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.

Does MnTBAP ameliorate DNA fragmentation and in vivo fertility of frozen-thawed Arabian stallion sperm?

Overproduction of reactive oxygen species during sperm freeze-thawing process leads to membrane lipid peroxidation, DNA damage, motility loss, and subsequent death. This oxidative stress can be alleviated by the addition of some antioxidants to semen extenders prior to freezing. This study was performed to evaluate the in vitro effectiveness of MnTBAP (a cell permeable antioxidant) on stallion sperm freezability and in vivo fertility rate. Twenty-one ejaculates were, collected with missouri model artificial vagina (n = 3 stallions, seven ejaculate each), and diluted (1:2 v/v) with phosphocaseinate base INRA extender, containing 0 (control), 100, 200 and 300 µM of MnTBAP and frozen using acontrolled-rate freezing system. The following parameters were determined: sperm motility, viability, membrane integrity, acrosome abnormalities, lipid peroxidation and DNA fragmentation. MnTBAP improved horse semen quality parameters in a dose-dependent manner. The100 µM concentration of MnTBAP did not show a significant difference in semen parameters compare with control group (p > 0.05). Accordingly, the extender supplemented with 200 µM resulted in higher sperm total and progressive motility (55.3 ± 4.28% and 33.2 ± 2.90%), viability (43.9 ± 2.14%), and membrane integrity (50.8 ± 2.14%), provided a greater protective effect in the percentage of total abnormalities compare to other groups (p < 0.05), and showed lower sperm with damaged DNA with lower MDA levels (p < 0.001). Higher concentrations (300 µM) not only did not improve the results but inversely affected sperm parameters. Twelve mares were used for fertility trial in the cross over study of 60 deep horn inseminations performed using control (9/30 pregnancy/mare) and 200 µM - MnTBAP (14/30 pregnancy/mere) groups frozen semen. The Average pregnancy rates were not significantly different between control and treated group (30% and 46.66%respectively) (p > 0.05). Under the conditions of this study, 200 µM - MnTBAP reduced the oxidative stress and protect the DNA fragmentation of Arabian stallion sperm during cryopreservation; but did not improved pregnancy rates.