Effects of linoleic acid supplementation in oocytes and embryos cultivated in vitro

Abstract

Studies have reported the possibility of increasing reproductive performance in cows through the use of polyunsaturated fatty acids (PUFAS) in the diet. Among these, linolenic acid (C18: 3, omega-3) and linoleic (C18: 2, n-6) are the most important in breeding context. In some studies, that such supplementation was incorporated into the diet of cows, it was observed increase in conception rate. The mechanisms responsible for this increase are unknown. It is suggested that part of this beneficial effect can be exerted by favoring the development and quality of oocytes and / or embryos. PUFAS inserted in the diet, to transit through the rumen are processed mostly in saturated fatty acids, a condition favored by biohydrogenation process played by rumen microorganisms. However, the effectiveness of such a process is changed by several factors, including the main ones: food type containing the PUFAS composition of ruminal microorganisms, amount of food consumed, animal category, female production status and composition of food supplement ingested along with PUFAS. Such variation factors certainly corroborate the wide variation in results reported in the literature concerning the action of PUFAS in increasing the reproductive performance of cows. As an alternative supplementation in some studies proposed to the direct addition of PUFAS in the middle of oocytes and in vitro produced embryos cultivation, exempting the transformation of PUFA caused the rumen. The hypothesis of this study is that supplementation of the medium used oocytes and embryos cultivation with linoleic acid (LA), promotes the development and quality of oocytes and embryos produced in vitro, as well as increases fertilization rates. This study aims to investigate the effect of supplementation with LA in the middle of oocyte cultivation and / or embryos, development and quality of cultured in vitro oocyte fertilization rate and the development and quality of in vitro produced embryos from Nelore cows slaughtered. pre-validation test will be performed (dose-response) AL for cultivation and also oocytes and embryos. Therefore, viable ovaries from Nelore females (n = 150 females), obtained from a slaughterhouse, will be evenly divided into two groups, which are cultured in vitro in culture medium supplemented with linoleic acid (LA Group) or not (C Group). After cultivation of oocytes, IVF will proceed. After fertilization, embryos derived from oocytes of both previous group are cultured for 9 days in the presence of linoleic acid (LA) or absence (C), a factorial experiment 2 x 2, a total of four groups of treatment: oocyte and embryo treated with linoleic acid (LALA Group), treated oocyte with linoleic acid and untreated embryo (LAC Group), untreated oocyte and treated embryo with linoleic acid (CLA Group) and oocytes and embryos not treated (CC Group). The development, size and quality of oocytes and embryos, as well as the fertilization rates will be compared between different groups. The embryos obtained in this study will be stored and later submitted to mind lipidomics analysis, the technique of mass spectrometry, in a Master's study by a student member of this research group. Strategies that can increase the production of embryos in vitro (PIV) for reporting the number of aspirated oocytes are crucial for increasing reproductive performance in female subjected to said procedure.