Barley inclusion and avoparcin supplementation in broiler diets. 2. Clinical, pathological, and bacteriological findings in a mild form of necrotic enteritis.

The clinical, pathological, and bacteriological findings of a mild form of necrotic enteritis (NE) in broiler chickens are presented. The term subclinical NE (SNE) is proposed for this condition. A diagnosis of SNE was based on the detection of macroscopically visible, focal necrotic lesions in the small intestinal mucosa. The ileal gut contents from SNE birds yielded increased numbers of Clostridium perfringens and reduced numbers of coliform bacteria. Reduced numbers of lactobacilli and streptococci were detected in birds from SNE pens and coccidial oocysts were not found in the rectal contents of SNE birds. Statistical analyses showed strong correlations between SNE and increased feed conversion ratio and retarded growth rate. An increased occurrence of SNE was observed in birds on a diet containing a large amount of barley.