Effect of Interaction of Gender and Energy Intake on Lean Body Mass and Fat Mass Gain in Infant Baboons

Abstract

The hypothesis that energy intake influences differently the composition of mass gain during the preweaning period was tested in male and female baboons. Infant baboons were fed either a high (92 kcal/100 g formula) or a low (49 kcal/100 g formula) caloric formula from birth. Body mass, lean body mass and fat mass of each baboon were measured directly at weaning (18 weeks of age). Lean mass and fat mass gained from birth to 18 weeks was estimated by using body composition data from eight newborn baboons. Both energy intake and gender significantly influenced gain of total mass, lean mass and fat mass. There was a significant gender by diet interaction effect on the gain of fat mass. When fed the high caloric formula, males gained 145 g more lean mass than females, but the increase of fat mass was approximately the same. In contrast, on the low caloric formula, males gained 150 g more lean mass than females but 74 g less fat mass than females. These results indicate that fundamental differences in the development of lean mass and fat mass exist between male and female baboons during preweaning life.