Abstract
Effects of administration of diets containing different nitrogen sources on the nitrogen metabolism in the rats subjected to gastrectomy or 75% enterectomy were studied. The nitrogen sources used were intact casein, its tryptic hydrolysate (NZ-Case, average peptide length 2-3), and amino acid mix-ture simulating casein (AA mix). No diets were given on the day of operation but water was supplied at all times. On the following day, 2.5g of the diet containing 20% of the nitrogen source was given. Subsequently the diet was increased gradually until day 6 and then given ad libitum from day 7 to day 14 after the operation. The weight gain, from day 7 to day 14, of rats fed AA mix diet in each operated group appered to be less than that of other dietary groups, but the difference was not sig-nificant. Relative weight of the caecum in the gastrectomized rats was more increased in NZ-Case and AA mix diet groups than in casein one, and the weight in the 75% enterectomized rats was more increased in AA mix than in other dietary groups. In addition to that, relative weight of the caecum in the 75% enterectomized rats was more increased than that in the gastrectomized animals regardless of the type of diets. There were no significant differences in relative weight of the kidney and the liver in any dietary groups. Hematocrit, A/G ratio, and plasma urea and total protein were similar in the same operated rats regardless of the type of dietary nitrogen sources consumed. However, between the operated groups, the concentration of plasma urea in the enterectomized rats was signifi-cantly higher than that in the gastrectomized rats. A similar positive nitrogen balance, measured for the last 3 days in the experiment, was observed in the gastrectomized rats but in the enterectomized animals, the nitrogen retention was the highest with NZ-Case diet. An increase of ammonia-N and a decrease of urea-N in the urine in the gastrectomized or the enterectomized rats fed AA mix diet were observed. These results indicate that small peptide form may be a useful dietary nitrogen source for short gut syndrome.
