Correlations Amongst Functional and Morphological Attributes and Oxidative Markers of Fresh and Cryopreserved Semen of Gir and Murrah Bulls

Abstract

This study was undertaken during the winter season on healthy mature Gir cattle and Murrah buffalo bulls (n=3 each). The semen
samples (6 ejaculates/bull, total 36 ejaculates) collected in the morning using artificial vagina were evaluated for routine seminal
attributes, including acrosomal and plasma membrane integrity. The samples were then diluted @ 100 million sperm/ml with tris fructose
yolk glycerol extender without and with sericin @ 0.1, 0.25, 0.5 and 1.0% (w/v), filled in French mini-straws, and frozen in LN2 using
biofreezer as per standard freezing protocol. Straws were thawed in water bath at 37°C for 30 sec and evaluated for post-thaw quality,
viz., motility, viability, morphology, acrosome integrity and plasma membrane integrity (HOST). Lipid peroxidation (malondialdehyde -
MDA production) and activities of enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) were assessed as oxidative
markers in seminal plasma of freshly diluted and frozen-thawed semen samples. Sericn at 0.5% level significantly (p<0.01) improved
the post-thaw sperm quality with reduced oxidative stress in both the species. The breed-wise correlation coefficients (r) among sperm
quality attributes and oxidative markers were studied in fresh and frozen-thawed semen of each species, and also for fresh with frozenthawed semen. The findings revealed significant interrelationships amongst most of the attributes of fresh as well as post-thawed
semen and also of fresh semen attributes with those of cryopreserved semen including oxidative markers in both the species. Sperm
motility estimation in fresh, pre-freeze and post-thawed semen was a legitimately good indicator of quality of spermatozoa at various
steps of semen processing/freezing, and its fertilizing potential. Thus, the sperm motility, HOS test and either MDA or SOD/GPx activity
alone may be used as valuable and practical tools for routine assessment of bovine semen quality considering significant correlations
found between them.