The effects of early nutrition on body weight and adipose tissue characteristics in the rat
This study examined the effects of early nutrition or, the body weight and adipose tissue characteristics of Sprague-Dawley rats. Different levels of caloric intake during the pre-weaning phase were achieved by manipulation of litter size. Immediately after birth, pups were redistributed into large (15-18 pups), control (1O pups), or small (4 pups) litters. Males from small litters demonstrated an increase in body weight and adipocyte, number (K.05), but this difference was not seen in the females. Litter size had no effect on adipc"cyte size or percent body fat. The effect of caloric restriction during the post-weaning phase was also examined. This was done by pair-feeding one-half of the rats raised in small litters to those raised in large litters for a period of 5 weeks. After ad libitum feeding was resumed, the pair-fed group demonstrated an increase "in adipocyte size which resulted in an increased level of fatness W.05). The results of this experiment demonstrate that the consequences of early nutrition are dependent on when it is undertaken, and suggest that sex hormones are involved in modulating these effects.