In vitro oocyte maturation rates in Spanish Bullfight bovine breed.

SEBASTIÁN DEMYDA PEYRÁS; ENRIQUE GÉNERO; LEONARDO DE LUCA; MIGUEL MORENO MILLÁN

Cluj Napoca

Congreso; 11th International Symposium "Prospects for the 3rd millennium agriculture; 2012

UASVM

The Spanish fighting bull is the most successful domestic cattle breed reared in the Iberian peninsula, being also a hallmark of Spanish traditions and image. (Jimenez, Criado et al. 2007). This animal population is characterized by a long history of isolation from the rest of the Spanish bovine breeds and was selected only for their aggressiveness for hundreds of years, without considering other phenotypic characteristics (Cañón, Tupac-Yupanqui et al. 2008). To our knowledge, this study was the first, to determinate the of in vitro maturation (IVM) rates of oocytes that belong to this breed. Furthermore, two different maturation media were evaluated to determine which supplementation type of the culture media is the 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. These results are lower than previous authors on different breeds by other authors: 6,3 in Podolian and 7,95 in Maremmana breeds. (Pauciullo, Nicodemo et al. 2012) and 5,35 in Czech Simmental; and that the average rate of 7,25 obtained in our laboratory when we use cull Holstein, Retinta and Charolais cows. This low number of recovered oocytes may be explained by the inbreeding depression found in this breed and is in concordance with the medium fertility observed in this animals (Cortés, Tupac-Yupanqui et al. 2011). To evaluate the IVM rates 334 oocytes were cultured for 20 h at 38,5ºC in a 5% CO2 atmosphere. In this experiment two different maturation media were used: M1, a base TCM-199 media supplemented only with BBS, glutamine and gentamycin. The other media used, M2 was similar to M1 media supplemented with FSH, LH and Estradiol at physiological concentrations. After maturation oocytes were fixed in Carnoy´s 3:1 fixative and stained with Hoestch 33342. Nuclear status was determined individually in a epifluorescent microscope. Maturation rates were 68,02% (100/147) in M1 and 75,30% (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 derived from bullfight cows have a normal development on IVM procedures using standard protocols. Further studies are required to determinate the overall efficiency of this breed through the overall IVF process.