UMD Collaborates to Improve Pig Muscle Growth, Implications for Sustainability and Health

The University of Maryland (UMD) received funding from the United States Department of Agriculture National Institute of Food and Agriculture (USDA-NIFA) to enhance the overall quality and efficiency of pork production through improved muscle growth in pigs. While early life nutrition seems to be especially important for how muscles grow and develop, less is known about how these benefits can be passed from mother to child during pregnancy. According to the USDA, the United States is the world's third-largest pork producer. In this $20 billion industry, increased and faster muscle growth means a healthier animal, less feed and waste to raise that animal, and ultimately a more competitive and sustainable pork industry. In partnership with the Uniformed Services University of the Health Sciences (USUHS) with the U.S. Department of Defense (DoD), this work could also have future applications beyond just the pork industry to optimize human performance and treat wounded service members.

The key to these applications could lie in the epigenetic changes (or changes to how your genes are expressed) and stem cell activity caused by a simple supplement - butyric acid. According to Chad Stahl, professor and chair in the Department of Animal & Avian Sciences at UMD and principal investigator of this work, butyric acid is a compound that humans and animals get naturally from their diet, and it has a profound effect on muscle growth, development, and even repair by stimulating muscle stem cells.

"Over the last decade, we've published some nutritional work in this area showing the impact of butyric acid and other dietary components on the activity of tissue-specific stem cells, and feeding butyric acid to pigs resulted in faster muscle growth," says Stahl. "So with this grant, if we are able to make the muscle fibers grow bigger because of the activity of these muscle stem cells, we want to see what happens if we are giving these compounds to the pregnant sow during fetal development. Could we actually increase the number of muscle fibers and get even greater improvements in growth rate?"

Stahl conducted previous work in this area with Robert Murray, a former doctoral student of Stahl's graduating from UMD in 2018. Murray is now an assistant professor with USUHS and a lieutenant in the U.S. Navy, working for DoD as a co-investigator on this grant. Together, Stahl and Murray are taking their work a step farther to see how these effects can be passed and enhanced from mother to child.

As Stahl explains it, the number of muscle fibers you have are fixed for life either at or shortly after birth, so the only thing you can do after birth is make those fibers grow bigger. That is why supplementation to the mother before birth presents an opportunity to increase the actual number of muscle fibers and improve muscle development. The researchers hope to discover what kinds of changes are actually occurring in stem cells thanks to butyric acid supplementation.

"With this research, we seek to answer some underlying basic questions behind stem cell programming and genomic changes that may persist into future generations of offspring," says Murray. "We hope to show that supplementation during pregnancy can have profound impacts on lifetime muscle growth for the offspring. We had previously found that early dietary inclusion of butyric acid had significant effects on improving muscle growth. It is exciting to get to test our hypotheses in fetal animals and really get to see just how much of an impact this supplementation can have on growth and development."

Improving the efficiency of muscle growth in pigs is especially important when thinking about environmental sustainability, a major focus of this grant. Stahl explains the many inputs that are necessary to feed a growing global population, so any reduction in these inputs translates to increased sustainability.

"Apart from reducing issues with low birth weight pigs and possible health benefits, another reason we care about any of this is that the growth related to muscle growth is the most efficient growth an animal can do," says Stahl. "If you want to reduce the cost or environmental implications of growing an animal for food, you want them to grow muscle as quickly as they can. What people don't always realize is that every input has a cost. So if pigs get to market more efficiently, you have to transport and grow less food for them. You didn't need as much fertilizer to grow that food. You didn't have the trucking cost and the burden of petroleum to get the food to the animals. So there is layer upon layer of improving efficiency to get that pound of meat, and all of that reduced cost improves sustainability."