International Journal of Molecular Zoology, 2024, Vol.14, No.6, 305-314 http://animalscipublisher.com/index.php/ijmz 307 3.3 In vitro fertilization (IVF) and embryo transfer (ET) In vitro fertilization (IVF) and embryo transfer (ET) are advanced reproductive technologies that allow for the genetic improvement of buffalo herds. These techniques involve the collection of oocytes, fertilization in vitro, and the transfer of embryos to recipient females. The combination of IVF with sexed semen can further enhance genetic gains by allowing for the selection of offspring sex. Although these technologies offer significant potential, their application in buffalo is still limited by factors such as the efficiency of oocyte retrieval and embryo development (Pellegrino et al., 2016; Baruselli et al., 2018). 3.4 Use of sex-sorted semen The use of sex-sorted semen in AI and IVF is a promising approach to control the sex ratio of offspring in buffalo breeding. This technology involves sorting sperm to favor either X- or Y-chromosome-bearing sperm, allowing for the production of predominantly female or male calves. Studies have demonstrated the feasibility of using sexed semen in buffalo, achieving high pregnancy rates and sex accuracy. However, the success of this technology can vary based on factors such as season, technician skill, and the genetic background of the buffalo (Lu et al., 2015; Chebel and Cunha, 2020). In summary, the optimization of reproductive technologies in water buffalo involves a combination of AI, estrus synchronization, IVF, and the use of sex-sorted semen. These technologies, when effectively applied, can significantly enhance reproductive efficiency and genetic improvement in buffalo herds. However, challenges such as estrous detection, seasonality, and the efficiency of advanced reproductive techniques need to be addressed to fully realize their potential. 4 Emerging Technologies in Water Buffalo Reproduction 4.1 Genome editing and its potential in reproductive enhancement Genome editing, particularly using CRISPR/Cas9 technology, has shown significant promise in enhancing reproductive capabilities in water buffalo. This technology allows for precise genetic modifications, such as the integration of specific genes into the Y chromosome, which can be used for sex control in pre-implantation embryos. The successful generation of transgenic cloned buffalo embryos demonstrates the potential of genome editing to improve reproductive outcomes by enabling the selection of desired traits at the embryonic stage (Figure 1) (Zhao et al., 2020; Singh et al., 2020). Figure 1 Evaluation of sgRNA efficiency and knock-in strategies in buffalo fetal fibroblast cells (Adapted from Zhao et al., 2020) Image caption: (A) The RGS reporter system was used to determine the efficiencies of sgRNAs; the cleavage activities were evaluated by FACS and are presented as the ratio of GFP+/RFP+ cells to all transfected cells; (B) Histograms show the relative cleavage activity of different sgRNAs; (C) Schematic overview of the strategy used to target the Actb locus in buffalo fetal fibroblast cells; (D) Knock-in efficiencies were evaluated by FACS and are presented as the ratio of mCherry+ cells to all transfected cells. **P < 0.01, ns, no significant difference (Adopted from Zhao et al., 2020)
RkJQdWJsaXNoZXIy MjQ4ODYzNA==