Combined Effects of Dietary Bacillus subtilis and Trans-cinnamic Acid on Growth Performance, Whole Body Compositions, Digestive Enzymes and Intestinal bacteria in Rainbow Trout (Oncorhynchus mykiss)

Abstract

In this study, the combined effects of dietary Bacillus subtilis (BS, 10 7 g/cfu) and different levels (0.025%, 0.050%, 0.075% and 0.150%) of trans-cinnamic acid (CA) on fish growth performance, whole body compositions, digestive enzymes, intestinal bacteria and internal organ index of rainbow trout (Oncorhynchus mykiss) were investigated. Six different experimental groups including control group (C), C+BS, 0.025%CA+BS, 0.050%CA+BS, 0.075CA+BS, 0.150%CA+BS) were established. According to the results obtained, growth performance, whole body compositions and digestive pH were not statistically significant among groups. Further, no significant differences were found between experimental groups in terms of the intestinal enzymes (trypsin, alkaline phosphatase and lipase) and gastric pepsin. Significantly higher levels of intestinal amylase were found in the control+BS, 0.025%CA+BS, 0.050% CA+BS, and 0.075%CA+BS compared to the control and 0.150%CA+BS groups. Moreover, coliform and Enterobacteriaceae counts were highest in the control+B. subtilis and lowest in the 0.150% CA + B. subtilis groups.