Screening of bacteria isolated from black tiger shrimp (penaeus monodon) intestine using as probiotics in aquaculture

Abstract

In this study, 14 bacterial strains isolated from gastrointestinal tract of black tiger shrimp (Penaeus monodon) was investigated for their probiotic potential. The results showed that 6 strains, namely S1, S3, S6, S7, T4 and T5 were able to degrade 3 nutrient substances including protein, starch, and lipid among which S3, S7, and S2 were the best tested nutrient-degrading bacteria, respectively. Six bacterial strains were unable to lyse red blood cells including S2, S3, T0, T1, T2 and T3. S2 strain showed the strongest antibacterial activity against shrimp pathogenic Vibrio harveyi following an agar overlay technique. Based on environmental tolerance tests, S2 and T0 strains grew well under wide ranges of environmental conditions, e.g. sodium chloride concentration (0-8%), pH (6-10), and temperature (25-37C). As a consequence, S2 strain had the most probiotic potential for shrimp culture owing to no hemolysis of red blood cells, inhibition of V. harveyi growth, protein and lipid degrading ability, and high environmental tolerance for shrimp cultivation. The strain was identified as Micrococcus sp. S2. However, additional study focused on immune response, nutrient digestibility and growth promotion of the strain should be further performed in marine shrimp.