Skeletal muscle mitochondrial bioenergetics and associations with myostatin genotypes in the Thoroughbred horse.
Authors: Rooney Mary F, Porter Richard K, Katz Lisa M, Hill Emmeline W
Journal: PloS one
Summary
# Editorial Summary: Myostatin Genotype and Mitochondrial Function in Thoroughbreds Myostatin genetic variation influences not only muscle fibre composition and body type in Thoroughbreds, but also the underlying cellular capacity for energy production—a finding with significant implications for training and conditioning strategies. Researchers examined muscle biopsies from 82 untrained young Thoroughbreds, measuring mitochondrial abundance, fibre type distribution and the activity of key mitochondrial enzyme complexes across three distinct myostatin genotypes. Horses carrying the C-allele and SINE insertion polymorphism showed notably lower mitochondrial content yet paradoxically higher complex I+III and II+III enzyme activities, whilst animals homozygous for the T-allele and lacking the insertion (TT/NN) demonstrated reduced expression of genes governing coenzyme Q biosynthesis and lower CoQ availability—deficiencies that were partially corrected when coenzyme Q was added to muscle samples in vitro. These findings suggest that myostatin genotype fundamentally shapes mitochondrial phenotype and bioenergetic capacity in young horses, offering potential targets for nutritional intervention; practitioners working with TT/NN-genotyped horses might consider CoQ supplementation to support aerobic capacity during early training, whilst recognising that C-allele carriers may have different metabolic optimisation requirements. Further investigation into how these genotype-dependent mitochondrial signatures influence athletic performance and trainability across different distances and disciplines would strengthen evidence-based conditioning programmes.
Read the full abstract on PubMed
Practical Takeaways
- •MSTN genotype influences skeletal muscle composition and mitochondrial function in young Thoroughbreds, with TT/NN horses potentially compromised in energy production capacity
- •Consider CoQ supplementation in TT/NN genotype horses to optimize mitochondrial function and athletic performance
- •Genetic testing for MSTN variants could inform training programs and supplement strategies, particularly for young or underperforming horses
Key Findings
- •Skeletal muscle fiber type proportions differed significantly among three MSTN genotypes (p<0.01)
- •Mitochondrial content was significantly lower in horses with C-allele/I insertion combination (p<0.01)
- •TT/NN genotype horses showed decreased coenzyme Q biosynthesis gene expression (COQ4, ADCK3) and reduced mitochondrial complex activities
- •Exogenous CoQ1 supplementation restored mitochondrial complex I+III and II+III activities in TT/NN cohort, suggesting CoQ deficiency