ABSTRACT
The natural ether-lipids 1-O-alkylglycerols (alkyl-Gro) from shark liver oil improve boar sperm motility and fertility in vitro. We examined the effects of oral shark liver oil on motility and velocity parameters of sperm together with modifications of lipid composition. Eleven boars were used as control and 11 were fed with 40 g/day for 28 days and sperm was collected on Days 0, 14 and 28 in control and treated groups. After 28 days treatment, sperm motility was improved by 2.9% as well as velocity parameters (curvilinear velocity +10.75%, progressive velocity +18.8% and average path velocity +13.5%) and sperm lipid composition was modified as follows: alkyl-Gro with saturated chains were increased (C16:0 +40.1%, C18:0 +87.2%) while alkyl-Gro with unsaturated chains remained absent, as in the control group, despite the prominence of C18:1 and C16:1 in shark liver oil. The treatment also resulted in an overall increase in the proportion of n - 3 and n - 6 polyunsaturated fatty acids in sperm lipids with a prominent increase of docosahexaenoic acid over time (18.9 +/- 1.34% at Day 0 to 25.7 +/- 1.11% at Day 28) and compared to control (25.7 +/- 1.11% for treated versus 16.1 +6/- 0.81 % for control at Day 28, respectively). These data demonstrate the influence of lipid intake on boar sperm composition and functions and suggest that oral intake of shark liver oil might improve reproduction.
Subject(s)
Fish Oils/administration & dosage , Lipids/analysis , Sharks , Sperm Motility/drug effects , Spermatozoa/drug effects , Swine , Animals , Dietary Fats, Unsaturated/administration & dosage , Docosahexaenoic Acids/analysis , Fatty Acids, Omega-3/analysis , Fatty Acids, Omega-6/analysis , Male , Spermatozoa/chemistry , Spermatozoa/physiology , Time FactorsABSTRACT
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.
