Nutrition and Longevity in the Rat

Abstract
A study of weaning weight in relation to adult body size and to the onset of disease was made on 1051 male Sprague-Dawley rats and 451 females from 500 to 1200 days old. The animals were free from lung or ear infection, and were raised under standardized conditions of temperature, humidity and light. The diet consisted of commercial vitamin D-free pellets supplied ad libitum from time of weaning. Littermates were divided at weaning into 4 groups according to weight which ranged from 40 to 89 g. Body weight curves (based on data obtained from rats over 900 days old) remained separate according to weaning weights. The higher the weaning weight, the heavier the animal. Peak body weight, body length, and tibia length were significantly greater in adult rats starting with highest weaning weights than in animals starting with lowest weaning weights. Observations at various ages on incidence of lesions of 4 major diseases, and on incidence of 4 benign tumors showed no significant differences according to weaning weights. The results demonstrate that adult body size is related to weaning weight. However, no relationship was observed between weaning weights and the age of onset of lesions.