The Biological Activity of β-Carotene in Poultry and Rats

Marusich, W. L.; Bauernfeind, J. C.

doi:10.3382/ps.0420949

Cited by 7 publications

(2 citation statements)

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“…The conversion ratio in rats has been estimated to be 2 μ g BC = 1 RE [135, 156], though Marusich and Bauernfeind measured a conversion ratio of 6–10 μ g BC (water-soluble beadlet form) = 1 RE based on hepatic VA stores using a functional bioassay model; the higher end of the conversion ratio was for higher levels of BC supplementation [157]. Brubacher and Weiser noted that the conversion ratio may only be as low as 2 μ g BC = 1 RE when rats are fed just enough BC to meet their requirement (<0.3 μ g/kg BW) [135].…”

Section: Species Differences In β-Carotene Metabolismmentioning

confidence: 99%

“…Birds do utilize BC as an important source of VA. Several functional bioassays in chickens have demonstrated that BC can replace preformed VA in the diets of chickens [157, 188, 194], and the NRC settled on a conversion ratio of 2 μ g BC = 1 RE [195], implying that chickens, along with rats, are among the most efficient animals at converting BC to VA; BC cleavage activity has also been measured ex vivo in the intestinal mucosa of chickens [196, 197]. The utilization of BC to meet the VA requirement has also been shown in cockatiels [198], canaries [199], bobwhite quail, and ducks [200].…”

Section: Species Differences In β-Carotene Metabolismmentioning

confidence: 99%

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Meeting the Vitamin A Requirement: The Efficacy and Importance ofβ-Carotene in Animal Species

Green

Fascetti

2016

The Scientific World Journal

106

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Vitamin A is essential for life in all vertebrate animals. Vitamin A requirement can be met from dietary preformed vitamin A or provitamin A carotenoids, the most important of which is β-carotene. The metabolism of β-carotene, including its intestinal absorption, accumulation in tissues, and conversion to vitamin A, varies widely across animal species and determines the role that β-carotene plays in meeting vitamin A requirement. This review begins with a brief discussion of vitamin A, with an emphasis on species differences in metabolism. A more detailed discussion of β-carotene follows, with a focus on factors impacting bioavailability and its conversion to vitamin A. Finally, the literature on how animals utilize β-carotene is reviewed individually for several species and classes of animals. We conclude that β-carotene conversion to vitamin A is variable and dependent on a number of factors, which are important to consider in the formulation and assessment of diets. Omnivores and herbivores are more efficient at converting β-carotene to vitamin A than carnivores. Absorption and accumulation of β-carotene in tissues vary with species and are poorly understood. More comparative and mechanistic studies are required in this area to improve the understanding of β-carotene metabolism.

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Section: Species Differences In β-Carotene Metabolismmentioning

confidence: 99%

Section: Species Differences In β-Carotene Metabolismmentioning

confidence: 99%

Meeting the Vitamin A Requirement: The Efficacy and Importance ofβ-Carotene in Animal Species

Green

Fascetti

2016

The Scientific World Journal

106

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Utilisation, by chicks, of carotene from fresh and dried plant sources

1969

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Some factors (autoclaving, addition of ethoxyquin, drying, degree of grinding) influencing utilisation of carotene from plant origin were investigated. Low storage of vitamin A in liver and low excretion of carotene in faeces, when fresh lucerne was given, indicated that carotene‐destroying enzymes of plant origin are likely to act before the lucerne is eaten and while it is passing through the intestines. Addition of ethoxyquin to autoclaved lucerne improved the utilisation of carotene. This indicates nonenzymic oxidation of carotene in the digestive tract. Carotene was more effectively utilised from lucerne meal than when given as green lucerne even if autoclaved and with ethoxyquin added. It seems that the influence of non‐enzymic factors on the availability of carotene from various dried plants is small and uniform, because carotene was utilised equally from these sources. The particle size (degree of grinding) had no significant influence on the utilisation of carotene from lucerne meal and it seemed that coarser meals could be used without hindering the utilisation of carotene or other carotenoids by chicks.

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