Efeito da raça da doadora e do touro (Holandesa e Gir) na produção in vitro de embriões bovinos

Abstract

Among the various factors that influence the efficiency of embryos in vitro production (IVP), the oocyte quality, the laboratorial conditions, the semen and the oocyte donor breed are the most important. Therefore, the aim of this study was to evaluate the effect of donor oocytes breed and the bull breed (Holstein and Gir) on IVP bovine embryos comparing the recovered and viable oocytes averages as well as the recovery, cleavage and blastocyst rates. Data were provided by the company In Vitro Rio, located in Barra do Pirai – Rio de Janeiro, Brazil. A thousand of ovum pick up (OPU) sessions were performed in Holstein (Bos taurus taurus, n = 500) and Gir (Bos taurus indicus, n = 500) oocyte donors. The embryos were produced with Holstein and Gir sexed semen for female. Data were analyzed by nonpaired Student´s ‘t’test (recovered and viable oocytes averages) and chi-square test (recovery, cleavage and blastocyst rates) with 5% of significance level. The averages and standard deviation of recovered and viable oocytes for Holstein and Gir breeds were, respectively, 15.14 ± 13.08; 8.74 ± 7.67 and 15.57 ± 11.9; 9.12 ± 7.97 with no statistical difference for recovered oocytes (p>0.05). The oocytes recovery rate was 57.73% and 58.57% (p<0.05) for Holstein and Gir breeds. It was observed that the oocyte donor and bull breed influenced the cleavage rates, and the results for the combinations (oocyte donor breed x bull breed) Holstein x Holstein (G1), Holstein x Gir (G2), Gir x Holstein (G3) and Gir x Gir (G4) were 65.79 e 60.36% (G1 and G2) and 59.67 and 56.54% (G3 and G4), respectively. For all analyzed parameters, the value of "p" was lower than 0.05, except between G2 and G3 (p>0.05). It was also observed differences between breeds when compared the blastocyst rates, where the rates were 28.18 and 33.34% for G1 and G2 and 26.82 and 31.09% for G3 and G4, respectively, with p>0,05 between G1 and G3 groups, and between G2 and G4 groups, and p<0,05 between the other groups. Thus, we can conclude that each step of IVP technique was influenced by oocyte donor and bull breed.