Cytogenetic analaysis of early stage buffalo embryos matured and fertilized in vitro

The in vitro fertilization technique offers the opportunity to study the karyotype of gametes and early embryos. Follicular buffalo oocytes were matured in TC-199 medium enriched with FCS, fertilized in vitro using thawed frozen buffalo semen and cultured at 38.5°C, 5% CO[2] and high humidity. Chromosome preparations were made from 232 buffalo embryos at 4 - to 8-cell stage after culturing for 48 hr in vitro. Only 74 embryos from 170 fixed embryos provided analyzable chromosome spreads. The percentage of embryos with chromosomal aberrations was 12.16%. The observed abnormal embryos were 5.41% haploid, 4.05% polyploid [2.70% triploid and 1.35% pentaploid] and 2.70 haploid/ diploid mosaicism. It is concluded that cytogenetic analysis of buffalo embryos is valuable for detection of chromosomal abnormalities which hinder the cleavage processes to reach to blastocyst stage

Effect of the seasonal changes on recovery, quality and maturation of buffalo oocytes in vitro

The present work aimed to study the effect of seasonal variations on the recovery rate, quality of recovered oocytes and maturation rate of buffalo oocytes in vitro. The effect of culture period on maturation rate was studied. The follicular oocytes were collected from ovarian follicles [2-5 mm in diameter] of slaughtered buffaloes by aspiration method. The recovered oocytes were classified morphologically into three categories [A, B and C]. The selected recovered oocytes [class A and B] were matured in tissue culture medium-199 supplemented with 10% fetal calf serum and antibiotics at 39°C, 5% Co[2] and high humidity for two different culture periods [21-24 hr and 25-28 hr]. Cultured oocytes were examined for nuclear maturation. The results indicated that, the average number of buffalo oocytes was 3.33 +/- 0.81 oocytes /ovary, without significant variation between the four, seasons. A higher [p<0.001] percentage of high quality oocytes was obtained in winter, autumn, spring than the summer season, while the percentage of poor quality oocyte [class C] was increased significantly [p<0.01] during summer. Moreover, the percentage of oocyte suitable for maturation decreased in summer than other seasons. The maturation rate of oocytes cultured for 21-24 hr was lowered than that recorded after 25-28 hr incubation period, among different four seasons. It is concluded that the quality of buffalo oocytes but not the recovery rate was affected by the seasonal variations. Increasing in the time of culture period was associated with improving in maturation rate. The high quality oocytes and high maturation rate can be obtained all over the year except summer season after culturing for 25-28 hr in vitro