Vitamin A nutrition of growing cockatiel chicks (Nymphicus hollandicus)

Clinical Management of Avian Renal Disease

Treatment of avian renal disease relies on supportive care, such as fluid therapy and nutritional support. Analgesia and adaptations of the environment are indicated in cases of renal disease associated with painful joints. Other treatments vary with the underlying etiology and may include systemic antibiotics, antifungal therapy, vitamin A supplementation, or chelation therapy.

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

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.