Embryo biopsies for genomic selection in tropical dairy cattle

Genomic selection has transformed the livestock industry, enabling early-life selection of animals. Biopsy sampling of pre-implantation embryos has been described since 1968. However, it was only after 2010, with the advancement of molecular biology techniques such as whole genomic amplification and SNP Chips, that next-generation sequencing became commercially available for bovine embryos. It is now possible to make decisions about which embryos to transfer not only based on recipients' availability or embryo morphology but also on genomic estimates. This technology can be implemented for a wide spectrum of applications in livestock. In this review, we discuss the use of embryo biopsy for genomic selection and share our experience with Gir and Girolando Brazilian breeding programs, as well as future goals for implementing it in Brazilian bovine in vitro embryo production practices.(AU)

Perspectives of gene editing for cattle farming in tropical and subtropical regions

Cattle productivity in tropical and subtropical regions can be severely affected by the environment. Reproductive performance, milk and meat production are compromised by the heat stress imposed by the elevated temperature and humidity. The resulting low productivity contributes to reduce the farmer's income and to increase the methane emissions per unit of animal protein produced and the pressure on land usage. The introduction of highly productive European cattle breeds as well as crossbreeding with local breeds have been adopted as strategies to increase productivity but the positive effects have been limited by the low adaptation of European animals to hot climates and by the reduction of the heterosis effect in the following generations. Gene editing tools allow precise modifications in the animal genome and can be an ally to the cattle industry in tropical and subtropical regions. Alleles associated with production or heat tolerance can be shifted between breeds without the need of crossbreeding. Alongside assisted reproductive biotechnologies and genome selection, gene editing can accelerate the genetic gain of indigenous breeds such as zebu cattle. This review focuses on some of the potential applications of gene editing for cattle farming in tropical and subtropical regions, bringing aspects related to heat stress, milk yield, bull reproduction and methane emissions.(AU)

Use of two new formulations as bovine embryo manipulation solution

This study aimed to evaluate the effect of two Embryo Manipulation Solutions (EMS and EMS supplemented) in maintenance of the viability of embryos, initially using structures derived from mice (first phase). Next, the efficiency of these solutions in routines of bovine embryo transfer was evaluated (second stage). Mice embryos were used in the stages of early blastocyst, and compact morula grades I and II. These embryos were initially randomly distributed and maintained for four hours in three solutions: Modified phosphate buffered saline (PBS; Control); EMS (treatment 1), and EMS supplemented (treatment 2). Subsequently, they were cultured in TCM 199 medium and evaluated in terms of total number of cells, morphometric characteristics, ultra structural aspects, detection of cell apoptosis, and quantification of Hsp70.3 gene expression. In the second phase, these same solutions were tested in the transfer of quality I and II bovine embryos (excellent and good). These embryos were transferred fresh to 58 recipients. The results showed that the total number of cells in embryos expanded blastocyst (ExB), the number of apoptotic cells, the cell, nuclear, nucleolar diameter and the nucleus/nucleolus ratio was similar among the treatments. The pregnancy rate shown on second phase was also similar. However, the EMS supplemented expressed more Hsp70.3 than EMS. The expression of Hsp70.3 was also greater for embryos in EMS than that of EMS supplemented. The McII embryos, EMS and EMS supplemented samples also expressed more Hsp70.3 compared to control embryos. In conclusion, the tested solutions can be used in routine embryo transfer techniques, replacing modified PBS solution as an effective media in maintaining embryo viability.

Use of two new formulations as bovine embryo manipulation solution

This study aimed to evaluate the effect of two Embryo Manipulation Solutions (EMS and EMS supplemented) in maintenance of the viability of embryos, initially using structures derived from mice (first phase). Next, the efficiency of these solutions in routines of bovine embryo transfer was evaluated (second stage). Mice embryos were used in the stages of early blastocyst, and compact morula grades I and II. These embryos were initially randomly distributed and maintained for four hours in three solutions: Modified phosphate buffered saline (PBS; Control); EMS (treatment 1), and EMS supplemented (treatment 2). Subsequently, they were cultured in TCM 199 medium and evaluated in terms of total number of cells, morphometric characteristics, ultra structural aspects, detection of cell apoptosis, and quantification of Hsp70.3 gene expression. In the second phase, these same solutions were tested in the transfer of quality I and II bovine embryos (excellent and good). These embryos were transferred fresh to 58 recipients. The results showed that the total number of cells in embryos expanded blastocyst (ExB), the number of apoptotic cells, the cell, nuclear, nucleolar diameter and the nucleus/nucleolus ratio was similar among the treatments. The pregnancy rate shown on second phase was also similar. However, the EMS supplemented expressed more Hsp70.3 than EMS. The expression of Hsp70.3 was also greater for embryos in EMS than that of EMS supplemented. The McII embryos, EMS and EMS supplemented samples also expressed more Hsp70.3 compared to control embryos. In conclusion, the tested solutions can be used in routine embryo transfer techniques, replacing modified PBS solution as an effective media in maintaining embryo viability.(AU)

The innovation network in animal reproduction: EMBRAPA's experience in organizing a research project on reproductive biotechnology

Background: In 2007 a broad Network project was proposed, aiming to organize in a more efficient way the different research and development actions related to new reproductive technologies in Embrapa. The initial proposal focused to develop new technological solutions to increase Brazilian livestock competitiveness; generate basic knowledge to support development of new technologies; to promote genetic improvement and evaluate dairy and beef animal models for the different ecosystems, to improve laboratorial infrastructure and promote capacity building; and to promote equal development of the technologies for the different livestock species. The final proposal, titled "Innovation Network in Animal Reproduction" was approved for the period 2008-2012. Review: The Network Project includes research activities in animal reproduction and in the interfaces of reproduction and animal health, nutrition, and genetics. A consortium of 12 of the Embrapa units, 14 Universities, 2 International Research Centers and 5 private companies are engaged in the project. The main structure follows the general guidelines of the Embrapa´s standard of network projects, being organized in 10 thematic Component Projects (CPs): CP1- Activities related to the organization of the Network, as the coordination of the CPs, financial management, promotion of meetings and workshops, and compilation of results and evaluations; CP2 ­ Development and evaluation of new technologies for the sanitary control of semen, oocytes, and embryos; CP3- Evaluation of nutritional strategies to improve reproductive efficiency; CP4- Development of methods to improve the quality and quantity of gametes used in assisted reproductive technologies; CP5- Development of in vivo and in vitro embryo production systems; CP6- Establishment of protocols for the isolation, culture and maintenance of cell lines aiming the production of animal clones; CP7- Establishment of alternative protocols to the production of transgenic or intragenic animals; CP8- Identification, selection, use and conservation of genetic resources; CP9- Validation and monitoring of technologies; CP10- Technological innovation. Conclusions: The establishment of the network allowed the organization of Embrapa's different ongoing research actions in animal reproduction in a large and multidisciplinary project. As consequences, there was a larger interaction among the different research groups of the company and external partners. The proposal of collaborative research improved the scientific production of the group and also the development of products, processes, and technical information to the private sector. The technology transference and capacity building activities were strategically reorganized in line with the scope of the Network Project. A last consequence of the network was the possibility of applying for consortium research funding opportunities. The group also expects to improve scientific collaboration and to increase the relevance of R&D projects in animal reproduction, to improve the interplay with the government agencies in charge of the establishment of laws and rules for reproductive biotechnology used in livestock, and to improve their capacity of identifying and measuring the impact of the new technologies in the different livestock production systems.