Selenium, vitamin E, and trace elements in the plasma of wild and farm-reared alligators during the reproductive cycle

Abstract

Eggs produced by farm-reared alligators have lower fertility and hatchability than eggs collected from wild alligators and incubated under identical conditions. To assess the effect of diet on trace elements essential for reproduction, plasma samples from farm-reared alligators fed fish (Micropogon undulatus) or nutria (Myocastor coypus) meat, and from wild alligators caught during the reproductive cycle (April–July) were assayed for vitamin E, selenium, calcium, magnesium, zinc, copper, iron, total protein, cholesterol, and estradiol-17β. Calcium, magnesium, zinc, iron, total protein, cholesterol, vitamin E, and estradiol-17β all showed significant increases in females during vitellogenesis (April–May), and all returned to levels not significantly different from males by July. There were no significant differences between the captive alligators fed fish or nutria, or between either group and wild alligators for any of these plasma constituents. Selenium and copper did not increase during egg production and were similar in males and females. There were significant differences due to diet in plasma selenium and vitamin E in female alligators. Fish-fed alligators had significantly higher plasma selenium and significantly lower vitamin E levels than nutria-fed and wild females which were not significantly different from one another.