NUTRITIONAL-STATUS AND BEHAVIOR DURING LACTATION

Effects of chronic maternal food restriction and time of day on matern al and pup behaviors were examined in ovariectomized Sprague-Dawley ra ts (n = 26). Darns were fed ad lib (AL) or were restricted to 85% (85 AL) or 70% (70 AL) of ad lib intake. Dams and their 5-pup litters were observed for 45 min at night on days 9, 14, and 19 of lactation and d uring the day on day 14. A novel behavioral instrument was used to obs erve maternal and pup behaviors. At night, food-restricted animals eng aged in more nursing behaviors than AL animals. Differential pup stimu li may account for this difference. AL animals engaged in more nursing behaviors during the day than night, whereas 70 AL animals demonstrat ed the opposite diurnal pattern. Time of feeding may explain this diff erence. On the other hand, 85 AL animals behaved similarly during the day and at night. Therefore, alterations in circadian behavior pattern s are less pronounced in rats mildly restricted (85 AL) than in rats m ore food restricted (70 AL).