Using weanling pigs to uncover gut secrets

Interview with Dr Douglas G. Burrin: In the last decade, animal nutrition and animal health have increasingly been linked together as one doesn’t go without the other. In Vancouver, the role of nutrition, amino acids and gut development will be presented by Dr Doug Burrin, USDA.

It’s not only pig diseases that will receive a central focus, related research can sometimes shed a different light on pig health as well. Keeping that in mind, Dr Douglas Burrin, attached to the USDA’s Children’s Nutrition Research Center in Texas, USA, will speak at the IPVS Congress about the role of nutrition in the weanling gut and in lactation.

His research and knowledge about weanling pigs and young developing pigs is not so much swine-focused as it is a spin-off of a broader research theme into getting to know the human infant’s gut better. “The pig is a very good model for the developing gut of the human infant,” Dr Burrin explains. “We are trying to address problems in the human population. Newborn pigs have about the same body size, body composition, immunological function, and gut anatomy as the human infant.

He also uses the pig to examine nutritional questions that can’t be expressed with humans. “Our team surgically implants ultrasonic blood flow probes and blood sample catheters into the artery and portal vein that supplies blood to and from the gut and then measures the rates of amino acid absorption and metabolism.”

Amino acids
The role of amino acids in the gut play an important role in his research, Burrin says. “Amino acids are important not only for growth, but also as gut fuels. They also have important functional effects on gut development.” Dr Burrin explains it’s mainly about measuring amino acid metabolic balance.

“Using a surgical method, we can measure what the animal eats in very accurate terms and we can measure what is absorbed in the blood from the gut. Not only can we say: the gut takes 20% of the methionine (pictured) from the diet, we can also say what happened to that methionine. Was it metabolised, incorporated into protein or perhaps metabolised to another product such as homocystines.”

Breakthroughs
So far, his research in weanling pigs and other animals, like mice, has not translated into practice, Dr Burrin explains. “It mainly yielded fundamental basic discoveries about how the gut metabolises nutrients.”

“One of the things that we have been progressing with is that we know that methionine is metabolised by the gut. One of the products of that metabolism is a compound, called methylthioadenosine (MTA) and we know from recent studies with mice that this compound is relevant to inflammatory bowel disease. What we found is if we put this particular product in the drinking water of mice, it is actually protective in an experimental model of colitis. So we think that MTA may have important anti-inflammatory effects. This may be important as a supplement for example in treating people with inflammatory bowel disease.”

The theme of amino acid metabolism will return in Dr Burrin’s lecture in Vancouver – also in relation to the use of antibiotics in feed. “We think that the gut bacteria are involved in the process of metabolism. The question of whether animals receive antibiotics or not and what are the beneficial effects of these antibiotics may have something to do with animals’ ability to metabolise amino acids in the gut.”