Development of technical and chemical supplementation for pig embryo transfer at a commercial scale

Using embryo technology in pig breeding is of interest, but it is a challenge to collect egg cells or embryos from live sows without surgery. This project has included the development of equipment and methods to make this possible. New and improved versions of the catheter produced at NTNU have been continuously tested, first on slaughter organs and then on live sows at SEARCH. In addition, several versions have been tested at a university in Edmonton, Canada. Important achievements are obtained regarding use of the catheters in large gilts and that the flushing technique itself has become more efficient. Additional challenges consist of fine-tuning the times for both insemination and flushing out embryos in relation to ovulation. We have also received help from our industrial PhD candidate in detecting embryos that have been flushed out and checking embryo quality. A process has started to apply for a patent for the newly developed catheter type. In the case of ovum pickup, a PhD candidate at SEARCH is in the process of testing instrumentation and protocols for handling the sows and retrieved oocytes. Our industrial PhD candidate has also contributed here in terms of staining and control of the oocytes, knowledge of media for further in vitro fertilization and embryo culture so that we can plan embryo transfers in the near future. Samples of follicular fluid have been sent to the Toxicology and Drug Metabolism department at the University of Copenhagen for steroid analysis. The analyses showed breed differences in the ratio between androgens and estrogens. There is a possibility that this can be associated with egg cell and embryo developmental competence. Understanding the basic oocyte and embryo development can help us increasing embryo production in the lab by for example supplementing medium with certain steroid hormones.

Vi er veldig nær optimaliserte protokoller for skylling av befruktede egg fra levende svin, og i tillegg er det gjort framskritt når det gjelder å hente ut ubefruktede egg fra levende svin. For begge disse typer biologisk materiale har vi landet på en versjon av oppbevarings- og kulturmedium som fungerer for overlevelse og videre utvikling i laboratoriet. Produksjon/kombinasjon av egnede katetertyper er en prosess som fortsetter med mål om kommersiell produksjon, og det er søkt patent på dette. Forhold rundt nødvendige dimensjoner, materialstyrke, skyllevolumer, trykk- og vakuumforhold for å hente ut nær 100% av eggene er i stor grad oppklart og inngår i protokollene som brukes. Håndtering av dyrene med tanke på velferd (minimalt ubehag) før, under og etter prosedyren har hele tida vært i fokus.

Embryo technology in pigs will decrease pig health and animal welfare challenges connected to live animal export with long transportation times. It also has the potential to accelerate the genetic progress and decrease the amount of feed needed to produce pork worldwide. Alternative pathways towards embryo transfer from live intact pigs without surgical procedures is the overall aim of the project. Combination of methods, instruments and equipment from human medicine with further development of embryo catheters from veterinary medicine is thought to bring progress in embryo collection in pigs. An alternative method is to collect mature oocytes ("ovum pickup") via minimal invasive techniques from sedated animals, resembling human IVF techniques. This will result in a need for improved protocols for in vitro fertilization with better survival of embryos. For in vitro maturation and fertilization, culture media need optimization especially towards standardization, without addition of biological fluids collected from sources that may be a biorisk. Many current in vitro protocols include addition of such fluids and our aim is to investigate the effect of adding such fluids on maturation and early embryo development and survival.