Effects of an astaxanthin-containing supplement on oxidative status in skeletal muscle and circulation during deconditioning and reconditioning periods in polo ponies.

This study investigated the effects of astaxanthin (ASTX) supplementation on oxidative status during a deconditioning-reconditioning cycle. Twelve polo ponies were assigned to no supplementation (CON) or an ASTX supplemented group, which received oral administration of a supplement containing 75 mg ASTX daily for 32 weeks. Polo ponies underwent a 16-week deconditioning period (DECON) followed by a 16-week reconditioning program (RECON). Submaximal exercise tests (SETs) were performed at the beginning of the study (Baseline), after DECON, and after RECON. Blood samples were collected at -30, 0, 15, 30, and 60 min relative to each SET for oxidative status analysis. Muscle samples were collected 2 weeks before (Pre-Ex) and 2 h after (Post-Ex) each SET for muscle oxidative status and gene expression analyses. Pre-Ex muscles were analyzed for high-resolution respirometry. Circulating glutathione peroxidase (GPX) activity was increased (p ≤ 0.02) and protein carbonylation was decreased in ASTX (p ≤ 0.05). Muscle oxidative status was affected by DECON and reconditioning (p ≤ 0.05). ASTX increased gene expression of PPARGC1A after reconditioning (p ≤ 0.05). Deconditioning reduced oxidative phosphorylation at complex I and II (p = 0.01). Thus, a deconditioning-reconditioning cycle had greater impacts on muscle oxidative capacity than ASTX supplementation.