Toxicity and oxidative stress of different forms of organic selenium and dietary protein in mallard ducklings.
Concentrations of over 100 ppm (mg/kg) selenium (Se) have been found in aquatic plants and insects associated with irrigation drainwater and toxicity to fish and wildlife. Composition of diet for wild ducklings can vary in selenium-contaminated environments. Earlier studies have compared toxicities and oxidative stress of Se as selenite to those of seleno-DL-methionine (DL) in mallards (Anas platyrhynchos). This study compares DL, seleno-L-methionine (L), selenized yeast (Y) and selenized wheat (W). Day-old mallard ducklings received an untreated diet (controls) containing 75% wheat (22% protein) or the same diet containing 15 or 30 ppm Se in the above forms except for 30 ppm Se as W. After 2 weeks, blood and liver samples were collected for biochemical assays and Se analysis. All forms of selenium caused significant increases in plasma and hepatic glutathione peroxidase activities. Se as L at 30 ppm in the diet was the most toxic form, resulting in high mortality (64%) and impaired growth (>50%) in survivors and the greatest increase in ratio of oxidized to reduced hepatic glutathione (GSH). Se as both L and DL decreased the concentrations of hepatic GSH and total thiols. Se as Y accumulated the least in liver (approximately 50% of other forms) and had less effect on GSH and total thiols. In a second experiment, in which the basal diet was a commercial duck feed (22% protein), survival was not affected by 30 ppm Se as DL, L, or Y and oxidative effects on GSH metabolism were less pronounced than with the wheat diet.
Hoffman
D J
DJ
U.S. National Biological Service, Patuxent Wildlife Research Center, Laurel, Maryland 20708-4041, USA.
Heinz
G H
GH
LeCaptain
L J
LJ
Eisemann
J D
JD
Pendleton
G W
GW
D000821:Animal Feed; D000818:Animals; D004044:Dietary Proteins / Q000633:toxicity*; D004372:Ducks / Q000378:metabolism*; D008099:Liver / Q000187:drug effects*; D018384:Oxidative Stress / Q000187:drug effects*; D011897:Random Allocation; D012643:Selenium / Q000633:toxicity*; D012645:Selenomethionine / Q000633:toxicity; D014908:Triticum / Q000378:metabolism
D004044:Dietary Proteins; D012645:Selenomethionine; D012643:Selenium