Avaliação De Embriões Ovinos Provenientes De Oócitos Submetidos a Estresse Calórico Durante a Maturação in Vitro

Abstract

The aim of this work was to evaluate the effect of heat stress during oocyte maturation on ovine in vitro embryo production. Ovaries were collected at abattoirs and oocytes retrieved from follicles ranging from 2 and 6 mm in diameter. After selection, all oocytes, in 10 replicates, were placed in in vitro maturation (IVM) during 24 hours. The oocytes were submitted to heat stress at 41º C during 3, 6, 12, 18 and 24 hours and were further transferred to 39º C in order to complete IVM, which was the temperature of maturation of control oocytes. Embryonic development was determined on days 3, 4, 5, and 8 post-fertilization. Embryo evaluation was performed as total cell count by DAPI staining and determination of positive blastomere for apoptosis by the TUNEL assay. We observed that heat stress diminishes (P < 0.05) oocyte maturation capacity in accordance with exposure time at 41º C. In the group of oocytes incubated at 39 ºC, 70.70% matured, while in the groups exposed to heat stress at 41º C, only 45.28%, 35.17%, 12.30%, 9.74% and 4.60% matured after 3, 6, 12, 18 and 24 hours of incubation, respectively. The duration of exposure to heat stress was inversely proportional (P < 0.05) to embryonic developmental capacity and directly proportional (P < 0.05) to the number of blastocysts positive to apoptosis. However, the cleavage rate and embryonic development from 8 to 16 cells and morulae stages were affected by heat stress (P > 0.05) only up to 18 hours of incubation. The results allow the conclusion that heat stress during oocyte in vitro maturation reduces the quantity and quality of ovine embryos produced in vitro determined by the high incidence of apoptosis

Análise Do Custo Econômico De Um Sistema Agroflorestal Na Comunidade Nova Betel, Município De Tomé Açu, Estado Do Pará

“…A caprinocultura na região nordeste em sua maioria é desenvolvida de forma extensiva, um modelo pouco tecnificado, sem planejamento alimentar e manejo reprodutivo, utilizando animais de baixa qualidade genética, o que consequentemente, ocasiona baixos índices produtivos. Todavia, a criação de caprinos da raça Anglo-Nubiana, por apresentar potencial produtivo e reprodutivo, alta adaptabilidade e rusticidade, destaca-se como uma alternativa viável para a produção de leite, carne e pele (SANTOS JUNIOR et al, 2013).…”