Hypoxic stress divergence time and metabolism-associated gut microbiome signatures — The strategy is to oxygenate for fat greenling (Hexagrammos otakii)

Abstract

Hypoxic stress has always been closely related to the physiology of fishes, but the impacts on the gut microbiota and metabolism have not been fully resolved. In this study, we analyzed the interaction between gut microbiota and host metabolism during hypoxic stress, and reveal the mechanism of growth retardation in fat greenling (Hexagrammos otakii) subjected to hypoxic stress over time. During ongoing hypoxic stress, the oxidative stress and inflammation responses significantly increased over three days compared to the control group, and these changes were restored over fifteen days. Next, we characterized changing microbial communities at different periods of hypoxic stress, and validated the communities for different fish groups subjected to hypoxic stress, based on which we found the temporal dynamics of gut microbiota. Among groups subjected to hypoxic stress, increased inflammatory (IL-1β and TNF-α) response was associated with sphingosine-1-phosphate (metabolites) and Aliivibrio (microbiota) through three days of hypoxia, as compared to the control group and individuals with shorter hypoxic stress (12h). This pattern under extended hypoxic stress (15 days) suggested that arginine and Exiguobacterium play regulating roles during the adaptation process (7–9 days) in H. otakii. These results have important implications for the understanding of the effects of aquaculture and environmental conditions upon H. otakii and offer potential contributions to an ongoing assessment of hypoxic effects upon fishery resources.