Development of a combined new mechanical and enzymatic method for the isolation of intact preantral follicles from fetal, calf and adult bovine ovaries

in Theriogenology (1993), 40(4), 789-99

The isolation of preantral follicles from the ovaries of bovine fetuses, calves and adult cows was performed using a simple, rapid mechanical and enzyme method. The ovaries were cut into small pieces with ... [more ▼]

The isolation of preantral follicles from the ovaries of bovine fetuses, calves and adult cows was performed using a simple, rapid mechanical and enzyme method. The ovaries were cut into small pieces with a tissue chopper. Then, the suspension was filtered successively through 500 and 100 mum nylon mesh filters. This simple mechanical procedure resulted in large numbers of isolated preantral follicles: 2,142 +/- 254; 512 +/- 92 and 298 +/- 54 from the ovaries of bovine fetuses, calves and cows, respectively. In addition, the ovarian fragments between 100 and 500 mum were suspended in 10 ml of M199 Hepes medium plus 5% FCS and divided into 2 equal parts: one portion was used for collagenase treatment (200 U/ml) for 20 minutes, while the other served as a control. Collagenase treatment resulted in 841 +/- 161; 216 +/- 51 and 52 +/- 17 preantral follicles from fetuses, calves and cows, respectively, compared with 312 +/- 86; 52 +/- 15 and 10 +/- 2 in the control group. The use of collagenase with ovarian fragments selected by filtration as a method for increasing the rate of recovery of preantral follicles is described here. [less ▲]

Le clonage par transfert de noyau dans l'espèce bovine: premiers résultats

in Bulletin et Mémoires de l'Académie Royale de Médecine de Belgique (1993), 148

In 1987, Prather et al. have performed the first embryo cloning by nuclear transfer in the bovine species. Since, many researchers try to develop and to apply the technique. While the enucleation of the ... [more ▼]

In 1987, Prather et al. have performed the first embryo cloning by nuclear transfer in the bovine species. Since, many researchers try to develop and to apply the technique. While the enucleation of the recipient oocyte, the injection of the donor blastomere and the fusion procedure are now well controlled, on the other hand, maturation and activation as the development and freezing of the cloned embryos need tobe more investigated. The cloned embryo is more fragile. An increase in embryonic mortality is observed after transfer in a recipient cow. [less ▲]

Comparison between culture of bovine embryos in vitro versus development in rabbit oviducts and in vivo

in Livestock Production Science (1993), 36

The aim of this work was to evaluate the efficiency of different embryo culture methods for in vitro embryo production: development in co-culture with bovine oviductal epithelial cells (BOEC), in BOEC ... [more ▼]

The aim of this work was to evaluate the efficiency of different embryo culture methods for in vitro embryo production: development in co-culture with bovine oviductal epithelial cells (BOEC), in BOEC conditioned medium (CM) or in rabbit oviducts, versus in vivo produced embryos. There was no significant difference in terms of percentages of cleaved and 8-cell stages obtained between CM and BOEC. In CM, 24.8% of the cleaved embryos became blastocysts. In BOEC, 14.5% of the cleaved embryos became blastocysts. Among the 190 zygotes transferred in the rabbit oviducts, 127 have been recovered 5 days later, and 17.4% became blastocysts. There was no significant difference in term of blastocyst formation between the development in rabbit and in BOEC. However, there was a significant difference between the CM group and the two other groups. The numbers of cells in blastocysts from different sources were investigated: in vivo blastocysts contained 107 cells assumed to be 100%, in vitro blastocysts developed in rabbit oviduct 100.1 cells (93.3%), BOEC blastocysts 90.8 cells (84.6%) and CM blastocysts 72.3 cells (67.3%). This study confirmed earlier works on the oviduct effect on blastocyst quality in terms of development rate and cell number. [less ▲]

Multiplication des embryons chez les bovins: possibilités actuelles et futures

in Biotechnologie en Sélection animale - IRSIA (1989)

Since several years, research efforts have been focused towards improving the reproductive potential of domestic animals. The authors present a review of different technics in particular the ... [more ▼]

Since several years, research efforts have been focused towards improving the reproductive potential of domestic animals. The authors present a review of different technics in particular the superovulation and priming, embryo micromanipulation and clonage. The technic of superovulation allows an increase of the total number fo the offspring by an increase of the ovocytes total number. Different FSH injections at the end of the cycle, preceded by small FSH quantity at the beginning of the cycle, procure a great number of mature follicles available for reproduction. Micromanipulation allows a multiplicaton by sectioning the embryo in two or more segments. Isolated blastmeres can also be used but it was observed that those cells very rapidly loose their differentiation potential. Clonage allows the reproduction of an animal from only one of his own cells. The nucleus of this cell is extracted and reimplanted in an enucleated ovocyte. Meanwhile from a practical point of vue, this technic is, at present, only possible using a stem cell and not using a mature somatic cell. [less ▲]

Effet d'une préstimulation ovarienne en début de cycle sur la réponse au traitement de superovulation chez la vache

in Annales de Médecine Vétérinaire (1989), 133

In this study, we have induced superovulation in 67 heifers according to a known based treatment based on the administration of 32 mg (Armour Units) of FSH/LH (ratio LH/FSH=20%). The animals were divided ... [more ▼]

In this study, we have induced superovulation in 67 heifers according to a known based treatment based on the administration of 32 mg (Armour Units) of FSH/LH (ratio LH/FSH=20%). The animals were divided in two groups: 30 control and 37 receiving 2.5mg (Armour units) of pure FSH on the third day and the fourth day of the estrous cycle. This pretreatment ("priming") was followed by a larger number of total (11.7 versus 6.4) and transferable (7.1 versus 3.6) embryos. This experiment demonstrates the efficiency of low doses of pure FSH administered 6 or 8 dyas before a superovulation in the final selection of ovarian follicles. [less ▲]

Some factors affecting successful vitrification of mouse blastocysts.

in Theriogenology (1988), 30(6), 1177-83

The effects of temperature and exposure time to vitrification solutions on In vitro survival of mouse blastocysts were investigated. Blastocysts were first exposed for 10 min to vitrification Solution 1 ... [more ▼]

The effects of temperature and exposure time to vitrification solutions on In vitro survival of mouse blastocysts were investigated. Blastocysts were first exposed for 10 min to vitrification Solution 1 (VS1) containing 10% glycerol-20% 1,2 propanediol in phosphate buffered saline (PBS), then to vitrification Solution 2 (VS2) with 25 % glycerol-25% 1,2 propanediol for various periods either at room temperature or at 4 degrees C. At room temperature survival dropped quickly, while at 4 degrees C an increase in survival was observed. It is concluded that the viability of mouse blastocyts after vitrification is dependent on the temperature and duration of equilibration in vitrification solutions. [less ▲]