Follicle development and selection: past, present and future

This paper reviews progress that has been made over the last 50 years and discusses how the development and application of new technologies have been utilized to increase our understanding of the development and selection of the dominant follicle. Our increased knowledge from research carried out worldwide, has demonstrated that the development of the dominant follicle, and importantly the production of a good quality oocyte, are controlled by a set of complex and interactive extra- and intra-ovarian control systems, impacted by underlying genetic and external environmental factors, such as nutrition. In totality this has resulted in improvements in fertility, as demonstrated by the impact of diet on oocyte quality and increased pregnancy rates. However, given the increasing global challenges of food security, coupled with climate change, more in-depth understanding of these complex multifactorial control systems will have even greater significance in overcoming today's livestock production challenges, including some that were present over 50 years ago. In conclusion, the continuing development of new technologies, coupled with new knowledge and understanding of these complex control systems, should ensure that ruminant fertility is maximized, while ensuring good animal welfare within sustainable production systems

Fibroblast growth factor 17 and bone morphogenetic protein 15 enhance cumulus expansion and improve quality of invitro-produced embryos in cattle

Abstract not availableMariana Fernandes Machado, Ester Siqueira Caixeta, Jaqueline Sudiman, Robert B. Gilchrist, Jeremy G. Thompson, Paula Fernanda Lima, Christopher A. Price, José Buratin

Somatic cell nuclear transfer is associated with altered expression of angiogenic factor systems in bovine placentomes at term

Low efficiency of somatic cell cloning by nuclear transfer has been associated with alterations of placental vascular architecture. Placental growth and function depend on the growth of blood vessels; VEGF-A and bFGF are the most important factors controlling neovascularization and vascular permeability in the placenta. We hypothesize that the VEGF-A and bFGF systems are disrupted in placentomes from cloned animals, contributing to the placental abnormalities that are common in these clones. We determined mRNA expression and protein tissue localization of VEGF-A, bFGF, and their receptors in placentomes from cloned and non-cloned bovine fetuses at term. Real-time RT-PCR revealed that VEGFR-2 mRNA was increased in cloned male-derived placentomes, while mRNA of bFGF and its receptors were decreased in placentomes of cloned females. VEGF-A system proteins were found to be located in placentomal endothelial, maternal and fetal epithelial and stromal cells; there was a variable pattern of cellular distribution of these proteins in both cloned and non-cloned animals. Alterations in the expression of VEGF-A and bFGF systems suggest that angiogenic factors are involved in abnormal placental development in cloned gestations, contributing to impaired fetal development and poor survival ratesFAPESP 02/07392-7CAPES (PROBRAL grant 272/7)\ud CAPES (PROBRAL grant D/06/33937

Paracrine and autocrine factors in the differentiation of the cumulus-oocyte complex

A better understanding of the paracrine and autocrine regulatory loops within the cumulus-oocyte complex (COC) is fundamental for the improvement of in vitro maturation (IVM) outcomes in humans and domestic species. This review presents the most important local regulators identified in the COC to date with special attention to those secreted by the oocyte and acting on cumulus cells, as well as their roles in different processes crucial for the successful maturation of the COC. An autocrine regulatory loop mediated by epidermal growth factor-like (EGF-like) peptides in cumulus cells triggers COC maturation. During COC differentiation, oocyte secreted factors (OSFs), particularly members of the transforming growth factor-beta (TGF beta) and fibroblast growth factor (FGF) families, regulate meiotic resumption, cumulus expansion, cumulus metabolism, apoptosis and steroidogenesis