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Yukihiro Fujino

Publications and source records attributed to Yukihiro Fujino.

2 recordsLinked to original sources
PubMed2006

Batchwise assessment of porcine embryos for cryotolerance.

The viability or developmental ability of porcine embryos after slow-freezing and thawing differs depending on the embryonic stage or the batch, which is defined as a group of embryos obtained from one donor at one time. We froze porcine blastocysts in batches and assessed their cryotolerance by using two expanded blastocysts (EBs) as samples to predict the developmental potential of other blastocysts from the same batch at different stages. Two EBs from the same batch that had been separately frozen were thawed and cultured in vitro for 48 h to examine their in vitro ability to develop to the hatched blastocyst stage. Thereafter, each batch was assigned to Grade A, B, or C according to the viability of the two EBs, i.e., 100% viability (2/2: number of hatched blastocysts/number of cultured EBs) was Grade A; 50% (1/2) was Grade B; and 0% (0/2) was Grade C. The viability of EBs after freeze-thawing and in vitro culture varied depending on the batch and was lower (31.0+/-10.2%, mean+/-S.E.M.; P<0.01) than that of unfrozen controls (96.8+/-2.3%). The viability of frozen-thawed hatched blastocysts (HBs) did not differ among the graded batches, but the blastocyst diameter decreased (from 409 to 326 microm) as the batch grade decreased (from A to C). When both EBs and HBs from batches of the same grade were transferred to recipients (average 11.7 EBs and 16.0 HBs per recipient), the rate of pregnancy and farrowing in recipients decreased (from 77.8% to 0%) and the number of piglets obtained decreased (from 15.3 to 0) as the batch grade decreased. However, when not only frozen-thawed EBs from Grade B or C batches, but also four helper embryos at the morula to early blastocyst stage (which were expected to support the pregnancy) were transferred, the number of piglets generated was higher from EBs from Grade B batches (16.0) than from EBs from Grade C batches (0.0). When frozen-thawed HBs and helper embryos were transferred, the number of piglets generated was higher from HBs from Grade B batches (12.7) than that from HBs from Grade C batches (1.9). After slow-freezing of porcine blastocysts, their rate of survival to the piglet stage differs batchwise, and in vitro viability assessment of sample EBs after freezing and thawing may help in assessing the post-freezing and post-thawing developmental potential of other blastocysts at different stages from the same batch.

Animals↗
PubMed2006

Relationship between time elapsed after human chorionic gonadotropin administration and developmental stage in porcine embryos collected from prepubertal gilts.

We examined the relationship between the time elapsed after human chorionic gonadotropin (hCG) administration and developmental stage of porcine embryos after collection. Prepubertal gilts, 7 to 8 months old, were given 1500 IU equine chorionic gonadotropin (eCG) intramuscularly, followed by 500 IU hCG 72 h later. The treated gilts were inseminated artificially on Day 1 (Day 0=the day of hCG administration) and on Day 2. Embryos were collected surgically on Day 6 (140, 144, and 147 h after hCG administration) or on Day 7 (164, 168, and 171 h), and the developmental stages of the collected embryos were examined. From 75.2% (276/367) of the prepubertal gilts treated with hormones, we collected an average of 20.7 embryos per gilt with normal morphology. At 140 h after hCG administration, morulae (54.4%) could be collected. At 144 h, morulae and early blastocysts (57.7% and 28.9%, respectively) were collected. By 147 h, the proportion of embryos at the blastocyst to expanded blastocyst stages had increased (10.0%). From 164 h to 171 h, expanding or expanded blastocysts of more than 200 microm in diameter and hatched blastocysts could be collected. The proportion of hatched blastocysts increased from 3.2% (164 h) to 41.0% (171 h). These results suggests that although the number of ovulations differed among gilts, porcine embryos at the appropriate stages can be collected efficiently by controlling the time elapsed between hCG administration and embryo collection.

Animals↗