Effects of Water Temperature and Photoperiod on the Oxidative Stress and Intestinal Microbiota in Larval Spotted Mandarin Fish Siniperca Scherzeri in the Yalu River

Abstract

The antioxidant capacity and intestinal microbiota play a crucial role in the nutrition, immunity, and overall health status of fish. It is significant to understand the impact of environmental changes on the health of Siniperca scherzeri, an important breeding species. Therefore, in order to investigate the effects of photoperiod and water temperature on the antioxidant capacity and intestinal microorganisms of S. scherzeri, liver and intestinal samples from cultured juvenile S. scherzeri were collected for related analyses. The photoperiod group of 12L: 12D and the water temperature group of 18 °C represented the higher abundance of MDA and lower abundances of SOD, GSH-Px, and CAT than other group (P < 0.05). No significant difference in intestinal microbial diversity was found among different groups (P > 0.05) except that ACE index showed significant differences among different temperature groups (P<0.05). Significant differences in the relative abundances of Proteobacteria and Tenericutes were found among different groups (P < 0.05). Modifying the duration of light exposure could effectively mitigate oxidative reactions and optimal high temperatures could suppress oxidation in juvenile S. scherzeri. However, these conditions also influenced the feeding behavior of juvenile S. scherzeri and the composition of intestinal microbiota and promoted the proliferation of pathogenic bacteria. The study provides the valuable data of the aquatic habitat of S. scherzeri.

Keywords: Siniperca scherzeri, Water temperature, Photoperiod, Oxidative stress, Intestinal microbiota