CLINICAL AND PATHOLOGICAL CHANGES IN CHICKENS (Gallus domesticus) EXPERIMENTALLY INFECTED WITH Eimeria acervulina (TIZZER, 1929) OOCYSTS.

MACHADO, R. Z.1; ALMEIDA,
K. S.1; FREITAS, F. L. C.1 and MACHADO, C. R.2.
1 Department of Animal Pathology Sao Paulo
State University, Jaboticabal - Sao Paulo
2 Department of Animal Physiology Sao Paulo State
University, Jaboticabal - Sao Paulo. Av. Prof. Paulo Donato
Castellane, s.n., Zona Rural, CEP: 14884-900.
Email: cmachado@fcav.unesp.br, fone (fax): (016) 3209-2656

In the present study, clinical signs and pathological changes were evaluated for thirty days in chickens experimentally infected with E. acervulina. One hundred and eighty Cobb male broiler often days of age were randomly distributed into three groups (A: inoculated with 1 x 106 oocysts; B: inoculated with 1 x 105 oocysts; C: inoculated with distilled water) of sixty birds. Iso-nutritional and iso-energetic diets without anticoccidial drugs were offered ad libitum to the chickens. Two chickens of each group were daily sacrificed. The pathological and clinical changes were identical in all groups, despite being more intense in group A. On the 1st DPI, both infected groups showed duodenum hyperemia, which developed as congestion on the 2nd DPI. The congestion remained present until the 30th DPI, and was associated to thickening of the gut mucous membrane. On the 2nd DPI, the two infected groups still presented petechial hemorrhages in the duodenum, which progressed to the jejunum and ileum. After the 5th DPI, a mucus exsudate was present in the lumen of the small intestine, especially in the duodenum. Other findings were food retention in proventriculus and gizzard, gall bladder full of liquid, pale yellow liver, and pale muscles. The clinical signs after the 4th DPI were: anorexia, apathy, and diarrhea. Other findings were digested blood in the feces, associated or not with the presence of small whitish streaks. Microscope examination showed immature oocysts attached to the intestinal mucous membrane. The results demonstrate that chickens experimentally infected with E. acervulina present progressive intestinal lesions of variable intensity, and that these abnormalities are the main cause of reduction of bird performance.