Reproductive biotechnologies: current status in porcine reproduction

During the past decade, considerable attention has been directed toward the development of reproductive technologies for both research purposes and fo r more controlled swine reproduction. Artificial insemination is an example of a technology that has continued to be expanded from early use in Europe an countries to the USA and Canada where it is now estimated that a majorit y of the sows bred are artificially inseminated. In addition, several signi ficant technological advancements have been made in the genetic modificatio n of swine and interest has been generated in the possible use of swine as donors of specific tissues and of organs for the improvement of human healt h. At the same time, the systems for production of swine for human food con tinue to undergo major changes including, in some countries, the consolidat ion of swine into large, integrated units. These swine operations are very receptive to the use of technologies to reduce labor costs as well as a bas is for increased production efficiency. Therefore, the combined interest in swine reproductive technologies by both the medical field and the swine in dustry creates an increased effort for the development of new technologies as well as for the implementation of existing ones. One of the more rapid t echnological advancements this decade has been the progress in in vitro pro duction (IVP) of swine embryos. Major advancements have been made on the de velopment of procedures for production of large numbers of embryos from ooc ytes collected at slaughter houses which are then matured (IVM) and fertili zed (IVF) in the laboratory. Success in IVP has stimulated increased resear ch in other areas that can be enhanced by the availability of embryos witho ut a requirement for surgical collection from gilts or sows. One example is the combined use of IVF, gender-sorted sperm cells, and embryo transfer to produce offspring of a predicted sex. In a related area, instrumentation f or non-surgical embryo transfer has recently been developed that results in significant improvement in this technology. Similar achievements have been gained in cryopreservation of embryos by vitrification. These developments will be reviewed with emphasis on the in vitro production of embryos from immature oocytes. (C) 2000 Elsevier Science B.V. All rights reserved.