Sperm binding to hyaluronan is an excellent predictor of Nili-Ravi buffalo bull fertility.

Abstract

This study reports the first evaluation of sperm hyaluronan binding assay (HBA) for predicting the fertility of Nili-Ravi buffalo bulls in relation to standard parameters of sperm quality. Cryopreserved semen doses of low (n=6), medium (n=3) and high fertility (n=8) bulls based on their respective return rates were used. Significantly, more spermatozoa bound to hyaluronan from the most fertile bulls (57.15%±1.44) compared with medium (42.46%±1.08) and low fertility bulls (29.70%±0.78). A strongly positive correlation (r=.824, p<.01) was found between HBA and fertility that predicts a 67.9% variability (r2 =.679, p<.01) in fertility. HBA was also strongly positively correlated with sperm viability (r=.679, p<.01) followed by their live/dead ratio (r=.637, p<.01), uncapacitated spermatozoa (r=.631, p<.01), normal apical ridge (r=.459, p<.01), motility (r=.434, p<.01), mature spermatozoa with low residual histones (r=.364, p<.01), high plasma membrane integrity (r=.316, p<.01) and nonfragmented DNA levels (r=.236, p<.05). It was negatively correlated with spermatozoa having reacted acrosome (r=-.654, p<.01). A fertility model built using a combination of sperm HBA and either sperm livability or viability predicts, respectively, 86.1% (r2 =.861, p<.01) and 85.9% (r2 =.859, p<.01) variability in buffalo bull fertility. In conclusion, sperm HBA may prove to be a single robust predictor of Nili-Ravi buffalo bull fertility.