Loss of Myostatin leads to low production of CH by altering rumen microbiota and metabolome in cattle.

Myostatin (MSTN) is a protein that plays a crucial role in regulating skeletal muscle development. Despite the known benefits of MSTN mutant cattle for increasing beef production, their potential impact on CH emissions has not been quantified. The study comparing wild-type (WT) cattle to MSTN-knockout (MSTN-KO) cattle revealed that CH production was lower. Macrogenomic analysis revealed a significant decrease in rumen archaea, with reduced Richness indices (P = 0.036). The MSTN-KO cattle also showed altered archaea distribution and composition at different taxonomic levels. LEfSe results showed changes in 21 methanogenic archaea clades, with obligately hydrogen (H)-dependent methylotrophs Candidatus Methanoplasma termitum species belonging to Methanomassiliicoccales order demonstrating the most significant decrease. Rumen metabolites revealed a decrease in the ratio of acetate to propionate, indicating a shift in rumen fermentation pattern towards propionate fermentation. Additionally, the changing trend of methanogenic archaea is consistent with the evolution of methanogens, and this is correlated with the higher levels of linoleic acid in the rumen of MSTN-KO cattle. Linoleic acid affects the utilization of H by methanogenic archaea, leading to a reduction in obligately H-dependent methylotrophs. Our study suggests that MSTN-KO cattle have potential as an economically and ecologically benign breed for reducing methane emissions.