Semen quality and biochemistry and blood antioxidant status in Mehraban rams supplemented with organic selenium alone or combined with organic chromium during the summer

Abstract

The effects of organic selenium (Se) alone or combined with organic chromium (Cr) on semen quality and metabolites and blood antioxidant status was evaluated during the summer in rams. Fourteen Mehraban rams (2-4 years, BSC 2.5-3.5, initial body weight 70.14 ­kg) were divided in to four groups (n=4) and two levels of Se (0 and 0.6 mg/ram/day, inactive dry Se-yeast) were tested at two levels of Cr (0 and 1 mg/ram/day, Cr-methionine) in a completely randomized design with 2×2 factorial layout for 60 days. Body weight changes and scrotal circumference (SC) were recorded fortnightly. Semen quality and metabolites, rams libido, spermatozoa motion characteristics, blood ferric reducing ability (FRAP) and thiobarbituric acid reactive substances (TBARS) were measured during the experiment. Body weight, dry mater intake and SC were not affected by treatments. Chromium alone increased FRAP, libido and sperm linearity and combined with Se increased spermatozoa viability, membrane integrity and decreased semen glucose and alkaline phosphatase activity (P≤0.05). Main effect of Cr tended to increase EV (P=0.095). Abnormal spermatozoa and TBARS decreased by Cr, Se or by their combination. Selenium alone had higher sperm concentration compared to its combination with Cr (P≤0.05). Average path velocity was numerically higher by Se alone and curvilinear velocity was lower by combined with Cr, but the difference was not significant (P>0.05). In conclusion, Cr and Se supplementation of rams during the summer improved semen quality and blood antioxidant status. However, co-supplementation of Cr and Se had no more additional effects on studied parameters.