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

Siti Aslamyah,Yushinta Fujaya,Nita Rukminasari

doi:10.3844/ojbsci.2021.181.187

Abstract

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.

Highlights

The indigenous microflora of fish in aquaculture has previously been studied for many purposes, including descriptions of microbial spoilage, the correlation between environment and fish microflora (Horsley, 1973), the monitoring of changes in fish farms (Allen et al, 1983), the nutritional role of the intestinal flora (Hansen et al, 1992) and the antibiotic resistance profile of the indigenous flora (Spanggaard et al, 2000).It is generally recognized that the intestinal flora of endothermic animals serves both as a digestive function and as a protective barrier against disease (Sissons, 1989)
The measurement results for microbial population and enzyme activity was shown in Table 1 and 2
Cherac quadricarinatus, which was fed with 100 IU mL 1 penicillin G. and 100 IU mL 1 streptomycin per kg of feed for eight days, showed a decrease in cellulase enzyme activity in the digestive tract by 40%, as well as a reduction of the bacterial population by 94% compared to controls (Xue et al, 1999)

Summary

Introduction

The indigenous microflora of fish in aquaculture has previously been studied for many purposes, including descriptions of microbial spoilage, the correlation between environment and fish microflora (Horsley, 1973), the monitoring of changes in fish farms (Allen et al, 1983), the nutritional role of the intestinal flora (Hansen et al, 1992) and the antibiotic resistance profile of the indigenous flora (Spanggaard et al, 2000).It is generally recognized that the intestinal flora of endothermic animals serves both as a digestive function and as a protective barrier against disease (Sissons, 1989). The main component in animal feed is protein, carbohydrate and fat. According to (Bakke et al, 2010), a chemical feed simplification process is called hydrolysis, involving digestive enzymes as biological catalysts. Steinberg (2017) explained that the hydrolysis of macronutrients into micronutrients in the digestive system was occurred due to the presence of digestive enzymes, namely protease, amylase, carbohydrase, lipase and stomach acid. Those compounds are produced by the stomach, intestines, liver and pancreas. The discovery of the enzyme cellulase in the digestive tract of aquatic animals allows these animals to digest feed containing fiber

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