Developmental Speed Affects the Cryotolerance ofIn VitroProduced Buffalo (Babalus Bubalis) Embryos

Abstract

The aim of this study was to evaluate whether the developmental speed affects the cryotolerance of in vitro produced buffalo embryos. In Experiment 1, abattoir-derived oocytes were in vitro matured, fertilized and cultured. The embryos produced by Say 7 of culture were vitrified at the tight morula (TM), early blastocyst (EBL), blastocyst (BL), expanded-blastocyst (XBL) and hatched-blastocyst (HBL) stage. The embryos were vitrified by cryotop in 16.5% ethylene glycol (EG) and 16.5% dimethyl sulfoxide (DMSO) and 0.5 M sucrose. Embryos were warmed in 0.25 M sucrose for 1 min and then in 0.15 M sucrose for 5 min and cultured in vitro for 24 h, to evaluate post-culture viability. In Experiment 2, ovum pick-up (OPU) was carried out on lactating buffaloes to produce embryos that were vitrified-warmed and transferred into synchronized recipients. The lowest (P<0.01) survival rates were recorded with TM (22.4%) and the highest (P<0.01) with HBL (84.5%), whereas intermediate results were observed with EBL, BL and XBL (54.5, 64.7, 67.9%, respectively). Pregnancy rate on both Days 25 and 45 was significantly higher (P<0.05) for faster (XBL and HBL) developing embryos (75.0% and 62.5%, respectively) than for the slower (TM, EBL and BL) developing counterparts (36.4% and 0, respectively). Interestingly, pregnancies to term were only recorded when HBL were transferred (20%). In conclusion, it was demonstrated that the chronology of development is a major factor affecting the cryotolerance of in vitro produced buffalo embryos.

Factors Affecting the Efficiency of In Vitro Embryo Production in Prepubertal Mediterranean Water Buffalo

“…Further opening the possibility of embryo sale and export when prepubertal LOPU-IVEP is used commercially. Embryo quality is known to be a major factor affecting cryotolerance [ 69 , 70 ], further emphasizing the quality of embryos that were obtained in our study. Indeed, although most recipients were still pregnant at the time of manuscript submission, vitrified embryos did yield healthy, live calves proving the embryos we produced were fully viable.…”

Hollow fiber vitrification allows cryopreservation of embryos with compromised cryotolerance

“…In addition, retarded or subnormal in vitro development of embryos produced by in vitro fertilization or intracytoplasmic sperm injection (ICSI) is not uncommon . Such low‐grade embryos are susceptible to cryopreservation‐related damage, which is why ART should prioritize a cryopreservation method with a superior performance. Application of the HFV method to human ARTs is expected to improve the pregnancy rate of patients.…”