Effect of the Level of Dietary Protein on the Toxicity of Dieldrin for the Laboratory Rat

Abstract

Male Long-Evans rats were fed low (10%) and high (25%) protein diets containing zero, 100, 150, and 200 ppm of dieldrin. At all levels of dieldrin, with high and low protein diets, there was an initial slight suppression of growth for 2 to 6 days. From day 6 to 31 there was a continued slight suppression of growth among all animals ingesting 150 or 200 ppm of dieldrin. Marked mortality occurred among animals ingesting 200 ppm of dieldrin with either low or high protein but also among animals ingesting 150 ppm of dieldrin with the low protein diet. Neither kidney nor heart weight were altered in any meaningful pattern with either protein diet. Liver weight was significantly increased at all levels of dieldrin intake with high protein but not low protein diets. Glucose-6-phosphate dehydrogenase and transaminase activities were not altered by dieldrin ingestion with low or high protein. Stress response, as measured by swimming time, was not affected in any consistent manner and body fat, as a percentage of total body weight, was the same in all groups. With low protein diets, but not high protein diets, at all levels of dieldrin ingestion, there was a significant increase in liver lipids. Vitamin A per gram of liver was decreased in all dieldrin groups ingesting either low or high protein diets. However, total liver vitamin A was decreased in the low protein group at 150 and 200 ppm of dieldrin but in the high protein group only at 200 ppm of dieldrin. Kidney and cardiac muscle exhibited no alterations that could be ascribed to dieldrin ingestion. Livers of rats ingesting dieldrin exhibited cellular edema and fatty infiltration. These changes were more marked in animals fed low protein diets than in animals fed high protein diets.