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

Table 3

Summary of -carotene metabolism in animal species.

Species	Absorption of intact BC into blood	Accumulation of BC in tissues	Conversion to retinol	References
Herbivorous mammals
Cows	Yes	Yes, but varies with breed	Yes	[9, 80, 83, 128, 129, 137, 140, 142–146, 223, 224]
Sheep and goats	Yes, but only with high dose	No	Yes	[123, 128, 137, 147, 148]
Other Artiodactyla	No	No (shown in white-tailed deer)	Assumed	[146, 147]
Rabbits	n/a	No	Yes	[130, 147]
Horses	Yes	Yes	Yes	[99, 147, 149–151]
Omnivorous mammals
Rat	No	No	Yes	[50, 120, 135, 145, 152, 154, 156, 157, 225]
Mongolian gerbil	Yes	Yes	Yes	[134, 158, 159]
Humans	Yes	Yes	Yes	[51, 74, 77–79, 147, 161, 162, 164–166, 168, 226, 227]
Nonhuman primates	Yes	Yes	Yes	[118, 152, 163, 167, 168]
Pigs	Yes, but only with high dose	Yes, but only with high doses	Yes	[124, 125, 147, 155, 169–172]
Carnivorous mammals
Ferrets	Yes	Yes	Yes (but inefficient)	[82, 92, 118, 178, 182–184]
Canids	Yes, but only with high dose	No	Yes	[147, 173–176, 180]
Felids	Yes, but only with high dose. Wild felids may absorb BC more efficiently than domestic cats	No	Yes (but inefficient)	[18, 27, 47, 130, 177, 185–187]
Birds	No, xanthophylls absorbed preferentially	No	Yes (shown in chickens, cockatiels, canaries, quail, and ducks	[157, 188, 194–200]
Fish	No, xanthophylls absorbed preferentially	No	Yes	[201, 203, 206–209]