Symposium 4 "Joint CSAS/5th International Meeting on Biotechnology in Animal Reproduction"

In ARCHIV - 10841

In vitro maturation, in vitro fertilization and embryos development of the domestic cat oocytes

Non disponibil

In vitro production of cattle × buffalo hybrid embryos using cattle oocytes and African buffalo (Syncerus caffer caffer) epididymal sperm

M. Agaba is ILRI authorInterspecies hybridization of bovids occurs between domestic cattle and at least three other species; American bison (Bison bison), yak (Bos grunniens) and banteng (Bos banteng). Birth of a cattle × buffalo (Bubalus bubalis) hybrid has reportedly occurred in Russia and in China, but these reports were not authenticated. Such hybrids could be important in improving livestock production and management of diseases that impede production in tropical Africa. This study investigated hybridization between cattle and its closest African wild bovid relative, the African buffalo (Syncerus caffer caffer). In an attempt to produce cattle × buffalo hybrid embryos in vitro, matured cattle oocytes were subjected to a standard in vitro fertilization (IVF) procedure with either homologous cattle (n = 1166 oocytes) or heterologous African buffalo (n = 1202 oocytes) frozen-thawed epididymal sperm. After IVF, 67.2% of the oocytes inseminated with the homologous cattle sperm cleaved. In contrast, fertilization with buffalo sperm resulted in only a 4.6% cleavage rate. The cleavage intervals were also slower in hybrid embryos than in the IVF-derived cattle embryos. Of the cleaved homologous cattle embryos 52.2% progressed to the morula stage compared with 12.7% for the buffalo hybrid embryos. No hybrid embryos developed beyond the early morula stage, while 40.1% of the cleaved cattle × cattle embryos developed to the blastocyst stage. Transfer of buffalo hybrid IVF embryos to domestic cattle surrogates resulted in no pregnancies at 60 days post-transfer. This study indicates that interspecies fertilization of cattle oocytes with African buffalo epididymal sperm can occur in vitro, and that a barrier to hybridization occurs in the early stages of embryonic development. Chromosomal disparity is likely the cause of the fertilization abnormalities, abnormal development and subsequent arrest impairing the formation of hybrid embryos beyond the early morula stage. Transfer of the buffalo hybrid embryos did not rescue the embryos from development arrest

Persistent breeding-induced endometritis after hysteroscopic insemination in the mare

Low-dose insemination has been proposed to reduce persistent breeding-induced endometritis (PBIE) in mares with delayed uterine clearance (DUC). Others proposed that hysteroscopic insemination induces an exaggerated inflammatory response and should be avoided in DUC mares. The objectives here were to evaluate presence and severity of PBIE in normal and DUC mares after hysteroscopic insemination with fresh semen, and to determine if hysteroscopy could be used in DUC mares without inducing excessive inflammation. Reproductively normal (n=4) and DUC (n=5) mares received four treatments in random order: uterine body insemination (UB, 1×10 9 spermatozoa, 20ml), hysteroscopic insemination (HYST, 5×10 6 spermatozoa, 0.5ml), sham hysteroscopic insemination (SHAM, semen extender, 0.5ml) and hysteroscopic infusion of seminal plasma (SP, 0.5ml). Significantly more DUC (50%) mares than normal (14%) mares accumulated intrauterine fluid 24h post-treatment. The difference in fluid accumulation between DUC (40%) mares and normal (7%) mares was also significant 48h post-treatment. Fluid scores were not significantly different between treatments in normal mares. However, treatments HYST and SHAM resulted in significantly higher fluid scores 24h but not 48h post-treatment in DUC mares. There was no effect of treatment or mare group on the percentage and total number of neutrophils in uterine fluid 48h post-treatment. Percentage of neutrophils was correlated with duration of hysteroscopy in normal mares, with procedures lasting ≥9min associated with PBIE. There was no effect of mare group, treatment or duration of hysteroscopy on pregnancy rate. Hysteroscopy induces a transient inflammation that is not more severe than that after conventional artificial insemination, suggesting no contraindication to its use in DUC mares