CASEIN, HYDROLYZED CASEIN, AND AMINO-ACIDS THAT SIMULATE CASEIN PRODUCE THE SAME EXTENT OF MUCOSAL ADAPTATION TO MASSIVE BOWEL RESECTION INADULT-RATS

We determined the effect of the extent of protein polymerization on th e intestinal hyperplastic adaptation of adult male Wistar rats after 8 0% resection of the jejunal-ileal segment. Rats received one of four c hemically defined solid diets prepared by using casein, two casein hyd rolysates of different peptide size distributions, or free amino acids simulating casein and identical in all other components for 12 d, sta rting 3 d after surgery. Semipaired feeding was used to ensure that th e same quantity of food was ingested by each group and as a consequenc e, nitrogen and energy intakes were reduced to 63% of that obtained wi th ad libitum feeding of the casein diet to intact rats. No significan t differences were demonstrable in food ingestion, weight gain, nitrog en balance, or morphometric data for the remaining jejunal and ileal s egments (number of cells/villus, number of cells/crypt, and crypt cell mitosis rate). These data demonstrate that the extent of polymerizati on of the protein nitrogen source did not affect the hyperplastic adap tative process of the rat. Additional studies in humans are necessary to determine whether intact protein diets can be used first as a nitro gen source in nutritional support of patients with a nonspecific hyper plastic response to surgical resection before the use of expensive hyd rolysates and the more expensive amino acid mixtures.