Contributed Papers: Posters Pathology |
APPLICATION OF Eimeria MAXIMA TO A CLOSTRIDIUM PERFRINGENS-ASSOCIATED
NECROTIC ENTERITIS MODEL FOR STUDYING BACTERIAL COMPETITIVE
EXCLUSION IN POULTRY.
Ralph N. Marshall, Stephen T.Cartman,
Roberto M. La Ragione, Jacqueline A. Marshall and
Martin J. Woodward. Veterinary Laboratories Agency
(Weybridge), Woodham Lane, New Haw, Addlestone, Surrey,
KT15 3NB, UK
C. perfringens-associated
necrotic enteritis (NE) is an enteric bacterial disease
of poultry. It may present as an acute clinical disease,
leading to increased mortality, or a sub-clinical
disease which impairs feed conversion. Recognised
predisposing factors include environmental stress,
diet (particularly when high in wheat, barley or fishmeal)
and coccidiosis. To test Bacillus subtilis as a competitive
exclusion (CE) agent for prophylactic control of NE,
we used a recently developed, non-lethal challenged
model. Chicks were fed a diet which was high in wheat
and fishmeal content to predispose them to C. perfringens
infection. Moreover, 2 x 104 Eimeria maxima oocyts
were administered to each bird by oral gavage, at
four weeks of age. C. perfringens challenge was then
administered via the cloaca one week later. NE lesions
were observed in all groups by histological examination
of tissue samples post mortem. Interestingly, C. perfringens
colonisation was reduced in one group of birds receiving
B. subtilis. This work demonstrates the value of E.
maxima administration in combination with diet content
controls, for modelling C. perfringens-associated
NE in poultry. Furthermore, our results show that
certain strains of B. subtilis may be useful CE agents
for prophylactic control of C. perfringens in poultry.