Finding ways to prevent or control necrotic enteritis (NE) in broilers is challenging because Clostridium perfringens, the bacterium that causes the disease, has chameleon-like qualities, and other factors, such as management, may be involved.

At the World’s Poultry Conference this summer in Brisbane, Dr. John Prescott, of the University of Guelph, called C. perfringens “an absolute thug.”

The bacterium is “exquisitely adapted as an environmental anaerobe to grow very rapidly in injured or dead animal tissue. Consider that Escherichia coli doubles every 20 minutes. In contrast, C. perfringens is the fastest growing organism known and, under optimal conditions, doubles every 8 to 10 minutes,” he said.

“It is superbly designed to take advantage of injured tissue,” he said. It secretes multiple toxins and enzymes that maximize the destruction of tissues.

Dr. Joan Schrader, a scientist with Intervet/Schering-Plough Animal Health who has researched NE and helped develop Netvax, the company's Clostridium perfringens type A toxoid for broilers, agrees.

“It’s as though virulent C. perfringens has an arsenal of toxins it can produce, and depending on the environment the bacterium is in, it will use the toxins that are most advantageous for the circumstances. It’s very much a multifactorial disease,” she says. Schrader echoes Prescott’s opinion, saying that while “alpha-toxin is a key player, other secreted proteins from C. perfringens may be involved in development of this complicated disease.”

In addition, secreted proteins may be only part of the story. In his OAPP talk, Prescott pointed to published evidence that dietary components might adversely affect intestinal motility or damage intestinal mucosa, which in turn affect C. perfringens toxin production or the growth of C. perfringens. Coccidial infection can be a contributing factor too, he said.

“The interaction of [C. perfringens] with other intestinal microflora, including non-NE isolates, and the effect of other microflora on intestinal innate immunity” may be important, he said. There’s no question, he and Schrader say, that NE is a complex infection.

Regresar a European Edition (#2)