| dc.description.abstract | Mitochondrial health is pertinent to optimizing athletic performance and is maintained in part by dietary antioxidants such as selenium (Se) and vitamin E (vitE). Mitochondrial adaptations to elevated dietary Se coupled with decreased vitE have not yet been determined. Young Quarter Horses (mean ± SEM; 17.6 ± 0.2 mo) were used to test the hypothesis that horses receiving a proprietary antioxidant blend containing Se yeast (EconomasE, Alltech, Inc., Nicholasville, KY) would have improved mitochondrial characteristics compared to horses receiving Se and vitE at current requirements, regardless of reduced vitE intake. Horses were balanced by age, sex, BW, and farm of origin and randomly assigned to one of three customformulated concentrates fed at 1% BW (DM basis): 1) 100 IU vitE/kg DM and 0.1 mg Se/kg DM (CON, n = 6), 2) no added vitE plus EconomasE to provide 0.1 mg Se/kg DM (ESe1, n = 6), or 3) no added vitE plus EconomasE to provide 0.3 mg Se/kg DM (ESe3, n=6). Tissue was collected from the gluteus medius at wk 0 and 12 of dietary treatment and evaluated for mitochondrial enzyme activities by kinetic, colorimetry and mitochondrial capacities by highresolution respirometry. Data were analyzed using PROC MIXED in SAS v9.4 with repeated measures (time) and fixed effects of time, diet, and time × diet; horse(diet) served as a random effect. Mitochondrial number (citrate synthase activity; CS), function (cytochrome c oxidase activity; CCO), and integrated (per mg tissue) oxidative (P) and electron transport (E) capacities increased from wk 0 to 12 in all horses (P ≤ 0.05). Intrinsic (relative to CS) CCO activity and P and E capacities, decreased from wk 0 to 12 (P ≤ 0.02). Horses in CON had higher integrated P with complex I and II substrates (PCI+II), ECI+II, and ECII than ESe1 throughout the study (P ≤ 0.03); integrated ECII was also higher in CON than ESe3 (P = 0.03).
Results from the current study suggest that feeding EconomasE to provide 0.3mg Se/kg DM may prevent adverse effects of removing 100 IU dietary vitE/kg DM on mitochondria in young horses. | en |
