The majority of research on gut function in weaned pigs has focused on the first 1-2 weeks post-weaning while the long-term impacts are often overlooked, said Adam Moeser, DVM PhD, in a presentation at the AASV meeting. Moeser is the Matilda R. Wilson Endowed Chair in Large Animal Clinical Sciences and director of The Gastrointestinal Stress Biology Laboratory at Michigan State University, College of Veterinary Medicine.

“The long-term impacts on pig heath and gut function have only recently begun to be realized,” he said. Moeser cited original work by “Main et al (2004) who demonstrated in a commercial multi-site swine production system that incremental increases in wean age from 12 to 21.5 days of age resulted in linear improvement in growth rate and feed efficiency and reductions in mortality to market.”  

Moeser’s research team is focused on understanding how stressors such as early weaning influence long-term gut health and disease susceptibility. Research from his laboratory has demonstrated that increasing weaning age linearly improved intestinal barrier function by reducing intestinal permeability when measured 2 weeks post-weaning. More recently, his research showed that intestinal permeability differences between early and late-weaned pigs persist into adulthood when measured at 170 d post-weaning.

“Recent evidence from our lab demonstrated that compared with late-weaned pigs (26 to 28 days of age), early-weaned pigs exhibited increased intestinal permeability as well as other gastro-intestinal (GI) functional disturbances and that the sex of the pig matters in that female early weaned pigs exhibit greater GI disease,” Moeser said. “Overall, this demonstrates that early weaning and factors such as sex of the pig have lasting impacts on GI health including intestinal barrier permeability.”

He added that there is also accumulating evidence for lasting functional changes in the GI immune barrier function and disease susceptibility. When challenged, early-weaned pigs exhibited heightened clinical disease, including diarrhea and growth performance reductions, and increased intestinal permeability compared with later-weaned pigs.

“While piglets eventually overcome the growth lag at weaning period, new research from Moeser’s laboratory has demonstrated that early-life stressors such as weaning alter the developmental trajectory of GI barrier functions leading to a lifelong increase in disease susceptibility of the animal throughout the production lifespan,” Moeser said. “The concept of early life origins of GI disease susceptibility in the pig is supported by paradigms in humans where early life adverse events (like psychological trauma, inflammation, infection) are risk factors for GI inflammatory and functional diseases later in life.”