Co-culture effect on early development of in vitro bovine embryos

Objective. To study the effect of co-culture with oviductal cells on the cleavage rate 48 hours post insemination (hpi) of bovine embryos in low oxygen tensions. Materials and methods. Slaughterhouse ovaries were collected for the extraction of oocytes put on TCM 199 medium supplemented with hormones, fertilized with semen cryo-preserved and co-cultured in CR1aa medium with oviductal cells during 48 hours. Total cleavage rate and cleavage per stages of 2-4 cells and 5-8 cells were evaluated. The viability of cells for the co-culture was determined by observation of the ciliary movement and monolayer observation. Treatments were T1: oviduct cells + oxygen 20%; T2: oviduct cells + oxygen 7%; T3 and T4 were controls without cells for both oxygen concentrations. Results. For cleavage rate there was not significant difference among the four treatments, but there was a tendency to more cleavage for co-cultured embryos with cells and 20% oxygen. Conclusions. The use of high oxygen rates (20%) in co-culture systems with oviductal cells intend to improve the cleavage percentages to 48 hpi.