A potential relationship between the 16;20 and 14;20 Robertsonian translocations and low in vitro embryo development

A possible effect of 16;20 and 14;20 Robertsonian translocations on the development of bovine oocytes matured and fertilized in vitro was assessed on the basis of embryo yield and blastocyst formation. Oocytes fertilized with semen from 2 bulls (A and B), which were heterozygous for these translocations, showed a significantly lower cleavage rate (36.3 +/- 2.25%; 39.8 +/- 3.88%) and percentage of blastocysts (3.7 +/- 1.24%; 3.2 +/- 1.20%) than those fertilized with semen from a bull (C) with a normal karyotype (control, 58.1 +/- 2.14%; 20.1 +/- 1.92%; P < 0.01). There was also a difference in the rate of further blastocyst development between the tested bulls and the control. The rates of expanded blastocysts were 6.6 and 11.1% for Bulls A and B, respectively, and 38.7% for the control bull on Day 7; while on Day 8 these values were 41.7 and 55.5% vs 76.0%. These results demonstrated that in the bulls carrying the 16;20 and 14;20 translocations, in vitro preimplantation embryo development was reduced, probably due to genetically unbalanced spermatozoa.