This is part 3 of a 4-part series exploring how epithelial integrity is the first line of defense to target immunomodulation, BCO and food safety issues. If you missed part 2, catch up here.
When a bird’s epithelial tissue is weakened, bacteria and other antigens can pass into the body. This can lead to several health conditions – including bacterial chondronecrosis and osteomyelitis (BCO). This condition occurs when harmful bacteria in the bloodstream settle in microfractures between growth plates and the articular cartilage of the femur, tibia and flexible thoracic vertebrae, leading to micro-abscesses and necrosis.
BCO is the most common cause of lameness in poultry around the world, especially in flocks that aren’t treated with antibiotics. Financial losses from BCO range from 1% to 3% in normal conditions, or as high as 10% to 15% in extreme cases, impacting culling, slower growth and condemnation.
Bacteria are the dominant organisms of the world, even more so than humans. Many species of bacteria cause BCO, but most frequently found are those that are familiar to poultry producers and consumers alike, including Enterococcus spp., E. cecorum, Staphylococcus spp. and S. agnetis. There are reports on recovering Salmonella from bones. These bacteria can break through the epithelial tissue, survive the inflammatory and immune responses and eventually be deposited in remote places where the presence of immune cells and phagocytes are limited, irrigation is reduced, or vascular epithelium is weak.
The first step to delaying the onset and reducing the prevalence of BCO in poultry flocks is to improve the integrity of the first line of defense: the epithelial tissue.
The epithelial tissue covers the body on the outside and the inside of tubular organs. It includes skin and epithelial lining in the gastrointestinal tract, respiratory system, reproductive system and others, even vascular endothelium covering the blood vessels. The epithelial tissue is a solid wall with cells attached by tight junctions. These cells are continuously being renewed, and some of them produce mucus and protective secretory components. When these cells are damaged by stress, parasites or bacteria, they must be replaced right away to maintain the integrity of the epithelium and ensure that these parasites cannot penetrate the body.
Therefore, these cell proteins need to be synthesized continuously. If there is not an adequate pool of new epithelial cells to immediately replace those that are damaged, bacteria will have an opportunity to enter the bloodstream.
Trace minerals, like zinc and manganese, are critical to the production and maintenance of epithelial tissues. Tight junction proteins like ZO1, ZO2, claudin and occluding, require zinc for their synthesis. To maintain a protective layer and cellular structure, epithelial cells contain a cytoskeleton matrix composed of collagen and keratin filaments or tightly wrapped protein fibers. Keratin’s primary role is to make skin a pliable, insoluble and unreactive barrier against the natural environment. Zinc is a key mineral in the process of keratinization.
The trace minerals in Availa®ZMC — zinc, manganese and copper — improve gut integrity by strengthening the tight junctions in the intestine so bacteria won’t leak out and settle into microfractures in the growth plates. These minerals also help improve bone quality and the overall health and immune function of the birds.
A research study conducted at the University of Arkansas using a strict model resulted in a significant reduction in the prevalence of BCO lameness and delayed the incidence by four to five days. Birds fed Availa-ZMC in wire flooring models experienced a 29% reduction of BCO lameness. Birds fed Availa-ZMC in a litter flooring model, challenged with Staphylococcus agnetis, showed a 23% reduction. This is largely due to the improvement performance trace minerals provide the epithelial cells.
Ensuring a strong epithelial barrier is the essential first step to reducing the prevalence of BCO in your poultry flock. If you can ensure that birds have an adequate pool of new fully functional cells to replace those damaged by bacteria, you will be able to keep those bacteria from entering their bloodstream.
To learn more about formulating your poultry nutrition program to improve epithelial integrity and prevent BCO, contact your Zinpro representative today.