Inactivation of the MSTN gene expression changes the composition and function of the gut microbiome in sheepOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study asked how inactivating the myostatin (MSTN) gene reshapes the gut microbiome of sheep. Myostatin normally limits muscle growth, so editing it out increases muscle mass. Researchers used CRISPR/Cas9 MSTN-edited Tan sheep and wild-type controls. They collected rectal fecal samples and ran shotgun metagenomic sequencing on the Illumina platform. They compared microbial diversity, taxonomic composition, KEGG functional pathways, and carbohydrate-active enzymes (CAZymes) between edited and wild-type animals. They also measured slaughter traits and meat quality.
Who was studied?
The subjects were domestic sheep, all 1.5 years old, housed at a single farm in Ningxia, China. Microbiome sequencing covered 16 MSTN-edited sheep (8 female, 8 male) and 16 wild-type sheep (8 female, 8 male). A separate slaughter comparison used 3 MSTN-edited males and 3 wild-type males for carcass and meat-quality testing. Sexes were analyzed separately to remove sex effects. Only microbes changing in the same direction in both sexes were carried forward as robust signals.
What were the most important findings?
MSTN-edited sheep had significantly higher body weight, carcass weight, and eye muscle area, with no difference in meat quality. Alpha diversity differed, and community composition separated clearly by PCoA. Firmicutes rose and Bacteroidota fell in edited sheep, raising the Firmicutes/Bacteroidota ratio in females. At genus level, Flavonifractor, Subdoligranulum, Ruthenibacterium, Agathobaculum, Anaerotignum, Oribacterium, and Lactobacillus increased significantly (P < 0.05). Functionally, carotenoid biosynthesis rose, while peroxisome, apoptosis, ferroptosis, N-glycan biosynthesis, thermogenesis, and adipocytokine pathways fell. CAZymes GH13_39, GH4, GH137, GH71, and PL17 rose; GT41 and CBM20 dropped.
What are the greatest implications of this study?
The results suggest a host muscle-growth gene indirectly reshapes hindgut microbes, enriching short-chain fatty acid producers that may support gut health and nutrient absorption. The authors frame the higher Firmicutes abundance as an adaptation to greater energy needs of larger muscle. This is an association in edited sheep, not proven causation. For livestock breeding, the data indicate MSTN editing can raise growth performance without degrading meat quality. Metabolomic validation would be needed to confirm the proposed health benefits.