Vitamin Requirements and Allowances for Poultry

Whitehead, C. C.

doi:10.1016/b978-0-408-04149-2.50008-8

Cited by 14 publications

(10 citation statements)

References 99 publications

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“…However the dietary bioavailability of choline is considered 'moderate' (Whitehead & Portsmouth, 1989;Baker, 1995). Nutrient bioavailability to livestock depends mainly on two factors: (1) stability in premixes, diets and supplements; (2) utilisation efficiency (Baker, 1995).…”

Section: Choline Sources and Bioavailabilitymentioning

confidence: 99%

“…From the point of view of animal nutrition, relatively rich sources of choline are soyabean, soyabean meal, rapeseed meal, fishmeal and dried yeast (Whitehead & Portsmouth, 1989;Baker, 1995). However the dietary bioavailability of choline is considered 'moderate' (Whitehead & Portsmouth, 1989;Baker, 1995).…”

Section: Choline Sources and Bioavailabilitymentioning

confidence: 99%

“…Choline has been classified as one of the B-complex vitamins but it does not satisfy the standard definition of a vitamin (McDowell, 1989): it is synthesised endogenously and there is no evidence that it is an enzyme cofactor; furthermore, unlike other water-soluble vitamins, it is difficult to identify a deficiency syndrome for choline in healthy mammals because of its interrelation with methionine (Met), folic acid, and vitamin B 12 (Zeisel, 1988;Scott, 1999). However choline is a vital component of tissues and is required in the diet of non-ruminant species at much higher levels than the water-soluble vitamins (g v. mg) (Whitehead & Portsmouth, 1989). The presence of an endogenous synthetic pathway does not render choline dispensable and deficiency results in several dysfunctions when other nutrients are limiting (Zeisel et al 1991).…”

Section: Introductionmentioning

confidence: 99%

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Comparative mammalian choline metabolism with emphasis on the high-yielding dairy cow

2002

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The present review examines the importance of choline in dairy cow nutrition. Choline is an essential nutrient for mammals when excess methionine and folate are not available in the diet. The requirement for choline can be met by dietary choline and by transmethylation reactions. Two types of functions for choline are known: functions of choline per se; functions as a methyl donor. The two principal methyl donors in animal metabolism are betaine, a metabolite of choline, and S-adenosyl-methionine, a metabolite of methionine. Choline and methionine are interchangeable with regard to their methyl group-furnishing functions. In adult ruminants, choline is extensively degraded in the rumen; for this reason dietary choline contributes insignificantly to the choline body pool and methyl group metabolism is generally conservative with a relatively low rate of methyl catabolism and an elevated rate of de novo synthesis of methyl groups via the tetrahydrofolate system. In dairy ruminants, the dietary availability of choline is still low, but the output of methylated compounds in milk is high, and precursors from the tetrahydrofolate pathway are limiting, especially at the onset of lactation. Therefore choline may be a limiting nutrient for milk production in high-yielding dairy cows.

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Section: Choline Sources and Bioavailabilitymentioning

confidence: 99%

Section: Choline Sources and Bioavailabilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comparative mammalian choline metabolism with emphasis on the high-yielding dairy cow

2002

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“…Finally, choline is a vital component of tissues and is required in the diet of non-ruminant species at much higher levels than the water-soluble vitamins (g vs. mg) (Whitehead & Portsmouth, 1989). However, the presence of an endogenous synthetic pathway does not render choline dispensable and deficiency results in several dysfunctions when other nutrients are limiting (Zeisel et al, 1991).…”

Section: Vitamin or Not?mentioning

confidence: 99%

“…From the point of view of animal nutrition, relatively rich sources of choline are soybean, soybean meal, rapeseed meal, fish meal and dried yeast, even though its bioavailability is considered "moderate" (Pinotti et al, 2002;Whitehead & Portsmouth, 1989). Dietary choline from a variety of choline-containing feed and food is absorbed by the intestine and uptake is mediated by choline transporters nutrient (McDowell, 1989).…”

Section: How Requirement For Choline Can Be Metmentioning

confidence: 99%