Abstract:
The meiotic competence of canine oocytes cultured for 72 h in mediumsupplemented with three different concentrations (5, 10 and 20%) ofanoestrous, oestrous or metoestrous bitch serum, or with 0.3% bovineserum albumin (BSA), was examined. The oestrous serum supplement had apositive effect on the resumption of meiosis, compared with the othersupplements (P<0.05). The number of oocytes thatreached metaphase I (MI) and metaphase II (MII) was significantly higher(P<0.05) with the oestrous serum supplement than withthe anoestrous serum supplement. There were no significant differences amongthe three different concentrations in each serum type with respect to theproportion of oocytes that completed meiosis (MI to MII). The number ofoocytes that resumed meiosis in the 10% oestrous serum supplement wassignificantly higher (P<0.05) than those of eachconcentration of the anoestrous and metoestrous serum supplements, and of the0.3% BSA supplement. Moreover, a higher number of oocytes reached MIIin the presence of the 10% oestrous serum supplement than with the10% anoestrous serum supplement. These results suggest thatsupplementation of the culture medium with 10% oestrous serum is theoptimal treatment for in vitro maturation of canineoocytes.