The effect of teprenone on the intestinal morphology and microbial community of Chinese sea bass (Lateolabrax maculatus) under intermittent hypoxic stress

Hypoxia stress may affect the fish intestine and thereby threaten the growth and survival of the fish. Teprenone is a clinically effective agent in protecting gastrointestinal mucosa. This study aims to assess the effect of teprenone in the intestine of Chinese sea bassLateolabrax maculatusunder intermittent hypoxic stress.L. maculatusjuveniles were either raised under intermittent hypoxic condition or normal condition (NC). Part of the hypoxic-intervened fish were treated with teprenone at different concentrations (HTs), and the rest were regarded as hypoxic control (HC). Histological analysis was performed on the epithelial tissue of the fish intestine. High-throughput sequencing technology was used to analyze the diversity and composition of the microbial community inL. maculatusintestine. Reduced villi length and goblet cell, exfoliated enterocyte, and improper arrangement of villi were observed in HC compared with NC and HTs.Proteobacteria,Firmicutes, andBacteroidetesrepresented the most abundant phyla in each sample. Significantly higher microbial diversity was detected in HC compared with NC (P < 0.05). At the phylum level, HC presented significantly decreased relative abundance ofProteobacteria, and significantly increased relative abundance ofBacteroidetes,Chloroflex, andCyanobacteriacompared with NC (P < 0.05). At the class level, HC showed significantly reduced relative abundance ofAlphaproteobacteriaandBacilli, and significantly increased relative abundance ofClostridia,Gammaproteobacteria, andBacteroides(P < 0.05). Teprenone protects the intestine from epithelial damages and maintains the microbial harmony inL. maculatusunder intermittent hypoxic stress.