SEASONAL INFLUENCE ON SEXUAL BEHAVIOUR AND PROTEIN PROFILING OF MAJOR HSPS (HSP 70, 90) IN RELATION TO SEMEN QUALITY AND FERTILITY OF JAFFARABADI BULLS
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Date
2019-08
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jau.junagadh
Abstract
For successful Artificial Insemination (AI) in buffaloes, quality of semen, superior germplasm, congenial agro-climatic conditions and bull fertility are of vital importance to the bovine industry. The thermotolerance at the cellular levels is mediated by family of heat shock proteins (HSPs) that include several isoforms, viz., HSP70 and HSP90. These proteins are the important molecular chaperone that can protect cells from thermal damage, apoptosis and help in maintaining the intracellular homeostasis.
In view of meager literature on these aspects in Jaffarabadi the world famous buffalo breed, the present investigation was undertaken at Cattle Breeding Farm, JAU, Junagadh during two seasons (summer and winter) from Nov 2017 to Oct 2018. The study was carried out to know the seasonal variation and correlations amongst and between the sexual behaviour, semen quality traits, conception rates and major heat shock proteins expression in four mature Jaffarabadi bulls. A total of 64 observations were availed at fortnightly interval for sexual behaviour study, while 192 semen samples at thrice-fortnightly interval during each season were utilized for the study. The first AI conception rate was calculated by inseminating a total of 800 Jaffarabadi buffaloes, equally dividing for each bull and season. The protein profiling of major HSP proteins (70, 90) in sperm from neat as well as post-thawed semen was also carried out.
The mean values/scores for temperament (0-5 scale), libido (0-9 scale), penile erection (0-4 scale), protrusion (0-4 scale), intensity of thrust (0-4 scale), reaction time (sec.) and Flehmen reaction (0, 1) during winter were 1.28±0.08, 6.75±0.19, 3.22±0.74, 2.88±0.59, 3.15±0.65, 125.00±6.92 and 0.91±0.43, respectively, while the respective values in summer season were 2.22±0.07, 5.93±0.43, 2.84±0.65, 2.75±0.59, 2.93±0.13, 143.5±7.07 and 0.88±0.06. There were significant differences among season for temperament, libido, and penile erection.
The neat seminal characteristics of Jaffarabadi bulls, viz., ejaculate volume (ml), colour/density (score), sperm concentration (million/ml), mass activity (score), initial motility (%), live sperm (%), abnormal sperm (%), HOST reactive sperm (%) and acrosomal integrity (%) observed during winter season were 5.19±0.18, 2.38±0.10, 1253.36±24.75, 3.73±0.05, 80.31±0.05, 86.20±0.64, 5.00±0.40, 85.75
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±0.43, 93.56±0.56, respectively, whereas the respective values in summer were 5.07±0.13, 2.00±0.00, 1186.60±24.78, 3.72±0.11, 78.75±0.46, 82.31±0.74, 7.13±0.52, 84.93±0.45, 90.56±0.23.
The mean percentages of post-thaw motility, live sperm, abnormal sperm, HOST reactive sperm, acrosomal integrity and first AI conception rate for semen cryopreserved during winter were 58.85±0.56, 67.06±0.77, 8.62±0.43, 58.52±0.67, 75.22±0.27 and 45.75±0.21, respectively, whereas, corresponding values for semen cryopreserved during summer were 56.35±0.43, 65.62±0.76, 9.08±0.51, 55.43±0.60, 74.29±0.22 and 43.50±0.11.
The temperament was significantly (P<0.05) and positively correlated with penile erection (r=383), penile protrusion score (r=0.352), intensity of thrust (r=0.378), and reaction time (r=0.358). Libido score had significant (P<0.05) positive correlations with penile erection, penile protrusion score and intensity of thrust. Penile erection score had a highly significant (P<0.01) correlations with penile protrusion (r=0.512), thrust(r=0.378), and Flehmen reaction (r= -0.362). Protrusion score showed a highly significant (P<0.01) positive correlation with thrust (r=0.419).
The seminal traits like semen volume and concentration showed highly significant positive correlations with post-thaw sperm motility (r=0.249; r=0.409, respectively). Sperm motility traits like mass activity (r=0.463), initial motility (r=0.508) and post thaw motility showed the significant positive correlations among themselves. Sperm viability was highly significant positively correlated with post-thaw motility (r=0.367) and conception rate (0.466). Acrosome integrity (r=0.456) and sperm plasma membrane integrity (r=0.403) were significantly and positively correlated with conception rate. While, post-thaw motility (PTM) had highly significant (P<0.01) positive correlation with first AI conception rate (r=0.475). Temperament, libido, and erection score didn’t show significant correlation with other semen characteristics. Reaction time was significantly and negatively correlated with mass activity (r=-0.360), initial motility (r=-0.391) and conception rate (r=-0.393).
The mean concentration (ng/mg of protein) of major heat shock protein 70 (HSP70) was non-significantly higher during summer as compared to winter season at a pre-freeze (146.50±8.48 vs. 138.10±4.41) and significantly higher at post-thaw stage (345.90±15.52 vs. 280.90±14.74), while the concentration (ng/mg of protein) of HSP90P was non-significantly higher during summer than winter both at the pre-freeze (2.49±0.43 vs. 1.63±0.31) and at the post-freeze stage (7.13±0.73 vs. 5.50±0.74). This was also confirmed qualitatively by western blotting. The HSP70P in neat semen had a significant positive correlations with mass activity (r=0.397), sperm viability (r=0.478), acrosomal integrity (r=0.373), while in post-thaw semen it had highly significant correlation with first AI conception rate (r=0.477). The HSP90P had a significant positive correlation with sperm motility (r=0.372) in neat semen, while in post-thaw it had highly significant correlation with conception rate (r=593) and it was significantly correlated with HSP90 in neat semen(r=0.398).
From the present study, it could be concluded that the Jaffarabadi bulls had good sexual behaviour, better semen quality and quantity throughout the year. However, semen quality was better during winter as compared to the summer season. The protein expression of major HSPs (70, 90) may be utilized as markers for heat tolerance, sexual behaviour, semen quality and conception rate for the Jaffarabadi bulls.