PLASMA CONCENTRATIONS OF VITAMIN A, B, D, AND E IN HUMBOLDT PENGUINS ( SPHENISCUS HUMBOLDTI) BEFORE AND AFTER DIETARY VITAMIN SUPPLEMENTATION OF THEIR FISH DIET.

In a practical feeding trial at Ouwehand Zoo, plasma concentrations of vitamin A, calcidiol (D), α-tocopherol (E), and B in 17 Humboldt penguins ( Spheniscus humboldti) were measured before and after supplementation to gain insight into the effect of supplementing these vitamins in animals being fed thawed frozen-fish diets. None of the penguins received vitamin supplements for at least 6 mo before the supplementation trial, which was conducted prior to their normal nesting and molting period. During the trial period, eight penguins received daily vitamin A, D, tocopheryl acetate, and B supplementation placed in their fish immediately prior to feeding and nine control penguins received no supplementation. Concentrations of vitamins A, D, α-tocopherol, and B were also measured in the thawed ready-to-feed fish. Concentrations of vitamins B and α-tocopherol were below the Association of Zoos and Aquariums (AZA) recommendations for penguin diets, while concentrations of vitamins A and D were far above AZA recommendations. At the start of the study and after 70 days of supplementation, plasma concentrations were determined for these vitamins. Vitamin B concentrations in plasma increased significantly ( P < 0.05) between Day 0 (mean 39.9 μg/L) and day 70 (mean 160.5 μg/L) in the supplemented group. Plasma vitamin D and α-tocopherol did not show a significant change. Vitamin A levels in the supplemented group decreased significantly from 1.65 mg/L on day 0 to 1.4 mg/L on day 70. In the control group no significant changes were observed. The results of the study support the necessity of supplementing vitamin B in penguins fed thawed frozen fish. Depletion of vitamin A and E concentrations in frozen food fish over time support recommendations to regularly measure vitamin concentrations in different batches of frozen fish.