Contributed Papers: Posters Pathology |
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.