The effect of protein malnutrition on the copulatory behavior of the male rat

Abstract

The copulatory behavior of male Sprague-Dawley rats reared under four dietary conditions was measured in three experiments at ages ranging from 95 to 325 days. Rats malnourished in preweaning stages of development were born to dams fed an 8% casein diet from 5 weeks before mating until weaning. Well-nourished rats were born to dams maintained on a 25% casein diet. At weaning half of the offspring in each group were switched to the other diet. In all three experiments rats subjected to the protein restriction in both pre- and postweaning periods, or in one period or the other only, were more effective copulators than well-nourished rats. The major differences between the protein-deprived and well-nourished rats were related to a diminished ability to intromit in the high-protein animals. Protein or protein—calorie malnutrition may enhance copulatory behavior in the male rat by retarding or prolonging several aspects of development, including body growth and changes in sex hormones.