EFFICIENCY OF FOURIER HARMONIC ANALYSIS OF SPERM NUCLEAR SHAPE IN PREDICTING FERTILITY IN WATER BUFFALO BULLS

Abstract

Fourier harmonic analysis (FHA) assessed the sperm nuclear shape of 31 buffalo bulls with known fertility to identify the bull with top conception rates of 28-36% and lowest conception rates of 13-19%. The FHA model developed for water buffalo, identified harmonic amplitude 1 as critical in selecting optimum cutoff values based on discriminant analysis. Using the model, 44 other bulls were classified as High- (n=12) or Low-fertile (n=10), while the rest (n=22) were mid-fertile bulls. Five bulls from High- and Low-fertility groups were randomly selected for semen quality tests. The tests included fertilization of buffalo oocytes, sperm motility parameters and Hypo-osmotic swelling (HOS) of the plasma membrane integrity. Results showed higher cleavage and blastocysts development with significant difference of hatching rates (P=0.021) for bulls that were predicted to be of High- vs. Low-fertility. Progressive motility (67.2±2.9 vs. 51.9±2.9%), straightness (85.4±0.7 vs. 81.3±0.7) and linearity (53.3±0.8 vs. 49.8±0.8) were higher in High- than Low-fertility bulls (P<0.05). Further, HOS test showed that High-fertility bulls had higher sperm cells (68.0 ± 6.2) with functional integrity than Low-fertility bulls (59.1 ± 6.2) though difference was not significant (P=0.346). The results suggest FHA is a potential tool in predicting bull fertility in water buffalo bulls.