Body Condition Effects in American Kestrels Fed Selenomethionine

Abstract

Body composition was measured in male American kestrels (Falco sparverius) beginning after a 77-day exposure to 0, 6, or 12 ppm (dry wt.) selenium as seleno-L-methionine in their diet. Total body mass, lean body mass, and body fat were compared among groups to identify potential wasting effects of selenium, as had been reported for wild waterfowl from a seleniumcontaminated site. On the last day of selenium treatment, selenium concentrations in the blood of kestrels was significantly negatively correlated with lean mass. Kestrels that had been exposed to 12 ppm selenium in the diet exhibited relatively higher lean mass (relative to total body mass) and lower normalized body fat than kestrels fed 0 or 6 ppm dietary selenium. These differences persisted throughout the 6 mo study period. The effect observed on body condition of kestrels at environmentally relevant exposure levels has implications for wild birds with respect to both overwinter survival and reproductive success.

Mercury in birds of San Francisco Bay-Delta, California: trophic pathways, bioaccumulation, and ecotoxicological risk to avian reproduction

“…For selenium, >50 percent of all scoters exceeded the 33 µg/g dw physiological effects threshold (Heinz, 1996), yet we found a slight positive relationship between selenium and total protein (partial correlation: r=0.19, P=0.04, slope=9.36). Takekawa and others (2002) found a negative relationship between total protein and hepatic selenium concentration in wintering canvasbacks (Aythya valisineria) and laboratory studies have shown similar results with captive birds (Yamamoto and Santolo, 2000;Franson and others, 2007). However, our findings are more similar to recent field studies showing no effect of selenium on protein and lipids in greater scaup (Aythya marila; Badzinski and others, 2009), lesser scaup (Aythya affinis), or white-winged scoters (Melanitta fusca; DeVink and others, 2008b), albeit selenium concentrations measured in these studies were 2-8 times lower than those for scoters in San Francisco Bay.…”

Selenium accumulation in coturnix quail fed seleno‐L‐methionine

“…Food consumption did not decrease, which would indicate that the birds were eating but not completely metabolizing their food in the high-Se group. Yamamoto and Santolo [8] observed loss of lean mass in American kestrels fed a diet containing 12 mg/g selenomethionine with no decrease in food consumption, suggesting a metabolic effect. In a study of chickens fed 12 mg/g selenized yeast by Detwiler [4], weight loss was observed without apparent food avoidance.…”

“…Loss of body mass, possibly due to anorexia, has been observed in laboratory studies of chickens (Gallus domesticus) [4], black-crowned night-herons (Nycticorax nycticorax) [12], mallards (Anas platyrhynchos) [5,13], Eastern screech-owls (Megascops asio) [14], and in American kestrels (Falco sparverius) [8].…”

“…Although embryo teratogenesis and mortality have been documented at many Se-contaminated sites [3], other effects may also be important in managing wildlife populations. Such effects include decreased body mass [4], liver damage [5,6], decreased hatchability [7], embryo mortality, decreased lean mass [8], and lower fertility [9,10]. In free-living birds, some of these sublethal effects may be masked by natural (individual or population) variability due to factors such as season, climate conditions, age, and sex.…”

Contaminant Uptake and Demography of the Loggerhead Shrike (Lanius ludovicianus) at the Lawrence Livermore National Laboratory, Site 300

“…American kestrels (Falco sparverius) fed 0, 6, and 12 mg Se/kg dietary selenium reflected the dietary selenium levels in their blood. Furthermore, they showed a negative relationship (r 2 = 0.496) between blood selenium concentration and lean mass, suggesting that elevated selenium levels have a negative effect on body condition of birds (Yamamoto and Santolo, 2000).…”