The Effects of Selenium on Rumen Fermentation Parameters and Microbial Metagenome in Goats

Abstract

This study evaluated the effects of selenium yeast (SY) on rumen fermentation parameters, rumen bacterial diversity, and expression pathways in goats. A total of 18 Qianbei-pockmarked weather goats from Guizhou (body weight, 25.75 ± 1.75 kg; mean ± standard deviation) were assigned to three groups according to a completely randomized design. Control group (CON, n = 6) kids were fed a basal diet, while treatment 1 (LS, n = 6) and treatment 2 (HS, n = 6) kids were fed a basal diet with 2.4 and 4.8 mg/kg SY, respectively. The feeding trial lasted for 74 days. The results indicated that the ruminal fluid of LS goats had significantly higher levels of propionic, caproic, isobutyric, and isovaleric acids than that of the CON. The levels of butyric and valeric acids were higher in the HS group than in the CON. The acetate:propionate ratio was significantly higher in the CON than in the two treatments. In addition, the inclusion of 2.4 mg/kg SY can lead to a significant decrease in the relative abundances of Euryarchaeota, and Proteobacteria at the phylum level compared to the CON and the HS groups. At the genus level, the LS group had a significant decrease in the relative abundance of Methanobrevibacter and Sarcina, whereas it could lead to a significant increase in the relative abundance of Clostridium in the ruminal fluid relative of the other two groups. At the species level, the LS group had a significant decrease in the relative abundance of bacterium_P3, bacterium_P201, and Sarcina_sp._DSM_11001 compared to the other groups. Moreover, the CON group had a significant decrease in the relative abundance of bacterium_P201 compared to the other two treatments. Compared to the CON, the addition of 2.4 mg/kg SY significantly enriched carbohydrate metabolism pathways in the ruminal fluid for gene encoding. Additionally, goats receiving SY showed a significant upregulation of glycosyl transferase and carbohydrate binding module pathways. These results suggest that dietary supplementation with SY modulates fermentation parameters, and it affects microbial diversity and microbial metagenome in the rumen of Qianbei-pockmarked goats.