Effects of different dietary preparations of Enterococcus faecalis F7 on the growth and intestinal microbiota of Pacific white shrimp ( Litopenaeus vannamei )

A 28-day feeding trial was conducted to evaluate the effects of different dietary preparations of Enterococcus faecalis F7 (blank control (BC), dead bacteria (DB), live bacteria (EF), cell-free extract of E. faecalis F7 (BF) and E. faecalis F7 treated with lithium chloride (Li)) on growth and intestinal microbiota of Litopenaeus vannamei. Results indicated that incorporation of live E. faecalis F7 into diet significantly improved the growth of L. vannamei by increasing weight gain rate (WGR), specific growth rate (SGR) and reducing feed conversion ratio (FCR). High-throughput sequencing data showed that incorporation of various preparations of E. faecalis F7 into diet altered intestinal microbiota richness and diversity in L. vannamei. In particular, live E. faecalis F7 improved the health of shrimp by increasing the abundance of beneficial bacteria and reducing the abundance of detrimental bacteria in the gut tract. Moreover, stability of intestinal microbiota was maintained for more than 7 days when shrimps were fed on basic diet after administration of live E. faecalis F7 for 28 days. These results demonstrate that diet enriched with live E. faecalis F7 promotes the growth and modulates the intestinal microbiota in Pacific white shrimp (L. vannamei).