If you want to kill the buzz at a party, bring up diarrhea. Though it’s rarely discussed off the farm, the condition is a major concern for producers, sparking science to look for solutions.

Given the stakes, developing an alternative and environmentally friendly strategy to combat PWD and improve the overall health of pigs is imperative. Post-weaning diarrhea (PWD) is caused by a group of E. coli that produce special toxins, and is widespread in swine production today. In addition to causing stress for the animals, it does the same for their owners by harming growth performance and increasing mortality in the barn.

In many cases, farms rely on antibiotics to treat PWD. Given the rise in antibiotic-resistant bacteria associated with livestock farming, pressure is growing to phase out the drugs completely, with some countries already banning their use in feed to promote growth. Under the heading “the cure is worse than the disease”, heavy metals like zinc oxide (ZnO) have proved effective in controlling PWD, yet have come under considerable scrutiny for their negative effects on animal health and the environment. These metals can accumulate in vital organs like the pancreas and liver, and can also damage the environment by contaminating soil and water.

Probiotics: All pros and no cons

Now that we know what doesn’t work, only one question remains: what does? Based on recent studies, the addition of probiotic bacteria (live microorganisms that are intended to have health benefits when consumed) to the diet has a number of advantages for piglets during weaning: improved nutrient digestibility, reduced pathogen levels, greater gut immunity and enhanced overall growth performance.

As a further benefit, including specific probiotics in pig feed could help reduce the number of antibiotic-resistant bacteria in the intestine. One such probiotic – lactobacillus – has been studied extensively for this purpose, and is now being used in commercial applications.

The right spore for the chore

Another promising option in the PWD battle is a particular strain of Bacillus species, known as Bacillus subtilis. Bacilli are rod-shaped bacteria that can form spores and survive in harsh conditions. These bacteria are plentiful, residing in soil, water, dust and air, and will thrive in various temperatures. Furthermore, their ability to create spores at high temperatures and endure low pH (phosphorus) environments make Bacillus subtilis a robust strain that could be developed as an in-feed probiotic supplement. In recent studies, augmenting pig diets with a probiotic-based in Bacillus subtilis reduced the incidence and severity of diarrhea and enhanced growth performance by boosting immunity in weanling piglets.

If the eyes glaze over at terms like lactobacillus and Bacillus subtilis, the benefits of this study should be eye-opening for producers. Apart from addressing PWD caused by E. coli, the inclusion of Bacillus-based probiotics in nursery pig diets may reduce the presence of feed-induced diarrhea and help maintain or improve growth performance. This is significant, since weaning-associated diarrhea can also be triggered by economical diets which are mostly plant-based (corn and soybean meal-based).

Because feed cost is a huge burden on the industry, less costly regimens are often necessary, but they have also been associated with a higher incidence of diarrhea and lower intestinal integrity (the ability of the intestine to maintain its structure and function).

It takes a village

Good research is an investment in the future, so the scientists in this study were grateful for financial support from Swine Innovation Porc (SIP), Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) and CBS Bio Platforms Canada.

From the University of Guelph’s Department of Animal Biosciences, a number of research minds joined forces for the project: Dr. Julang Li, professor; Sudhanshu Sudan (a PhD student at the time, now a research scientist at U of G); Dr. Lee-Anne Huber, assistant professor; Dr. Robert Friendship, professor, Ontario Veterinary College; Dr. Elijah Kiarie, professor; Xiaoshu Zhan, Ph.D. candidate; Lauren Fletcher, Ph.D. candidate; and Serena Dingle, M. Sc.

Also integral to the project were Rob Patterson, vice president - Innovation & Commercialization at CBS Bio-Platforms, and the animal care and sampling assistance provided by the Arkell Swine barn staff, research associates Cuilan Zhu and Douglas Wey, and undergraduate research interns. Metabolite sample processing and data extraction were delivered by Robert Flick, Mass Spectrometry and Metabolomics Services Manager at BioZone, University of Toronto.

Based on the current results, low-dose supplementation can achieve significant improvements in growth performance in a research environment. From here, larger studies in a similar setting, as well as in production/commercial settings, must be conducted to confirm these findings.

While there is still work ahead, this study adds to a limited body of research on the use of probiotics as an alternative to ZnO and antibiotics in guarding against PWD. The results also suggest that supplementing piglets with a novel bacillus-based probiotic may improve feed efficiency and growth performance, offering an economical feeding strategy to benefit producers around the world.

As a dinner topic, that sure beats diarrhea.