SEASONAL INFLUENCE ON SEXUAL BEHAVIOUR AND PROTEIN PROFILING OF MAJOR HSP (HSP 70, 90) IN RELATION TO SEMEN QUALITY AND FERTILITY OF GIR BULL 2893
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Date
2019-07
Journal Title
Journal ISSN
Volume Title
Publisher
JAU, JUNAGADH
Abstract
For successful AI in cattle and buffalo, bull fertility is essential to assure
optimal reproductive efficiency. Routinely used traditional semen quality tests and
even CASA provide limited information about the potential fertility of bulls. Several
studies have been conducted in the past decades in the search of exact and potential
fertility markers in bulls. So determining the seminal proteomic pattern of bulls with
high semen freezability and low semen freezability, we can use this technique as a
prediction tool to choose the semen donor bulls.
Studies on sexual behaviour, semen characteristics, fertility and potential
biomarkers of fertility, viz., heat shock proteins (HSP 70, 90) in semen as such, and
the documented reports on the influence of seasons on these aspects are meager in Gir
bulls, the world famous milch purpose cattle breed of India. These indices could be
used in selection and culling of Gir bulls in the breeding program. Hence these
investigations were 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 six mature Gir bulls. The effect of season on individual bulls for these
parameters was also studied. A total of 96 observations were availed at fortnightly
interval for sexual behaviour study, while 384 semen samples at twice-weekly interval
during each season from six bulls were utilized. The first AI conception rate was
found by inseminating a total of 1200 Gir cows, 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 carried out.
The mean 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 summer were 1.77±0.08, 5.23±0.22, 2.73±0.07,
2.68±0.07, 3.19±0.11, 153.54±4.82 and 0.46±0.07, respectively, while the respective
values in winter season were 2.08±0.06, 5.96±0.22, 3.02±0.06, 2.96±0.43, 3.40±0.39,
128.09±4.24 and 0.56±0.07. There were significant differences among bulls for these
traits in both the seasons. However, in general, summer significantly exerted an
adverse effect on the sexual behaviour of Gir bulls, while winter was the favoured
season.Abstract
ii
The neat seminal characteristics of Gir bulls, viz., volume (ml), colour (score),
concentration (million/ml), mass activity (score), initial motility (%), live sperm (%),
abnormal sperm (%), HOST reactive sperm (%) and acrosomal integrity (%) observed
in summer season were 5.02±0.27, 3.06±0.11, 1.070.46±49.56, 3.83±0.05,
79.58±0.05, 87.23±0.75, 6.73±0.47, 76.02±0.57, 90.35±0.35, respectively, whereas
the respective values in winter were 5.81±0.26, 3.35±0.11, 1282.98±58.08, 3.94±0.25,
82.40±0.56, 90.17±0.71, 5.13±0.51, 78.23±0.49, 92.42±0.31.
The percentages of post-thaw motility, post-thaw live sperm, post-thaw
abnormal sperm, post-thaw HOST reactive sperm, post-thaw acrosomal integrity and
first AI conception rate for semen cryopreserved during summer were 53.19±0.32,
65.90±0.92, 9.94±0.57, 55.27±0.82, 74.38±0.38 and 49.33±0.32, respectively,
whereas the corresponding values for semen cryopreserved during winter were
55.29±0.39, 69.06±1.09, 8.19±0.54, 58.58±0.86, 75.17±0.35 and 55.04±0.35. There
were significant differences among bulls for all of these traits in both the seasons.
Despite the fact that the sperm motility, concentration, viability, abnormality,
membrane integrity and acrosomal integrity were within permissible limit for semen
processing throughout the year, the quality was significantly better during the winter
than the summer season under Junagadh Agro-climatic conditions.
Temperament, libido, penile erection, penile protrusion, and intensity of thrust
were significantly and positively correlated among each other, and negatively with
reaction time and Flehmen reaction. Sperm motility traits like mass activity, initial
motility and post-thaw motility showed significant positive correlations among
themselves (r=0.562 to 0.689) and with first AI conception rates (r=0.133 to 0.357).
Sperm viability was positively correlated with post-thaw motility (r=0.164) and
conception rate (r=0.266). Membrane integrity (r=0.188) and acrosomal integrity
(0.373) were positively correlated with the conception rate. Reaction time was
significantly negatively correlated with mass activity (r=-0.203) and initial motility
(r=-0.181). Conception rate was significantly positively correlated with temperament
(r=0.261), penile erection (r=0.253), penile protrusion (r= 0.277) and thrust (r=0.324),
while negatively with reaction time (r=-0.293). The reaction time was also negatively
correlated with initial live sperm, acrosomal integrity and post-thaw motility.
The mean protein concentrations (ng/mg of protein) of major heat shock protein
70 (HSP70) were significantly higher during summer as compared to winter season
both at a pre-freeze ((56.68 ±43.19 vs. 40.25±3.07) and post-thaw stage (118.24±6.44
vs. 80.81±5.11). While the concentration (ng/mg of protein) of HSP90P at the pre freeze stage was non-significantly higher during summer than winter (1.27±0.05 vs.
1.19±0.07) season, while the respective values at the post-freeze stage were 2.36±0.08
and 2.37±0.13. This was also confirmed qualitatively by western blotting. The
HSP70P in neat semen had a significant positive correlation with mass activity
(r=0.326), initial motility (r=0.463), sperm viability (0.565), acrosomal integrity
(r=0.330), first AI conception rate (r=0.431) and HSP70P in post-thaw semen
(r=0.474). The HSP90P had a significant positive correlation with sperm motility
(r=0.322), viability (r=0.301) and conception rate (r=0.409).
It could be concluded from the present study that the Gir 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 Gir bull.