Exploring bacterial diversity in intestines of the black tiger shrimp Penaeus monodon  

The gut bacterial community of an animal plays essential roles on animal health by helping with nutrient digestion, competing with pathogenic bacteria or stimulating host immunity. Although the applications of beneficial bacteria as a preventive medicine or health supplement have been widely implemented in various organisms, the knowledge of intestinal bacteria in an economically important black tiger shrimp is still too limited to utilize the promising alternative in shrimp probiotics development. Therefore, the characterization of shrimp gut bacteria will crucially lead to an utilization of beneficial bacteria for sustainable farming practice. Here, Sanger sequencing, denaturing gradient gel electrophoresis (DGGE) and pyrosequencing analyses were employed to decipher 16S rRNA sequences for bacteria identification in shrimp intestines. Different shrimp intestine samples were collected from i) farm locations for juvenile shrimp, ii) developmental stages (15-day post larvae, 1-, 2-, and 3-month-old juveniles), iii) habitats in adult shrimp (wild and domestication) to provide the fundamental knowledge on bacterial community structures. Bacteria belong to phyla Bacteroides, Firmicutes and Proteobacteria were commonly found in shrimp intestines from all conditions. Hence, they might potentially be a part of core intestinal bacteria in shrimp. However, further evidence with more samples from different farming conditions is still underway to draw a structure on the core gut bacteria in shrimp. The bacterial population analyses under this study provide an initial insight for future development of shrimp probiotics to prevent or reduce the economic loss due to disease outbreak.

Key words: bacteria diversity, black tiger shrimp, Penaeus monodon, 16S rRNA, pyrosequencing, DGGE