 7-year-old 18-hands heavyweight show hunter
resulting from biotin supplementation. The horse had a history of tender feet.
(A) The walls of the hooves were very weak crumbling at the lower edges, with
large areas breaking out and detaching when shoes were nailed. (B) Five months
after supplementation with 15 mg of biotin per day, the walls of the hooves
were thicker and harder,so nailing was achieved.
A B
21
6

Fig. A Egg-white injury as a result of feeding a rat raw egg white, which
contains a biotin antagonist, avidin. The resulting dermatitis progressed to
generalized alopecia.
Fig. B After 3 months of treatment, the animal returned to normal.
A
B
21
7

Fig. The newborn fox pup on the left is from a biotin-deficient dam that
received a diet containing raw egg white. Thin, gray pelt and deformed legs are
apparent. A control diet containing cooked egg white was fed to the dam of the
new born pup on the right.
21
8

Feedstuff (μg/g) Feedstuff (μg/g)
Alfalfa meal, dehydrated 0.33 Fish meal 0.14
Barley grain 0.14 Milk, cow’s 0.05
Beef, steak 0.04 Molasses, blackstrap 0.7
Cabbage 0.02 Oats 0.25
Carrots 0.03 Rice bran 0.42
Chicken 0.10 Rice polishings 0.37
Corn , yellow grain 0.08 Skim milk, dried 0.25
Corn , gluten meal 0.19 Sorghum 0.29
extracted
0.08-0.47 Soybean meal 0.27
Distiller’s solubles, dried 0.44-1.1 Wheat 0.10
Eggs, whole 0.25 Wheat bran 0.36
NATURAL SOURCES
Sources: Modified from NRC (1982b) and Frigg and Volker (1994).

History
Synonym Folic acid, Folacin, Folate, Vitamin M, Vitamin Bc.
1935-An anemia preventive factor for monkeys was found in yeast or liver extracts
and designated vitamin M in by Day.
1939-Hogan and Parrot prevented anemia in chicks with a factor in liver called Bc.
I1940- Snell and coworkers found a growth factor for L. casei, and in the same year,
a growth factor for S. lacti was found in spinach. The growth factor had been isolated
from 4 tons of spinach leaves. The isolated factor was called folic acid from folium, the
Latin word for leaf.
 Its structure contains three parts- glutamic acid, ρ-aminobenzoic acid (PABA), and
a pteridine nucleus.
 Pteroic acid consist- ρ-aminobenzoic acid (PABA) and a Pteridine nucleus.
 Much of the folacin in natural feedstuffs is conjugated with a varying number of
extra glutamic acid molecules.
 Folacin as pteroyloligo-γ-L-glutamates (PteGlun) & it is one to nine glutamates
long, linked by peptide bonds.
 n-indicating the number of glutamyl residues.
22
2

 Folacin are the natural coenzymes that are most abundant in every
tissue.
 The conjugated forms with two or more glutamic acid residues are
joined by γ-glutamyl linkages to the single glutamic acid moiety of
the vitamin.
 Synthetic folacin, however, is in the monoglutamate form.
 Folacin is a yellowish-orange crystalline powder, tasteless and
odorless,
 and insoluble in alcohol, ether, and other organic solvents.
 Molecular weight - 441.4,
22
3

METABOLISM Digestion, Absorption, and Transport
Dietary folate predominately occurs in a polyglutamate form
digested via hydrolysis to pteroylmonoglutamate prior to transport
across the intestinal mucosa.
Pteroylmonoglutamate is absorbed predominantly in the jejunum,
with lesser amounts in the duodenum, by a Na+-coupled carrier-
mediated
process.
Folacin taken up by the liver is converted primarily to 5-
methyltetrahydrofolate and 10-formyltetrahydrofolate and then
transported to the peripheral tissues.

Storage
Folacin is widely distributed in tissues largely in the conjugated
polyglutamate forms.
Excretion
Urinary excretion of folacin represents a small fraction of total
excretion (e.g., < 1% of total body stores).
Fecal folacin concentrations are quite high, often higher than
intake, representing not only undigested folacin but, more
important, the considerable bacterial synthesis of the vitamin in
the intestine.

FUNCTIONS
Folic acid is converted into tetrahydrofolic acid which functions as
a coenzyme in the mobilization and utilisation of single-carbon
groups (e.g.) formyl, methyl that are added to, or removed from,
such metabolites as histidine, serine, glycine, methionine and
purines.

Fig.A Folacin-deficient bird on left with depigmentation and reduction in
growth (compare with normal bird on the right).
Fig. B Folacin-deficient chick, with cervical paralysis, at 5 weeks of age. Note
the weakened condition of legs and the way the bird holds the left wing.
Folacin-deficient bird will shake the end of the wing, and the whole bird will
quiver at times.
Deficiency
22
7

Fig. A Folacin-deficient poult was hatched from a hen fed a diet low in folacin.
Fig. 12.6 Folic acid deficiency. Abnormal embryo from an egg laid by a hen on a
low-folacindiet.
22
8

Feedstuff (μg/g) Feedstuff (μg/g)
NATURAL SOURCES

HistorySynonym Cobalamin, Cyanocobalamin.
Vitamin B12 was the last vitamin to be discovered (1948) and the most potent
of the vitamins, with the lowest concentrations required to meet daily
requirements.
In 1920 Whipple provided liver in diets to dogs and showed regenerated blood
and a specific liver protein that was needed for the formation of hemoglobin.
Minot, Murphy, and Whipple received the Nobel Prize in 1934 for liver
therapy of pernicious anemia.
Karl Folkers and his group from Merck, and their transatlantic competitors at
Glaxo led by E. Lester Smith, almost simultaneously announced successful
purification and crystallization of reddish needle-like crystals of a new
vitamin.
This vitamin showed clinical and biological activity by the gold standard assay
of demonstrating efficacy in inducing and maintaining remission in patients
with pernicious anemia.
In 1961 Lenhert and Hodgkin reported the structure of the enzyme form of
vitamin B12. In 1964 another Nobel Prize was awarded to Hodgkin for her part
in the elucidation of the chemical structure of vitamin B12 by x-ray
crystallography.
232

Vitamin B12 is unique i.e.synthesized by microorganisms.
The empirical formula of B12 is C63H88O14N14PCo.
features is the content of 4.5% cobalt.
Structure-four pyrrole nuclei coupled directly to each other, with the inner nitrogen
atom of each pyrrole coordinated with a single atom of cobalt.
The basic tetrapyrrole structure is the corrin nucleus.
The large ring formed by the four reduced rings is called “corrin” because it is the core
of the vitamin.
Cobalt atom is in the center of the corrin nucleus, therefore called “cobalamin”.
Cyanide, which lies above the planar ring, is attached to the cobalt atom thus the name
cyanocobalamin.
Cyanide can be replaced by other groups- OH (Hydroxycobalamin),
-H2O (Aquacobalamin),
-NO2 (Nitrocobalamin),
-CH3 (Methylcobalamin).
It is a dark red, crystalline, hygroscopic substance, freely soluble in water and alcohol
but insoluble in acetone, chloroform, or ether.
Molecular weight - 1354
the most complex structure and heaviest compound of all the vitamins.
23
3

Fig. Structure of vitamin B12 (Cyanocobalamin).
23
4

collectively called corrinoids.
These include two major subclassifications:
1. cobamides, which contain substitutions in the place of ribose, for example,
adenoside
2. cobinamides, which lack a nucleotide.
235

METABOLISM
B12 bound to protein in food
B12 released from food protein by gastric acid and pepsin
B12 bound to salivary R binder (haptocorrin)
IF produced by parietal cells
B12 released from R binder
B12 bound to IF
R binder degraded
IF–B12 complex taken up by receptor mediated endocytosis
involving cubulin, RAP, and megalin
B12 released from IF in lysosome
B12 bound to TC and carried into blood (TC-B12)
Diet
Stomach
lumen
Intestinal
lumen
Enterocyte
(Ileum)
23
7

In normal human subjects, vitamin B12 is found principally in the liver; the
average amount is 1.5 mg. Kidneys, heart, spleen, and brain each contain about
20 to 30 μg.
(Ellenbogen and Cooper, 1991).
In humans, methylcobalamin constitutes 60 to 80% of total plasma cobalamin,
while adenosylcobalamin is the major cobalamin in all cellular tissues,
constituting about 60 to 70% in the liver and about 50% in other organs
(Ellenbogen and Cooper, 1991).
Vitamin B12 is stored in the liver in the largest quantities for most animals that
have been studied, but it is stored in the kidney of the bat.
.
Storage
23
8

The main excretion of absorbed vitamin B12 is via urinary, biliary, and fecal
routes. Total body loss ranges from 2 to 5 μg daily in humans
(Shinton, 1972).
23
9

Of special interest in ruminant nutrition is the role of vitamin B12 in the metabolism
of propionic acid into succinic acid ,which then enters the tricarboxylic acid
(Krebs) cycle.
Blood Cells – it is essential for production of RBCs
Nervous – It improves concentration, memory,& balance.
It is important for metabolism of fat,carbohydrate ,proteins, folic acid.
It promotes growth and increases apatite.
BIOCHEMICAL FUNCTIONS OF B12.
Methylmalonyl-CoA-isomerase: Itcatalyzes the reaction using B12 as acoenzyme
Methylmalonyl-CoA → succinyl-CoA2.
Methionine synthase or homocysteinemethyl transferase requires B12 ascoenzyme:
Conversion of Ribonucleotide to deoxyribonucleotide also needs B12. It is important in
the synthesis of DNA hence deficiency of B12 leads to the defective synthesis of DNA.
Role as Hemopoietic Factor: Like folic acid,vitamin B12 is also concerned
withhemopoiesis and is needed for maturationof RBCs. 240

Abnormal Homocysteine Level: Invitamin B12 deficiency, Homocysteine
Conversion to methionine a block so that homocysteine is accumulated, leading
tohomocystienuria. Homocysteine level in blood is related with myocardialin
farction. So1, B12 is protective against cardiac disease.
Demyelination and Neurological Deficits: InB12 deficiency, methylation of
phosphatidyl ethanolamine to phosphatidylcholine is not adequate. This leads to
deficient formation of myelin sheaths of nerves, demyelination and neurological
lesions.
241

Fig. (A) A cobalt-deficient heifer that had access to an iron-copper salt
supplement. Note severe emaciation, which resulted from failure to synthesize
B12. Her blood contained 6.6 g of hemoglobin per 100 ml (B) The same heifer
fully recovered with an iron-copper-cobalt salt supplement while on the same
pasture.
A B
24
2

Fig. (A) Vitamin B12-deficient pig. Note rough hair coat and dermatitis.
(B) Control pig.
A
B
24
3

TOXICITY
the maximum tolerable amount of dietary cobalt for ruminants is estimated
at 5 ppm.
Cobalt toxicosis in cattle is characterized by mild polycythemia; excessive
urination, defecation, and salivation; shortness of breath; and increased
hemoglobin, red cell count, and packed cell volume.
244

Vitamin B12 Concentrations of Various Foods and Feedstuffs (ppb, dry basis)
Blood meal 49 Horse meat 142
Corn, grain 0 Liver meal 542
Crab meal 475 Meat meal 72
Distiller’s solubles 3 Milk, skim, cow’s 54
Fish solubles 1007 Poultry by-product meal 322
Fish meal, anchovy 233 Soybean meal 0
Fish meal, herring 467 Spleen, cow 247
Fish meal, menhaden 133 Wheat, grain 1
Fish meal, tuna 324 Whey, cow 20
Yeast 1
Source: NRC (1982b). 245

History
Synonym Ascorbic acid
Vitamin C is synthesized in almost all species, the exceptions including humans,
guinea pigs, fish, fruiteating bats, insects, and some birds.
Two forms- 1.Reduced ascorbic acid
2.Oxidized dehydroascorbic acid.
 There are four stereoisomers of ascorbic acid.
Ascorbic acid is so readily oxidized to dehydroascorbic acid.
Vitamin C is the least stable and therefore most easily destroyed, of all vitamins.
Ascorbic acid is a white to yellow-tinged crystalline powder.
Not found in dry foods.
Destroyed by cooking, particularly when the ph is alkaline.
Glycoascorbic acid acts as an antimetabolite for vitamin c
insoluble in diethyl ether,chloroform, benzene,petroleum ether, oils, fats
Melting point-190 °C
1928- Szent-Györgyi isolated hexuronic acid from orange juice, cabbage juice,
and cattle adrenal glands.
1937-both Szent-Gyorgyi and Haworth received Nobel Prizes in medicine and
chemistry, respectively, for work related to vitamin C
1932- Waugh and King isolated hexuronic acid from lemons and identified it as
vitamin C.
1933 -Haworth determined structure of vitamin C.
248

Fig. Basic steps in the commercial synthesis of ascorbic acid from D-glucose via
theReichstein–Grussner synthesis pathway or fermentation starting with D-
glucose or L-sorbitol. If ample quantities of sorbosone are produced, ascorbic
acid can be generated by the action of sorbosone dehydrogenase
24
9

Cellular pathways for the synthesis of ascorbic acid. The direct oxidative
pathway for glucose is utilized in animals that make ascorbic acid.
Gulonolactone oxidase is compromised or absent in animals that cannot make
ascorbic acid. In plants and bacteria that make L-ascorbic acid (pathway to the
left), galactose and mannose, in addition to D-glucose can contribute to 25
0

METABOLISM
In its metabolism, ascorbic acid is first converted to dehydroascorbate by a number of
enzyme or nonenzymatic processes and is then reduced in cells
(Rose et al., 1986).
The site of absorption in the guinea pig is in the duodenal and proximal small
intestine, whereas the rat showed highest absorption in the ileum
(Hornig et al.,1984).
In humans, ascorbic acid is absorbed predominantly in the distal portion of the small
intestine and, to a lesser extent, in the mouth, stomach, and proximal intestine
(Moser and Bendich, 1991).
Vitamin C is transported in the plasma in association with the protein albumin.
In experimental animals, highest concentrations of vitamin C are found in the
pituitary and adrenal glands, with high levels also found in the liver, spleen, brain, and
pancreas. The vitamin tends to localize around healing wounds.
Absorbed ascorbic acid is excreted in urine, sweat, and feces. 251

FUNCTIONS
Collagen Synthesis:-
Syntheses of collagens involve enzymatic hydroxylations of proline to form
a stable extracellular matrix and of lysine for glycosylation and formation
of cross-links in the fibers
(Barnes and Kodicek, 1972).
Antioxidant and Immunity Role
Vitamin C is the most important antioxidant in extracellular fluids
(Stocker and Frei, 1991).
Antioxidants serve to stabilize these highly reactive free radicals, thereby
maintaining the structural and functional integrity of cells
(Chew, 1995).
25
2

enhance immunity by maintaining the functional and structural integrity
of important immune cells.
Vitamin C can stimulate the production of interferons, the proteins that
protect cells against viral attack
(Siegel,1974).
Ascorbic acid has a role in metal ion metabolism because of its reducing
and chelating properties.
Ascorbic acid promotes non-heme iron absorption from food
(Olivares et al., 1997)
25
3

Fig. Vitamin C deficiency in catfish. (A) Fingerling channel catfish fed a
diet devoid of vitamin C for 8 weeks. Note scoliosis and lordosis. (B) Channel
catfish from commercial cage culture where the regular diet was devoid of
vitamin C. Fish at left shows lateral curvature of the spine (scoliosis); fish at
right shows vertical curvature (lordosis) and a vertical depigmented band at 25
4

Vitamin C Concentrations in Various Foods (mg/100 g, as-fed basis)
Vegetables Bananas 6-12
Cabbage, red 55 Lemons 80
Carrots 2-6 Limes 250
Cauliflower, raw 50-90 Animal Products
Corn 12 Fish 5-30
Oats, whole 0 Kidney, lamb 9
Rice 0 Kidney, pig 11
Wheat, whole 0 Liver, calf 13
Potatoes, new 18 Liver, pig 15
Fruit Milk, cow 1-2
Apples, unpeeled 10-30 Milk, human 3-6
NATURAL SOURCES

Vitamins originate primarily in plant tissues and are present in animal tissue only as a
consequence of consumption of plants, or because the animal harbors microorganisms
that synthesize them.
Vitamin B12 is unique in that it occurs in plant tissues as a result of microbial
synthesis.
Two of the four fat-soluble vitamins, A and D, differ from the water soluble B vitamins
in that they occur in plant tissue in the form of a provitamin (a precursor of the
vitamin), which can be converted into a vitamin in the animal body.
However, the amino acid tryptophan can be converted to niacin for most species.
256

Carnitine, vitamin BT
Carnitine was isolated from meat extracts and identified in 1905. In
1948, Fraenkel’s research on dietary requirements of the mealworm
(Tenebrio molitor) led to recognition of a new B vitamin, which in 1932
was identified as carnitine (Friedman and Fraenkel, 1972).
Since it was a small water-soluble compound required in the diet of T. molitor
258

two types of carnitine, L- and D-carnitine, only L-carnitine is biologically
active.
Carnitine is a quaternary amine, β-hydroxy-γ-trimethylaminobutyrate.
It is a very hygroscopic compound, easily soluble in water
molecular weight- 161.2.
259

METABOLISM
Under normal conditions in omnivores, about 70 to 80% of dietary carnitine is
absorbed
(Rebouche and Chenard, 1991).
Carnitine is synthesized in liver and kidney and stored in skeletal muscle; free
carnitine is excreted mainly in the urine
(Tanphaichitr and Leelahagul, 1993).
The product is trimethylamine oxide
(Mitchell,1978).
Carnitine synthesis depends on two precursors, L-lysine and methionine, as
well as ascorbic acid, nicotinamide, vitamin B6, and iron
(Borum, 1991).
260

Steps in carnitine biosynthesis. In order to form L-carnitine from lysine, three consecutive
methylation reactions are required utilizing S-adenosylmethionine (SAM) as the methyl donor. This
step occurs as a posttranslational protein modification. Next, trimethyllysine is obtained (after
protein hydrolysis). Trimethyllysine is enzymatically transformed into 3-hydroxy-trimethyllysine in a
reaction requiring a-ketoglutarate, O2, and ascorbic acid. Following the loss of glycine and
oxidation to trimethylammoniobutyrate, a second hydroxylation involving an ascorbic acid-assisted
step results in carnitine. 261

FUNCTIONS
Carnitine is an important cofactor for normal cellular metabolism.
Optimal utilization of fuel substrates for adenosine triphosphate (ATP)
generation by skeletal muscle during exercise is dependent on adequate
carnitine stores
Carnitine is required for transport of long-chain fatty acids into the matrix
compartment of mitochondria from cytoplasm for subsequent oxidation by the
fatty acid oxidase complex for energy production.
262

Vitamin-like Substances(Pseudovitamins)

myo-Inositol, also referred to as inositol, is a water-soluble growth factor for which no
coenzyme function is known.
It was first isolated from muscle in 1850 and was identified as a growth factor for
yeast and molds, though not for bacteria.
Chemical Structure and Properties
It is a cyclohexane compound
Inositol exists in nine forms.
myo-Inositol is an alcohol, similar to a hexose sugar.
It is a white, crystalline, water-soluble compound with a sweet taste, and is stable in
acids, alkalines, and heat up to about 250⁰C.
Because of hydroxyl groups, it forms various ester, ethers, and acetals.
The hexaphosphoric acid ester (combined with six phosphate molecules) of myo-
inositol is phytic acid, a compound that complexes with phosphorus and other minerals,
making them less available for absorption
264

myo-Inositol is absorbed by active transport from dietary sources, or it may be
synthesized de novo from glucose. Based on animal studies, myo-inositol may also be
converted to glucose.
three metabolic fates:
1. Oxidation to CO2,
2. use in gluconeogenesis,
3. synthesis of phospholipids.
265

Inter- relationship of minerals with other nutrients
Vitamin D stimulates active transport of Ca & P across intesinal
epihtlium.
Na & Cl help control the passage of nutrients into cells & waste products
out.
Insufficient Na lower the utilization of digested protein & energy.
Cl is essential for activation of intestinal amylase.
K activates or functions as a cofactor in several enzyme systems & the
include energy transfer & utilization, protein synthesis & carbohydrate
metabolism.
Mg also activates pyruvic acid carboxylase, pyruvic acid oxidase & the
condensing enzyme for the reaction in krebs cycle.
Mg is involved in protein synthesis through it’s action on ribosomal
aggregation, its role in binding messenger RNA to 70S ribosome's.
Iron exist in the animal body mainly in complex forms to protein
(hemoprotein).
Iron plays a significant role in TCA , as all of the 24 enzymes in this
cycle contain Fe at their active in this cycle contain Fe either at their active
centers or as essential cofactor .
Copper deficeiency results in elevated level of serum triglyceride,
phospholipid & cholesterol in the rat.
Copper helps to propionate of deficiency or metabolic origin converted
into succinate, then enters into TCA.
26
7

Year of
discovery
Vitamin
1909 McCollum and Davis described “fat-
soluble A
Vitamin A (Retinol)
1912 Vitamin B1 (Thiamin)
1912 Vitamin C (Ascorbic Acid)
1918 Sir Edward Mellanby Vitamin D (Calciferol)
1920 Vitamin B2 (Riboflavin)
1922 Evans and Bishop Vitamin E (Tocopherol)
1926 Vitamin B12 (Siano
Cobalamin)
1929 Henrik Dam Vitamin K (Phylloquinone)
1931 Vitamin B5 (Pantothenic
acid)
1931 Vitamin B7 (Biotin)
1934 Vitamin B6 (Pyridoxine)
1936 Vitamin B3 (Niacin) 26
8

Animal Nutrition
Chapter 41
26
9

Vitamins in animals

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