Host-Microbe Interactions (HMI), Animal Breeding and Genomics (ABG) of Wageningen University & Research and Breed4Food (B4F) performed a proof of principle to investigate the use of organoids in order to study the ability of pigs to turn feed into consumable meat, also referred to as feed efficiency. During the seminar “Organoids to investigate efficiency in pigs” in Wageningen on the 5th of April, the proof of principle and some early results were presented.
The aim of this seminar was to gain more knowledge on the use of organoids to study complex genetically determined characteristics known as traits and to present the results of a proof of principle experiment studying feed efficiency in pigs.
*Organoids are small-scale simplified versions of organs, grown in a petri dish, which can be used for experimental purposes.
Improving feed efficiency
Improving feed efficiency is an important trait in many livestock species. However, the biological mechanisms that form the basis of feed efficiency are largely unknown. Organoids provide an excellent in vitro (in a petri dish) model system to study complex traits which are not easily accessible in vivo (in live animals).
Proof of principle experiment
HMI, ABG and B4F collaborated in setting up a proof of principle experiment. They did so by using organoids grown from intestine samples of consumption pigs with differing phenotypes (sets of observable traits) relating to feed efficiency, in order to measure the absorption of nutrients. In total, 12 pigs were selected: 6 efficient pigs and 6 less efficient pigs. From these pigs, tissue from the ileum – part of the small intestine – was collected and grown into organoids.
From both groups, 3 organoid cultures were challenged with E. coli – a bacterium that naturally occurs in the intestine of these animals – whereas 3 organoid cultures were unchallenged. A study was performed to measure differences in histology (the study of the microscopic structure of cells and tissues) and gene expression (expression of a trait created by a particular gene). Some first results indicate that there are some differences in gene expression between pigs. However, further research is needed to do some more in-depth analysis.
Challenges of the organoid model system
Developing the organoid system is very important for studying many traits of importance. A literature review showed that the organoid model system has been applied to most of the livestock species, using different organ tissues. Although the organoid model system seems promising for studying complex traits, there are still a number of challenges. For instance, developing a robust culture of organoids, confirmation and approval of the use of organoids as a substitute for in vivo study and large scale phenotyping.
The proof of principle performed by HMI, ABG and B4F is one of the first to demonstrate organoids as a substitute for in vivo study. In the long term, the results of this study can possibly be used for selection based on better feed efficiency by including biological information in future genomic selection analysis.