Protein hydrolysate vs free amino acid-based diets on the nutritional recovery of the starved rat

Background and Aims To test the hypothesis that a peptide-based enteral product was equivalent to a low-fat, free amino acid-based formula in the nutritional and functional recovery of the starved rat. Methods Sixteen male Wistar rats were starved for 3 days. Then, rats were randomised to a whey protein hydrolysate-based diet or a free amino acid-based diet and refed for 3 days. The experiment was designed to provide the same energy intake in both groups. The parameters studied included body weight gain, nitrogen retention, plasma free amino acid concentrations, muscle glutamine concentrations and glutathione levels in gut mucosa and liver. Results Weight gain was statistically higher on the peptide-based diet than on the elemental diet after the refeeding period. This difference in weight gain was associated with a statistically higher nitrogen retention. Plasma and muscle free glutamine concentrations were higher in rats fed the whey protein hydrolysate-based diet than those in rats refed the free amino acid-based diet, even though the glutamine intake was higher in the latter group. Glutathione concentrations in liver and gut mucosa were similar in the groups. Conclusion We conclude that enteral diets containing peptides were more effective than a diet containing free amino acids in the nutritional recovery of the starved rat.