Effects of low and high levels of nano-selenium on intestinal microbiota of Chinese tongue sole (Cynoglossus semilaevis).

Abstract Nano-selenium (Se) has attracted growing attention due to its high bioavailability, low toxicity and its possible applications in the prevention of oxidative damage in animal tissues. Recent research works have conveyed that the use of nano-seleniumas food additive could have positive effects on the nutrition of aquatic animals.In this study, the intestinal bacterial communities associated with low and high concentrations of nano-selenium in the diet of Chinese tongue sole were characterized, through 16S rRNA V3–V4 sequencing.Samples were derived from fish fed with diet containing different nano-selenium level, 0 mg/kg for the control group, 1.6 mg/kg for low dose group, and 2.4 mg/kg for high dose group The intestinal microbial community structure showed a low overall diversity, among which the vibro genus occupied the most important position with more than 90% relative abundance in all three group. Significant differences in specie diversity occurred between the nano-selenium treated (both low dose [IL] and high dose [LH]) groups and the control group(IC). Acinetobacter, Arthrobacter, and Streptophytes were the top three enriched genera after the treatment with nano-selenium compared to IC. Meantime, the weight gain rate of the LH group was 9% higher than control. The results revealed the effect of nano-selenium on microbial community structure of gut and growth performance of C.semilaevis, Future research exploring the interaction mechanism between micronutrients and the microbial communities would increase our understanding of the fish nutrition.