Microflora Contribution to Cellulase and Digestion Enzyme in Mud Crab Digestive Tract

Microflora in the digestive tract of aquatic animals is thought to be not only the microbes that contribute to the production of cellulase enzymes but also contribute to other digestive enzymes, such as protease, amylase and lipase. This study aims to examine the microflora contribution to the mud crab’s digestive tract. Scylla sp. were maintained in the crab box individually and placed in a pond. Two groups of crabs were fed without antibiotics and containing antibiotics at a dose of 100 IU mL^-1 penicillin G and 100 IU mL^-1 streptomycin, respectively. Each treatment had two replications. Crabs were kept for eight days and fed 5% of body weight per day in the afternoon. The results showed that the cellulitis, amylolytic, proteolytic and lipolytic microbial population in the digestive tract of mud crabs that received feed added with antibiotics decreased significantly compared to those feed without antibiotics. Furthermore, the α-amylase, protease and lipase enzyme activity also decreased. The decrease in cellulase activity, α-amylase, protease and lipase enzymes were 89.55, 41.90, 26.50 and 37.26%, respectively. The decreasing percentage of cellulase, α-amylase, protease and lipase enzymes indicated a significant microflora contribution in the mud crab digestive tract.