Clinical outcome of an SCNT-derived MSTN knockout buffalo: a case study

Myostatin (MSTN) gene knockout has attracted considerable interest for enhancing meat production in livestock species due to its well-established role as a negative regulator of skeletal muscle growth. In this study, we report the clinical outcome of a bi-allelic MSTN knockout buffalo produced via somatic cell nuclear transfer (SCNT) that failed to survive beyond 100 days of age. The MSTN knockout calf exhibited a double-muscling phenotype, which was validated by changes in mRNA expression of transcripts associated with increased muscle mass and reduced subcutaneous fat. In addition, the calf had a telomere length similar to that of age-matched calves produced through artificial insemination. However, serum biochemistry analysis revealed decreased levels of globulin, GGTP, ALP, and bilirubin, alongside increased concentrations of AST, urea, blood urea nitrogen, uric acid, phosphorus, and potassium. Cytokine profiling (including IFN-γ, IL-1α, IL-1β, IL-4, IL-6, IL-8, IL-10, IL-17α, IL-36Rα, TNF-α, MIP-1α, MIP-1β, MCP-1, IP-10, and VEGF-α) demonstrated dysregulation of several inflammatory and chemotactic mediators. This case report highlights potential health and welfare challenges associated with producing MSTN knockout buffalo through cloning-based approaches.