EVALUATION OF THE EFFECTS OF DIET LEPIDIUM MEYENII (MACA) SUPPLEMENTATION ON STALLION SEMEN LIPOXIDATION

The stallion for reproductive aims is chosen on the basis of its appearance, performance, pedigree and lineage. The ideal stallion is dominant in the transmission of its genetic heritage. Sometimes, for ageing or overexploitation, the reproductive performances of good stallions get worse. It often occurs the necessity, in these cases, to improve the fertilizing capacity aimed to the conservation of semen for assisted reproductive technologies (ART) with safe and effective methods. The sperm cells, especially the damaged ones, produce reactive oxygen species (ROS). ROS include radicals like hydroxyl ions, superoxide, peroxyls and others (1). A certain, still low, concentration of ROS is necessary for the sperm function like capacitation, hyperactivation, acrosome integrity and sperm-oocyte fusion (2), but ROS become detrimental at excessive amounts or if it occurs a low antioxidant status or both. In the case of metabolic oxidative stress, however, provoked by imbalance between ROS production and antioxidant barrier, impaired sperm function may occur due to the rising of a series of chain reactions, in the course of which the radicalic sites can be transferred to the biomacromolecules, e.g. lipids, that compose the cell structures. The sperm is very sensitive to lipid peroxidation because its plasma membrane is rich in polyunsaturated fatty acids (PUFA), especially in the long-chain PUFA docosahexaenoic acid and docosapentaenoic acid (3). Lepidium meyenii (Maca) is a traditional Andean crop that grows best at high altitudes in the Peruvian Highlands. It owns aphrodisiac and fertility-enhancing properties. In the present study, we evaluated the effects of Maca diet supplementation on lipid peroxidation of horse ejaculates. In the experimental group of 2 hypofertiles (H) and 2 fertiles (F) stallions, the hypofertile (HM) one and the fertile (FM) one were administered Maca for 60 days, 20 g/day in the food. The remaining two stallions were the control ones (H and F). Ejaculate was withdrawn from each horse at day 0 and every 15 days for four times and processed for cooling at 5C and stored up to 72h. For each sample the degree of semen lipoxidation (LP sperm) was assessed. The results show a reduction of semen lipoxidation in both HM and FM, respect to H and F, and the same effect was observed during the storage in treated stallions too. In particular, we found a more steady decrease of lipoxidation in HM respect to H. Further, Maca showed benefit effects in sexual behavior, in fact HM was able to ejaculate during the first jump of the last withdrawal. In conclusion, the data obtained suggest a beneficial effect of Maca on reproductive function and performances. 1) Makker K. et al. Oxidative stress and male infertility. Indian J. Med. Res. 129, 357-367, 2009; 2) Awda B.J. et al. Reactive oxygen species and boar sperm function. Biol. Reprod. 81, 553-561, 2009; 3) Brinsko S.P. et al. Cholesterol to phospholipid ratio in sperm of stallions with unexplained subfertility. Anim. Reprod. Sci. 89, 217-219, 2005