Effects of malnutrition during early lactation on development and feeding behavior under the self-selection paradigm

Selection of food can be affected by several factors, and with the method o f self-selection, qualitative changes in nutritional balance may be detecte d. The goal of the present study was to evaluate feeding preferences in wea ning rats using three macronutrients (protein, carbohydrate, and fat), thro ugh a free-choice method, evaluating the alteration in their feeding patter ns as compared with the previous nutritional status during the early lactat ion period. We analyzed the effects of protein restriction during lactation over the nitrogen balance after the weaning. The dams were assigned to one of two diet conditions (nourished or malnourished). At weaning, two pups f rom each litter were housed individually in metabolic cages, and they were maintained on self-selection under a free-choice paradigm and were provided with separate sources of macronutrients. The parameter for evaluating the nutritional effectiveness of the diets was nitrogen balance. We observed th at protein intake tended to increase and consumption of carbohydrate and fa t tended to decrease progressively during the 3 wk of experiment. In select ing their own food, growing rats and malnourished rats consumed a larger am ount of protein than the other rats. Nourished rats selecting their diet ha d a larger nitrogen balance than nourished rats receiving a composed diet; no nitrogen balance difference was found between the self-selecting groups. Rats can choose an adaptive form when recovering from protein malnutrition . (C) Elsevier Science Inc. 2001.