Necrotic Enteritis Association with
Eimeria acervulina and E. maxima
Greg F. Mathis, Southern Poultry Research, Inc. and C.
Hofacre, Univ. of Georgia, Department of Avian Medicine
Necrotic
enteritis is a common poultry disease caused by Clostridium perfringens.
Reductions in feed efficiency, lower weight gain, and mortality are associated
with this disease. Clostridium perfringens can rapidly grow when disturbances in
the intestinal microflora or damage to the intestinal mucosa occur. An example
of damage to the intestinal mucosa occurs with coccidiosis. Restrictions on
in-feed anticoccidial usage and increasing usage of live coccidial vaccines,
increases the potential for Necrotic Enteritis in commercial broiler chickens.
The objective of this study was to examine association and experimental
reproduction of Necrotic Enteritis (NE) in broiler chickens using Eimeria
acervulina, E. maxima, or a combination of the two. The study consisted of
rearing 10 male chickens/cage from day of hatch until 22 days of age. The
treatments were noninfected, E. acervulina (75,000 oocysts/ bird) challenged, E.
maxima (10,000 oocysts/ bird) challenged, and a combination at the same dose
levels of E. acervulina and E. maxima. Each treatment was replicated 4 times.
Birds were coccidia challenged at 14 days of age and Clostridium perfringens
challenged at 19, 20, and 21 days of age. The performance parameters measured
were feed conversion, average live weight gain, NE mortality, coccidiosis lesion
scores (Day 20) and NE lesion scores (Day 22). Birds infected with E. maxima
alone were more significantly affected by NE than birds challenged with the
combination of species or E. acervulina alone. The least affected birds were
those inoculated with E. acervulina alone. This study showed that both E.
acervulina and E. maxima can cause enough intestinal damage to allow Clostridium
perfringens proliferation and NE development. Even though NE developed with E.
acervulina alone, the primary Eimeria species causing NE was E. maxima.