Effects of oyster (Crassostrea gigas) supplementation on the function of skeletal muscles in SD rats

Oysters are rich in taurine, an amino acid essential for skeletal muscle function. Seasonal and regional variations in taurine content in Crassostrea gigas from Hiroshima and Hyogo ranged from 546.0 ± 20.6 to 1081.1 ± 28.1 mg/100 g. To evaluate physiological effects, Sprague-Dawley rats were orally administered oyster homogenates for 10 days. Taurine levels significantly increased in plasma (130.4 ± 5.3 μmol/L vs. 97.8 ± 5.4 μmol/L, P < 0.05) and in the gastrocnemius muscle (60.7 ± 2.5 μmol/g vs. 52.1 ± 1.6 μmol/g, P < 0.05). Expression of myocyte enhancer factor 2 A, succinate dehydrogenase (SDH), and GLUT4 genes was upregulated (1.3–1.7 times), and phosphorylated AMP-activated protein kinase (AMPK) increased in the soleus muscle (1.6 times, P < 0.05). Enhanced mitochondrial activity was also supported by increased SDH staining and mitochondrial DNA content. These results suggest that oyster supplementation improves skeletal muscle oxidative capacity, potentially via AMPK activation. • Taurine content in oysters from Hiroshima and Hyogo showed consistent seasonal variation, peaking between January and March. • Oyster supplementation increased taurine levels in plasma and skeletal muscles and enhanced AMPK phosphorylation. • Oyster intake promoted mitochondrial biogenesis in skeletal muscles with upregulation of MEF2A, SDH, and GLUT4.