Biomarkers identified as likely indicators of gut barrier health in poultry
Authors: Juxing Chen, Structure/Function Manager, Biology and Jeffery Escobar, Executive Manager, Nutritional Physiology
Gut barrier function is crucial to adequate gut health in chickens, but oxidative stress, poorly digestible protein and coccidiosis can cause gut barrier failure. The increased use of alternative grains, such as wheat, barley and rye, has been linked to performance reductions. These ingredients contain high levels of non-starch polysaccharides (NSP). Because poultry have little or no intrinsic enzymes capable of hydrolyzing NSPs, high concentrations of these ingredients lead to reduced nutrient digestibility. The undigested feed ingredients provide nutrients for bacteria overgrowth in the hindgut, leading to dysbacteriosis. High-NSP diets have also been associated with necrotic enteritis, which can have substantial negative economic impacts for broiler producers.
With the removal of anti-microbial growth promoters throughout the industry, new multi-factorial diseases causing enteritis and gut disorders have emerged in broilers, decreasing animal health and performance.
Dysbacteriosis, the presence of abnormal microbiota in the small intestine, associated with reduced nutrient digestibility, impaired intestinal barrier function, bacterial translocation and inflammatory responses, has been reported. And more recently, poor gut health has also been associated with bacterial chondronecrosis with osteomyelitis in broilers and breeders.
As one of the largest organs in the bird, the gut serves as a selective barrier to take up nutrients and fluids into the body, while excluding undesirable molecules and pathogens. Consequently, proper gut barrier function is essential to maintain optimal health and balance throughout the body and represents a key line of defense against foreign antigens from the environment.
To date, no biomarkers have been labeled as tools to evaluate gut inflammation or gut barrier failure in broilers. However, a recent study was conducted to do just that – identify potential biomarkers for gut barrier failure.
In a collaborative project between the University of Arkansas and Novus, researchers attempted to intensify gut barrier failure (GBF) by feeding a high NSP diet containing rye, wheat and barley to induce high digesta viscosity in combination with a coccidiosis vaccination to prompt gut health challenge.
The results suggest the combination of a high NSP diet and a coccidia challenge induced gut barrier failure and inflammation in broilers, characterized by differential expression of seven identified potential biomarkers within the gastrointestinal tract between the GBF induced group and the control. These findings indicate the possibility of further using biomarkers as indicators of gut health in poultry. Now that we have a better understanding of the relevant indicators, further studies can be done to investigate the effects of different ingredients on gut barrier function.
To access the full journal article, click here: http://journal.frontiersin.org/article/10.3389/fvets.2015.00014/full