Challenging Re-emergence of Necrotic Enteritis in Poultry

Refraining the use of antibiotics in poultry feed has aggravated outbreaks of Necrotic enteritis (NE) even more often. NE is an acute Clostridium infection characterized by severe necrosis of the intestinal mucosa. The disease begins suddenly, with a sharp increase in the death rate. The disease usually persists in a flock for 5–10 days, and mortality is 50%. The causative agent is the gram-positive, obligate, anaerobic bacteria Clostridium perfringens. There are two primary Cl. perfringens types, A and C, associated with NE in poultry.

Cl. perfringens is a nearly ubiquitous bacteria readily found in soil, dust, faeces, feed, and used poultry litter. It is also a normal inhabitant of the intestines of healthy chickens and turkeys. The enterotoxaemia that results in NE most often occurs either after a change in the intestinal microflora or from a condition that results in damage to the intestinal mucosa (eg, coccidiosis, mycotoxicosis, salmonellosis, parasitic infection, etc).

Chickens at the age of 25 weeks are usually affected, NE is also encountered in hens particularly near the period of the beginning of egg-laying or peak egg-laying, most commonly associated with coccidiosis. In acute cases, marked congestion of the liver, responsible for its dark red to black appearance, is present. Intestinal content is bloody, mixed with necrotic debris and gas bubbles. The diagnosis is based on distinctive gross lesions. Toxins produced by the bacteria cause damage to the small intestine, liver lesions, and mortality.

While researchers still paving a way to develop a substitute as functional as antibiotics, administration of selected probiotics or competitive cultures has been used successfully to both prevent and treat clinical necrotic enteritis (presumably for the prophylactic proliferation of Cl. perfringens).