Maternal adaptations for fetal growth in young malnourished rats

Carcass composition and serum free fatty acids were determined in young (45 days old) control and malnourished (25 and 6% protein diet, respectively) pregnant and nonpregnant rats. Pregnant rats were sacrificed shortly after parturition and nonpregnant rats on the 22nd day of experiment. Carcass fat content increased in control pregnant rats. This alteration was not seen in the pregnant malnourished rats. Serum free fatty acids and pup birth weight were lower for malnourished than for control mothers. No significant difference was observed in carcass protein of Na+ and K+ content among rats of all groups. These data appear to indicate that the inability to accumulate fat in the carcass and the preservation of carcass protein at nonpregnant levels during pregnancy may be important factors involved in the genesis of the low birth weight seen in the pups of young malnourished rats, presumably reducing the availability of nutrient supplies for fetal growth.