The impact of retrieval method and breed on the motility and kinematic parameters of fresh and post-thaw ram epididymal spermatozoa

Abstract

This study was conducted to develop ideal post-mortem gamete retrieval and conservation methods to establish a Hungarian ex-situ in vitro gene bank. Pairs of testes from German Mutton Merino (n = 7) and Hungarian Black Racka (n = 7) rams were collected at a slaughterhouse, transported to the laboratory and stored overnight (4-5 °C) before processing. Post mortem ram epididymal spermatozoa (REPS) were obtained from the cauda epididymidis by slice or incision methods. Fresh samples were extended to 200 × 106/mL cell concentration, filled into mini straws and equilibrated at 5 °C for 2 h. Freezing was performed manually in a Styrofoam box. The fresh and post-thaw total motility, progressive motility and kinematic parameters of REPS were assessed using the CASA technique. The collection method did not affect significantly the fresh and post-thaw motility and kinematic parameters. Merino had higher (P < 0.05) testicular weight. Racka had significantly better fresh and post-thaw linear movement but had statistically the same (P > 0.05) cryotolerance as Merino. In conclusion, both collection methods were found suitable for REPS retrieval. The REPS from Racka exhibited better linear movement values than those from the Merino breed. The cryotolerance of REPS of both breeds was comparable.

Keywords: German Mutton Merino; Hungarian Racka; collection methods; cryopreservation; epididymal spermatozoa; ram.