Effects of starvation on enzyme activities and intestinal microflora composition in loach (Paramisgurnus dabryanus)

Abstract

A 30-day feeding investigation was conducted to resolve the effects of starvation in juvenile loach (Paramisgurnus dabryanus). In this study, the digestive enzyme activity, antioxidant activity, immune enzyme activity, and microflora compositions were analyzed to investigate the effects of starvation. At the end of the 30-day trial, loaches in the feed and starved groups were sampled for enzyme activities and microflora analysis. Results revealed that the superoxide dismutase (SOD) and catalase (CAT) activities increased significantly in the starved group than in the feed group. Starvation was also observed to lower the digestive enzymes activities and improve the immune system of loach. Additionally, the findings of this study indicated that starvation greatly affected the abundance of different bacterial phyla in the two groups. Proteobacteria (57.14 %), Firmicutes (12.79 %), and Bacteroidetes (7.41 %) were the dominant phyla found in the feed group, while Proteobacteria (35.56 %), Bacteroidetes (35.01 %), and Firmicutes (9.56 %) were the dominant phyla found in the starved group. Clearly, starvation disturbed this fish’s immune system, and nourishment, in turn, affected gut microbiota. This study involved a comprehensive investigation on the synergism among intestinal microorganisms and hosts under changing conditions. These findings will enhance our knowledge on how intestinal microbiota and hosts react with their dynamic surroundings and will serve as an important resource for future studies.