Effect of the diet level of whole-plant corn silage on the colonic microflora of Hezuo pigs

Abstract

Background Whole-plant corn silage (WPCS) is an important roughage source for livestock, and have critical influences on rumen or intestinal microbiota, thus affecting the growth performance and feed efficiency. Our previous studies showed that adding WPCS to the diet of Hezuo pigs could promote the growth and fiber digestibility. While the aim of this study is to understand the effect of dietary WPCS on the colonic microflora in Hezuo pigs, which is essential for improving the roughage exploitation of pigs. Methods Thirty-two Hezuo pigs with similar body weight (7.88 ± 0.81) kg were selected and randomly divided into four groups with eight pigs in each group. Pigs in the control group were fed a basal diet, pigs in the experimental groups (Groups I, II, and III) were fed basal diet supplemented with 5%, 10%, and 15% WPCS, respectively, under 120 d experimental period. Six pigs from each group were picked for collecting colonic contents samples. 16S rRNA sequencing was performed to analyze the colonic microbiota of experimental pigs. Results The results showed that community richness indexes Chao1 and Observed_species in group III of Hezuo pig were significantly lower than that of the other three groups, community diversity indexes Shannon and Simpson were significantly higher in group I and II in comparison to the control group, and significantly lower in group III in comparison to the control group, group I and II. Adding WPCS to the diet of Hezuo pigs has no influence on the colonic dominant phylum, Clostridium sensu stricto 1 and Rikenellaceae RC9 gut group were most prevalent in the colon of Hezuo pig. When compared with the control group, the relative abundance of Streptococcus was significantly decreased in three experimental groups, while p-251-o5, Parabacteroides, Prevotellaceae UCG-003, Prevotellaceae UCG-001, and F082 exhibited significantly higher relative abundances in at least two experimental groups. Fibrobacter, Rikenellaceae RC9 gut group in group I, UCG-010 in group II, Bacteroides in group III exhibited increased relative abundance as compared with the control group. PICRUSt functional annotation indicated that the functions of cellular process and signaling were significantly increased in all WPCS-rationed groups, cancers, nervous system, immune system and environmental adaptation were all differed from groups I and II; three predominant pathways of translation, nucleotide metabolism and signal were only differed from the group II. Conclusions Feeding with 5% and 10% WPCS for Hezuo pigs could improve their colonic microflora diversity, and increase the relative abundance of fiber-digesting bacteria, which may potentially help to improve the fibre digestibility of Hezuo pigs by regulating the microbial function of cellular process and signaling, nucleotide metabolism, translation.