Printer Friendly

Chapter 10 Vitamins.

The story of the vitamins, one of the most important episodes in the history of biochemistry, has touched profoundly on man's health and well-being and on our understanding of the catalytic processes taking place in the metabolism of living organisms.

A. L. LEHNINGER, 1978

INTRODUCTION

Vitamin nutrients are organic compounds that play roles in the metabolism of livestock. As a group, the various vitamins have very little in common structurally and are generally classified as either fat soluble or water soluble. For some vitamins, the symptoms of deficiency can be eliminated with any one of several compounds. For these vitamins, the vitamin content of feedstuffs is expressed in units of potency rather than in weighed amounts of a specific compound, and animal requirements are expressed in International Units (IU). Not all vitamins are dietary essentials for all livestock.

IMPORTANCE OF VITAMINS AND VITAMIN SUPPLEMENTATION

Vitamins are essential organic substances needed in small amounts in the diet for normal function, growth, and maintenance of body tissues. Being organic, they are composed primarily of carbon and hydrogen, but may also contain oxygen, phosphorus, sulfur, or other elements. Most vitamins function as cofactors in enzyme reactions that synthesize important chemicals, including the nonessential amino acids. Vitamins also play vital roles in calcium balance and in the extraction of energy from carbohydrate, fat, and protein. Figure 10-1 summarizes the role of the B vitamins in energy production. Because the functions of vitamins are so diverse, a lack of a particular vitamin can have widespread effects.

Livestock require 14 vitamins, but not all of these are dietary essentials for all species. Some are synthesized within animal tissues, and some are synthesized and made available to livestock by the microbes inhabiting the digestive tract. Those vitamins that are dietary essentials may or may not be found in sufficient quantities in the usual feedstuffs fed to that animal. Table 10-1 lists the usual vitamins supplemented in livestock diets.

[FIGURE 10-1 OMITTED]

CLASSIFICATION OF VITAMINS

Vitamins are classified as fat soluble and water soluble. Solubility characteristics of vitamins have consequences relating to the mechanism of absorption and body storage. Vitamins A, D, E, and K are fat soluble. The B complex and vitamin C are water soluble.

VITAMIN POTENCY

The daily requirements for all vitamins except A, D, and E are expressed in milligrams (mg) or micrograms (_g). Daily requirements for vitamins A, D, and E are expressed in units of potency. There are multiple sources of these vitamins with varying potency. Potency refers to the ability of the source to remove signs of vitamin deficiency. The potency unit that is used in the feed industry is the International Unit (IU). It is sometimes referred to as the U.S. Pharmacoepeia unit (USP).

VITAMIN SUPPLEMENTATION

The vitamins that livestock require can be supplied through consumption of fresh feedstuffs rich in vitamin content, addition of vitamins to the ration, or injection of vitamins into animals. Given the fact that during at least some seasons of the year, livestock are fed feedstuffs that have been in storage for several months, it is not possible to meet livestock requirements through the first option during all seasons of the year. The third option--injection of vitamins--will be the most expensive method of vitamin supplementation. For most livestock during most seasons of the year, vitamin supplementation will be accomplished through the addition of vitamin supplements to the diet. In fact, vitamin premixes containing the required types and amounts of vitamins are usually added to livestock rations without regard for the vitamins that may be present in the ration from other ingredients.

VITAMIN STABILITY

Vitamins are biologically active chemicals that are sensitive to their environment. Many vitamins contain functional groups and double bonds that are liable to react with oxygen. Such a reaction would destroy the vitamin. When vitaminfortified formulations are mixed and transported, their exposure to oxygen is increased, and unless the vitamin is protected, losses may be significant.

Processes such as pelleting and extruding will result in increased destruction of vitamins (Table 10-2). To ensure that the desired level of vitamin is present in the finished feed, manufacturers of pelleted and extruded feed products must consider the cost and stability of various vitamin sources and overfortify their formulations accordingly.

Vitamin-fortified feed products stored for prolonged periods in the presence of moisture, rancid fat, acid or alkaline pH, trace minerals, choline chloride or heat will have less vitamin content than the original product. Vitamin-fortified feed products should be protected from oxygen and stored in a cool, dry location. They should be used within 3 months.

THE FAT-SOLUBLE VITAMINS

Because body fat is not turned over as often as water, the storage capability for fat-soluble vitamins is significant. Deficiencies of fat-soluble vitamins, therefore, may not immediately occur, even if the ration is devoid of vitamin. Nevertheless, in developing rations, it is best to meet daily required levels of the fat-soluble vitamins.

The mechanics of absorption of fat-soluble vitamins has much in common with the absorption of fat or triacylglycerol. In the intestine, the fat-soluble vitamins are transported to the site of absorption via the micelles. In the intestinal cell, the fat-soluble vitamin is packaged into a lipoprotein particle. The lipoproteins containing the fat-soluble vitamins are passed into the lymphatic system, and at that point are referred to as chylomicrons. The chylomicrons are passed into the bloodstream, where they are attacked by enzymes in the walls of the capillaries. What remains of the chylomicron after the triacylglycerols are dispensed with is called the remnant. It is the remnant that contains the fat-soluble vitamin. The remnant remains in the bloodstream and is picked up by the cells for their use or by the liver for storage and redistribution.

Vitamin A

Table 10-3 gives vitamin A requirements for selected livestock.

Sources

The potency of 1 IU of vitamin A is delivered by 0.3 micrograms ([micro]g) crystalline vitamin A alcohol (retinol), or 0.344 [micro]g of vitamin A acetate, or 0.55 [micro]g of vitamin A palmitate. Pure forms of vitamin A may be found in animal tissues and animal products. Vitamin A alcohol, vitamin A acetate, and vitamin A palmitate may also be made synthetically.

None of these three forms of vitamin A occurs in plant material. However, fresh plant material does contain compounds that are vitamin A precursors that livestock are capable of converting to vitamin A. This conversion takes place in the intestinal cells during the absorption process. The precursors are called carotenes or carotenoids and they include alpha carotene, beta carotene, gamma carotene, and cryptoxanthin. As indicated in Table 10-4, carotenoids are converted to vitamin A with varying efficiencies, depending on the species. It is important therefore, that feedstuffs assigned an IU number based on carotenoid content be reevaluated before use with a different species of livestock.

Function and Signs of Deficiency

Vitamin A has been shown to be essential for maintenance of epithelial tissue. Because epithelial tissue is found throughout the body, many and diverse symptoms will accompany a vitamin A deficiency. Vision, growth, reproduction, and resistance to infection will be impaired with a vitamin A deficiency. Other symptoms include lacrimation, tissue keratinization, urinary calculi, hind-legs paralysis, bone-shape abnormalities, and elevated cerebrospinal fluid pressure. As with all the fat-soluble vitamins, the body does have some storage ability and dietary deficiency will not lead immediately to deficiency symptoms.

Hypervitaminosis A

Prolonged intake of excess vitamin A has been reported to cause various problems including rough hair coat, skin cracks, tremors, hyperirritability, and bone fragility. The safe upper limit for vitamin A is 4 to 10 times the requirement for nonruminants and about 30 times the requirement for ruminants (NRC, 1987). Excessive dietary levels of carotenoid compounds are not converted to vitamin A and so do not create toxicity. Table 10-5 gives the safe upper limits for vitamin A in livestock diets as presented by the NRC (1987).

Vitamin D

Table 10-6 gives vitamin D requirements for selected livestock.

Sources

As a nutrient, vitamin D exists in two forms. Vitamin [D.sub.2] comes from plant sources and vitamin [D.sub.3] comes from animal sources. The chemical name of vitamin [D.sub.2] is ergocalciferol. The chemical name of vitamin [D.sub.3] is cholecalciferol. For poultry and fish, vitamin [D.sub.2] has very low activity, so diets requiring supplementation should include the [D.sub.3] form of the vitamin. Vitamin [D.sub.3] is found in fish oils and is made by irradiation of animal sterol.

Whether it is vitamin [D.sub.2] or vitamin [D.sub.3], vitamin D content of feedstuffs is measured in terms of potency in alleviating symptoms of rickets. The unit of potency for vitamin [D.sub.2] is the international unit (IU). The unit of potency for vitamin [D.sub.3] is the international chick unit (ICU). Both the IU and ICU are defined as the antirachitic activity of 0.025 [micro]g of cholecalciferol. When discussing vitamin D, the IU may be applied to either vitamin [D.sub.2] or vitamin [D.sub.3] but the ICU may be applied only to vitamin [D.sub.3].

Function and Signs of Deficiency

The function of vitamin D is to facilitate mobilization, transport, absorption, and use of calcium and phosphorus in concert with the actions of the hormones of the thyroid and parathyroid glands. A deficiency causes a disturbance in calcium and phosphorus absorption and metabolism. Deficiency symptoms in young animals result in insufficient bone mineralization leading to rickets.

Deficiency symptoms in adult animals result in diminished mineral content of bone. This is called osteoporosis. Parturient paresis (milk fever) may result from a vitamin D deficiency, primarily in dairy cows, but the disorder has also been reported in ewes and doe goats. All livestock with the possible exception of fish can make vitamin D if exposed to sunlight. As with all the fat-soluble vitamins, the body does have some storage ability and dietary deficiency will not lead immediately to deficiency symptoms.

Hypervitaminosis D

Prolonged intake of excess vitamin D can lead to calcification of the soft tissues of the body including the heart muscle, kidney, and lung. The safe upper limit for vitamin [D.sub.3] is 4 to 10 times the requirement (NRC, 1987). Vitamin [D.sub.3] is 10 to 20 times more toxic than is vitamin [D.sub.2] so the upper limit for vitamin [D.sub.2] would be 40 to 100 times the requirement. Table 10-5 gives the safe upper limits for vitamin D in livestock diets as presented by the NRC (1987).

Vitamin E

Table 10-7 gives vitamin E requirements for selected livestock.

Sources

The potency of 1 IU of vitamin E is delivered by 1 mg DL-[alpha]-tocopheryl acetate, 0.735 mg D-[alpha]-tocopheryl acetate, 0.671 mg D-[alpha]-tocopherol, or 0.909 mg DL-[alpha]-tocopherol. Natural sources of vitamin E are vegetable oils, but vitamin E is generally supplemented to the level required using one of the tocopheryl or tocopherol compounds.

Functions and Signs of Deficiency

Adequate vitamin E is necessary for normal reproductive function in male and female animals. Vitamin E functions as an antioxidant to protect the lipids in cell membranes from oxidation. A deficiency of this antioxidant results in numerous and varied symptoms including muscle degeneration, anemia, digestive disorders, impaired immune function, liver problems, and sudden death. Vitamin E and other antioxidant vitamins are sometimes added to feed to function as antioxidants and prevent the degradation of unsaturated fats. It is important to know that as they protect unsaturated fats, these vitamins are consumed and will not be present at the levels in the original formulation.

Vitamin E shares its antioxidant function with selenium, and these nutrients appear to have a mutual sparing effect on one another. Animals receiving diets that are marginal in either vitamin E or selenium will respond to additional amounts of the other nutrient. The nature of the relationship, however, has not been quantified.

Hypervitaminosis E

Excess dietary vitamin E is rare in the feed and nutrition industries because the vitamin is so expensive. Table 10-5 gives the safe upper limits for vitamin E in livestock diets as presented by the NRC (1987).

Vitamin K

Table 10-8 gives vitamin K requirements for selected livestock.

Sources

Unlike the other fat-soluble vitamins, vitamin K requirement is not expressed in IU but rather in milligrams. Sources of vitamin K are found naturally in both animal tissues and fresh plant material. Synthetic vitamin K is identified by the chemical name menadione. Menadione is extremely unstable, so pure vitamin K is not utilized in the feed industry. There are numerous forms of vitamin K that have improved stability, all of which are formed by reaction with sodium bisulfite or derivatives of sodium bisulfite. The vitamin K requirement is given as menadione equivalent, so it is important to use the menadione content of the vitamin K source to meet the requirement. Three examples of menadione sources are menadione sodium bisulfite (MSB) (50 percent menadione); menadione sodium bisulfite complex (MSBC) (33 percent menadione); and menadione dimethylpyrimidinol bisulfite (MPB) (45 percent menadione).

Functions and Signs of Deficiency

Vitamin K is used in the body's blood-clotting mechanism. A deficiency results in reduced ability to form clots, and may result in unchecked internal hemorrhages and death. The microbes living in animals' digestive systems make vitamin K, and without a source of dietary vitamin K, antibiotic therapy may result in vitamin K deficiency. Dicumarol, the active ingredient in some rat poisons, kills rats by virtue of its anti-vitamin K activity. Dicumarol is also produced by a mold that sometimes grows in hay made from sweet clover.

Hypervitaminosis K

Animals tolerate large excesses of this vitamin and toxicity is not a problem. Table 10-5 gives the safe upper limits for vitamin K in livestock diets as presented by the NRC (1987).

THE WATER-SOLUBLE VITAMINS

Because these vitamins are soluble in water, the body has the capability of disposing of any excess through activities at the kidneys. This means that problems due to excesses are unlikely, but it also means that daily intake is essential.

The water-soluble vitamins include vitamin C and the B vitamins. A numbering system for the B vitamins has been established but this system has not been well accepted in its entirety, so some of the B vitamins are referred to by their number in addition to their name, but others are not.

The original "vitamin B" is now known to include a number of specific chemical compounds now referred to as the B complex. These include thiamin ([B.sub.1]), riboflavin ([B.sub.2]), nicotinic acid or niacin ([B.sub.3]), pantothenic acid ([B.sub.5]), pyridoxine ([B.sub.6]), biotin ([B.sub.7]), folic acid, folacin, or folate ([B.sub.9]), cyanocobalamin ([B.sub.12]), choline, and myoinositol.

Thiamin ([B.sub.1])

Table 10-9 gives thiamin requirements for selected livestock.

Sources

Thiamin is usually supplemented in the form of thiamin mononitrate, which is 91.9 percent thiamin. Cereal grains contain significant amounts of thiamin and diets containing cereal grains will contain adequate thiamin for most animals. Microorganisms inhabiting the digestive systems of livestock synthesize thiamin.

Functions and Signs of Deficiency

Thiamin is involved in nervous system function and it participates in the production of adenosine triphosphate (ATP) from organic molecules (Figure 10-1). Deficiency symptoms include appetite suppression and digestive problems, reduced weight gain, nervous disorders, and heart-muscle degeneration. Polioencephalomalacia (PEM) or "blind staggers" is a disorder in ruminants that may be caused by a thiamin deficiency. PEM may also be caused by excessive sulfur intake and is discussed in Chapter 9 under Sulfur. In the chicken, reproductive function is impaired by thiamin deficiency.

Raw fishmeal contains thiaminase, an enzyme that destroys thiamin after contact for a prolonged period of time. A thiamin deficiency could, therefore, be created in animals fed diets containing fishmeal. Since fish diets often contain more than 50 percent fishmeal, fishmeal treatment, feed freshness, and adequate thiamin fortification are especially critical.

Hypervitaminosis Thiamin

Table 10-5 gives the safe upper limits for thiamin in livestock diets as presented by the NRC (1987).

Riboflavin ([B.sub.2])

Table 10-10 gives riboflavin requirements for selected livestock.

Sources

Riboflavin is usually supplemented in the pure form. This water-soluble vitamin, along with vitamin [B.sub.12], are the ones most likely to be deficient in unsupplemented diets made up of ingredients normally fed to herbivores. Much of the riboflavin that exists in plant material has low bioavailability for most species. Riboflavin is made by microbes inhabiting the digestive tracts of livestock.

Function and Signs of Deficiency

Riboflavin is a cofactor for many enzyme systems. Riboflavin participates in the production of ATP from organic molecules (Figure 10-1). Riboflavin also functions as an antioxidant. Deficiency symptoms include poor hair coat, neurological problems, and changes in blood composition. In the chicken, reproductive function is impaired by riboflavin deficiency.

Hypervitaminosis Riboflavin

Table 10-5 gives the safe upper limits for riboflavin in livestock diets as presented by the NRC (1987).

Pyridoxine ([B.sub.6])

Table 10-11 gives pyridoxine requirements for selected livestock.

Sources

The term pyridoxine is used to include the compounds pyridoxine, pyridoxal, and pyridoxamine. Pyridoxine is found naturally in most fresh feedstuffs. However, pyridoxine is destroyed by heat and some of the pyridoxine that exists in plant material is not bioavailable. Microorganisms inhabiting the digestive systems of livestock synthesize pyridoxine.

Functions and Signs of Deficiency

Pyridoxine is involved in the metabolism of proteins. Pyridoxine is a cofactor for many enzyme systems, including those involved in the synthesis of neurotransmitters. Pyridoxine participates in the production of ATP from organic molecules (Figure 10-1). A deficiency results in reduced growth rate, impaired immune function, fatty liver, nervous symptoms, and blood composition changes. In the chicken, reproductive function is impaired by pyridoxine deficiency.

Hypervitaminosis Pyridoxine

Table 10-5 gives the safe upper limits for pyridoxine in livestock diets as presented by the NRC (1987).

Cyanocobalamin ([B.sub.12])

Table 10-12 gives vitamin [B.sub.12] requirements for selected livestock.

Sources

Cyanocobalamin (more common referred to as [B.sub.12]) contains cobalt. Vitamin [B.sub.12] does not occur in plant materials, so herbivores depend on the synthetic activities of the microbes inhabiting their digestive tracts for their supply of vitamin [B.sub.12]. Because vitamin [B.sub.12] contains cobalt, this micromineral must be supplied in the diet if the animal's requirement is to be met through microbial synthesis. Monogastric animals that have access to their feces can meet their [B.sub.12] requirement through coprophagy.

Functions and Signs of Deficiency

Vitamin [B.sub.12] is a cofactor for many enzyme systems, including those involved in protein metabolism and DNA synthesis. Vitamin [B.sub.12] participates in the production of ATP from organic molecules (Figure 10-1). A deficiency of [B.sub.12] results in poor hair coat, kidney damage, reduced growth, nervous disorders, and blood composition changes. In the chicken, reproductive function is impaired by [B.sub.12] deficiency.

Vitamin [B.sub.12] is used in the production of red blood cells. Pernicious anemia is caused by a lack of functional red blood cells due to inadequate availability of vitamin [B.sub.12]. In humans, this form of anemia can also be caused by infection with the tapeworm Diphyllobothrium latum. Though pernicious anemia caused by parasites has not been documented in livestock, it is possible that nutritional deficiencies in livestock may also be caused or aggravated by worm infections. Parasite prevention programs play an essential role in maximizing feed efficiency in livestock.

Hypervitaminosis [B.sub.12]

Table 10-5 gives the safe upper limits for vitamin [B.sub.12] in livestock diets as presented by the NRC (1987).

Myoinositol

Sources

Inositol in feedstuffs exists in several forms, but the biologically active form is myoinositol. Although there is an established myoinositol requirement for rainbow trout, catfish can apparently synthesize inositol in their livers and intestines (Burtle & Lovell, 1989), and no dietary requirement has been demonstrated for catfish. Ruminants can utilize the myoinositol found in phytic acid and do not respond to supplemental dietary myoinositol (Gerloff, Herdt, Emery, & Wells, 1984; Grummer, Armentano, & Marcus, 1987). Cats may have a requirement for myoinositol. For the remaining species of livestock, inositol does not appear to be deficient in healthy animals fed usual rations.

Functions and Signs of Deficiency

Inositol is a structural component of phospholipids that are found in cell membranes. It is involved in the metabolism and transport of lipids, and many cellular processes, including liver glycogenolysis (the conversion of glycogen stores to glucose) and insulin release from the pancreas. Of all domestic animals considered in this text, only rainbow trout have an established myoinositol requirement. Symptoms of myoinositol deficiency in rainbow trout include anorexia, poor growth, anemia, fin erosion, fatty liver, dark skin coloration, delayed gastric emptying, and decreased cholinesterase and aminotransferase activities.

Hypervitaminosis Myoinositol

There are insufficient data available to support estimates of the maximum tolerable levels of dietary myoinositol.

Pantothenic Acid ([B.sub.5])

Table 10-13 gives pantothenic acid requirements for selected livestock.

Sources

Pantothenic acid is found naturally in most fresh feedstuffs. It is usually supplemented in diets for monogastrics, however, because the level present in feedstuffs and the bioavailability is usually unknown. The most commonly used supplement for pantothenic acid is calcium pantothenate. It is a salt that exists as a D and L isomer. The D isomer of calcium pantothenate has 92 percent activity and the racemic mixture of the calcium salt has 46 percent activity. Microorganisms inhabiting the digestive systems of livestock synthesize pantothenic acid.

Functions and Signs of Deficiency

Pantothenic acid participates in the production of ATP from organic molecules (Figure 10-1). Pantothenic acid is also necessary to maintain normal skin health and is involved in fat metabolism and ketone synthesis. A deficiency results in skin problems, nervous disorders, digestive problems, and impaired immune function. In swine, a deficiency of pantothenic acid results in an abnormal gait called "goose-stepping." In the chicken, reproductive function is impaired by pantothenic acid deficiency.

Hypervitaminosis Pantothenic Acid

Table 10-5 gives the safe upper limits for pantothenic acid in livestock diets as presented by the NRC (1987).

Nicotinic Acid or Niacin ([B.sub.3])

Table 10-14 gives niacin requirements for selected livestock.

Sources

Niacin supplements include nicotinic acid and nicotinamide (niacinamide). Relative to nicotinic acid, nicatinamide is 124 percent as bioavailable for chicks (NRC, 1998). The niacin in corn, oats, wheat, and grain sorghum is in a bound form that is unavailable to monogastric animals. Niacin from these sources must not be considered in balancing rations for these animals. Except in cats, niacin can be made metabolically from a dietary excess of the amino acid tryptophan. Microorganisms inhabiting the digestive systems of livestock synthesize niacin.

Functions and Signs of Deficiency

Niacin participates in the production of ATP from organic molecules (Figure 10-1). Niacin is also necessary to maintain normal skin health. A deficiency of niacin results in reduced growth, digestive disturbances, and skin problems. In lactating dairy cattle, a high level of dietary niacin has shown to reduce plasma ketone concentration (Grummer, 1993) and may help reduce the incidence of ketosis.

Hypervitaminosis Niacin

High doses of niacin have been shown to reduce fat mobilization in transition cows and may thereby play a role in ketosis prevention (Overton, 2001). Table 10-5 gives the safe upper limits for niacin in livestock diets as presented by the NRC (1987).

Folacin, Folate, or Folic Acid (B9)

Table 10-15 gives folacin requirements for selected livestock.

Sources

Folacin and folate are terms for compounds that provide folic acid activity. Most fresh feedstuffs provide sufficient folacin for most animals. Microorganisms inhabiting the digestive systems of livestock synthesize folacin. Monogastric animals that have access to their feces can meet their folacin requirement through coprophagy.

Functions and Signs of Deficiency

Folacin is involved in the manufacture of red and white blood cells. Folacin is also involved in the conversion of serine to glycine, which is of special significance in poultry because for these species, glycine is an amino acid that cannot be synthesized in amounts needed to support maximum growth. Symptoms of folacin deficiency include changes in blood composition, poor skin condition, and problems with bone and cartilage development. In the chicken, reproductive function is impaired by folacin deficiency.

Hypervitaminosis Folic Acid

Table 10-5 gives the safe upper limits for folic acid in livestock diets as presented by the NRC (1987).

Biotin (B7)

Table 10-16 gives biotin requirements for selected livestock.

Sources

Much of the biotin in feedstuffs is bound to lysine. Its availability to the animal depends on whether the lysine is in a protein that the animal can digest. Microorganisms inhabiting the digestive systems of livestock synthesize biotin.

Functions and Signs of Deficiency

Biotin participates in the production of ATP from organic molecules (Figure 10-1). Biotin plays an important role in gluconeogenesis and fatty acid synthesis. Biotin is involved in maintenance of collagen. Symptoms of biotin deficiency include skin, eye, and foot problems. In the chicken, reproductive function is impaired by biotin deficiency. Raw egg white contains a compound --avidin--that forms an indigestible complex with biotin, and animals fed raw egg white may show signs of biotin deficiency.

Hypervitaminosis Biotin

Table 10-5 gives the safe upper limits for biotin in livestock diets as presented by the NRC (1987).

Choline

Table 10-17 gives choline requirements for selected livestock.

Sources

Soybean meal is rich in bioavailable choline, and livestock whose diets include soybean meal may not require supplemental choline. Lecithin is a phospholipid with varying nitrogenous components, one of which may be choline. Choline is usually supplemented as choline chloride, which has 74.6 percent choline activity. There is also a choline chloride product available to the feed industry that has a 60 percent choline activity. Choline chloride is extremely hygroscopic, meaning it absorbs moisture from the atmosphere. It should be stored in a sealed container. It is also liable to react with other vitamins in the presence of trace minerals; if prolonged storage is anticipated, choline chloride should be stored unmixed (Table 10-2). With the help of vitamin [B.sub.12] and folacin, the liver can synthesize choline from the amino acids methionine and serine.

Functions and Signs of Deficiency

Choline is a nitrogen-containing compound that is classified as a B vitamin even though the level required is more in line with amino acids than vitamins. Choline functions in metabolism as a methylating agent and plays important roles in the formation of cell membranes and fatty acid metabolism. Choline is a component of the neurotransmitter acetylcholine. Deficiency symptoms include reduced growth, blood composition changes, and fat infiltration into the liver and kidney. In the chicken, a choline deficiency leads to perosis and impaired reproductive function. Betaine is a widely distributed compound that can be used interchangeably with choline to meet the growing animal's need for methylating agents and is, therefore, important in sparing choline. Vitamin [B.sub.12] may also have a choline-sparing effect.

Hypervitaminosis Choline

In lactating dairy cattle, studies in which high doses of rumen-protected choline chloride were fed have suggested that choline may be a limiting nutrient for milk production (Erdman & Sharma, 1991). High doses of rumen-protected choline have also resulted in improved liver performance in early-lactation dairy cows (Piepenbrink & Overton, 2003). Table 10-5 gives the safe upper limits for choline in livestock diets as presented by the NRC (1987).

Vitamin C (Ascorbic Acid)

Table 10-18 gives vitamin C requirements for selected livestock.

Sources

Most animals can synthesize vitamin C in their tissues from glucose and related compounds. Exceptions include fish, guinea pigs, and primates.

Vitamin C is extremely labile and difficult to maintain in feed products. It is destroyed by many environmental factors. Fish nutrition presents a special challenge regarding vitamin C because for some species of fish, the feed is extruded to produce a floating feed. The extrusion process is stressful even on the most stable vitamins, so mixed feeds containing unprotected forms of vitamin C that are extruded will suffer high losses of the vitamin (Table 10-2). This situation has been addressed in four ways:

1. The feed is overfortified with vitamin C to ensure that the final product still contains enough vitamin C to meet the fish's requirement.

2. An expensive protected form of vitamin C is used that can better survive the extrusion process.

3. Supplemental vitamin C is added at the tank, raceway, or pond.

4. The feeder settles for a sinking pellet to avoid the extrusion process.

Functions and Signs of Deficiency

Vitamin C is an antioxidant. As such, it helps protect lipids in cell membranes from destruction through reaction with oxygen. It also facilitates iron absorption. It is involved in amino acid metabolism, and in the growth and maintenance of bone and collagen. Collagen is a protein that helps reinforce connective tissues throughout the body. Signs of vitamin C deficiency include structural deformities and abnormalities of supportive cartilage. Anemia and small hemorrhages have also been reported, presumably because the body's connective tissue begins to break down. Vitamin C deficiency also results in impaired wound healing, immune response, and reproductive function. In fish, it has been reported that dietary and environmental contaminants such as heavy metals (Yamamoto & Inoue, 1985) and pesticides (Mayer, Mehrle, & Crutcher, 1978) increase vitamin C requirements.

Hypervitaminosis C (ascorbic acid)

Table 10-5 gives the safe upper limits for vitamin C in livestock diets as presented by the NRC (1987).

FACTORS INFLUENCING THE VITAMIN NEEDS OF LIVESTOCK

Factors that may influence the vitamin needs of livestock under commercial production include:

* Environmental stressors leading to animal strain, infectious disease, internal and external parasites, and other conditions that lower feed intake and/or reduce intestinal absorption of vitamins

* Disturbance of intestinal microflora

* Bioavailability and/or stability of various vitamin sources in certain feedstuffs

* Interrelationship of certain vitamins with other nutrients

SUMMARY

Vitamins play essential and varied roles in animal metabolism. Livestock generally have some ability to store the fat-soluble vitamins during periods of excess intake, but the water-soluble vitamins must be ingested at required levels daily. Because vitamins are biologically active compounds, vitamins in mixed feeds will deteriorate over time. Processing of vitamin-supplemented feed may result in the destruction of the vitamins.

END-OF-CHAPTER QUESTIONS

1. Antioxidants help protect lipids in cell membranes and elsewhere in the body from destruction through reaction with oxygen. Name a fat-soluble vitamin that functions as an antioxidant. Name a B vitamin that functions as an antioxidant. Name a third vitamin that functions as an antioxidant.

2. Unlike the case with most other nutrients, it is not routine to quantify the vitamin content in feedstuffs prior to deciding on the level that must be supplemented. Explain why.

3. Fish require vitamin C. Fish feed is always processed into a pelleted form. These two facts present the manufacturer of fish feed with a special challenge. Explain why.

4. What vitamin is destroyed by prolonged contact with a compound in raw fishmeal? What term describes the deficiency of this vitamin seen in ruminants that are fed large amounts of raw fishmeal?

5. What characteristic of choline chloride leads to the destruction of other vitamins with which it might be stored?

6. What domestic animal lacks the ability to convert beta carotene into vitamin A?

7. Name the fat-soluble vitamins. Of what nutritional consequence is the fact that these vitamins are soluble in fat? Name the water-soluble vitamins. Of what nutritional consequence is the fact that these vitamins are soluble in water?

8. Name four species of domestic animals that, after maturity, do not require a dietary source of B vitamins.

9. Name two vitamins for which the safe upper limit is less than 10 times the requirement for at least some livestock species. Name two vitamins for which the safe upper limit is more than 100 times the requirement.

10. Carotenoid compounds are sources of vitamin A for most animals. Can an animal experience vitamin A toxicity (hypervitaminosis A) from the ingestion of an excess of these carotenoid compounds? Explain why or why not.

REFERENCES

Burtle, G. J., & Lovell, R. T. (1989). Lack of response of channel catfish (Ictalurus punctatus) to dietary myoinositol. Canadian Journal of Fisheries and Aquatic Sciences. 46, 218-222.

Coelho, M. (2002). Vitamin stability in premixes and feeds, A practical approach in ruminant diets. In Proceedings 13th annual Florida ruminant nutrition symposium. Retrieved 12/1/2003 from: http://www.animal.ufl.edu/ dairy/2002ruminantconference/coelho.pdf

Erdman, R. A., & Sharma, R. D. (1991). Effect of dietary Rumen-protected choline in lactating dairy cows. Journal of Dairy Science. 74, 1641-1647.

Gerloff, B. J., Herdt, T. H., Emery, R. S., & Wells, W. W. (1984). Inositol as a lipotropic agent in dairy cattle diets. Journal of Animal Science. 59, 806-812.

Grummer, R. R. (1993). Etiology of lipid-related metabolic disorders in periparturient dairy cows. Journal of Dairy Science. 76, 3882-3896.

Grummer, R. R., Armentano, L. E., & Marcus, M. S. (1987). Lactation response to short-term abomasal infusion of choline, inositol and soy lecithin. Journal of Dairy Science. 70, 2518-2524.

Lehninger, A. L. (1978). Biochemistry (2nd ed.). New York: Worth Publishers, Inc.

Mayer, F. L., Mehrle, P. M., & Crutcher, P. L. (1978). Interactions of toxaphene and vitamin C in channel catfish. Transactions of the American Fisheries Society. 107, 326-333.

National Research Council. (1987). Vitamin tolerance in animals. Washington, DC: National Academy Press. National Research Council. (1998). Nutrient requirements of swine (10th revised edition). Washington, DC: National Academy Press.

Overton, T. R. (2001, November 16-17). Managing the metabolism of transition cows. In Proceedings: Transition Cows Conference (pp. 107-116). Canandaigua, NY.

Piepenbrink, M. S., & Overton, T. R. (2003). Liver metabolism and production of cows fed increasing amounts of rumen-protected choline during the periparturient period. Journal of Dairy Science. 86, 1722-1733.

Yamamoto, Y., & Inoue, M. (1985). Effects of dietary ascorbic acid and dehydroascorbic acid on the acute cadmium toxicity in rainbow trout. Bulletin of the Japanese Society of Scientific Fisheries. 51, 1299-1303.
Table 10-1
Usual vitamins supplemented in rations of healthy adult livestock

Species                          Ruminants      Swine       Chickens

Vitamin A                         [check]      [check]      [check]
Vitamin D                         [check]      [check]      [check]
Vitamin E                         [check]      [check]      [check]
Vitamin K                                      [check]      [check]
Thiamin                                        [check]      [check]
Riboflavin                                     [check]      [check]
Pyridoxine                                     [check]      [check]
Pantothenic acid                               [check]      [check]
Niacin                                         [check]      [check]
[B.sub.12]                                     [check]      [check]
Choline                                        [check]      [check]
Biotin                                         [check]      [check]
Folacin (folate or folic acid)                 [check]      [check]
Myoinositol
Vitamin C

Species                             Dogs         Cats        Horses

Vitamin A                         [check]      [check]      [check]
Vitamin D                         [check]      [check]      [check]
Vitamin E                         [check]      [check]      [check]
Vitamin K                         [check]      [check]
Thiamin                           [check]      [check]
Riboflavin                        [check]      [check]
Pyridoxine                        [check]      [check]
Pantothenic acid                  [check]      [check]
Niacin                            [check]      [check]
[B.sub.12]                        [check]      [check]
Choline                           [check]      [check]
Biotin                            [check]      [check]
Folacin (folate or folic acid)    [check]      [check]
Myoinositol                                    [check]
Vitamin C

Species                           Rabbits        Fish

Vitamin A                         [check]      [check]
Vitamin D                         [check]      [check]
Vitamin E                         [check]      [check]
Vitamin K                         [check]      [check]
Thiamin                           [check]      [check]
Riboflavin                        [check]      [check]
Pyridoxine                        [check]      [check]
Pantothenic acid                  [check]      [check]
Niacin                            [check]      [check]
[B.sub.12]                        [check]      [check]
Choline                           [check]      [check]
Biotin                                         [check]
Folacin (folate or folic acid)    [check]      [check]
Myoinositol                                    [check]
Vitamin C                                      [check]

Table 10-2
Vitamin retention percentage under three different conditions

                                                          Expanding/
                                        Pelleting:        Extruding:
                                       178[degrees]-     241[degrees]-
Vitamin                                185[degrees]F     248[degrees]F

A beadlet cross-linked                      95                65
A beadlet non-spray cong.
  non-cross-linked                          78                46
[D.sub.3] beadlet
  (A/[D.sub.3])X-Link                       94                87
[D.sub.3] drum dried                        88                70
E acetate 50%                               94                83
E alcohol                                   60                10
K-Menadione dimethylpyrimidinol
  bisulfite (MPB)                           75                34
K-Menadione sodium bisulfite (MSB)          59                12
Thiamin mononitrate                         88                71
Thiamin HCl                                 84                50
Riboflavin                                  91                91
Pyridoxine                                  90                78
[B.sub.12]                                  97                87
Calcium pantothenate                        91                79
Folic acid                                  90                67
Biotin                                      90                66
Niacin                                      91                68
Choline chloride                            98                95
C-ascorbyl phosphate                        94                84
C-ascorbic acid                             50                10

                                       Storage with      Storage with
                                      Trace Minerals    Trace Minerals
                                       and Vitamins      and Vitamins
                                        (no choline      (incl.choline
                                      chloride) after   chloride) after
Vitamin                                  3 Months          3 Months

A beadlet cross-linked                      90                84
A beadlet non-spray cong.
  non-cross-linked                          80                50
[D.sub.3] beadlet
  (A/[D.sub.3])X-Link                       93                86
[D.sub.3] drum dried                        84                75
E acetate 50%                               93                88
E alcohol                                   14                 7
K-Menadione dimethylpyrimidinol
  bisulfite (MPB)                           79                62
K-Menadione sodium bisulfite (MSB)          73                34
Thiamin mononitrate                         90                70
Thiamin HCl                                 72                57
Riboflavin                                  92                85
Pyridoxine                                  91                83
[B.sub.12]                                  98                95
Calcium pantothenate                        96                79
Folic acid                                  90                77
Biotin                                      92                83
Niacin                                      90                85
Choline chloride                            --                97
C-ascorbyl phosphate                        90                86
C-ascorbic acid                             59                58

From Coelho, 2002.

Table 10-3
Vitamin A requirement for
selected livestock

                                                Required     Required
                                                  (IU)       (IU/lb.)

Fish, channel catfish, 100-g body weight            6.667      1,008
Fish, rainbow trout, 100-g body weight              3.500      1,260
Chicken, broiler, 5 wks of age                    452.00       1,667
Chicken, white egg layer, 3-lb. body weight       300.02       1,512
Pig, growing, 45-lb. body weight                1,732            655
Dog, growing, 30-lb. body weight                1,308          1,683
Cat, growing kitten, 4.2-lb. body weight          754          4,082
Rabbit, growing, 5 wks of age                     937          3,183
Horse, light work, 1,100-lb. body weight       29,409          1,008
Goat, maintenance, 88-lb. body weight           1,175            742
Ewe, maintenance, 110-lb. body weight           2,736          1,244
Beef animal, growing, 800-lb. body weight      19,267            998
Dairy cow, lactating, 1,400-lb. body weight    69,854          1,276

Table 10-4
Conversion efficiencies from
beta carotene to International
Units of vitamin A

Species      Number of IU converted from 1 mg Beta Carotene

Poultry      1667
Swine        267
Ruminants    400
Horses       400
Rabbits      400 (Not confirmed in controlled studies)
Dogs         Capable of conversion but efficiency unknown
Cats         Lack the ability to convert beta carotene to vitamin A
Fish         Capable of conversion but efficiency unknown

Table 10-5

Safe upper limits of vitamins in livestock rations
for long term feeding (1)

                      Fish      Chickens   Swine     Dogs

Vitamin A             4X        4X         4X        4X
Vitamin D             20X       4X         4X        4X
  ([D.sub.3]
  for fish
  & chickens,
  [D.sub.2] for
  others)
Vitamin E             20X       20X        20X       20X
Vitamin K             1000X     1000X      1000X     1000X
Vitamin C             1.11%     --         --        --
                        DM
                        basis
Thiamin ([B.sub.1])   1000X     1000X      1000X     1000X
Niacin                350       350        350       350
                        mg/kg     mg/kg      mg/kg     mg/kg
                        BW        BW         BW        BW
Riboflavin            20X       20X        20X       20X
  ([B.sub.2])
Pyridoxine            50X       50X        50X       50X
  ([B.sub.6])
Folacin               1000X     1000X      1000X     1000X
Pantothenic           100X      100X       100X      100X
  acid
Biotin                10X       10X        10X       10X
Vitamin [B.sub.12]    300X      300X       300X      300X
Choline               10X       2X         10X       3X
Myoinositol           None      --         --        --

                      Cats      Rabbits    Beef      Horses

Vitamin A             4X        4X         4X        30X
Vitamin D             4X        4X         4X        4X
  ([D.sub.3]
  for fish
  & chickens,
  [D.sub.2] for
  others)
Vitamin E             20X       20X        20X       20X
Vitamin K             1000X     1000X      --        --
Vitamin C             --        --         --        --

Thiamin ([B.sub.1])   1000X     1000X      --        --
Niacin                350       350        --        --
                        mg/kg     mg/kg
                        BW        BW
Riboflavin            20X       20X        --        --
  ([B.sub.2])
Pyridoxine            50X       50X        --        --
  ([B.sub.6])
Folacin               1000X     1000X      --        --
Pantothenic           100X      100X       --        --
  acid
Biotin                10X       --         --        --
Vitamin [B.sub.12]    300X      300X       --        --
Choline               10X       10X        --        --
Myoinositol           None      --         --        --

                                           Beef      Dairy
                      Goats     Sheep      Animals   Cows

Vitamin A             30X       30X        30X       30X
Vitamin D             4X        4X         4X        4X
  ([D.sub.3]
  for fish
  & chickens,
  [D.sub.2] for
  others)
Vitamin E             20X       20X        20X       20X
Vitamin K             --        --         --        --
Vitamin C             --        --         --        --

Thiamin ([B.sub.1])   --        --         --        --
Niacin                --        --         --        --

Riboflavin            --        --         --        --
  ([B.sub.2])
Pyridoxine            --        --         --        --
  ([B.sub.6])
Folacin               --        --         --        --
Pantothenic           --        --         --        --
  acid
Biotin                --        --         --        --
Vitamin [B.sub.12]    --        --         --        --
Choline               --        --         --        --
Myoinositol           --        --         --        --

(1) Unless given otherwise, the safe upper limit is expressed as a
multiple (X) of the requirement. Entries of "--" indicate that the
vitamin is not supplemented in usual rations. Entries of "None"
indicate that the vitamin is supplemented but toxicity has not been
studied. Save upper limits for all except choline in fish, swine,
cat and rabbit rations are taken from National Research Council,
1987. The safe upper limit for choline in fish, swine, cat and
rabbit rations was estimated by the author.

Table 10-6
Vitamin D requirement for
selected livestock

                                                Required     Required
                                                  (IU)       (IU/lb.)

Fish, channel catfish, 100-g body weight            1.667         252
  (vit [D.sub.3])
Fish, rainbow trout, 100-g body weight              3.36        1,210
  (vit [D.sub.3])
Chicken, broiler, 5 wks of age                     60.27          222
  (vit [D.sub.3])
Chicken, white egg layer, 3-lb.body weight         29.98          151
  (vit [D.sub.3])
Pig, growing, 45-lb. body weight                  200              76
Dog, growing, 30-lb. body weight                  142             183
Cat, growing kitten, 4.2-lb. body weight           62.8           340
Rabbit, growing, 5 wks of age                     140             477
Horse, light work, 1,100-lb. body weight        4,407             151
Goat, maintenance, 88-lb. body weight             241             152
Ewe, maintenance, 110-lb. body weight             277             126
Beef animal, growing, 800-lb. body weight       2,409             125
Dairy cow, lactating, 1,400-lb. body weight    19,051             348

Table 10-7
Vitamin E requirement for selected livestock

                                                Required     Required
                                                  (IU)       (IU/lb.)

Fish, channel catfish, 100-g body weight           0.1667     25.2
Fish, rainbow trout, 100-g body weight             0.07       25.2
Chicken, broiler, 5 wks of age                     3.0133     11.11
Chicken, white egg layer, 3-lb. body weight        0.5004      2.52
Pig, growing, 45-lb. body weight                  14.7         5.5
Dog, growing, 30-lb. body weight                   7.89       10.16
Cat, growing kitten, 4.2-lb. body weight           2.51       13.6
Rabbit, growing, 5 wks of age                      7.82       26.55
Horse, light work, 1,100-lb. body weight       1,178          40
Goat, maintenance, 88-lb. body weight             10.8         6.8
Ewe, maintenance, 110-lb. body weight             15.0         6.8
Beef animal, growing, 800-lb. body weight        438          22.7
Dairy cow, lactating, 1,400-lb. body weight      508           9.3

Table 10-8
Vitamin K requirement for
selected livestock (1)

                                                Required     Required
                                                  (mg)       (mg/kg)

Fish, channel catfish, 100-g body weight        unknown      unknown
Fish, rainbow trout, 100-g body weight          unknown      unknown
Chicken, broiler, 5 wks of age                     0.0683       0.56
Chicken, white egg layer, 3-lb. body weight        0.0500       0.56
Pig, growing, 45-lb. body weight                   0.67         0.56
Dog, growing, 30-lb. body weight                unknown      unknown
Cat, growing kitten, 4.2-lb. body weight           0.01         0.10
Rabbit, growing, 5 wks of age                      0.3122       2.34
Horse, light work, 1,100-lb. body weight           0            0
Goat, maintenance, 88-lb. body weight              0            0
Ewe, maintenance, 110-lb. body weight              0            0
Beef animal, growing, 800-lb. body weight          0            0
Dairy cow, lactating, 1,400-lb. body weight        0            0

(1) Animals with a requirement of 0 do not require a dietary source
of vitamin K because microbial synthesis of vitamin K in the digestive
tract is adequate to meet the requirement. This assumes the animal is
healthy.

Table 10-9
Thiamin requirement for
selected livestock (1)

                                               Required     Required
                                                 (mg)       (mg/kg)

Fish, channel catfish, 100-g body weight          0.0033       1.11
Fish, rainbow trout, 100-g body weight            0.0014       1.11
Chicken, broiler, 5 wks of age                    0.2460       2.00
Chicken, white egg layer, 3-lb. body weight       0.0700       0.78
Pig, growing, 45-lb. body weight                  1.33         1.11
Dog, growing, 30-lb. body weight                  0.35         0.99
Cat, growing kitten, 4.2-lb. body weight          0.42         5.00
Rabbit, growing, 5 wks of age                     0.3122       2.34
Horse, light work, 1,100-lb. body weight          0            0
Goat, maintenance, 88-lb. body weight             0            0
Ewe, maintenance, 110-lb. body weight             0            0
Beef animal, growing, 800-lb. body weight         0            0
Dairy cow, lactating, 1,400-lb. body weight       0            0

(1) Animals with a requirement of 0 do not require a dietary source
of thiamin because microbial synthesis of thiamin in the digestive
tract is adequate to meet the requirement. This assumes the animal
is healthy.

Table 10-10
Riboflavin requirements for
selected livestock (1)
                                               Required    Required
                                                 (mg)      (mg/kg)

Fish, channel catfish, 100-g body weight        0.0300      10.00
Fish, rainbow trout, 100-g body weight          0.0056       4.44
Chicken, broiler, 5 wks of age                  0.4921       4.00
Chicken, white egg layer, 3-lb. body weight     0.2500       2.78
Pig, growing, 45-lb. body weight                3.33         2.78
Dog, growing, 30-lb. body weight                0.88         2.50
Cat, growing kitten, 4.2-lb. body weight        0.34         4.00
Rabbit, growing, 5 wks of age                   0.938        7.02
Horse, light work, 1,100-lb. body weight        0            0
Goat, maintenance, 88-lb. body weight           0            0
Ewe, maintenance, 110-lb. body weight           0            0
Beef animal, growing, 800-lb. body weight       0            0
Dairy cow, lactating, 1,400-lb. body weight     0            0

(1) Animals with a requirement of 0 do not require a dietary source
of riboflavin because microbial synthesis of riboflavin in the
digestive tract is adequate to meet the requirement. This assumes the
animal is healthy.

Table 10-11
Pyridoxine requirements for
selected livestock (1)

                                              Required   Required
                                                (mg)     (mg/kg)

Fish, channel catfish, 100-g body weight       0.0100      3.33
Fish, rainbow trout, 100-g body weight         0.0042      3.33
Chicken, broiler, 5 wks of age                 0.4784      3.89
Chicken, white egg layer, 3-lb. body weight    0.2500      2.78
Pig, growing, 45-lb. body weight               1.33        1.11
Dog, growing, 30-lb. body weight               0.39        1.10
Cat, growing kitten, 4.2-lb. body weight       0.34        4.00
Rabbit, growing, 5 wks of age                  6.249      46.78
Horse, light work, 1,100-lb. body weight       0           0
Goat, maintenance, 88-lb. body weight          0           0
Ewe, maintenance, 110-lb. body weight          0           0
Beef animal, growing, 800-lb. body weight      0           0
Dairy cow, lactating, 1,400-lb. body weight    0           0

(1) Animals with a requirement of 0 do not require a dietary source
of pyridoxine because microbial synthesis of pyridoxine in the
digestive tract is adequate to meet the requirement. This assumes
the animal is healthy.

Table 10-12
Cyanocobalamin (vitamin
[B.sub.12]) requirements for selected
livestock (1)

                                                            Required
                                               Required    ([micro]g/
                                              ([micro]g)      kg)

Fish, channel catfish, 100-g body weight       Unknown      Unknown
Fish, rainbow trout, 100-g body weight           0.014        11.11
Chicken, broiler, 5 wks of age                   1.3668       11.11
Chicken, white egg layer, 3-lb. body weight      0.4000        4.44
Pig, growing, 45-lb. body weight                13.32         11.11
Dog, growing, 30-lb. body weight                 9.1          26
Cat, growing kitten, 4.2-lb. body weight         1.68          0.02
Rabbit, growing, 5 wks of age                    0             0
Horse, light work, 1,100-lb. body weight         0             0
Goat, maintenance, 88-lb. body weight            0             0
Ewe, maintenance, 110-lb. body weight            0             0
Beef animal, growing, 800-lb. body weight        0             0
Dairy cow, lactating, 1,400-lb. body weight      0             0

(1) Animals with a requirement of 0 do not require a dietary source
of vitamin [B.sub.12] because microbial synthesis of vitamin
[B.sub.12] in the digestive tract is adequate to meet the requirement.
This assumes the animal is healthy and that the diet contains adequate
cobalt which microbes use to make vitamin [B.sub.12].

Table 10-13
Pantothenic acid (pan. acid)
requirements for selected
livestock (1)

                                              Required   Required
                                                (mg)     (mg/kg)

Fish, channel catfish, 100-g body weight       0.0500     16.67
Fish, rainbow trout, 100-g body weight         0.028      22.22
Chicken, broiler, 5 wks of age                 1.3668     11.11
Chicken, white egg layer, 3-lb. body weight    0.2000      2.22
Pig, growing, 45-lb. body weight              10.66        8.89
Dog, growing, 30-lb. body weight               3.49        9.91
Cat, growing kitten, 4.2-lb. body weight       0.42        5
Rabbit, growing, 5 wks of age                  3.124      23.39
Horse, light work, 1,100-lb. body weight       0           0
Goat, maintenance, 88-lb. body weight          0           0
Ewe, maintenance, 110-lb. body weight          0           0
Beef animal, growing, 800-lb. body weight      0           0
Dairy cow, lactating, 1,400-lb. body weight    0           0

(1) Animals with a requirement of 0 do not require a dietary source
of pantothenic acid because microbial synthesis of pantothenic acid
in the digestive tract is adequate to meet the requirement. This
assumes the animal is healthy.

Table 10-14
Niacin requirements for
selected livestock. Values for
fish, dogs and swine
represent bioavailable niacin.
Values for other species are
requirements based on total
dietary niacin. (1)

                                              Required   Required
                                                (mg)     (mg/kg)

Fish, channel catfish, 100-g body weight        0.0467     15.56
Fish, rainbow trout, 100-g body weight          0.014      11.11
Chicken, broiler, 5 wks of age                  4.1005     33.33
Chicken, white egg layer, 3-lb. body weight     0.9999     11.11
Pig, growing, 45-lb. body weight               13.32       11.11
Dog, growing, 30-lb. body weight                3.88       11.01
Cat, growing kitten, 4.2-lb. body weight        5.03       60.00
Rabbit, growing, 5 wks of age                  28.12      210.5
Horse, light work, 1,100-lb. body weight        0           0
Goat, maintenance, 88-lb. body weight           0           0
Ewe, maintenance, 110-lb. body weight           0           0
Beef animal, growing, 800-lb. body weight       0           0
Dairy cow, lactating, 1,400-lb. body weight     0           0

(1) Animals with a requirement of 0 do not require a dietary
source of niacin because microbial synthesis of niacin in the
digestive tract is adequate to meet the requirement. This assumes
the animal is healthy.

Table 10-15
Folacin (folate or folic acid)
requirements for selected
livestock (1)

                                               Required   Required
                                                 (mg)     (mg/kg)

Fish, channel catfish, 100-g body weight        0.0050     1.67
Fish, rainbow trout, 100-g body weight          0.0014     1.11
Chicken, broiler, 5 wks of age                  0.0752     0.61
Chickens, white egg layer, 3-lb. body weight    0.0250     0.28
Pig, growing, 45-lb. body weight                0.40       0.33
Dog, growing, 30-lb. body weight                0.07       0.20
Cat, growing kitten, 4.2-lb. body weight        0.07       0.80
Rabbit, growing, 5 wks of age                   0.1561     1.17
Horse, light work, 1,100-lb. body weight        0          0
Goat, maintenance, 88-lb. body weight           0          0
Ewe, maintenance, 110-lb. body weight           0          0
Beef animal, growing, 800-lb. body weight       0          0
Dairy cow, lactating, 1,400-lb. body weight     0          0

(1) Animals with a requirement of 0 do not require a dietary source
of folacin because microbial synthesis of folacin in the digestive
tract is adequate to meet the requirement. This assumes the animal
is healthy.

Table 10-16
Biotin requirements for
selected livestock (1)

                                               Required    Required
                                                 (mg)      (mg/kg)

Fish, channel catfish, 100-g body weight       Unknown      Unknown
Fish, rainbow trout, 100-g body weight         0.00021      0.167
Chicken, broiler, 5 wks of age                 0.0205       0.17
Chicken, white egg layer, 3-lb. body weight    0.0100       0.11
Pig, growing, 45-lb. body weight               0.07         0.06
Dog, growing, 30-lb. body weight               Unknown      Unknown
Cat, growing kitten, 4.2-lb. body weight       0.01         0.07
Rabbit, growing, 5 wks of age                  0            0
Horse, light work, 1,100-lb. body weight       0            0
Goat, maintenance, 88-lb. body weight          0            0
Ewe, maintenance, 110-lb. body weight          0            0
Beef animal, growing, 800-lb. body weight      0            0
Dairy cow, lactating, 1,400-lb. body weight    0            0

(1) Animals with a requirement of 0 do not require a dietary source
of biotin because microbial synthesis of biotin in the digestive
tract is adequate to meet the requirement. This assumes the animal
is healthy.

Table 10-17
Choline requirements for
selected livestock (1)

                                              Required   Required
                                                (mg)     (mg/kg)

Fish, channel catfish, 100-g body weight          1.332     444
Fish, rainbow trout, 100-g body weight            1.4     1,111
Chicken, broiler, 5 wks of age                  136.68    1,111
Chicken, white egg layer, 3-lb. body weight     104.99    1,167
Pig, growing, 45-lb. body weight                400         333
Dog, growing, 30-lb. body weight                440       1,248
Cat, growing kitten, 4.2-lb. body weight        201       2,400
Rabbit, growing, 5 wks of age                   187       1,403
Horse, light work, 1,100-lb. body weight          0           0
Goat, maintenance, 88-lb. body weight             0           0
Ewe, maintenance, 110-lb. body weight             0           0
Beef animal, growing, 800-lb. body weight         0           0
Dairy cow, lactating, 1,400-lb. body weight       0           0

(1) Animals with a requirement of 0 do not require a dietary source
of choline because microbial synthesis of choline in the digestive
tract is adequate to meet the requirement. This assumes the animal
is healthy.

Table 10-18
Vitamin C (ascorbic acid)
requirements for selected
livestock (1)
                                              Required   Required
                                              (mg)       (mg/kg)

Fish, channel catfish, 100-g body weight      0.167      55.6
Fish, rainbow trout, 100-g body weight        0.07       55.6
Chicken, broiler, 5 wks of age                0          0
Chicken, white egg layer, 3-lb. body weight   0          0
Pig, growing, 45-lb. body weight              0          0
Dog, growing, 30-lb. body weight              0          0
Cat, growing kitten, 4.2-lb. body weight      0          0
Rabbit, growing, 5 wks of age                 0          0
Horse, light work, 1,100-lb. body weight      0          0
Goat, maintenance, 88-lb. body weight         0          0
Ewe, maintenance, 110-lb. body weight         0          0
Beef animal, growing, 800-lb. body weight     0          0
Dairy cow, lactating, 1,400-lb. body weight   0          0

(1) Animals with a requirement of 0 do not require a dietary source
of vitamin C because synthesis of vitamin C in animal tissues is
adequate to meet the requirement. This assumes the animal is healthy.
COPYRIGHT 2006 Delmar Learning
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2006 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:Tisch, David A.
Publication:Animal Feeds, Feeding and Nutrition, and Ration Evaluation
Geographic Code:1USA
Date:Jan 1, 2006
Words:8808
Previous Article:Chapter 9 Minerals.
Next Article:Chapter 11 Water.
Topics:

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters