Effects of yeast and yeast extract on growth performance, antioxidant ability and intestinal microbiota of juvenile Pacific white shrimp (Litopenaeus vannamei).

An 8-week feeding trial was proceeded to assess the effects of yeast and yeast extract on growth performance, anti-oxidant ability and intestinal microbiota of Litopenaeus vannamei. Five diets supplemented with 0% (Control), 3% beer yeast (Y), 0.5% yeast extract (YE0.5), 1% yeast extract (YE1) and 2% yeast extract (YE2) respectively were assigned to L. vannamei (four replicates per diet, 30 shrimp in each replicate, initial body weight 1.38 ± 0.01 g). The results showed higher weight gain and specific growth rate in shrimp fed diet YE2 compared with those fed the Control (P <.05). Both dietary yeast and yeast extract increased condition factor of shrimp (P <.05). Whole body moisture was significantly lower in shrimp fed yeast and yeast extract than those fed diet Control (P <.05). Shrimp fed yeast extract showed higher total antioxidant capacity compared to Control group (P <.05). Shrimp fed diet YE2 obtained higher catalase and glutathione peroxidase activities than those fed diet Control, YE0.5 and YE1 (P <.05). The main phyla in intestine of shrimp were Tenericutes, Proteobacteria, Bacteroidetes, Firmicutes and Actinobacteria. With the increasing dietary yeast extract supplementation, the relative abundances of Ruegeria , and its belonging Rhodobacteraceae, Rhodobacterales, Alphaproteobacteria, Proteobacteria in intestine increased gradually, which were significantly higher than those fed diet Control and Y (P <.05). Moreover, yeast and yeast extract significantly increased the Shannon indexes of intestinal microbiota (P <.05). Overall, dietary 2.0% yeast extract supplementation significantly increased growth performance and antioxidant ability of shrimp, also enhanced microbial diversity and microbiota structure in intestine of L. vannamei. • The first time to reveal the effect of yeast extract on intestinal microbiota of L. vannamei. • 2% yeast extract supplemented improved growth performance and anti-oxidative ability of L. vannamei significantly. • Both yeast and yeast extract enhanced the stability of bacterial community in intestine of shrimp. • Yeast extract optimized microbiota structure by the increase of beneficial bacteria and decrease of pathogenic bacteria. [ABSTRACT FROM AUTHOR]