In vitro embryo production in buffalo species: state of the art.

In the last several years, there has been an increasing interest in in vitro embryo production (IVEP) technologies for faster propagation of superior germplasm in buffalo because of the low efficiency of superovulation (SO) and embryo transfer (ET) programs in this species. Although the IVEP efficiency has improved, embryo yield and development to term are still very low. This paper reviews the progress made in optimizing the IVM, IVF, and IVC systems. It also highlights the importance of embryo cryopreservation, which might critically contribute to the diffusion of ET procedures in the field. The acquisition of more information on embryo physiology, metabolism, and culture requirements in this species is critical to optimize the efficiency of advanced reproductive strategies. Further studies are also needed to improve the cryopreservation of IVEP embryos. The second part of the work underlines the potential impact of ovum pick-up (OPU) technique combined with IVEP on genetic improvement of buffalos. The OPU technique is a non-invasive and repeatable procedure for recovering large numbers of meiotically competent oocytes from antral follicles of live animals. Our experience, in buffalo, has demonstrated that OPU is superior to SO because it can yield more transferable embryos (TE) per donor on a monthly basis (2 TE vs 0.6, respectively). Therefore this technology has great potential to improve the genetic progress of buffalo through the maternal lineage.