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Improving the efficiency of pig production

With the increasing world population and the awareness of the negative environmental impact of livestock, meeting the growing demand for animal protein in a sustainable way is a major challenge to ensure food security in the future. In this context, improving the efficiency of pig production is a key target. The ratio of lean to fat in the body participates into production efficiency. Controlling this ratio requires a better understanding of the dynamic balance between the number and volume of adipocytes and the number and type of muscle cells. The mechanisms governing cell numbers in muscle and adipose tissue remain partly unknown whatever the species considered. The objective of this work was to identify the different populations of adult stem cells, also called progenitor cells in differentiated tissues, which could commit to muscle and(or) to fat lineages. For that, we have determined the types of progenitor cells in muscle and adipose tissue, their respective proportions when different factors of variation of body composition were applied (genetics and feeding), and their ability to differentiate into adipocytes or muscle cells.

Cellular composition of adipose tissue and of muscle highly dependent of pig genetics and of feed composition

Specific tools for pig tissues have been developed based on cell surface markers defined in the literature (CD11b, CD14, CD31, CD34, CD45, CD56, CD90 and PDGFRα) to identify the different populations of adult stem cells. For the first time in pigs, we were then able to define the proportions and lineages of different progenitor cell populations in skeletal muscle and adipose tissue. Muscle progenitors were characterized by an important plasticity, because they could differentiate into a fully differentiated myogenic and/or adipogenic phenotype. On the opposite, adipose progenitor cells could differentiate into adipocytes but could not achieve a complete myogenic differentiation. To determine whether changes in body composition were associated with changes in the proportion or in the functionality of adult stem cells, we have also studied the different populations of progenitor cells in muscle and adipose tissues from pigs divergently selected for feed efficiency and fed diets with contrasted energy source and nutrients. We have reported that the cellular composition of adipose tissue and of muscle were highly dependent of pig genetics as well as of feed composition. Especially, a decrease in the proportion of CD56+/PDGFRα+ in adipose tissue was associated with the dietary-related decrease in body adiposity. The increase in the proportion of CD34+/PDGFRα- cells in skeletal muscle was associated with the leaner phenotype of the most efficient pigs.

New targets for a better control of production efficiency in livestock species

These new data on stem cell populations for porcine adipose tissue and skeletal muscle are of great importance for a better control of production efficiency in livestock species. They can be considered as new targets to modulate tissue composition and production quality. Studies are in course to investigate more precisely the plasticity of each population of adult stem cells in response to different breeding challenges during pig growth.

Bibliography

• M.H. Perruchot, L. Lefaucheur, C. Barreau, L. Casteilla, I. Louveau. 2013. Age-related changes in the features of porcine adult stem cells isolated from adipose tissue and skeletal muscle. American Journal of Physiology - Cell Physiology 305: C728-C738. (DOI)
• M.H. Perruchot, C. Tréfeu, L. Lefaucheur, C. Barreau, L. Casteilla, I. Louveau. 2012. Exploration of progenitor cells in adipose tissue and skeletal muscle during growth. Satellite ECO Congress, Paris – 7 and 8 May. [lien]
• M.H. Perruchot, L. Lefaucheur, F. Gondret, I. Louveau. 2014. Adult stem cells in adipose tissue and skeletal muscle of pigs differing in body composition. In Book of Abstract of the 65th EAAP, EAAP 2014 Copenhagen, Denmark, 25-29 August 2014. P84. (Wageningen Academic Publishers, eds). [lien]

Contact

Marie-Hélène Perruchot (marie-helene.perruchot[at]rennes.inra.fr)