Necrotic enteritis is an avian disease that affects 40% of commercial broiler flocks worldwide, costing the global broiler industry $5 to $6 billion annually. The disease affects poultry, such as chickens and turkeys. It typically affects broiler chickens 2 to 5 weeks of age raised on litter. However, it can also affect commercial layer pullets raised in cages.
Necrotic enteritis can cause depression, diarrhea, intestinal lesions, liver lesions, and mortality in chickens. In severe cases, the enteric disease can result in up to 50% flock mortality. Preventing and controlling the disease is of the utmost importance for professionals in poultry producers.
This article will discuss predisposing factors and tips to help control and prevent the disease within your flocks.
What is necrotic enteritis?
Necrotic enteritis is a poultry disease that results from the over-proliferation of Clostridium perfringens, a sporulated gram-positive bacteria typically found in chicken intestines. Usually, Clostridium perfringens is present in chicken’s intestines but doesn’t cause disease.
However, when C. perfringens begins toxin production, it can be lethal to broiler chicks. The use of antibiotics in the poultry industry reduced the prevalence of this disease.
However, certain factors — such as changes in diet, immune suppression, and changes in intestinal microflora due to antibiotics or vaccines — can exacerbate the replication of the bacteria. When Clostridium perfringens has a substrate that allows it to multiply, it can cause the enteric disease.
The disease usually only lasts five to 10 days but can increase mortality quickly without much warning. It’s important to watch out for the clinical signs that could indicate necrotic enteritis in your flock.
Symptoms of necrotic enteritis in chickens
The clinical form of necrotic enteritis can cause symptoms in chickens, such as:
- Severe depression
- Diarrhea
- Ruffled feathers
- Dehydration
- Decreased appetite and food consumption
- Reluctance to move
- Reduced weight gain
Subclinical necrotic enteritis is accompanied by symptoms of poor growth
performance, which should become noticeable around 35 days of age. Chronic damage to the small intestine and increased mucus production can impair digestion, hindering weight gain.
Additionally, clinical signs of necrosis can be found postmortem. Some signs include:
- Darkened skin
- Intestinal lesions
- Dark brown, foul-smelling liquid in the intestines
- Swollen intestines
- Burned intestinal mucosa
- Lesions in the liver
How is necrotic enteritis spread in chickens?
Necrotic enteritis is spread through fecal-oral transmission. Because infected chickens’ feces stay in the litter, the disease can spread throughout the flock.
How to control and prevent necrotic enteritis in chickens
You can treat necrotic enteritis by administering antibiotics like bacitracin, lincomycin, oxytetracycline, and virginiamycin. But because the disease is so fast-acting, controlling and preventing necrotic enteritis in your chicken flock is vital to minimizing flock mortality. However, animal production is steering away from the use of antibiotics due to concerns about antimicrobial resistance.
However, because C. perfringens is so common, you must take steps beyond normal biosecurity measures. Preventing and controlling the avian disease includes minimizing its predisposing factors.
Here are the key strategies to help control necrotic enteritis.
Optimize the chicken’s diet
Your chickens’ diet is a predisposing factor impacting the likelihood of a necrotic enteritis outbreak. Clostridium perfringens live in the gastrointestinal tract. When the feed changes the intestines and other organs can become a breeding ground for the disease-causing bacteria.
Some feed qualities that increase the chances of a necrotic enteritis incidence include:
- Low-quality protein with poor digestibility
- Mycotoxin contamination
- High-fiber diets
- Diets with a high concentration of protein
- Amino acidssupplementation
Low-digestibility proteins include animal proteins like meat, fish meal, and bone meal. Instead of getting absorbed by the upper intestinal tract, the protein settles in the lower intestinal tract. Then, the protein acts as a substrate for gut microbiota to flourish.
Protein fermentation and its byproducts, such as amines and ammonia, increase the chicken’s intestinal pH and encourage the proliferation of the pathogen.
To prevent the disease, switch your chickens to an all-nutrient, more digestible diet. If the Clostridium perfringens doesn’t have access to much protein, it won’t have the grounds to multiply. When formulating a diet, consider reducing animal protein and animal fat in addition to rye, barley, and wheat, as they increase the incidence of necrotic enteritis.
Additionally, use phytogenic feed additives that act as promoters of chickens’ digestion, making it easier for them to properly absorb protein and other nutrients. The use of prebiotics has also proved promising in mitigating subclinical necrotic enteritis.
Engrain’s eMAX Feed Technologies can provide your chickens with a healthier diet. The technology relies on the ability of the Bacillus to produce substances that can inhibit the growth and proliferation of pathogenic bacteria. Besides this, with eMAX you can utilize lower metabolic energy requirements in broiler or layer diets without affecting the flock’s growth performance. Engrain’s solutions also address the removal of antibiotics and poor intestinal health.
Aside from the makeup of your chickens’ diet, you should also manage mycotoxins. Mycotoxins are toxic fungal metabolites produced by common molds found in many components of poultry diets. They can reduce the integrity of your chickens’ gastrointestinal tracts, making it harder for them to digest nutrients. As a result, the intestines can promote the reproduction of C. perfringens.
Mycotoxins can also adversely affect immunity. Practice a proper mycotoxin management system by using feed and ingredients free of mycotoxins and ensuring feed is kept in an environment that doesn’t promote mold growth.
Manage coccidiosis
Coccidiosis is caused by protozoan parasites (coccidia) from the Eimeria genus, typically found in the intestinal tract. It’s one of the most common diseases affecting small flocks of chickens in the world.
Coccidiosis doesn’t directly cause necrotic enteritis. However, necrotic enteritis is more likely to occur after a coccidiosis infection. While an active or past infection can increase the likelihood of necrotic enteritis, small introductions to the disease through vaccination can also have positive effects.
The disease can damage the intestinal epithelium and leak plasma proteins into intestinal lumens, creating a substrate that C. perfringens can use to multiply. This predisposes birds to necrosis.
Probiotics and phytogenic feed additives can help alleviate the negative effects of Clostridial infection. Infected chickens can also take anticoccidial drugs. Other methods of coccidiosis control include vaccination, maintaining ideal bird density, and keeping good quality litter.
Wet and caked litter can promote the spread of parasites, so moving feeders and waterers to dry spots and removing caked litter is advised to prevent coccidiosis.
Maintain proper litter management
Understanding proper litter management is another vital part of controlling and preventing necrotic enteritis. Because litter contains poultry excreta, spilled feed, and feathers, it can sometimes contain C. perfringens.
According to DSM, exposing the flock to litter from a previous flock that could be contaminated with C. perfringens can be helpful as early exposure decreases the severity of necrotic enteritis. Contrastingly, first flocks following litter cleanouts or first flocks in clean broiler houses are more likely to have a severe outbreak.
To help prevent necrotic enteritis, let the living space litter build up over time instead of regularly cleaning it out. Additionally, you can use litter acidification to help control the disease.
Brood in a warmer environment
Brooding in a warmer environment can also help limit necrotic enteritis. But the temperature of the environment and the litter may not be the only factor to consider.
Vapors of hydrogen peroxide can also inactivate C. perfringens spores. Heating humid litter can decrease the number of viable C. perfringens spores, mainly due to the ammonia vapors released from the litter.
Keep clean and disinfected premises
Keeping your chickens’ environment clean can help prevent necrotic enteritis. It’s especially helpful in controlling coccidiosis.
However, cleaning won’t always do an effective job. Because the disease-causing bacteria Clostridium perfringens is already present in chickens’ intestines, it’s unlikely you can eliminate it. Instead, controlling the factors that it needs to grow (such as the diet, litter, and drugs) is recommended.
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