Dietary fatty acids influence sperm quality and function.

Recently, obesity has been linked to male infertility. In animal models the administration of a high-fat diet caused a reduction in sperm quality, by impairing gamete energy metabolism. The aim of this study was to investigate a possible effect of dietary fatty acids supplementation in the modulation of sperm energy metabolism and, in turn, in the improvement of sperm quality in rats fed a high-fat diet. Sexually mature male Sprague-Dawley rats were divided into four groups and fed for 4 weeks a standard diet (control group), a high-fat diet (enriched in 35% of fat and 15% sucrose), a high-fat diet supplemented with 2.5% olive oil (a source of monounsaturated fatty acids) or a high-fat diet supplemented with 2.5% krill oil (a source of n-3 polyunsaturated fatty acids). Liver and adipose tissue weight, plasma glucose, insulin and lipid concentrations were determined. Activities of enzymes involved in sperm energetic metabolism were evaluated by spectrophotometric assays. Sperm mitochondrial respiratory efficiency was also assayed. The obtained results suggest that olive oil partially counteracts the negative effects of a high-fat diet on sperm quality, by increasing gamete motility, by reducing oxidative stress and slightly improving mitochondrial respiration efficiency. On the other hand, krill oil determines an increase in sperm concentration and motility, an increase in the activities of lactate dehydrogenase, Krebs cycle enzymes and respiratory chain complexes; a parallel increase in the cellular levels of ATP and a reduction in oxidative damage were also observed. These results suggest that dietary fatty acids are able to positively influence sperm quality and function.