Impact of qualitative and quantitative variations in nitrogen supply on catch-up growth in food-deprived-refed young rats.

ABSTRACT

BACKGROUND: Optimization of the refeeding strategy for the management of malnutrition in early life may enable to improve the quality of catch-up growth. While some data suggest better assimilation of peptides rather than whole proteins the evidence are scarce. OBJECTIVE: To compare the nutritional properties of peptides, partially hydrolyzed proteins or whole proteins in food-deprived/refed young rats. METHODS: Male SD rats (n = 109, 60-70 g) were food-deprived for 48 h and refed for 2-13 days. According to the set of experiments, refeeding was performed at 90% or 100% basal spontaneous intake or ad libitum with either peptide-, partially hydrolyzed protein- or whole protein-containing pediatric enteral nutrition formulas. Body weight, caloric intake and nitrogen balance were measured daily, intestinal trophicity was measured after two-day refeeding, and body composition was determined at the end of the refeeding period. RESULTS: A 2-day food deprivation in young rats led to significant body and organ weight losses, alterations of gut morphology, and decreased plasma citrulline, a marker of gut function. A cautious 2-day renutrition at 90% pre-deprivation level did not restore nutritional status whatever the form of nitrogen supply. Ad libitum feeding was shown to be feasible with improved nitrogen efficiency. After 13 days, compared to chow diet, body weight gain was the lowest with peptide- and whole protein-containing diets, and significantly improved with partially hydrolyzed proteins with limited improvement in body lean mass (+8%, NS). Additional experiments indicated that in this model it will be necessary to significantly increase nitrogen supply in order to restore initial body weight and lean body mass. CONCLUSIONS: Our results show benefits of ad libitum refeeding on catch-up growth. Our data suggest that partially hydrolyzed proteins may be beneficial in terms of body weight gain but that probably their effectiveness may be improved with higher nitrogen supply.