Correlation of the rumen fluid microbiome and the average daily gain with a dietary supplementation of Allium mongolicum Regel extracts in sheep1.

Plant extracts can affect the rumen microbiome and ADG in ruminants, and studies of the association between the rumen microbiome and ADG provide information applicable to improving ruminant growth performance. The objectives were to investigate the effects of Allium mongolicum Regel extracts on the rumen microbiome and ADG and their association in sheep. Forty healthy, male, small-tailed Han sheep (6 mo, 34 ± 3.5 kg body weight) were randomly assigned to 1 of the following 4 dietary treatments: basal diet as control group (CK, n = 10), basal diet supplemented with 3.4 g·sheep-1·d-1A. mongolicum Regel powder extract as PAM group (PAM, n = 10), basal diet supplemented with 10 g·sheep-1·d-1A. mongolicum Regel powder as AM group (AM, n = 10), and basal diet supplemented with 10 g·sheep-1·d-1A. mongolicum Regel powder extract residue as RAM group (RAM, n = 10). The ADG for individual sheep was calculated using the sum of the ADGs observed during the experimental period divided by the number of days in the experimental period. At the end of the experiment, sheep were randomly selected from each treatment for slaughter (n = 6), and the rumen fluids were collected and stored immediately at -80 °C. Illumina HiSeq was subsequently used to investigate the changes in the rumen microbiome profile, and the associations with ADG were analyzed by Spearman correlation coefficient analysis. The results demonstrated that, compared with that in CK group, the ADG in AM and RAM significantly increased (P = 0.0171). The abundances of Tenericutes and Mollicutes ([ρ] = 0.5021, P = 0.0124) were positively correlated with ADG. Within Mollicutes, the abundances of Anaeroplasmatales ([ρ] = 0.5458, P = 0.0058) and Anaeroplasmataceae ([ρ] = 0.5458, P = 0.0058) were positively correlated with ADG. The main negatively correlated bacteria were Saccharibacteria ([ρ] = -0.4762, P = 0.0187) and Betaproteobacteria ([ρ] = -0.5669, P = 0.039). Although Anaeroplasmatales and Anaeroplasmataceae were positively correlated with ADG, Saccharibacteria and Betaproteobacteria were negatively correlated with ADG. In conclusion, supplementation with A. mongolicum Regel powder and extracts will influence the rumen microbiome and increase the ADG.