Effect of feeding pomegranate seed oil as a source of conjugated linolenic acid on Arabian stallion semen quality in cooled and postthawed condition

The objective was to assess the influence of pomegranate seed oil supplementation on the quality of fresh, cooled and frozen–thawed Arabian breed stallion semen. Eight stallions (n = 4 per group) received their normal diet (control group) or normal diet top dressed with 200 ml of pomegranate seed oil (PSO group). Semen was collected every fifteen days for 90 days. Stallions were reversed across the treatments after a sixty‐day interval. In cooled and stored condition (2, 12 and 24 hr), spermatozoa motion characteristics, membrane integrity, viability, morphology and lipid peroxidation were analysed. In frozen–thawed semen, sperm dynamic characteristics were analysed by CASA, acrosome status and mitochondrial activity (evaluated by Flow cytometry) determined. The effects of treatment, time, semen type and their interactions were submitted to PROCMIX (SAS^®), and means compared by the Tukey test. Also, collected semen samples were artificially inseminated to evaluate fertility and pregnancy rate after day 60 of the experiment. The results from fresh condition showed that semen volume, sperm concentration, abnormality and live sperm were not affected by dietary treatment (p > 0.05). In cooled condition, the higher value for sperm plasma membrane integrity and viability was observed in PSO group compared to control after 24 hr cooled and stored in 5°C. In postthawed condition, the higher value for CASA total motility and acrosome status was observed in PSO group compared to control group (p < 0.05). One hundred and twenty‐six mares were artificially inseminated for fertility trial using control and PSO groups’ fresh semen. The average pregnancy rates were not significantly different between control and treated group (62.88% and 65.90%, respectively) (p > 0.05). We concluded that under the conditions of this study, dietary supplementation of 200 ml pomegranate seed oil seems to relatively improved Arabian horse sperm quality during storage in cooled and frozen condition via increasing plasma membrane integrity, viability and acrosome status, but did not improve the pregnancy rates.