Bumble foot, an inflammatory pododermatitis, is frequently developed in rearing and exhibiting penguins. Inflammatory dermatitis due to hyperkeratosis is induced by deficiency and excess of vitamin A, and there have been some reports indicating the improvement of inflammatory pododermatitis by supplementation with vitamin E and/or zinc in other bird species. For clarifying the relationship between the incidences of bumble foot and vitamin A, vitamin E or zinc nutrition in African penguins (Spheniscus demersus), we investigated dietary and plasma vitamin A, vitamin E and zinc concentrations in penguins with and without bumble foot. The diet contained 27-fold more vitamin A than its estimated requirement (ER). Dietary vitamin E concentration was less than ER in almost all of penguins. Dietary zinc concentration was close to and satisfied ER. Plasma retinol and zinc concentrations were lower in the penguins with bumble foot than in the healthy penguins. On the other hand, the incidence of bumble foot did not affect plasma concentrations of retinyl ester and α-tocopherol.
Because of high vitamin A concentration in diet, the low plasma retinol concentration is not owing to vitamin A deficiency in the penguins with bumble foot and is assumed to result from the suppressed production of retinol binding protein 4 by inflammatory response. Plasma α-tocopherol concentration was not lower than its reported levels, suggesting that dietary vitamin E satisfied its requirement. The incidence of bumble foot may be related to the shortage of zinc. Further experiment is necessary for clarifying the effect of zinc supplementation on the prevention and improvement of bumble foot in penguins.
