1-O-alkylglycerols improve boar sperm motility and fertility

1-O-alkylglycerols are naturally occurring ether lipids with potent biological activities. They may interfere with lipidic signaling, and they amplify platelet-activating factor (PAF) biosynthesis in a monocyte cell line. The PAF is produced by mammalian sperm and is an important activator of sperm motility. The aim of this study was to evaluate the effect of in vitro treatment of boar spermatozoa with natural 1-O-alkylglycerols (10 microM) on 1) boar sperm motility; 2) production of PAF and its metabolite, lyso-PAF, by spermatozoa; and 3) fertility in artificial inseminations of breeding sows. Using a computer-assisted spermatozoa analyzer, we found that 1-O-alkylglycerols increased percentage motility as well as velocity parameters after 24 h. These effects were partially or totally reversed by the PAF receptor-antagonist SR 27417. After [3H]-1-O-alkylglycerol incubation with boar spermatozoa, we identified [3H]lyso-PAF by high-performance liquid chromatography. Production of PAF and lyso-PAF was measured with a biological assay using [3H]serotonin release from rabbit platelets. 1-O-alkylglycerols significantly increased lyso-PAF production but had no effect on PAF production. The effect of 1-O-alkylglycerols on fertilization was also evaluated in industrial breedings: 1-O-alkylglycerol-treated or untreated semen dilutions were alternately used for artificial inseminations of sows on 12 farms. 1-O-alkylglycerol treatment increased the number of farrows but had no effect on the mean size of the litters. This study demonstrates that 1-O-alkylglycerol treatment of boar spermatozoa in vitro improves their motility and fertility, and it suggests that this effect is related to PAF metabolism and function in boar spermatozoa.