Gut microbiota induced by dietary GWF? contributes to growth promotion, immune regulation and disease resistance in hybrid sturgeon (Acipenserbaerii x Acipenserschrenckii): Insights from a germ-free zebrafish model

Gut microbiota of aquatic animals have a crucial impact on several host physiological processes and some of commensal bacteria may have the potential to be used as probiotics. The aim of the present study was to investigate the effects of hybrid sturgeon (Acipenserbaerii x Acipenserschrenckii) gut microbiota induced by growth worry free (GWF (R)) on the growth, immune regulation and disease resistance in sturgeon using a germ free (GF) zebrafish model. Sturgeons were fed for three weeks with GWF (R) supplemented or basal diet. At the end of the experiment gut microbiota of sturgeon, fed on either experimental diet were transferred to GF zebrafish for three days. Then the expression of growth promotion, inflammation and non-specific immune related genes were assessed. Moreover, zebrafish colonized with either the experimental microbiota were challenged with Aeromonas veronii Hm091 for two days. Results indicated that the expression of growth promotion related genes (mTOR, MYoD, Myogenin) and non-specific immune related genes (DEFBL-1, lysozyme, C3a, and anti-inflammatory gene TGF-beta), was significantly up-regulated in GF zebrafish colonized with microbiota from GWF (R) sturgeon (P<.05), whereas the expression of pro-inflammatory gene IL-1 beta was significantly decreased (P<.05). Moreover, group of GF zebrafish colonized with microbiota from GWF (R) sturgeon had significantly higher survival rate against A. veronii Hm091 (P<.05). Our study suggests that, the gut microbiota of sturgeon induced by GWF (R) played a great role in growth, immune system improvement and disease resistance in sturgeon using a germ free zebrafish model.