RESUMO
To test our hypothesis that antisperm antibodies (ASA) might alter sperm phenotypic attributes thus leading to sub-fertility/infertility in bulls, ASA were generated in crossbred male calves by immunizing with sperm two times. Cryopreserved spermatozoa from crossbred bulls (nâ¯=â¯24) with different field fertility ratings were incubated with ASA and different patterns of ASA immunolocalization were studied. In addition, sperm membrane integrity, acrosomal integrity and cryo-capacitation status were also assessed. Immunolocalization of sperm antigens using antisperm antibody revealed three major patterns (Acrosomal-AR, apical-AP and, acrosome and tail-AT). The proportion of ASA reactive spermatozoa was significantly (Pâ¯<â¯0.05) higher in low- and medium-fertile bulls compared to high-fertile bulls. Among the three patterns, the proportion of spermatozoa with AR pattern was significantly (Pâ¯<â¯0.05) higher in low- and medium-fertile bulls compared to high-fertile bulls. The proportion of membrane and acrosome intact spermatozoa was significantly (Pâ¯<â¯0.05) higher in high-fertile bulls compared to medium- and low-fertile bulls. There were no significant differences in the proportion of cryo-capacitated spermatozoa among high-, medium- and low-fertile bulls. The relationship between ASA reactive spermatozoa and conception rates (CR) of bulls was highly (Pâ¯<â¯0.01) significant and negative. Similarly, AR and AT pattern were also significantly (Pâ¯<â¯0.01) and negatively related to CR of bulls. The reactivity of spermatozoa with ASA was also significantly (Pâ¯<â¯0.01) and negatively related to the membrane and acrosome integrity of spermatozoa. It was concluded that the proportion of spermatozoa responding to ASA was higher in low-compared to high-fertile bulls and ASA localization in sperm acrosomal area was negatively related to sperm membrane and acrosomal integrity and bull fertility.
