Adição da melatonina em diferentes concentrações sobre produção in vitro de embriões bovinos

Abstract

The objective of this study was to evaluate the effects of melatonin on morphological aspects of cumulus-oocyte complexes (CCOs) and in vitro production of bovine embryos. The experiment was conducted at the Animal Reproduction Laboratory of the State University of Maranhão. About 100 viable CCOs were used which were distributed between 0, 10-1, 10-3 and 10-5 μM Melatonin treatments. The experiment was divided in two phases, where the first one evaluated the effect of different concentrations of melatonin (treatments) on the maturation rate of the CCOs and the second, the effect of the treatments with melatonin on the in vitro production of bovine embryos. The CCOs were classified according to morphological quality in degrees I, II, III and IV. The design was completely by chance with four treatments in 100 replicates and the variables studied were compared by the χ2 test, for P <0.05. In the first phase, the in vitro cultivated CCO maturation rate showed no difference between the treatments (P <0.05). In the second phase the rate of cleavage and embryonic development did not differ between treatments (P <0.05). However, for the blastocyst rate, the group treated with melatonin in the 10-5 μM concentration was statistically superior (P <0.05) to the other groups under study. Thus, the in vitro maturation of melatonin did not show improvement in the maturation rate of in vitro cultured CCO, as it did not show improvement in the rate of embryo development and cleavage, but was efficient in the production of blastocysts of embryos produced in vitro.