Effect of tyrode albumin lactate pyruvate and modified Krebs Ringers broth media on in vitro capacitation of HD-K75 boar spermatozoa at different period of incubation.

In vitro capacitation allows for a greater understanding of the mechanisms underlying fertilization and the development of improved reproductive techniques for improving fertility rates in porcine. Tyrodes albumin lactate pyruvate (TALP) and modified Krebs Ringers Broth (m-KRB) are two medias that are commonly used in research experiments to induce capacitation in boar spermatozoa (Cañón-Beltrán et al., Theriogenology, 198, 2023 and 231; Oberlender et al., Archivos de Medicina Veterinaria, 44, 2012 and 201; Sahoo et al., International Journal of Biological Macromolecules, 241, 2023 and 124502). Moreover, understanding the morphological and functional changes in boar spermatozoa at different hours of capacitation periods might aid in the development of novel techniques for improving sperm quality and increasing the litter size. This study was carried out to investigate the effect of Tyrode albumin lactate pyruvate and modified Krebs Ringers Broth media on in vitro capacitation of HD-K75 boar spermatozoa at three different periods of incubation. A total of 24 ejaculate from four clinically healthy, 10-12 months aged HD-K75 boars, maintained at ICAR-All India Coordinated Research Project (AICRP) on pig were selected. Semen was collected by 'Simple fist' method using a portable dummy. The semen samples having 200 mL volume, 103 × 106 spermatozoa/ml concentration and 70% initial motility were selected and split into two parts and suspended in TALP and m-KRB media, respectively, and incubated for 5 h at 37°C. Seminal parameters viz. sperm viability, plasma membrane integrity and acrosomal integrity were estimated in the samples at 0, 3 and 5 h of incubation. This study revealed that there was significant variation between media in live acrosome-reacted (p < .05) and HOST-reacted (p < .01) spermatozoa, while between capacitation periods significant (p < .01) variation was observed in hyperactivated spermatozoa, live acrosome-reacted spermatozoa, HOST-reacted spermatozoa, FITC-labelled PSA, extracellular protein and sperm cholesterol. Non-significant variation was observed in total phospholipid. TALP showed overall better consequence on sperm viability, plasma membrane and acrosomal integrity of boar spermatozoa. From this study, it could be concluded that both TALP and m-KRB media were virtuous to induce capacitation in HD-K75 boar spermatozoa. TALP media, however, had a better effect on sperm viability, plasma membrane and acrosomal integrity of boar spermatozoa. Out of the three different periods, 3 h capacitation period resulted in significantly (p < .01) higher incidence of sperm viability, plasma membrane and acrosomal integrity in HD-K75 boar spermatozoa.

Effect of thawing methods on frozen semen quality of yak (Poephagus grunniens L.) bulls.

AIM: To evaluate different thawing temperatures and duration on the post-thaw semen quality of Indian yaks bulls. MATERIALS AND METHODS: Semen ejaculates from four different yak bulls were collected using artificial vagina method and extended with tris extender containing 6.4% glycerol at 35°C, cooled gradually from 35°C to 5°C at 1°C/3 min and equilibrated at 4-5°C for 4 h and frozen in French mini straws using a programmable bio-freezer and finally stored in liquid nitrogen. Thawing of frozen semen straws was carried out using three methods i.e., 35°C for 60 s (thawing method I), 37°C for 30 s (thawing method II) and 75°C for 9 s (thawing method III). The post-thaw semen quality parameters assessed were sperm motility, percent live sperm, hypo-osmotic swelling test (HOST)-reacted sperm, acrosomal changes, and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in the extracellular media. RESULTS: The percent sperm motility, total incidence of acrosomal changes, and extracellular release of AST varied significantly (p<0.01) between thawing methods but live sperm and HOST-reacted sperm did not vary significantly between thawing methods. The percent sperm motility of frozen yak semen for thawing method III was significantly (p<0.05) higher than that for thawing methods I and II, the difference between thawing methods I and II being non-significant. The critical difference test revealed that the total incidence of acrosomal changes and extracellular release of AST were significantly (p<0.05) lower when thawing was done using methods I and II than in method III. CONCLUSION: On the basis of the present experiment, we can conclude that barring the post-thaw sperm motility, thawing of frozen yak semen in water either at 35°C for 60 s or 37°C for 30 s gives better post-thaw semen quality than at 75°C for 09 s.