Partial Characterization of Digestive Proteases in the Common Snook Centropomus undecimalis

Common snook (Centropomus undecimalis) is a marine species with high aquaculture potential; although its digestive physiology is still unknown and knowledge of that could allow the development of a balanced feed for commercial culture of this fish. The objective of this study was to partially characterize the digestive proteases in C. undecimalis using electrophoretic and biochemical techniques. A total of 50 wild snook juveniles were used to determine the optimal values of pH stability and temperature as well as the effect of inhibitors on digestive, gastric and intestinal proteases. The optimal pH for gastric proteases was obtained to be 2 with stability obtained between 2 and 8; the optimal temperature was detected at 75ºC for in vitro test, and the thermal stability was between 25 and 45ºC. Intestinal proteases showed two peaks of activity at a pH of 7 and 11; meanwhile, the greatest stability was found between a pH of 4 and 10; the optimal temperature was at 65ºC, and the greatest stability was detected between 35 and 45ºC. Up to 86% of the gastric protease activity was inhibited by pepstatin A; meanwhile, the intestinal proteases TPCK, TLCK, 1-10 Phenanthroline, SBT1, EDTA, PMSF and ovalbumin reduced the activity by 17%, 68%, 85%, 41%, 40.5%, 60% and 59%, respectively.