Influence of undernutrition during gestation and suckling on development and sexual maturity in the rat

The effects of undernourishment during gestation and suckling on rats subsequently fed ad libitum for 4 mo after weaning are explored. We measured the following: weight at birth and over a 5-mo period; sexual behavior of adult males; curiosity; basal physical activity; morphometric measures; organ weights (absolute and relative) including brain, testicles and seminal vesicles in males 5 mo of age; and the O2 uptake of some brain and glandular structures in males at 5 mo of age. Body weight of the malnourished animals was consistently lower than that of the controls. Compared to controls sexual behavior in undernourished males was significantly reduced, while curiosity test and basal physical activity were increased. The absolute weights of all organs (except the pituitary gland) were significantly lower in malnourished males at 5 mo than in controls. Compared to controls, relative weight of brain was greater and that of seminal vesicles was less in the male rats. Oxygen uptake was significantly lower in the pituitary gland and testicles of malnourished males than of controls. In view of these results, it can be concluded that malnutrition in utero and while suckling affects fundamental parameters of both development and reproductive function in the male offspring 4 mo after feeding ad libitum is begun at weaning.