Gut microbiome diversity analysis of wild freshwater fishes shaped by different feeding habits

Freshwater fish are an important source of protein in human diet. The gut microbiota of fish is influenced by dietary habits and environmental conditions. To understand the diversity and abundance of intestinal flora of wild freshwater fish with different dietary habits, different species of fish were collected for research. In terms of microbial diversity, the intestinal microbial diversity of omnivorous fish was higher. A core group of bacteria, including Proteobacteria, Firmicutes, Clostridium, and Bacteroidetes, was detected in all individuals. The proportion of each phylum in the core flora of freshwater fish varied based on feeding habits, even if the habits were the same, the differences still exist. Among the omnivorous fishes, the proportion of bacteria in yellow catfish was more balanced, while carp was concentrated in Proteobacteria. The gut microorganisms in carnivorous fish were mainly Proteobacteria and Firmicutes, while Weissella and Lactococcus in Firmicutes were found only in carnivorous fish.