Effect of platelet activating factor on the motility and acrosome reaction of buffalo (Bubalus bubalis) spermatozoa

Platelet activating factor (PAF;1-O-alkyl-2 acetyl-sn- glycerol-3 phosphocholine) has been shown to have a wide range of biological activities. In this study, PAF was used to induce acrosome reactions in fresh as well as frozen-thawed buffalo spermatozoa at different incubation periods and PAF levels. As the period of incubation increased, there was a gradual decrease in motility and increase in acrosome reaction in both fresh and frozen-thawed spermatozoa. With increasing PAF levels, the motility of fresh spermatozoa decreased and acrosome reaction increased whereas in frozen-thawed semen, motility remained almost constant, and the increase in acrosome reaction was not pronounced. Differences in motility and acrosome reaction among different bulls, types of semen, periods of incubation and PAF levels were significant (P<0.01). A PAF level of 100 mu M and an incubation period of 15 min were found to be optimum for inducing acrosome reaction in buffalo spermatozoa, since at this combination acrosome reaction increased significantly (P<0.01) over that of the control without much loss of motility.