Bismuth citrate, a citric acid salt, may help control necrotic enteritis in broilers, indicates preliminary research conducted by researchers at Texas A&M University.

Necrotic enteritis (NE) is a costly disease caused by the bacterium Clostridium perfringens. The incidence of NE has increased due to the reduced use of in-feed antibiotic growth promoters with anticlostridial activity, they say.

The first of three separate, controlled studies was designed to determine a dose response to bismuth citrate in broilers challenged with isolates of C. perfringens obtained from active field cases in Virginia, North Carolina and Georgia. When 100 or 200 ppm bismuth citrate was fed, broilers had reduced intestinal C. perfringens colonization and lesion development compared to birds not fed bismuth citrate. Bismuth citrate fed at 50 ppm also reduced intestinal lesions but did not reduce colonization.

In the second study, the investigators also fed the acidifiers lactose or citric acid to determine if they would enhance the effects of bismuth citrate, which was evaluated by C. perfringens colonization and pH levels. No significant interactions were found. However, the addition of lactose along with bismuth citrate did significantly reduce intestinal pH when compared only to negative controls — birds that were treated but not challenged, say K. Stringfellow and colleagues.

A third study further evaluated the effect of lactose and bismuth citrate on C. perfringens colonization and lesions. Birds challenged with C. perfringens had significantly reduced NE lesions compared to birds receiving control diets, the researchers say in the November 2009 issue of Poultry Science.

The investigators point out that bismuth compounds have been used to treat gastric disorders in humans for over 300 years, and in poultry, bismuth citrate has been shown to reduce cecal colonization by other pathogens. Lactose has been used to reduce pathogens in poultry, and citric acid was included in the study because of speculations that it decreases the pH of intestinal contents.

“In conclusion, bismuth citrate treatments of 100 ppm and 200 ppm significantly reduced C. perfringens colonization and intestinal lesion development,” the investigators say.