Effects of Chinese Herbal Formulas on Gut Microflora to Juvenile Chinese Softshell Turtles Pelodiscus sinensis Wiegmann

Abstract

As a natural “green” feed additive, Chinese herbal medicines (CHMs) are extensively used in aquaculture. Nevertheless, little information is obtainable regarding the performance of CHMs on the composition of gastrointestinal microbiota in healthy juvenile Pelodiscus sinensis. Here, we investigated the intestinal microbial community composition of P. sinensis fed with artificial feed added with CHM feeding additive. Three hundred juvenile P. sinensis (3.92 ± 0.08 g) were randomly divided into 5 groups in quadruplicate. 0.0%, 1.0%, 2.0%, 3.0%, and 4.0% of CHMs were added to the control group (CG), test group 1 (TG1), test group 2 (TG2), test group 3 (TG3), and test group 4 (TG4), respectively. After the aquaculture experiment was completed, the intestinal microbial community of P. sinensis was examined by 16S rDNA sequencing method. The results showed that the relative abundance of Proteobacteria and Firmicutes were the two most dominant phyla, and there were significant differences in TG1, TG2, TG3, and TG4 compared to the CG. The abundance of phylum Proteobacteria and genus Citrobacter increased with the increase of the dose of CHMs (p < 0.05), while a clear decrease in the relative abundance of phylum Firmicutes and genus Romboutsia, genus unclassified_f_Enterobacteriaceae, and genus Clostridium_sensu_stricto_1 was observed in the CHMs groups (p < 0.05), which could be considered as the indicators of the medication due to CHMs as a feed additive modulating the gut microbiota. The results of this study indicated that dietary supplementation with 2.0% of CHM feeding additive could significantly improve the intestinal microbiota composition of juvenile P. sinensis.