Selenium Accumulation and Effects on Reproduction in Captive American Kestrels Fed Selenomethionine

Abstract

Reproductive effects of selenium have been well demonstrated in aquatic bird species, both experimentally and in the field. However, potential selenium effects in other birds, in particular wild terrestrial species, have not been well characterized. We studied reproductive effects of selenium in American kestrels (Falco sparverius) fed diets containing 6 or 12 ppm selenium (dry mass) as selenomethionine for 11 weel Near-maximal mean selenium concentrations in blood were observed by Day 35 of treatment in selenomethionine-treated kestrels. An approximately 1:1 ratio was observed between maximal blood concentrations and dietary concentrations, and an accumulation factor for selenium of approximately 2.2 was observed from diet to egg. Fertility was reduced in the 12-ppm selenium group, but treatment groups were not different in egg production. hatchability. or incidence of embryonic malformations. Overt selenium toxicity was not observed in adult kestrels. These findings suggest kestrels may be less sensitive to selenium effects than mallards (Anas platyrhynchos) and other previously studied aquatic birds, but that chronic exposure to dietary concentrations found at selenium-contaminated sites may be associated with reproductive effects.