Suplementação com beta-NGF no processo de maturação ovocitária e seu impacto nas taxas da produção in vitro de embriões bovinos

Abstract

In vitro embryo production (IVEP) in cattle in Brazil has become a prominent and effective technology for genetic improvement of herds. This process allows the production of embryos from the fertilization of oocytes collected from genetically superior cows, which are subsequently transferred to other recipient females. A positive correlation has already been identified between the levels of Beta-NGF (nerve growth factor beta) in spermatozoa and the cleavage and blastocyst development rates in the IVP process, indicating that this factor may play an important role in improving the efficiency of the technique. The objective of this study was to evaluate how supplementation with 100 ng/mL of Beta-NGF in the oocyte maturation medium influences the cleavage, embryonic development, blastocyst, and implantation rates of embryos in the in vitro production of bovine embryos. For this purpose, a commercial laboratory that performs hundreds of IVP procedures per year was used. After obtaining the owners' consent, part of the IVF cycles from 4 routines were performed with half of the oocytes using oocyte maturation medium without Beta-NGF and half using 100 ng/ml of Beta-NGF. At the end of the cycles, normal blastocysts were implanted into synchronized recipient cows. The results demonstrate that supplementation with beta-NGF resulted in notable increases in the embryonic development rate (70.9 vs 55.6) and blastocyst rate (38.6 vs 31.1) when compared to the control group. The conception rate showed a tendency to increase (52.5 vs 45.3). On the other hand, the cleavage rate remained practically stable between the two groups (55.2 vs 55.8). It is concluded that supplementation with 100 ng/ml of Beta-NGF in the oocyte maturation medium improves the efficiency of IVP (in vitro production), and may improve the conception rate after blastocyst transfer to recipient cows.