Advancing maternal age predisposes to mitochondrial damage and loss during maturation of equine oocytes invitro

In many mammalian species, reproductive success decreases with maternal age. One proposed contributor to this age-related decrease in fertility is a reduction in the quantity or functionality of mitochondria in oocytes. This study examined whether maternal age or (in vitro maturation). IVM affect the quantity of mitochondria in equine oocytes. Oocytes were collected from the ovaries of slaughtered mares categorized as young (<12years) or aged (≥12years) and either denuded and prepared for analysis immediately (not-IVM) or matured invitro for 30hours before preparation (IVM). The mean oocyte mitochondrial DNA copy number was estimated by quantitative polymerase chain reaction and found to be significantly lower in oocytes from aged mares and that had been subjected to IVM than in any other group. Transmission electron microscopy demonstrated that mitochondria in aged mare oocytes subjected to IVM experienced significantly more swelling and loss of cristae than in other groups. We conclude that maternal aging is associated with a heightened susceptibility to mitochondrial damage and loss in equine oocytes, which manifests during IVM. This predisposition to mitochondrial degeneration probably contributes to reduced fertility in aged mares

Aspectos produtivos e vegetativos de macieiras cv. Imperial Gala interenxertadas com EM-9 Productive and vegetative aspects of the imperial gala apple trees with EM-9 interstem in different lengths

A obtenção de pomares compactos, com plantas de menor vigor e alta produção, constitui uma forte tendência da horticultura atual, tendo em vista o aumento na produtividade. Uma das técnicas de redução do vigor das plantas é a interenxertia. Este estudo foi desenvolvido no pomar comercial da empresa Randon Agro Silvo Pastoril S.A. (RASIP), localizado no Estado Rio Grande do Sul, Brasil. O objetivo foi avaliar o desenvolvimento vegetativo e produtivo de macieiras cv. Imperial Gala, com diferentes comprimentos de interenxerto: 10; 15; 20; 25 e 30 cm. Os parâmetros avaliados no sétimo e oitavo anos de implantação foram os seguintes: área da seção do tronco da cultivar copa a 5 cm do segundo ponto de enxertia; altura da planta; volume da copa; índice de fertilidade; número de frutos por planta; produtividade estimada e eficiência produtiva. Conclui-se que o uso do interenxerto de EM-9 de 30 cm no porta-enxerto Marubakaido é o mais indicado para o controle do vigor de macieiras cv. Imperial Gala, garantindo a maior eficiência produtiva e frutos de maior tamanho.<br>Obtaining a compact orchard, with less vigorous plants and high production, constitutes a strong tendency in the current horticulture, aiming the raise of the productivity. One of the techniques for reducing vigor is the interstem. This study was developed in a commercial orchard of Randon Agro Silvo Pastoril S.A. (RASIP), located in Rio Grande do Sul State, Brazil. The purpose of this work was to evaluate the vegetative and productive development of apple trees cv. Imperial Gala with different lengths of EM-9 interstem. The treatments consisted of five interstem lengths: 10, 15, 20, 25, 30 cm. The following parameters were evaluated, in the seventh and eighth year of implantation: the sectional area of the Imperial Gala 5 cm above the second graft point; height of the plant; the tree-head size; fertility index; the number of fruits per plant; estimated productivity and productive efficiency. The use of interstem EM-9 of 30 cm in the rootstock Marubakaido is the most indicated for vigor control of Imperial Gala apple trees, provides greater productive efficiency and produces bigger fruits