Cloning of Buffalo, a Highly Valued Livestock Species of South and Southeast Asia: Any Achievements?
Buffalo (Bubalus bubalis) is a major source of milk, meat, and draught power in many developing countries in Asia. Animal cloning holds a lot of potential for fast multiplication of elite buffaloes and conservation of their valuable germplasm. Although the progress of buffalo cloning has been slow in comparison to cattle or pig, several breakthroughs were reported in buffalo cloning such as the production of cloned calves from somatic cells isolated from over one-decade old frozen-thawed semen or from urine-derived cells. Since the initiation of buffalo cloning, several approaches have been tried to refine nuclear transfer protocols. This has resulted in increasing the blastocyst production rate and improving their quality leading to an increase in live birth rate. In this review, we discuss current developments in buffalo cloning, its challenges, and the future roadmap.
Successful cloning of a superior buffalo bull
Somatic cell nuclear transfer (SCNT) technology provides an opportunity to multiply superior animals that could speed up dissemination of favorable genes into the population. In the present study, we attempted to reproduce a superior breeding bull of Murrah buffalo, the best dairy breed of buffalo, using donor cells that were established from tail-skin biopsy and seminal plasma. We studied several parameters such as cell cycle stages, histone modifications (H3K9ac and H3K27me3) and expression of developmental genes in donor cells to determine their SCNT reprogramming potentials. We successfully produced the cloned bull from an embryo that was produced from the skin-derived cell. Growth, blood hematology, plasma biochemistries, and reproductive organs of the produced cloned bull were found normal. Subsequently, the bull was employed for semen production. Semen parameters such as CASA (Computer Assisted Semen Analysis) variables and in vitro fertilizing ability of sperms of the cloned bull were found similar to non-cloned bulls, including the donor bull. At present, we have 12 live healthy progenies that were produced using artificial insemination of frozen semen of the cloned bull, which indicate that the cloned bull is fertile and can be utilized in the buffalo breeding schemes. Taken together, we demonstrate that SCNT can be used to reproduce superior buffalo bulls.
Effect of scriptaid, a histone deacetylase inhibitor, on the developmental competence of Handmade cloned buffalo (Bubalus bubalis) embryos.
The aim of the present study was to investigate the effect of scriptaid, a histone deacetylase inhibitor, on the developmental competence of Handmade cloned (HMC) and parthenogenetically activated (PA) buffalo embryos. Scriptaid treatment was given for 10 h immediately after reconstruction of HMC and PA embryos. Treatment of HMC embryos with 500 or 1000 nmol/L scriptaid significantly increased (P<0.01) the cleavage rate (91.3±2.8 and 91.9±2.0%, respectively) than that of controls (80.7±2.4%). Blastocyst rate was significantly higher (P<0.01) following treatment with 1000 nmol/L (54.1±5.0%) than that with 500 nmol/L scriptaid (42.6±2.9%) which, in turn, was higher (P<0.01) than that of the controls (38.0±2.6%). Also, HMC embryos treated with 500 or 1000 nmol/L scriptaid had higher (P<0.01) cell number (339.9±1.4 and 343.4±2.4, respectively) than the untreated embryos (150.7±2.0). In contrast, in zona-free PA embryos, the cleavage and blastocyst rate was significantly lower (P<0.01) following treatment with 500 (46.3±1.0 and 22.0±1.4%, respectively) or 1000 nmol/L scriptaid (46.2±1.9 and 16.6±1.3%, respectively) than that of untreated embryos (60.4±3.2 and 29.5±2.1%, respectively). Transfer of HMC embryos that had been untreated (N=13) or treated with 1000 nmol/L scriptaid (N=15) to synchronized recipients resulted in one pregnancy each. In conclusion, these results demonstrate that scriptaid treatment improves the developmental potential of HMC buffalo embryos, but compromises that of zona-free PA embryos.