RESUMO
There are limited studies on the factors affecting the success of ram epididymal spermatozoa (REPS) cryopreservation. On this note, the current study assessed the influence of three commercial soy lecithin-based semen extenders, AndroMed® (AND), BioXcell® (BIO), and OviXcell® (OVI), and two concentrations (400 × 106 vs. 200 × 106 spermatozoa/mL) on the pre-freeze and post-thaw quality of REPS. The REPS were retrieved from nine adult rams' testes and diluted with each of the three extenders to both concentrations. Straws were frozen manually. Standard motility (SMP) and kinematic parameters (KPs) were assessed via a CASA, while spermatozoa viability, morphology, and acrosomal integrity were assessed via the Kovács-Foote staining technique. The concentration did not significantly affect the pre-freeze and post-thaw SMP and KPs of REPS. BIO and OVI had significantly higher pre-freeze and post-thaw BCFs, post-thaw VAP, and the percentage of all intact heads than AND. In contrast, AND had a significantly lower percentage of REPS with tail defects than BIO and OVI. The 400 × 106 spermatozoa/mL concentration resulted in a significantly higher percentage of all intact heads than the 200 × 106 spermatozoa/mL concentration. Freezing significantly increased tail defects and decreased the percentage of REPS with distal cytoplasmic droplets. The cryopreservation of REPS at the 400 × 106 spermatozoa/mL concentration is recommended. All three extenders must be optimized to preserve the viability, membrane integrity, and better normal morphology of REPS; the reason for increased tail abnormality after the freezing/thawing process needs to be studied.
RESUMO
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.
