Garlic skin induced shifts in the rumen microbiome and metabolome of fattening sheep

Abstract

Background Garlic and its constituents exhibit activities on modifying rumen fermentation and improving growth performance. As a by-product of garlic processing, garlic skin contains similar bioactive components as garlic bulb. However, studies in ruminants using garlic skin are scarce. This study was conducted to investigate the effects of garlic skin supplementation on rumen fermentation characterizes, growth performance, ruminal microbes and metabolites in ruminants. Twelve Hu lambs were randomly assigned into one of two treatments: basal diet (CON) or basal diet supplemented with 80 g/kg DM of gallic skin (GAS). The experiment lasted for10 weeks, with the first 2 weeks for adaptation. Results The results revealed that the average daily gain and volatile fatty acid concentration were higher (P < 0.05) in lambs fed GAS than that in the control group. Garlic skin supplementation did not significantly (P > 0.10) affect the α-diversity indices. Increased (P < 0.05) abundances of Prevotella, Bulleidia, Howardella, Methanosphaera but a decreased (P < 0.05) abundance of Fretibacterium were observed in GAS-fed lambs. In addition, the garlic skin supplementation favorably regulated (P < 0.05) pyrimidine metabolism, purine metabolism, vitamin B6 and B1 metabolism. Moreover, high correlations were observed between fluctuant rumen microbiota and metabolites. Conclusions Supplementation of garlic skin improved the growth performance of sheep by modifying rumen fermentation through inducing shifts in the rumen microbiome and metabolome.