HBP concentration affects in vitro acrosome reaction and conception rate in murrah buffalo Bulls: Interrelationship among sperm function tests

The aim of this study was to identify relationship between heparin binding proteins (HBP) concentration and in vitro acrosome reaction/conception rate/sperm function tests in murrah buffalo bulls. Frozen-thawed semen of 31 bulls was analyzed for HBP concentration, in vitro acrosome reaction, acrosome integrity, DNA integrity and lipid peroxidation. Conception rate of 10 bulls (21–30) was also obtained. Relationship between HBP and in vitro acrosome reaction/conception rate was evaluated. Inter-relationship among sperm function tests was also observed. A considerable variation in motility (PTM), DNA integrity, acrosome damage (fully damaged: FDA, partially damaged: PDA), in vitro capacitation/acrosome reaction and LPO was observed among 31 tested buffalo bulls after thawing during the present study. A significant positive correlation was observed among various sperm parameters. Thirty one bulls were divided into G-1 (> 40% AR) and G-II (≤ 40% AR). There was no difference in HBP concentration, PTM and DNA damaged sperms among the two groups. Percentage of spermatozoa with partially, fully damaged and acrosome reacted spermatozoa was significantly (p ≤ 0.05) higher in G-I as compared to G-II. MDA level (μmoles/10⁹ spermatozoa) was non-significantly (p ≥ 0.05) higher in G-II as compared to G-I. Ten bulls (22–31) were divided into two groups; G-I (> 35% conception rate) and G-II (< 35% conception rate). Concentration of HBPs was significantly (p ≤ 0.05) higher in G-I as compared to G-II. Percentage of acrosome reacted spermatozoa was also significantly (P ≤0.05) higher in G-I than G-II. Therefore, HBP concentration in spermatozoa may be useful in predicting the fertility of buffalo bull semen.