This study evaluated the effects of the different dietary zinc (Zn) levels on semen quality, on spermatozoa and seminal plasma antioxidant status, and on the seminal and blood plasma mineral status in mature male Cashmere goats during the breeding season. Twenty-eight mature male Liaoning Cashmere goats were divided into four groups based on body weight (56.2 ± 2.45 kg) and semen characteristics; these goats were fed with basal diet supplemented with 0, 20, 40, or 80 mg Zn/kg DM (zinc sulfate) for 3 months. Results showed that the Zn-supplemented diets linearly increased the semen volume (0.98, 1.04, 1.27, and 1.17 ml for the 0, 20, 40, and 80 mg Zn/kg DM supplementation, respectively) (P < 0.05) and the total sperm output (3.87, 4.52, 5.73, and 5.33 × 109/ml for the 0, 20, 40, and 80 mg Zn/kg DM supplementation, respectively) (P < 0.05); by contrast, Zn supplementation exerted no effect on sperm concentration, motility, and abnormal sperms rate. The activities of copper zinc superoxide dismutase (CuZn-SOD) (linear P < 0.05) and glutathione peroxidase (GSH-Px) (linear P < 0.05; quadratic P < 0.01) were highest in the intermediate supplementation (40 mg Zn/kg DM). Moreover, the malondialdehyde (MDA) content of spermatozoa decreased linearly (P < 0.01) with the increase in Zn supplementation. In seminal plasma, the highest GSH-Px activity was observed in 20 mg Zn/kg DM supplementation (P < 0.05). Catalase (CAT) activities both in the spermatozoa and seminal plasma showed no difference in all treatments. Seminal plasma Zn level was highest in 40 mg Zn/kg DM (linear P = 0.068), and K increased linearly (P = 0.001) with increasing Zn level. Furthermore, blood plasma Zn (linear P < 0.01; quadratic P < 0.05), Fe (linear P < 0.05; quadratic P < 0.05), and Mg (linear P < 0.05) increased with increasing Zn supplementation. These results indicated that dietary Zn supplementation in Cashmere goats during the breeding season improved the semen quality and quantity, elevated the antioxidative indices and Zn concentration, and decreased the MDA content both in spermatozoa and seminal plasma.
Keywords: Antioxidant ability; Cashmere goat; Mineral profile; Semen quality; Zinc.