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145 Comparison of skeletal muscle citrate synthase activity across equine breeds

2021; Elsevier BV; Volume: 100; Linguagem: Inglês

10.1016/j.jevs.2021.103608

1542-7412

Hailey Iglewski, Marisa L. Henry, Clara Fenger, Joe D. Pagan, Erica C. McKenzie, Stephanie J. Valberg,

Veterinary Equine Medical Research

Skeletal muscle citrate synthase (CS) activity serves as a marker for muscle oxidative capacity. CS activity was compared among Quarter Horses (QH), Arabians (AR), Thoroughbreds (TB), Standardbreds and Warmbloods at various ages and stages of training. Gluteus medius muscle biopsies were obtained at ages 6–23 m (n = 10), 2 y (n = 37), 3 y (n = 44) and >3 y (n = 55). Disciplines included reining (QH n = 17), ≥ 50-mile endurance (AR n = 20), racing (TB n = 47, STD n = 14) and dressage (WB n = 15). CS activity was measured fluorometrically. An unpaired t-test or one-way ANOVA compared age groups within breeds and age groups across breeds. A 2-way ANOVA compared breed and age effects across 2 and 3 y-old QH and TB, 3 and 4–7 y-old WB (insufficient numbers of 2 y-old AR and STD). CS was significantly lower in 2 y-old QH than either 2 y-old TB (43% higher, P < 0.0001) or 3 y-old WB (12%, P = 0.018). CS did not differ between 3 y-old QH and 3 y-old TB and was higher in 3 y-old TB than 4–7 y-old WB (P = 0.046). Within breeds, CS was lower in 3 y in training.