Effects of fermented Siraitia grosvenorii residue replacing part of diet on large intestinal microbial community diversity of Fufeng Ma chickens

【Objective】 The objective of this study was to explore the effects of fermented Siraitia grosvenorii residue replacing part of diet on large intestinal microbial community diversity of Fufeng Ma chickens，and to provide a reference basis for the application of fermented S. Grosvenorii residue in chicken breeding production.【Method】 Twenty 60-day-old Fufeng Ma chickens（hens）were selected and randomly divided into four groups. The diets of 3%，6%，and 9% were replaced with fermented S. grosvenorii residue respectively. The whole diet（CK replacement）was used as the control group（CK）in a feeding trial for 97 d. After feeding，the contents of the chicken large intestine were collected，and the effects of three alternative dietary proportions on the diversity of the large intestine microbial community in Fufeng Ma chickens were explored based on Illumina high-throughput sequencing technology.【Result】 The Chao1 index of the large intestinal microbial community of Fufeng Ma chickens treated with different proportions of alternative diets was ranked as CK＞replacing 9%＞replacing 3%＞replacing 6%， the Shannon index was ranked as CK＞replacing 9%＞replacing 3%=replacing 6%，and the Simpson index was ranked as CK=replacing 9%＞replacing 3%=replacing 6%. Wilcoxon test showed that there was no significant difference in the Chao1 index between the test groups and CK（ P＞0.05，the same below），indicating that the treatment of fermented S. grosvenorii residue replacing diet had no effect on the species richness of large intestinal microbial community in Fufeng Ma chickens. The Shannon index of the large intestinal microbial community of Fufeng Ma chickens replacing 3% of the diet was significantly lower than CK（P＜0.05，the same below），and there was no significant difference in the Shannon index between the other test groups and CK. The Simpson index of the large intestinal microbial community in the treatment of replacing 3% and 6% diets was significantly lower than CK，while the Simpson index of replacing 9% diets was not significantly different from CK. At the phylum level，a total of 29 bacterial phyla were annotated，among which Bacteroidetes，Firmicutes，and Proteobacteria were the absolute dominant phyla in the four groups of experiments. The relative abundance of Bacteroidetes was ranked as replacing 9%＞CK＞replacing 3%＞ replacing 6%，Firmicutes was ranked as replacing 6%＞replacing 3%＞CK＞replacing 9%，and Proteobacteria was ranked as replacing 3%＞replacing 6%＞CK＞replacing 9%. Among them，the relative abundance of Proteobacteria in the large intestinal microbial community was significantly higher than CK in the treatment of replacing 3% of the diet，while the relative abundance of Proteobacteria in the treatment of replacing 9% of the diet was significantly lower than CK. However， there was no significant difference in the relative abundance of Proteobacteria between the treatment of replacing 6% of the diet and CK. At the level of genus classification，there were significant differences in the relative abundance of Proteus genus among the four groups of experiments，with a relative abundance ranking of replacing 6%＞replacing 3%＞CK＞ replacing 9%. Among them，the abundance of Proteus genus in the treatment of replacing 9% diet was significantly lower than CK，while there was no significant difference between the treatment of replacing 3% and 6% diet and CK.【Conclusion】 Based on the conservative assessment of the effects of species richness，nutrient composition of S. grosvenorii residue and the abundance of Proteobacteria on the large intestinal microbial community in Fufeng Ma chickens，the optimal replacement proportion of fermented S. grosvenorii residue to diet is 6%.