Effect of early nutritional experience on the feeding behaviour of adult female rats

In the present paper the effect of postnatal undernutrition on feeding behaviour has been evaluated in mature female Wistar rats subjected to food restriction a) during the suckling period, i. e. up to day 15 (SR), b) during the weaning period from day 15 to 30 (WR), c) throughout 30 days post partum (SWR) and d) during adulthood, i.e. from day 60-75 of life (AR). In comparison with the ad libitum fed controls (C), the lactating mothers and the pups of the food-restricted groups were allowed free access to food for only two hours daily. In experimental groups this restriction was then changed to an ad libitum regime. On day 90 food intake was evalu-ated daily in five 20 min lasting sessions after 23 h of fasting in group-housed and single-housed rats exposed to their home as well as to their experimental environment. The significantly decreased body weight found on day 30 and 90 in females coming from litters of restrictedly fed mothers, as compared with those fed ad libitum, showed that these animals were considerably undernourished. Appetitive motivation increased in those groups of females that had been exposed to a restricted feeding regime during their infant period but remained unaffected in females restrictedly fed during their adult age. In comparison with the ad libitum fed controls and AR groups, significantly increased mean food intake was observed in all postnatally underfed groups (P < 0.001). The greatest inclination to hyperphagia and qualitative changes in feeding behaviour were observed in SWR females whose feeding regime was restricted for the longest time, i. e. during the suckling and the weaning period, as compared to groups with shorter food restriction. These animals showed hyperphagia even in the new environment regardless whether the whole group or only one female was tested. Our results reveal a) a determinant influence of the feeding regime of the animals at early age (41%) while environmental and social factors represent only about 17% and 4%, respectively and that b) changes in feeding habits in adult female rats may significantly depend on the length of postnatal undernutrition.