Maturation and fertilization of blue fox (Alopex lagopus) oocytes in vitro

The aim of the present study was to assess the progression of meiotic maturation and fertilization of in vitro matured blue fox (Alopex lagopus) oocytes at different time intervals after in vitro maturation and insemination by the use of confocal laser scanning microscopy. A total of 242 immature oocytes from ovarian follicles 1-2 mm in diameter from seven ovulating blue fox vixens at oestrus were cultured for 48 h in TCM-199 before in vitro insemination with 5.0 x 10(5) frozen-thawed fox spermatozoa. Oocytes were transferred to 50 microliters microdroplets of modified Tyrode's medium without glucose at pH 7.7 under mineral oil, inseminated and cultured at 38 degrees C in a humidified atmosphere with 5% CO2 for 2 (n = 10), 4 (n = 22), 8 (n = 41), 20 (n = 52), 24 (n = 10), 30 (n = 48) and 48 h (n = 59). The oocytes and zygotes were stained with propidium iodide and were analysed by confocal laser scanning microscopy or epifluorescence microscopy. Only 125 of 242 oocytes (52%) could be evaluated: of these germinal vesicle breakdown (GVBD) was observed in five of nine oocytes (56%) at 2 h, eight of 18 oocytes (44%) at 4 h, eight of 18 oocytes (44%) at 8 h, 27 of 42 oocytes (64%) at 20-24 h, 14 of 19 oocytes (74%) at 30 h, and 13 of 19 oocytes (68%) at 48 h after insemination. In total, 75 of 125 oocytes (60%) underwent GVBD. All stages from the germinal vesicle to the four-cell stage embryos were observed, but the rate of cleavage was low (9%). Immature oocytes collected from small subordinate ovarian follicles of oestrous vixens after ovulation of the dominant follicles were able to mature and be fertilized, as well as undergo the first two cleavage divisions in vitro.

In vitro reproductive toxicity of polychlorinated biphenyl congeners 153 and 126

This study was conducted to investigate the applicability of an in vitro technique for maturation, fertilization, cleavage, and growth to blastocysts of bovine oocytes to investigate reproductive toxicologic effects. During maturation, the oocytes were exposed to the di-ortho-substituted PCB congener 2,2',4,4',5,5'-CB (PCB 153) in the three concentrations 0.84 ng/mL, 8.4 ng/mL, and 84 ng/mL or to the non-ortho-substituted PCB congener 3,3'4,4',5-CB (PCB 126) in the three concentrations 1.006 pg/mL, 10.06 pg/mL, and 100.6 pg/mL and compared with control groups. PCB 153 had no effect on maturation but resulted in a reduced proportion of oocytes that cleaved at the highest concentration. There were no differences in blastocyst development among groups. PCB 126 resulted in a reduction in maturation percentage at the highest concentration and in blastocyst development at all concentrations. These results demonstrated adverse effects of PCB congeners on bovine oocytes and showed that this system can be used to evaluate toxic effects on oocytes and preimplantation-stage embryos.

Membrane alterations in bull spermatozoa after freezing and thawing and after in vitro fertilization

Membrane alterations in bull spermatozoa after freezing and thawing and after the process of in vitro capacitation and fertilization were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Even if the majority of the spermatozoa exhibited intact membranes after freezing and thawing (90%), one could distinguish between 3 types of membrane defects depending of the different structures involved. The first type showed loss of plasmalemma over the entire acrosome. In the second category the anterior part of the outer acrosomal membrane exhibited a pronounced extension, but was covered by a partly intact plasmalemma. The last category consisted of spermatozoa with extensive vesiculation and disruption of plasmalemma and the outer acrosomal membrane. This type of defect could not easily be distinguished from a true acrosome reaction. The cumulus cells showed an active phagocytosis of both intact and acrosome reacted spermatozoa.

Comparison of two semen extenders in terms of in vitro development of bovine embryos following IVF

In order to conform with current EC standards with regard to antibiotic cover, the Norwegian Cattle Association is currently investigating the use of Biladyl as an alternative to the milk-based extender which has been traditionally used in Norway. A study was carried out to investigate the effect of using semen frozen with either milk extender or Biladyl on the outcome of in vitro fertilization and embryo culture. Semen from 6 Norwegian Red bulls was used. There was a significant difference p < 0.05 in terms of cleavage rate between the 2 extenders for 1 bull, 78.2% vs 94.9% for milk and Biladyl extenders, respectively, and for the overall total of 71.3% vs 76.1% for milk and Biladyl extenders, respectively. There were no significant differences in terms of blastocyst yield amongst any of the bulls. In conclusion, the results suggest that Biladyl can be used as a replacement for the traditional milk-based extender without any adverse effects on blastocyst yields following in vitro fertilization.

Comparison of two semen extenders in terms of in vitro development of bovine embryos following IVF

In order to conform with current EC standards with regard to antibiotic cover, the Norwegian Cattle Association is currently investigating the use of Biladyl as an alternative to the milk-based extender which has been traditionally used in Norway. A study was carried out to investigate the effect of using semen frozen with either milk extender or Biladyl on the outcome of in vitro fertilization and embryo culture. Semen from 6 Norwegian Red bulls was used. There was a significant difference p < 0.05 in terms of cleavage rate between the 2 extenders for 1 bull, 78.2% vs 94.9% for milk and Biladyl extenders, respectively, and for the overall total of 71.3% vs 76.1% for milk and Biladyl extenders, respectively. There were no significant differences in terms of blastocyst yield amongst any of the bulls. In conclusion, the results suggest that Biladyl can be used as a replacement for the traditional milk-based extender without any adverse effects on blastocyst yields following in vitro fertilization.

Membrane alterations in bull spermatozoa after freezing and thawing and after in vitro fertilization

Membrane alterations in bull spermatozoa after freezing and thawing and after the process of in vitro capacitation and fertilization were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Even if the majority of the spermatozoa exhibited intact membranes after freezing and thawing (90%), one could distinguish between 3 types of membrane defects depending of the different structures involved. The first type showed loss of plasmalemma over the entire acrosome. In the second category the anterior part of the outer acrosomal membrane exhibited a pronounced extension, but was covered by a partly intact plasmalemma. The last category consisted of spermatozoa with extensive vesiculation and disruption of plasmalemma and the outer acrosomal membrane. This type of defect could not easily be distinguished from a true acrosome reaction. The cumulus cells showed an active phagocytosis of both intact and acrosome reacted spermatozoa.

Effects of non-steroidal anti-inflammatory drugs in the maturation and fertilization media on bovine oocytes

In the present investigation the effects of 2 non-steroidal anti-inflammatory drugs commonly used in veterinary practice, flunixin-meglumin (FM) and phenylbutazone (PB), were studied. These drugs were added to the in vitro maturation medium of bovine oocytes. The effect of FM on in vitro fertilization was also tested. The results indicated that in vitro concentrations corresponding to maximal concentrations of FM in the plasma after therapeutic doses did not influence the in vitro maturation or fertilization rates of oocytes. However, doses higher than physiologic concentrations resulted in significant decreases in oocyte maturation and complete failure of fertilization. Concentrations of PB corresponding to concentrations commonly found in the plasma after therapeutic doses resulted in a significant decrease in the number of matured oocytes.