Introduction to Vitamin Supplements
Vitamins are chemically unrelated, organic compounds. Each vitamin performs
a specific function in the body. As with minerals, vitamins are micronutrients,
essential for animal health and optimal production. The cost of adequate
provision is minimal compared to the potential impact on productivity
and profitability.
Vitamins are classified as fat-soluble or water-soluble.
Table 10.5 lists the primary functions of each of the fat- and water-soluble
vitamins.
Table 10.5 - Function(s) of Fat and Water Soluble Vitamins
Vitamin |
Primary
Function(s) |
| Vitamin A |
-Maintenance of vision
-Body and bone growth
-Development of teeth
-Maintenance of epithelial cells and cells lining nose, throat, respiratory
and digestive systems, and genital and urinary tracts
-Glycoprotein, protein, thyroxin, glycogen, and corticosterone synthesis
-Tissue differentiation
-Antioxidant |
| Vitamin D |
-Assimilation and utilization of calcium and phosphorus
-Growth and mineralization of bones
-Development of teeth
-Maintains citrate level in blood
-Minimizes loss of amino acids |
| Vitamin E |
-Antioxidant
-Maintenance of red blood cells
-Cellular respiration
-Regulates synthesis of DNA, vitamin C, and coenzyme Q |
| Vitamin K |
-Blood coagulation |
| Thiamin (B1) |
-Energy metabolism
-Transketolation process or conversion of glucose to lipids
-Peripheral nerves
-Maintenance of appetite
-Muscle tone |
| Riboflavin (B2) |
-Metabolism of carbohydrates, lipids, and proteins
-Formation of specific water-soluble vitamins
-Potential functions include: component of the eye, functioning of
the adrenal gland, and
production of corticosteroids in adrenal cortex |
| Pyridoxine (B6) |
-Metabolism of proteins, lipids, and carbohydrates |
| Cyanocobalamin (B12) |
-Carbohydrate, lipid, and protein metabolism
-Formation of red blood cells
-Maintenance of nerve tissue
-Synthesis and transfer of carbon groups
-Reduction reactions
-Interrelated with other vitamins such as choline, folic acid, and
pantothenic acid |
| Pantothenic acid |
-Metabolism of carbohydrates, lipids, and proteins
-Transmission of nerve impulses
-Synthesis of hemoglobin
-Synthesis of cholesterol and other sterols
-Synthesis of steroid hormones
-Maintenance of blood sugar
-Immune function
-Detoxification
-Synthesis of fatty acids |
| Nicotinic acid (Niacin) |
-Metabolism of carbohydrates, lipids, and proteins
-Synthesis of fatty acids, protein, and DNA
-Biological oxidation-reduction reactions
-Growth
-Metabolism of cholesterol |
| Folic acid |
-Nucleic acid synthesis
-Formation of heme for hemoglobin
-Synthesis and metabolism of amino acids
-Metabolism of select water-soluble vitamins |
| Biotin |
-Metabolism of carbohydrates, lipids, and proteins
-Deamination of proteins |
| Choline |
-Prevention of triglyceride accumulation in liver
-Transmission of nerve impulses
-Metabolism of lipids |
| Inositol |
-Lipid metabolism
|
| Paraaminobenzoic acid (PABA) |
-Component of folic acid molecule |
| Vitamin C (Ascorbic acid) |
-Formation and maintenance of collagen
-Metabolism of amino acids, lipids, iron, and folic acid
-Teeth and bone structure
-Maintenance of the circulatory system
-Antioxidant |
As described earlier, water-soluble vitamins perform many of their respective
metabolic functions as enzyme cofactors. In the case of vitamins, cofactors
are organic molecules required for the activation of enzymes. As discussed
earlier, water-soluble vitamins are not stored in the tissues of the body,
therefore daily dietary supplementation is required. In contrast, fat-soluble
vitamins are stored in the tissues of the body therefore, technically,
daily dietary supplementation is not required.
Vitamins are provided via the natural feedstuffs of the ration and supplementation
with natural and synthetic sources. Table 8-4 on page 176 of the text
describes recognized supplementary sources of vitamins. Appendix Table
7 on page 518 of the text describes various synthetic vitamin supplements
and their vitamin contents. In general, supplemental vitamins are provided
in a complete feed or a mixture.
As with minerals, the vitamins in the feedstuffs of the ration contribute
to fulfill the dietary vitamin requirement of the animal. The vitamin
content in plant-, animal-, and microorganism-based feedstuffs varies.
For plant-based feeds, vitamin content varies by species, component of
the plant, growing conditions, and harvesting, processing, and storage
methods. For animal-based feeds, vitamin content varies by tissue. In
general, microorganisms are favorable sources of vitamins. As a result
of the variation in natural feedstuffs, generally, an effective method
to fulfill vitamin requirements is via a vitamin supplement. Vitamins
are susceptible to heat, sunlight, oxidation, and microorganisms.
The following paragraph is a general discussion of the vitamins required
by the various species. As a result of vitamin synthesis by rumen microorganisms,
ruminants do not require dietary supplementation of the B-complex vitamins
and vitamin K. Specific classes of ruminants may require supplemental
niacin, thiamine, and/or choline. Ruminants do require dietary supplementation
of vitamins A, D, and/or E. For young ruminants, the various vitamins
produced in mature rumen systems must be provided via a dietary supplement
until the maturation of the rumen system. As a result of the synthesis
of vitamins by microorganisms of the cecum and colon, horses do not require
supplementation of the B-complex vitamins. In general, horses require
supplementation of vitamins A, D, E, and K. In general, swine require
dietary supplementation of riboflavin, niacin, pantothenic acid, cyanocobalamine,
and vitamins A, D, E, and K. In general, poultry require dietary supplementation
of a majority of the water-soluble vitamins and vitamins A, D, E, and
K. The water-soluble vitamins poultry may not require a supplemental source
of are inositol and PABA. As livestock species are able to synthesize
adequate amounts of vitamin C, in general, livestock species do not have
a dietary requirement for vitamin C.
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