Semen supplementation with palmitoleic acid promotes kinematics,microscopic and antioxidative parameters of ram spermatozoa during liquid storage

The purpose of the present experiment was to investigate the protective effects of palmitoleate on the quality of ram semen during low temperature liquid storage. Ejaculates were collected using the artificial vagina from four Qezel rams twice a week. Ejaculates were pooled, diluted with Tris–egg yolk extender without palmitoleate (control) or supplemented with 0.125 (P 0.125), 0.25 (P 0.25), 0.5 (P 0.5) and 1 (P 1) mM palmitoleate at a final concentration of 500 × 10⁶ spermatozoa/ml. Total motility and forward progressive motility (FPM) as well as other spermatozoa kinematics were evaluated by computer‐assisted sperm analysis. Moreover, viability and membrane functionality were determined in the spermatozoa. Additionally, amounts of malondialdehyde (MDA), total antioxidant activity (AOA), nitric oxide (NO) and superoxide dismutase (SOD) activities were evaluated in the medium and spermatozoa at 0, 24, 48 and 72 hr of storage. The palmitoleate supplementation resulted in a significant (p < .05) increase in total motility and FPM with the highest increase at 0.5 mM concentration for 72 hr. P 0.5 group also resulted in the highest percentage of membrane‐intact spermatozoa (76.60 ± 1.95%) and viability (75.81 ± 1.34%) at 72 hr (p < .05). The amounts of MDA and NO were lower in P 0.125, P 0.25 and P 0.5 groups compared to control at 48 hr and 72 hr (p < .05). Higher amounts of AOA were obtained in palmitoleate‐treated groups in medium and spermatozoa during storage time (p < .05). Furthermore, palmitoleate supplementation increased the SOD activities in spermatozoa compared to the control (p < .05). The results of the present experiment reveal that supplementation with 0.5 mM palmitoleate improves ram spermatozoa motion characteristics, AOA levels and SOD activities during liquid storage. Then, palmitoleate could be used as an antioxidant source during liquid storage of ram semen.