How intestinal damage causes disease and how to avoid it

Damage in the intestinal wall of chickens can play a role in the transmission of foodborne illnesses as well as avian diseases.

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When the litter is level in poultry barns, so are the feeders and water lines, Amy Syester said during the Midwest Poultry Federation Convention. (Maple Leaf Foods)
When the litter is level in poultry barns, so are the feeders and water lines, Amy Syester said during the Midwest Poultry Federation Convention. (Maple Leaf Foods)

Damage in the intestinal wall of chickens can play a role in the transmission of foodborne illnesses as well as avian diseases.

As part of the Virtual Poultry Tech Summit, Dr. Charles Hofacre, president of the Southern Poultry Research Group and professor emeritus at the University of Georgia’s College of Veterinary Medicine, spoke on October 20, 2020 about how gut integrity impacts both bird health and food safety. His presentation was sponsored by Zinpro Corp.

Intestinal wall damage

When the gut wall is damaged, it allows two things to happen: normal bacteria inside the intestine leak into the blood stream and infect other organs and the bird’s body reacts to tissue damage in a way that some pathogens find advantageous.

Hofacre said the most common cause of intestinal wall damage is coccidia. The parasitic microbe lives and reproduces within animal cells. It is also ubiquitous in nearly every broiler house around the world. As coccidia goes through its normal lifecycle, it infects and damages the epithelial cells of the intestine.

There are other ways the intestinal wall is damaged such as mycotoxins or the use of feed ingredients that damage the intestine.

When the gut is damaged, it leaks microbial flora that is normal in the intestine into the bird’s bloodstream. Once that happens, bacteria like Salmonella can infect internal organs. The presence of that bacteria, a foodborne illness concern for humans, in the bird’s organs enhances the risk of Salmonella transmission onto meat.

A leaky gut can lead to infections of other body parts, such as the legs and knees. The condition bacterial chondronecrosis with osteomyelitis (BCO) causes lameness in birds. BCO is caused bacteria leaking from the gut and infecting the knee joint.

Necrotic enteritis is another potential consequence of gut wall damage. When the intestinal wall is damaged, the organ produces additional mucus to protect itself until it can heal. Clostridium perfringens, another normal bacteria in the intestine of the broiler, uses that extra mucus as a food source. Then, the bacteria grows and produces a toxin which causes the disease necrotic enteritis. For growers, this disease poses issues with mortality and flock uniformity since birds with damaged guts don’t grow well.

Another food safety risk posed by uniformity arrives during processing. Machinery is set in accordance with average flock size, so when there is significant variance there is higher risk of fecal and intestinal content contamination during processing due to machinery damaging organs. That means potentially more Salmonella and Campylobacter contamination on bird carcasses in the plant.

Improving the intestinal barrier

Hofacre said the best way to protect the intestines is to fight coccidia. He said poultry growers can minimize the impact coccidia will have on the intestine by using natural products or chemical anticoccidials. Companies that are not on an antibiotic-free (ABF) or no-antibiotics-ever (NAE) program can use ionophores to protect the intestine.

Those who are on an ABF or NAE program can use natural and phytogenic products, such as organic acids to protect the intestine and keep either Salmonella or Clostridium from growing in the gut.

Other ways to maintain gut health include:

  • Enzymes such as phytase and amylase
  • Organic minerals such as zinc, manganese and copper.
  • Prebiotics
  • Probiotics
  • Inorganic acids
  • Phytoceuticals such as essential oils and saponins
  • Immune stimulants and or modulators

“We have a lot of tools in our quiver," Hofacre said. "We just have to understand controlling coccidiosis and controlling the growth of the bacteria that are normal flora in the intestine and utilizing some of those natural products that a lot of companies now are developing and are demonstrating can work to help reduce intestinal disease and also help reduce Salmonella colonization.”

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