Background In pigs, the ratio between lean mass and fat mass in the carcass determines production efficiency and is strongly influenced by the number and size of cells in tissues. We hypothesized that the impact of hygiene of housing conditions during growth on the proportions of MSCs in adipose tissue and skeletal muscle may differ between pigs with different residual feed intake RFI , a measure of feed efficiency.
Methods At the age of 12 weeks, Large White pigs from two lines divergently selected for low and high RFI were housed in two contrasting hygiene conditions good vs poor. Results Adipose tissue and muscle shared some common MSC populations although MSC diversity was higher in muscle than in adipose tissue.
This study shows that the proportions of some MSC populations were affected by hygiene of housing conditions in a tissue-dependent manner in pigs of both RFI lines. It suggests that MSCs may play a significant role in adipose tissue and skeletal muscle homeostasis and may influence later growth and body composition in growing animals.
Stressful situations like transport and housing in poor hygiene conditions result in immune system hyper-activation Stavrakakis et al. The animal ability to cope with these different challenges will influence the growth of tissues associated with meat production and subsequently their growth efficiency. Fat animals are generally less efficient in the conversion of feed into meat Sillence, Hence, a better control of body composition in growing pigs requires a better understanding of the dynamics and flexibility of muscle and adipose tissue growth when the surrounding environment of pigs is modified.
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The mass of skeletal muscle and adipose tissue is largely determined by the number and size of muscle fibers and adipocytes Lefaucheur, ; Louveau et al. These cells comprise heterogeneous populations of undifferentiated cells able of self-renewal with the capacity to differentiate into cells of the mesenchymal lineage adipocytes, myocytes or osteocytes for instance.
