The effect of oleic and linoleic acids on in vitro bovineembryonic development and embryo quality

Abstract

IntroductionIt has been proven that the morphological and physiological quality of in vivo-derived embryos is better than that of in vitro-derived embryos (1,2). One of the major reasons for the relative inadequacy of in vitro embryonic development is the generation of reactive oxygen species (ROS) (2). ROS generation occurs as a result of the reduction of free oxygen during the metabolism of molecular oxygen required for embryonic development. The major ROS produced by the embryo itself are the superoxide anion radical, hydrogen peroxide, and the hydroxyl radical. When released at a basal level, ROS have a regulatory effect on embryonic metabolism, embryonic development, and embryo implantation (3).Oxidative stress-induced damage to the embryo arises from excessively released ROS, and these radicals pass the cell membrane, causing structural changes in cellular molecules such as lipids, proteins, and nucleic acids, which, in turn, result in mitochondrial alterations, blockage of cellular development in the embryo, excessive consumption of ATP, and apoptosis (3-5). Eventually, embryonic development is inhibited and the implantation of the embryo is negatively affected (3).Against the oxidative stress and damages caused by ROS, in vivo antioxidant defense systems, which protect the embryo, exist in both the embryo and the female reproductive tract that it resides in. These antioxidant systems include, among others, glutathione, taurine, hypotaurine, ascorbate, pyruvate, vitamin E, glutathione peroxidase, superoxide dismutase, and catalase (3). Under in vitro conditions, as the embryo depends only on the antioxidant systems it is itself equipped with against oxidative stress, additional preventive measures need to be taken (6-8). However, the elimination of oxidative stress and oxidative stress factors from the embryo culture medium is both an inevitable and complex problem. The selection of antioxidants and antioxidant doses for the supplementation of culture media can be challenging, as excessive antioxidant doses in the medium may cause negative impacts (6,9).Previous research has shown that fatty acids incorporated into in vitro culture media exhibit positive effects on oocyte maturation, fertilization, and embryonic development (10,11). The feeding of ruminants on rations of high fat content produces positive impacts on reproductive performance and enables high blastocyst

Oleic acid in the modulation of oocyte and preimplantation embryo development

“…Based on previous evidence for the association between unsaturated fatty acid content and cryopreservation success of embryos (Shehab-El-Deen et al, 2009;Sudano et al, 2012), an in vitro study demonstrated that supplementation of bovine embryo culture medium with OlAc at a concentration of 1.0 mM increased the rates of embryonic cleavage, development and quality (Karaşahiṅ & Arikan, 2015). Stinshoff et al (2014) have observed that conjugated LnAc significantly suppressed the expression of SCD, a key enzyme for de novo OlAc synthesis, and resulted in reduced bovine embryo development in vitro, a phenotype very similar to when mouse embryos (Ben-David et al, 2013) were exposed to selective inhibitors of SCD.…”

“…Based on previous evidence for the association between unsaturated fatty acid content and cryopreservation success of embryos (Shehab-El-Deen et al ., 2009; Sudano et al ., 2012), an in vitro study demonstrated that supplementation of bovine embryo culture medium with OlAc at a concentration of 1.0 mM increased the rates of embryonic cleavage, development and quality (Karaşahiṅ & Arikan, 2015).…”

“…The requirement for LnAc, as another abundant unsaturated fatty acid, in embryo development is controversial. Only limited positive effects on in vitro embryonic development and quality were observed in bovine by supplementation of LnAc (Karaşahiṅ & Arikan, 2015). Remarkably, treatment of mouse pronuclear and 2-cell stages with albumin-bound PUFAs including LnAc resulted in a significantly lower percentage of cleaved embryos and blastocysts (Nonogaki et al ., 1994).…”

Cysteamine in Maturation Medium Enhances Nuclear Maturation and Fertilization Rate of Sheep Oocytes In Vitro

“…Abnormal ROS levels might facilitate various pathological processes, such as mitochondrial dysfunction, apoptosis, decreased fertilization rate, poor embryo quality, and abnormalities in offspring (Lord and Aitken 2013). Many researchers reported the beneficial effect of antioxidant supplementation either in maturation medium (Sadeesh et al 2014;Kang et al 2016;Sovernigo et al 2017) or in culture embryo (Hosseini et al 2009;Karasahin and Arikan 2015) for developmental oocyte competence. Glutathione (GSH) is very popular antioxidant added in the culture system.…”

Comparative efficacy of antioxidant retinol, melatonin, and zinc during in vitro maturation of bovine oocytes under induced heat stress

“…Incorporation of antioxidants, on the other hand, has been reported to moderate the deleterious effects of heat stress on oocytes (4). Supplementation with exogenous antioxidants has been found to increase the chance of embryos, even those of fair quality, to develop to blastocysts, and not only during heat stress (5,6).…”