There have been significant improvements in housing, genetics, and nutrition over the last 60 years within the poultry industry (Yegani and Korver, 2008). Alongside those improvements, the health of the bird’s gastrointestinal tract has also become increasingly important due to its role in digestion and absorption, disease resistance, and immune response. Any disruption in these critical functions can lead to enteric diseases such as viruses, macro-parasites, and bacteria.

One of the most common by-products of gastrointestinal disruption is a clostridial disease known as necrotic enteritis. Necrotic enteritis was first reported 61 years ago (Parish, 1961) and has been determined to be caused by a gram positive, spore-forming anaerobe known as Clostridium perfringens. There are several sources that can be held responsible for the spread of the bacteria such as the birds themselves, the hatchery, litter, or even the bird’s feces. Currently, Clostridium perfringens is the 3rd leading bacterial induced food-borne disease in the United States (CDC, 2021), and in 2016, the global annual loss from this disease was $6 billion dollars. Five years later, we can only assume that number has significantly increased.

Interestingly, Clostridium perfringens is naturally occurring in birds, so it alone cannot be a determining factor for disease development. Predisposing factors such gut stasis, viral infections, nutrition, and Eimeria infection can all lead to an overgrowth of Clostridium perfringens which ultimately determines the severity of the disease (Adhikari et al., 2020). There are two types of necrotic enteritis infections, a clinical and sub-clinical infection. Anorexia, diarrhea, and high morality are all signs of a clinical infection while sub-clinical infections are identified by chronic damage to the mucosal intestinal lining, reduction in nutrient utilization, and depressed growth performance. Sub-clinical is much more common and because of that, much more costly.

While necrotic enteritis has traditionally been more of a concern in broiler houses due to their contact with bedding material and cycling of coccidiosis, we’re starting to see a slight uptick of the disease in cage-free layer houses. Especially as the layer industry begins to convert more houses over to cage-free layer facilities. In 2021, 29% of total hens in egg production were in cage-free production. By 2026, they’re projecting the demand for cage-free layer production will be close to 66%. That means necrotic enteritis could become a much larger problem in cage-free layer operations than anticipated. So, what are our options to help mitigate this disease challenge?

On the management side, there are vaccines being administered at the hatcheries and anticoccidials added into the water or feed. On the nutrition side, there are several classes of additives that could be useful to combat a necrotic enteritis challenge. The first being probiotics, prebiotics, and synbiotics. This class of additives work to competitively exclude pathogenic bacteria while also stimulating the immune system and increasing digestive enzyme activity (Fuller, 1991; Gibson and Roberfroid, 1995). Another class of additives are known as phytogenics which are defined as biologically active substances extracted from plants (Yang et al., 2015). Thymol, carvacrol, and cinnamaldehyde are all commonly used phytogenics to combat Clostridium perfringens due to their antimicrobial, antioxidant, and anti-inflammatory properties. Lastly, enzymes such non-starch polysaccharides can also be used to help combat Clostridum perfringens as they work to reduce excess substrate in the gastrointestinal tract, ultimately suppressing the growth of pathogenic bacteria (Van Immerseel et al., 2004).

In summary, necrotic enteritis is responsible for significant losses within the poultry industry. While historically this wasn’t a concern for conventionally reared layers, the rise in cage-free layer operations may lead to higher disease challenges. Management and nutritional strategies can be implemented in the face of a challenge such as vaccines, anticoccidials, and feed additives.