UDK 636.4:591.465.12:576.3/.7.086.83 MODELLING OF MATURATION SYSTEMS FOR PORCINE OOCYTE in vitro T.I. Kuzmina1, D.A. Novichkova1, N.A.Volkova2 1 All-Russia Research and Development Institute of Farm Animal Genetics and Breeding, RAAS, St.Petersburg-Pushkin 196601, Russia e-mail: prof.kouzmina@mail.ru, live8avis@mail.ru 2 All-Russia Research and Development Institute for Livestock Husbandry, RAAS, Dubrovitsy 142132, Moscow province, Russia e-mail: natavolkova@inbox.ru Received January 15, 2013 S umma r y A system of extracorporal maturation of growing and fully grown oocytes have been developed on the basis of research of a role of structural elements of porcine follicles in formation of mature oocytes and a preventive estimation of the functional status of oocytes (BCB-test). <...> The cultivation of oocytes in the developed system allows to receive till 45 % of embryos at the stages of late morulae and blastocysts. <...> Creation of biologically valuable pig embryos (native or reconstructed) by a simple method in vitro can be used in innovative cellular reproductive techniques (embryo transfer, transgenesis, cloning, embryonic stem cells) and their implementation in pig breeding, biomedicine, and pharmacology (1-3). <...> Today a basic approach to the method is developed and applied to produce the offspring from oocytes cultured in vitro, but the outcome of oocytes at metaphase II in this case is lower than those obtained in vivo (4). <...> Fertilization of porcine oocytes matured in vitro is often associated with polyspermy and violations in the formation of male pronucleus (5). <...> The resulting number of blastocyst embryos is insufficient for experiments on creation of embryonic stem cell lines. <...> All these facts underlie the development of effective systems for maturation of porcine oocytes in vitro and high outcome of mature oocytes. <...> The purpose of this study was modeling in vitro the system for maturation of porcine oocytes completely grown in vivo or in vitro based on markers of nuclear-cytoplasmic maturation of oocytes (chromatin status and mitochondrial activity) for their use in cell reproduction techniques. <...> Oocyte-cumulus complexes (OCC), somatic cells of ovarian follicles, and pre-implantation embryos were derived from Landrace pigs (6-8 months age). <...> OOC were aspirated from follicles with a diameter of 3-5 mm. Follicle walls were examined for vascuolarization and turgor. <...> Follicular fluid was aspirated from follicles with a diameter of 3-5 <...>