Poultry necrotic enteritis (NE) has, over recent decades, been prevented and treated by
addition of antimicrobials to poultry feed. Recent bans of antimicrobial growth promoters
in feed, as well as other factors, have led to a slow, worldwide re-emergence of NE.
Understanding of pathogenesis of NE has been hampered by lack of a consistent and
effective experimental model in which virulence of strains can be reliably evaluated, with
an endpoint yielding lesions comparable to those seen in acute NE in the field. The overall
objective of this work was to develop an experimental approach that would allow
consistent production of a full range of clinical signs and lesions of the disease, and to do so
without use of coccidia as inciting agents. In addition, we assessed the virulence of strains
of Clostridium perfringens from field cases of NE. Broiler chicks fed a commercial chick
starter for 7 days post-hatch were switched to a high protein feed mixed 50:50 with
fishmeal for an additional 7 days. On day 14, feed was withheld for 20 h, and birds were
then offered feed mixed with C. perfringens (3 parts culture to 4 parts feed) twice daily on 4
consecutive days. On average, >75% of challenged birds developed typical gross lesions
when inoculated with type A strains from field cases of NE. In addition, in vivo passage
apparently increases strain virulence. Virulence varies from strain-to-strain; NetBproducing
strains were virulent, as were some NetB non-producing strains.