Advances in the study of activity additivity of supplemented proteases to improve digestion of feed protein by Penaeus vannamei

摘要

In vitro assays used porcine or bovine trypsin as models of exogenous enzymes to determine functioning in the presence of enzymatic extracts from the digestive gland of white leg shrimp Penaeus vannamei. Using electrophoresis and zymograms, when enzymes from the shrimp were mixed in the absence of protein substrate, they hydrolysed the trypsin from bovine or porcine origin. Porcine or bovine trypsin, when mixed with shrimp enzymes in pH-stat assays in the presence of shrimp commercial feed, fish meal, or casein, there was added activity to hydrolyse the protein substrate. Hydrolysis of protein substrate was twofold to threefold stronger if exogenous enzymes were added. Results suggest that porcine or bovine trypsin could be used as feed supplements for white leg shrimp P.vannamei to enhance hydrolysis of proteins in feeds, because the commercial enzymes contributed to the hydrolysis of the protein in the three substrates in the presence of shrimp enzymes.