Investigation of apparent digestibility, caecal fermentation and microbiota of rabbit fed with raffinose

The present study aimed to investigate the influence on caecal microbial communities of the supplementation of raffinose (RA) in rabbit's diet, also considering apparent digestibility and caecal fermentation. Rabbits (n = 120) with a similar weight were randomly divided into four groups and fed a basal diet (RA0) and a basal diet supplemented with 0.5 g/kg RA (RA0.5), 1 g/kg RA (RA1) and 2 g/kg RA (RA2), respectively. 16 s rRNA high-throughput sequencing of the V3–V4 segment of the bacterial was performed on each group (n = 6). The results showed that, compared with the control group, dietary 0.5 g/kg RA inclusion improved the digestibility of crude protein (CP) (P < 0.05). Meanwhile, the proportion of volatile fatty acids, including propionate and butyrate, in the RA0.5 and RA1 groups were increased compared with the RA0 group (P < 0.05). Moreover, the microbiota diversity and richness of the cecum in RA0.5 group were significantly higher than other groups (P < 0.05). Furthermore, at the phylum level, dietary 0.5 g/kg RA increased the relative abundance of Bacteroidetes and Actinobacteria (P < 0.05); At the genus level, feeding 0.5 g/kg RA increased the relative abundance of Subdoligranulum (P < 0.05). Phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis revealed potential metabolic changes associated with RA treatment, the microbial genes involved in the chlorocyclohexane and chlorobenzene degradation, phosphonate and phosphinate metabolism and methane metabolism pathways were all decreased in the present study (P < 0.05). Overall, diet supplemented with 0.5 g/kg RA is effective in improving CP digestibility and caecal fermentation, optimizing the cecum microflora of rabbits.