The Toxic Level of Sodium Selenite in the Diet of Laying Chickens

Abstract

Female chickens were fed graded levels of sodium selenite to determine at what level a selenium toxicity occurred. In the first experiment a basal diet was supplemented with 0, 0.1, 1.0, 3.0, and 5.0 ppm of selenium. These levels had no effect on egg production, egg weight or fertility of the eggs. Hatchability of fertile eggs was significantly decreased by 5 ppm of dietary selenium. In the second experiment a basal diet was supplemented with 0, 5.0, 7.0, and 9.0 ppm of selenium. Egg weight and hatchability were significantly decreased by 7 and 9 ppm, and egg production was decreased by 9 ppm of selenium in the diet. When selenite was added to the diet, there was a lag of 2 to 3 weeks before the selenium content of the egg reflected the content of the diet. As long as the selenium content of the diet remained the same, egg selenium remained the same. When selenium was no longer supplemented, egg selenium content decreased. Two weeks after cessation of selenite supplementation, egg selenium was markedly reduced. Four weeks after cessation of selenite supplementation, egg selenium levels approached those of birds fed a basal diet continuously.

Tolerance of Diets Deficient or Excessive in Selenium by Syrian Hamsters

“…and changes at the different measure ments were more likely due to seasonal or aging factors. Large Se increments found in the liver and kidneys with high dietary Se were similar to those in other animals [5,26,35]. Se content of these organs and of the pancreas was not altered by basal diet fed; however, Se content of the muscle, although not significantly modified by dietary Se level, was higher in animals fed the high Se diets and in those fed C diets.…”

“…Their tolerance of very low dietary Se is shared with the rabbit [16] and the guinea pig [4] and long survival with Se levels up to 10 ppm is similar to that of the mouse [41], The range of tolerance of high dietary Se by different species is great. Trout, for example, tolerated up to 6 ppm Se [15] and chicks up to 5 ppm [26]. However, gerbils were influenced adversely by 5 ppm Se [17], and 4 ppm Se is generally considered toxic for domestic animals [20].…”

Detailed study of water quality, bottom sediment, and biota associated with irrigation drainage in the Salton Sea area, California, 1988-90

“…Extensive bioaccumulation, which occurs throughout the food chain, results because selenium is an essential micronutrient and is chemically similar to sulfur (Lemly and Smith, 1987). Bioaccumulation of selenium in birds from elevated dietary levels has been found to impair reproduction (Ort and Latshaw, 1978;Eisler, 1985;Heinz and others, 1989;Ohlendorf, 1989). Field studies in areas of seleniumladen agricultural drainwater have shown embryonic mortality and deformities in water birds attributable to the adverse effects of selenium (Ohlendorf andothers, 1986a, 1986b;Schroeder and others, 1988;Ohlendorf and Skorupa, 1989).…”

Reconnaissance investigation of water quality, bottom sediment, and biota associated with irrigation drainage in the Malheur National Wildlife Refuge, Harney County, Oregon, 1988-89

“…Animals generally accumulate high levels of selenium by consuming contaminated food (Sharma and Singh, 1983). In experimental feeding studies, concentrations of 25 A*g/g in the diet have caused mortality in some bird species, while concentrations as low as 5 A*g/g caused reproductive impairment (Ort andLatshaw, 1978, Heinz andothers, 1987;Heinz and others, 1989). Selenium concentrations in food-chain items from this study were below dietary concentrations of 3 to 8 A*g/g known to cause toxic effects in aquatic birds (Heinz andothers, 1987, 1989;Lemly and Smith, 1987;Ohlendorf, 1989).…”