Effects of fish meal as source of protein on intestinal maltase activity and intestinal and renal leucine aminopeptidase activity of growing rats.

The effect of high-protein fish meal on maltase and leucine aminopeptidase (LAPase) activities of the intestinal mucosa as well as the renal LAPase activity was studied. Four groups of female Wistar rats, weighing between 40-60 g, were fed diets with a 4 or 12% protein content of dry matter for 25 days. The protein source was casein for the control groups and fish meal derived from Coryphaenoides rupestris for the test groups. The results show a decrease (p less than 0.005) in intestinal maltase and LAPase activities and renal LAPase activity in animals fed with 12% of fish meal protein compared to those fed with casein, while the rats fed 4% of fish meal protein showed a decrease in intestinal maltase activity and no significant difference in LAPase activity compared with the control group. These results seem to indicate that the intestinal maltase is influenced by the quality and quantity of dietary protein, while the intestinal and renal LAPase activity is only changed by the quality of protein.