In vitro oocyte maturation rates in Spanish Bullfight bovine breed

Abstract

The Spanish fighting bull is the most successful domestic cattle breed reared in the Iberianpeninsula, being also a hallmark of Spanish traditions and image. (Jimenez, Criado et al. 2007). This animalpopulation is characterized by a long history of isolation from the rest of the Spanish bovine breeds and wasselected only for their aggressiveness for hundreds of years, without considering other phenotypiccharacteristics (CaA±A³n, Tupac-Yupanqui et al. 2008). To our knowledge, this study was the first, todeterminate the of in vitro maturation (IVM) rates of oocytes that belong to this breed. Furthermore, twodifferent maturation media were evaluated to determine which supplementation type of the culture media isthe most suitable for the female gametes derived from this breed. A total of 249 ovaries were punctured,recovering 1294 oocytes of different qualities. The average recovery rates was 5,20 oocytes per ovary. Theseresults are lower than previous authors on different breeds by other authors: 6,3 in Podolian and 7,95 inMaremmana breeds. (Pauciullo, Nicodemo et al. 2012) and 5,35 in Czech Simmental; and that the averagerate of 7,25 obtained in our laboratory when we use cull Holstein, Retinta and Charolais cows. This lownumber of recovered oocytes may be explained by the inbreeding depression found in this breed and is inconcordance with the medium fertility observed in this animals (CortA©s, Tupac-Yupanqui et al. 2011). Toevaluate the IVM rates 334 oocytes were cultured for 20 h at 38,5ÂoC in a 5% CO2 atmosphere. In thisexperiment two different maturation media were used: M1, a base TCM-199 media supplemented only withBBS, glutamine and gentamycin. The other media used, M2 was similar to M1 media supplemented withFSH, LH and Estradiol at physiological concentrations. Maturation rates were 68,02% (100/147) in M1 and75,30% (122/162) in M2. These results are similar to those obtained previously by other authors (Pauciullo,Nicodemo et al. 2012)(Zago, Neto et al. 2011) in other breeds. Therefore, we can conclude that oocytes derivedfrom bullfight cows have a normal development on IVM procedures using standard protocols. Further studiesare required to determinate the overall efficiency of this breed through the overall IVF process.