Effect of Starvation and Re- feeding on of Trypsin and Chymotrypsin Activities in Common Carp ( Cyprinus carpio L . )

Abstract

The aim of this study is to evaluate the effect of starvation and re- feeding on alteration of protease (trypsin and chymotrypsin) in common carp (Cyprinus carpio). Regulation of gastrointestinal protease becomes particularly important, when fish starved. In this work fish were distributed to control group and various treatments including starvation time {2, 4 and 6 days} of re-feeding after various starvation times to test whether food deprivation causes changes in protease activities in the gastrointestinal tract. The relative intestinal weight of the starved group after 6 days of starvation was significantly higher than that of control group. Besides, re – feeding resulted in the relative stomach weight increase after 4 and 6 days of starvation. The activity of trypsin (T) in fish subjected to a short starvation period 2 days was higher than that in fish fed normally and starvation period 4 and 6 days , whereas chymotrypsin (C) activity increased with increasing starvation period . The (T/C) ratio decreased with starvation time, which inversely effected growth, such that the possibility that the growth of carp is inhibited by starvation . These data suggest that long term starvation dampens trypsin activities and the(S T/C ratio) in relation to the growth of carp, and that re-feeding consequently stimulates the activities of intestinal proteolytic enzyme in carp and this subject would need more study .