To a non-scientist, the notion of “good bacteria” is like the idea of a friendly monster - it seems counterintuitive or even contradictory at first glance. In fact, the bodies of pigs and people contain more helpful bacteria than the bad kind, especially in the gut. Since good bacteria, also known as probiotics, play a critical role in keeping pigs healthy and producers above water, researchers ran a study to better understand both types of bacteria.

Probiotics offer a number of benefits for pigs, such as improved digestion, protection from pathogens and the production of nutrients and antibodies. These advantages are especially valuable for peri- and post-weaning pigs, as they are often exposed to diseases like E. coli and rotovirus, a highly contagious infection that causes diarrhea and dehydration. At present, the main means of combating these conditions on farm are vaccination, zinc supplements and the inclusion of antimicrobials in feed; but all three have limitations.

Good news, meet bad news

For their part, antimicrobials have sparked a public health concern as more and more infections show resistance to these drugs. They also represent another cost to producers and could render future pathogens harder to treat.

While vaccination has its place in the barn, it is less effective with younger pigs, as their immune system is not yet properly developed to respond to vaccines.

As for zinc, its negative impact on the environment has been well documented, leading some countries to ban its use with pigs, and Canada may soon follow suit. In the eyes of scientists on this project, the best alternative to these measures are probiotics. Previous research has shown that piglets who are not exposed to good bacteria early on can be highly susceptible to disease. With the addition of probiotics to swine diets, like Lactobacillus that is also found in yogurt, the influx of good bacteria in the gut works to crowd out the bad ones. Lactobacillus is a probiotic that restores the balance of good bacteria in the intestine that may be disrupted after the application of antibiotics or due to intestinal infections.

A gutsy effort

In their quest to learn more about bacteria as it relates to pig health, scientists explored the composition of the gut microbiota, which comprises thousands of bacteria. One finding of interest is that the microbiota changes as pigs age. At birth, piglets have no bacteria in the gut, but begin to acquire them when exposed to the sow during farrowing. Because the bacteria needed to digest liquids and solids are different, the microbiota changes again when piglets move from a liquid milk diet to solid food after weaning.

Researchers also examined the relationship between the gut microbiota and growth performance, and found that pigs of a certain microbiota enterotype showed better growth and less incidence of diarrhea. An enterotype is a classification of living organisms based on the bacterial composition of the gut’s microbiome.

Finally, the team sought a connection linking the microbiota and genetics, noting that some bacteria is unable to survive in the pig’s gut due to a genetic variation in the animal.

Knowledge is powerful

When it comes to pigs, health and bacteria, the more science knows, the more it can aid producers. With antimicrobials being slowly phased out, industry needs an alternative to keep pigs thriving in the face of a disease challenge, and probiotics show the best potential. Many pharmaceutical companies have expressed interest in developing probiotics. To support these efforts, science must gather as much knowledge as possible, such as how to distinguish good and bad bacteria in the gut.

If the work from this study leads to a new probiotic that can be commercialized and used by producers, it could amount to a triple threat: healthier pigs, a more productive swine industry, and less reliance on antimicrobial use in animals.  

To ensure success for researchers, collaboration was critical. They received funding from Swine Innovation Porc (SIP), Cargill Limited, and the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA).

The research team included Dr. Vahab Farzan, Dr. Brandon Lillie, Dr. Khurram Nadeem, and graduate student Madison Arsenal from University of Guelph, as well as Dr. Ehsan Khafipour from Cargill Inc.

In the years ahead, scientists envision a time when they pinpoint the specific bacteria that are associated with better performance and health, and use them to produce effective probiotics for pigs. If they can also identify the genetic markers for these traits, that information could be shared with swine breeding farms for the betterment of their herds.