Comparative Analysis of Gut Bacterial Communities in Fish and Shellfish of Great Himalayan River System.

The gut microbiota comprises a unique micro-ecosystem and plays important role in various metabolic functions of the host. Cirrhinus mrigala and Maydelliathelphusa masoniana are two important species of fish and shellfish found in Chenab and Ravi rivers of Himalayan river system. This is the first report on the core gut microbiota of M. masoniana and C. mrigala using Illumina Miseq Sequencing. Gut bacterial diversity of crabs and fishes are studied from the rivers as well as farms. The core microbiome of crab gut samples consists of genera: Bacteroides, Dysgonomonas, Lactobacillus, Leptotrichia, Acinetobacter, Prevotella, Prevotella 1, Pseudomonas, Fusobacterium and Streptococcus. The core microbiome of fish gut samples consists of genera: Acinetobacter, Lactobacillus, Methanosaeta, Prevotella and Pseudomonas. The result shows higher relative abundance of Bacteroides and Lactobacillus in river Ravi than Chenab. Gut bacterial diversity of fishes and crabs of river Chenab is comparatively lower than the river Ravi. Three genera (Bacteroides, Oceanobacillus and Lactococcus) show significant variation (p value < 0.05) in fishes and crabs. Our study generated sequencing data on the gut microbiota of M. masoniana and C. mrigala can establish a base for the development of therapeutic approaches in dealing with the health conditions of diseased fishes and crabs. Gut microbial characterization will not only help in growth and development of the host but also helps in minimizing the disease susceptibility.