EFFECT OF FOOD RESTRICTION CONSUMED BY DA M RAT DURING PREGNANCY AND LACTATION ON THE POSTNATAL-GROWTH AND TISSUE COMPOSITION OF THE PUPS

The repercussion of food restriction consumed by the adult rat during pregnancy and lactation, on the postnatal growth and tissue compositio n of the young was evaluated during lactation. Two groups of Sprague-D awley rats were used, one control group was fed ''ad libitum'' (AL) an d the other group, a restricted diet (RD), 30% less of the normal diet . From the eigth day of pregnancy and throughout lactation, the food i ntake and weight of the animals was registered daily. At birth the num ber of young was adjusted to eigth and the weight and tail length were registered daily. At 7, 14, and 21 days of lactation the young of bot h groups were sacrificed. The liver and the muscles of the extreme pos terior were dissected and the wet weight, dry weight, proteins and nuc leic acids determined. The mother rats fed ''ad libitum increase their intake to 300% from the first day of lactation and they presented a g reater body weight than those rats under restricted diet, also begun o n the first day of lactation. At birth there were no differences in th e weight and the lenght of the young, however at the end of the lactat ion the growth rate was significantly lower among the group of rats RD . In the group of young under RD, protein and nucleic acids concentrat ion in the liver were significantly less than those of the AL group an d similarly in the muscle, the dry weight, proteins, RNA and DNA were significatively less. From these results it is concluded that the food restriction of the adult rat by 30% during lactation, has a negative effect on the postnatal growth of the young, in terms of weight, lengt h, liver tissue composition and muscular mass.