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Aquaculture: Vitamin A
Requirements

Table 1 lists vitamin A requirements for various species.

Most forms of vitamin A are crystallizable but have low melting points (e.g., retinol, 62° to 64°C; retinal, 65°C). Vitamin A and the provitamin A carotenoids are very sensitive to oxygen, especially in the presence of light and heat. They are normally used as the acetate, palmitate or propionate ester, in powdered or stabilized beadlet form.

Although vitamin A is insoluble in water and stable within dry multivitamin premixes, it is readily oxidized at elevated storage temperatures and in the presence of oxidation products (rancid oils). Vitamin A status affects provitamin A conversion (Dupree, 1970; Schiedt et al., 1985; Al-Khalifa and Simpson, 1988). Rich sources of vitamin A1 (retinol) include marine fish oils (100 to 10,000 IU/g) and animal liver meals (25 to 100 IU/g). Fish meal and diets containing high levels of fish oil may contain substantial amounts of vitamin A.

 
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