Can centrifugation improve cryotolerance of bovine embryos produced in vitro?

Moreski, Danieli Aparecida BóbboMazucheli, JosmarCavalieri, Fabio Luiz BimCastilho, Anthony Cesar de SouzaSouza, Anne KemmerCosta, Camila BortolieroSeneda, Marcelo MarcondesEmanuelli, Isabele Picada

Abstract We tested the effects of centrifuging in vitro matured bovine oocytes for varying times on embryo development and cryotolerance. The oocytes were divided into four groups: control (GC) and centrifuged groups [5433 x g: G5, n = 463 (5 min); G10, n = 461 (10 min); and G15, n = 483 (15 min)]. After centrifugation, the oocytes underwent in vitro fertilization for embryo production. Two parameters were evaluated: i) embryonic development (n = 1,878), and ii) cryotolerance evaluation (survival and hatching rates; n = 303). The CG and G10 groups showed blastocyst rates of 42.25% and 45.77%, respectively, higher than those of the other groups (p = 0.02). The hatching rate was equal (p > 0.05) in CG (91.96%), G5: (87.74%), and G10: (95.73%) groups; however, it was lower in G15: 77.06% (p < 0.01). In the CG group, 65.88% of cryopreserved embryos survived, which was different (p < 0.05) from that in G5 (82.02%) and G10 (82.28%) (p > 0.05). Post-freeze hatching percentage was 74.0%, 87.7%, and 47.7%, in G5, G10, and G15, respectively, which was significantly greater than that in CG (p < 0.01; 26.8%). Post-freeze hatching percentage in only G10 matched that of the non-cryopreserved embryos CG (p = 0.06, 92%). We conclude that oocyte centrifugation for 10 minutes was efficient for in vitro embryonic development and cryopreservation of cattle embryos.