Fatty acids play an important role in the health, growth, development and evolution of the body. Omega-6 and omega-3 fatty acids play a significant role in reproduction via various mechanisms. It has been reported that among essential fatty acids, omega-6 and omega-3 fatty acids affect reproduction in different ways in males and females. The aim of this study was to investigate the effect of ration with different ratios of omega-6 to omega-3 on quantity and quality of semen in Shal male lambs. For this purpose, an experiment was conducted using 16 male Shal male lambs in Lavark Research and Educational Farm of Isfahan University of Technology and Royan Biotechnology Research Institute. Lambs were allocated to 4 experimental treatments with omega-6 to omega-3 ratios of 10:1, 4:1, 2:1 and 1:1, and the animals were fed with experimental diets for two months. Lambs were trained to take sperm every week during the feeding period using artificial vagina. Blood sampling was performed at the beginning and end of experiment before the morning feeding. Metabolic parameters including cholesterol, triglycerides, glucose and albumin were tested in blood samples. Following two months of feeding, twice a week sperm collection was performed. Various factors such as volume, color, presence of blood clots and etc. were eva‎luated and recorded in fresh semen. Immediately the semen samples transferred to the embryology laboratory of Isfahan Royan Research Institute and the quality of sperm including percentage of live and dead sperms, sperm concentration in seminal plasma, amount of reactive oxygen species (ROS), sperms with abnormal morphological status and motility parameters in fresh and frozen samples were eva‎luated using microscope. A histopathological eva‎luation was performed of testicular tissue at the end of the experiment. Results showed that the blood cholesterol in treatment 2, with 4:1 ratio of omega-6 to omega-3, had a significant difference (p ≤ 0.01). Also, the second treatment (ration of 4:1) had positive effects (p ≤ 0.01) on sperm motility, sperm count, ROS level, survival and morphology in fresh semen samples. The ROS level and survival rate were improved (p ≤ 0.01) In frozen thawed sperms. In histopathological eva‎luation of testicular tissue, according to Johnson classification, the second treatment (ratio 4: 1) had a score of 9 and classified as good score, the first (10:1) and third (2:1) treatments had average scores and the fourth treatment had poor score. The findings of the present experiment indicated that omega-6 to omega-3 fatty acids ratio of 4:1 may have positive effects on sperm parameters in male lambs and significantly increase the sperm quality

احمد رياسي، مهدي حاجيان حسين آبادي

اميرحسين مهدوي، محمدحسين نصر اصفهاني

فرزاد هاشم زاده، مهدي كديور