Abstract:
The objectives of the study were to evaluate the effect of two extenders (Triladyl® and Bioxcell®) and the removal of seminal plasma on goat buck semen. Six ejaculates were collected from six indigenous bucks by means of electro-ejaculator method, and semen was pooled, and replicated 10 times. Raw semen were randomly allocated into six groups as follows: (i) Raw non-washed, (ii) Raw washed, (iii) Triladyl®-washed, (iv) Triladyl®-non-washed, (v) Bioxcell®-washed and (vi) Bioxcell®-non-washed. All six groups were analysed for spermatozoa motility rates using computer-aided sperm analysis (CASA). The spermatozoa viability for all groups were assessed using Eosin-Nigrosin, acrosome integrity using Spermac, chromatin structure using Acridine Orange, and mitochondria using JC-1 staining solutions. Both the Triladyl® and Bioxcell® washed semen groups were diluted (1:4) with Phosphate Buffered Saline (PBS) then centrifuged at 1500 x g for ten min and seminal plasma was aspirated using 1 mL sterile plastic pipette. Semen samples were diluted (1:4) as follows: Triladyl® (washed and non-washed) or Bioxcell® (washed and non-washed) and then equilibrated at 5 ºC for 2 hours. Following equilibration, semen parameters were analysed. Thereafter, the semen samples were loaded into straws and placed 5 cm above a liquid nitrogen vapour for 10 min, and then stored at -196 ºC until use. Following one month of storage, frozen semen straws per treatment group were thawed at 37 ºC for 30 seconds, then semen parameters were analysed again. Significant differences among the mean values of semen parameters were determined by Tukey’s test using ANOVA, GLM procedure of SAS version 12.1 of 2010. Total Spermatozoa motility rate of Bioxcell® (92.5±4.6), (68.2±13.5) and Triladyl® (94.9±5.5), (63.1±15.1) were significantly reduced (P < 0.05) following equilibration and freeze-thawing process, respectively on washed semen groups. Live and normal spermatozoa percentages were drastically reduced in Bioxcell® (5.2±4.9) and Triladyl® (6.9±8.6) washed semen groups, following freeze-thawing. There was a significantly lower number of spermatozoa with high mitochondrial membrane potential in non-washed semen extended with Triladyl® (68.7±26.8) compared to non-washed semen extended with Bioxcell® (49.8±20.1) following the freeze-thawing process. In conclusion, the freezing-thawing process did reduce the indigenous buck semen parameters irrespective of removal or non-removal of seminal plasma. However, Bioxcell® extender was found to be more suitable for preserving spermatozoa during equilibration and freezing/thawing process of buck semen.
