Vitrification for bovine embryos with low‐quality grade

Abstract

This study was conducted to examine the utility of vitrification for bovine embryos with low-quality grade, and simple cryoprotectants dilution method for practitioners. In Experiment 1, survival of frozen embryos was compared with that of vitrified embryos using minimum volume cooling (MVC). Then, vitrified embryos were used to confirm the optimum sucrose concentration in Experiment 2. The survival rates of embryos that had been vitrified following diluted cryoprotectants with the one-step in-straw method were compared with those of fresh control embryos in Experiment 3. Frozen-thawed or vitrified-warmed blastocysts were cultured with TCM-199 supplemented with 100 μmol/L beta-mercaptoethanol +5% fetal bovine serum at 38.5°C in an atmosphere of 5% CO in air, their survival after 24 hr were compared. The development to term of fair quality in vivo embryos after vitrification was examined in Experiment 4. Results show that survival rates of frozen-thawed embryos were lower (p < .05) than that of vitrified-warmed ones. When vitrified embryos were warmed in 0.3 mol/L sucrose in straws, their survival rate was 100%. The total cell numbers of vitrified-warmed embryos were comparable to those of fresh control embryos. The six calves from 13 vitrified embryos were delivered in Experiment 4. These results indicate that MVC vitrification following one-step cryoprotectants dilution is utilized to preserve low-quality bovine embryos.

A Shorter Equilibration Period Improves Post-Warming Outcomes after Vitrification and in Straw Dilution of In Vitro-Produced Bovine Embryos

“…When using vitrification technology in veterinary practice, a practical approach is needed for the warming of vitrified embryos so that embryos can be directly and easily transferred to the uterus. Thus far, there have been several attempts to replace successive dilution steps with one-step in-straw cryoprotectant dilution [3][4][5][6][7][8][9][10][11][12][13][14][15] However, in some of these procedures, in-straw embryo warming requires more than one dilution step and the proper handling of the carrier system, thus demanding more accuracy when these techniques are to be used in the field by embryo-transfer practitioners [7,9,10,12]. Using the VitTrans device designed by our group, IVP embryos are easily warmed/diluted in-straw for their transfer to recipient females in field conditions [16].…”

Comparative evaluation of the cost and efficiency of four types of sexing methods for the production of dairy female calves

“…Research has shown that the rates of IVF using spermatozoa with a shorter life span and/or damage were also improved when intracytoplasmic sperm injection was introduced into the IVEP industry [40, 41]. Recently, vitrification, an additional technique related to MOET, has been used as a method for preserving bovine embryos of low-grade quality [42, 43], although the pregnancy rate after cryopreservation depends on the quality of the embryos. This technical improvement could contribute to increases in female embryo and calf production by IVEP with X-sorted semen and FGS oocytes.…”

A shorter equilibration period in the VitTrans in-straw bovine embryo vitrification method improves post-warming outcomes

“…So far, there have been several attempts to replace successive dilution steps with one-step in-straw cryoprotectant dilution [3][4][5][6][7][8][9][10][11][12][13][14]. However, in some of these procedures, in-straw embryo warming requires more than one dilution step and proper handling of the carrier system, demanding more accuracy when these techniques are to be used in the eld by embryo-transfer practitioners [7,9,10,12]. Using the device VitTrans designed by our group, IVP embryos are easily warmed/diluted in-straw for their transfer to recipient females in eld conditions [15].…”