Relationship of Sperm Characteristics, in Reference with DNA Fragmentation, with Fertility of Some Sheep Breeds in Egypt.

ABSTRACTThe objective of this study was to adopt an accurate in vitro test (sperm DNA damage) to predictfertility through ram spermatozoa. Semen was collected once a week for 8 collection weeks from six rams ofRahmani and Romanov breeds, 3 rams from each breed. Semen was evaluated for ejaculate volume, spermconcentration, progressive motility, livability and abnormality of spermatozoa. DNA damage test wasapplied with Halosperm kit. Results showed significant (P<0.05) individual differences in percentages ofabnormality and DNA damage in both breeds as well as in percentages of progressive motility, livabilityand total sperm output in Romanove breed. Breed had a significant (P<0.05) effect only on ejaculate volumeand total sperm output, being higher in Rahmani compared to Romanove breed. Sperm abnormality, spermcell concentration and DNA damage showed an opposite trend with respect to breed effect. Rams showedthe best semen quality in both breed had the highest conception rate (CR). Mean of CR was higher (P<0.05)in Rahmani than Romanov breed (88.38 vs. 78.79%, respectively). Percentages of progressive motility andlivability of spermatozoa were negatively correlated (P<0.05) with DNA damage and positively with CRonly in Rahmani breed. In both breeds, DNA damage had (P<0.01) a positive and strong correlation withpercentage of abnormal sperm where it was r= 0.557 in Rahmani and r=0.840 in Romanov. In addition, CRhad a positive correlation with sperm cell concentration in Rahmani and Romanove rams. The correlationbetween CR and sperm DNA damage was strong and negative (P<0.01) in both breeds (r=-0.699 forRahmani and -0.795 for Romanov). In conclusion, the present study indicated the strong negativecorrelations between sperm DNA damage percentage of abnormal spermatozoa and conception ratesespecially for Romanov rams which showed lower CR. Thus, in vitro sperm DNA damage test can used forevaluating fertility, in accompany with standard semen analysis assays.