Use of a paraprobiotic and postbiotic feed supplement (HWF™) improves the growth performance, composition and function of gut microbiota in hybrid sturgeon (Acipenser baerii x Acipenser schrenckii).

The contribution of cold water aquaculture for the world fish production is significant. Although sturgeon farming is an important part of China's cold water aquaculture industry, its production is less compared with the current potentiality of the country. There are many reasons for the lower production of cold water fish farming including feed and disease. The aim of the present study was to investigate the effect of a paraprobiotic and postbiotic feed supplement (Herpes Worry Free or HWF™) on the growth, feeding efficiency and gut microbiota balance of hybrid sturgeon. Besides, the effect of sturgeon gut microbiota fed on the diet supplemented with HWF™ on the expression of growth promoter, and immune regulatory genes of germ free (GF) zebrafish was evaluated. Sturgeon were fed for three weeks with HWF™ supplemented or basal diet. At the end of the experiment gut content of sturgeon, fed on either experimental diet was transferred and colonized to GF zebrafish. Sturgeon fed with HWF™ supplemented diet showed significantly higher weight gain rate and lower feed conversion ratio (FCR) as compared with the control (P < 0.05). Compared with the control group, the relative abundance of Firmicutes, were significantly higher in the HWF™ group (P < 0.05), whereas Proteobacteria, Actinobacteria and Chlamydiae were significantly higher in the control group (P < 0.05). Furthermore, at the genus level Clostridium (64.50 ± 5.99%) and Lactococcus (29.5 ± 3.05%) were the most dominant gut bacteria in the HWF™ group and the control group of sturgeon, respectively. The expression of genes related to growth, inflammation and non-specific immunity was significantly upregulated in GF zebrafish colonized with gut microbiota of HWF™ sturgeon group. In conclusion, HWF™ played significant role in growth, feed efficiency and modulation of gut microbiota of sturgeon. The gut microbiota of sturgeon fed on the diet supplemented with HWF™ upregulated the expression of genes related to growth, inflammation and non-specific immunity in GF zebrafish model. • Dietary HWF™ improved weight gain and feed conversion ratio of hybrid sturgeon. • Dietary HWF™ improved the composition of gut microbiota of hybrid sturgeon. • The expression of growth promoter and immune regulatory related genes was upregulated in GF zebrafish colonized with HWF™ induced gut microbiota. [ABSTRACT FROM AUTHOR]