pH Characterization of Digestive Enzyme and In vitro Digestibility of Red Bee Shrimp Caridina cantonensis (Decapoda: Atyidae)

Abstract

The characteristics of digestive enzyme from red bee shrimp (Caridina Cantonensis), a tiny ornamental shrimp, were investigated under various pH ranging from 2 to 12. The aim of this study was to find out the specific activities of protease, amylase, lipase, cellulose, trypsin and chymotrypsin and in vitro raw materials by shrimp enzyme digestibility. Fifteen and sixty-day old shrimp were obtained from private farms in Bangkok, Thailand. Protease, lipase, amylase, cellulase, trypsin and chymotrypsin specific activity were determined. The results showed that protease activity had its optimal activity at pH ranging from 8 to 10 and showed the highest activity at pH 10 in both age groups. The alkaline amylase activities were found to be significantly higher than acidic amylase in both age groups. Both acidic and alkaline amylase activity of the 15-day old shrimp was significantly lower than the larger shrimp. The Lipase activity in the 60-day old shrimp showed the highest activity at pH 12, pH 10 and 11, respectively. In the 15-day old shrimp, the lipase activity was stable over a broad pH ranging from 2-12. In the 60-day old shrimp, the cellulase activity showed the highest activity at assay condition pH 7 and decreased when pH levels increased. In the 15-day old shrimp, cellulase activity showed optimal pH at pH 8 and 11. The trypsin and chymotrypsin activity at neutral to weak alkaline condition was greater under acidic condition in both age groups. The activity of 15-day old shrimp was significantly lower than the older shrimp. Regarding in vitro digestibility, the study on protein digestion showed that fish meal was suitable to be a protein source for red bee shrimp. The carbohydrate digestibility showed that wheat flour and maltodextrin were more appropriate as a carbohydrate source for red bee shrimp than cassava, rice bran and Na-alginate. Therefore, it can be concluded that red bee shrimp had diet digestibility in neutral to mid alkaline condition. The animal protein materials are appropriate to be red bee shrimp feed ingredients with low fiber and carbohydrate source.