Necrotic Enteritis in Poultry: Nutritional Strategies and Supplements

Necrotic enteritis is one of the most costly diseases in modern poultry production. The disease is caused by Clostridium perfringens, a bacterium that proliferates when conditions in the gut favor its growth. I’ve dealt with necrotic enteritis outbreaks that caused 1-2% mortality and 5-8 point FCR penalties.

Understanding the Disease

Necrotic enteritis typically occurs as a secondary disease following coccidiosis or other gut damage. The sequence is:

1. Coccidia infection damages the intestinal lining
2. Mucus and protein leak into the gut lumen
3. Clostridium perfringens, which is normally present at low levels, finds a rich food source
4. C. perfringens multiplies rapidly and produces toxins
5. The toxins destroy intestinal tissue, causing necrosis

The disease can be acute (high mortality over 3-5 days) or subclinical (poor growth and FCR without obvious mortality). Subclinical necrotic enteritis is estimated to cost the global poultry industry $2-3 billion annually in lost performance.

Nutritional Risk Factors

Several nutritional factors increase necrotic enteritis risk:

High dietary protein. Undigested protein reaching the hindgut is a food source for C. perfringens. Lowering protein by 1-2% while maintaining amino acid levels reduces risk.

Wheat-based diets. Wheat contains more non-starch polysaccharides than corn, which increase gut viscosity and slow digesta passage. This creates conditions favorable for C. perfringens growth.

Animal protein sources. Meat and bone meal, fish meal, and blood meal may carry C. perfringens spores if not properly processed.

High polyunsaturated fat levels. PUFAs can increase gut inflammation and permeability.

Mycotoxin contamination. Mycotoxins damage the gut lining, making it easier for C. perfringens to establish.

Key Prevention Supplements

Probiotics (Bacillus subtilis). Multiple studies show that Bacillus subtilis reduces necrotic enteritis lesion scores by 40-70%. The mechanism is competitive exclusion and bacteriocin production. I use Bacillus subtilis at 500-1,000 g/ton in all antibiotic-free programs.

Organic acids. Formic acid, propionic acid, and butyric acid reduce C. perfringens growth. Protected forms that reach the lower gut are most effective. I use 3-5 kg/ton during high-risk periods.

Mannan-oligosaccharides (MOS). MOS bind C. perfringens in the gut and prevent attachment. At 500-1,000 g/ton, MOS reduce necrotic enteritis mortality by 30-50%.

Zinc. Zinc at 80-120 ppm supports gut barrier integrity, making it harder for toxins to cross the intestinal lining.

Copper. High copper (125-175 ppm) has antimicrobial activity against C. perfringens. In conventional production, copper is an effective component of necrotic enteritis control.

Enzyme Strategies

Enzymes that improve protein digestibility reduce the substrate available for C. perfringens:

• Protease at 100-200 g/ton improves protein digestibility by 3-5%, reducing undigested protein in the hindgut
• Xylanase reduces gut viscosity in wheat-based diets
• Phytase improves phosphorus availability and reduces the anti-nutritional effects of phytate

In my field experience, protease supplementation consistently reduces necrotic enteritis risk in antibiotic-free programs.

Low-Protein Diet Strategy

Reducing dietary crude protein while maintaining amino acid levels is an effective strategy:

I’ve successfully reduced CP from 22% to 19% in broiler starter feeds using supplemental methionine, lysine, threonine, and valine. This reduces the protein entering the hindgut and limits substrate for C. perfringens.

The key is maintaining digestible amino acid levels while reducing total protein. With current amino acid prices, this usually adds $2-5/ton to feed cost but reduces necrotic enteritis risk significantly.

Management Factors

Nutrition alone cannot control necrotic enteritis. Management factors are equally important:

• Coccidiosis control (vaccination or anticoccidials)
• Litter management (dry litter reduces bacterial loads)
• Ventilation (ammonia below 10 ppm)
• Feed particle size (coarse particles improve gizzard function and reduce pH)
• Feed form (pellets increase risk slightly compared to mash)

Treatment Protocol

During an acute necrotic enteritis outbreak:

1. Remove high-risk feed ingredients (animal proteins, high wheat)
2. Add Bacillus probiotic at 1,000 g/ton
3. Add protected organic acids at 5 kg/ton
4. Add zinc at 120 ppm
5. Consider water-soluble antimicrobials as directed by veterinarian
6. Clean and dry litter thoroughly

The nutritional changes should be implemented within 24 hours of diagnosis.

Summary

Necrotic enteritis is a complex disease with multiple risk factors. Nutritional strategies that reduce protein reaching the hindgut, stabilize the gut microbiome, and support gut barrier function are the foundation of prevention. In antibiotic-free production, a comprehensive nutritional program is essential for controlling this costly disease.