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Abstract

In the bovine IVP system, it has been obtained a high percentage of male embryos. This experiment was carried ou to determine if the glucose presence in the culture medium affects the sex ratio of bovine embryos IVP from the IVF with spermatozoa prepared for the swim-up (S) or Percoll gradient (P) methods. After the IVM, the COCs had been divided in two groups and inseminated with spermatozoa prepared for one of the methods. The zygotes had been cultivated in medium with or without 5.56mM of glucose, totalizing 4 treatments: S-Glu, S+Glu, P-Glu and P+Glu, and 48h post-insemination, the embryos of each treatment had been sexed for the PCR method (n=845). The effect of glucose in the culture medium on sex ratio of embryos IVP from the two methods was similar (c² test), resulting in a percentage of males lower than 50% in the 2-C stage (S: 30.8%; P: 23.8%: P<0.01) and higher than 50% in the 8-C stage (S: 79.4%; P: 68.8%: P<0.01). These percentages were different (P<0.05) of the observed when the embryos were cultivated without glucose, as much in the 2-C stage (S: 48.5%; P: 41.5%) as in the 8-C stage (S: 62.5%; P: 50.8%). The glucose presence did not affect the sex ratio in the total of produced embryos (S: 56.7%; P: 49.0%), that was similar to the observed in the glucose absence (S: 55.7%; P: 46.2%). Therefore, the glucose exacerbated the difference in the development speed between the female and male embryos.