Changes in the koilin layer of the avian ventriculus have been found at postmortem examinations of many species of birds that died of systemic diseases1,2. However, little is known about the relationship between koilin metabolism and the overall health of the bird. Greater understanding of this relationship may allow koilin examination to be an early indicator of subclinical disease. In this study, we hypothesized that the primary diseases diagnosed at necropsy are correlated with specific changes in the koilin. To investigate this, a standard methodology for categorizing the nature and severity of koilin lesions was established and applied to histologic sections of the ventriculus from 140 adult birds in the families Psittacidae, Phasianidae, and Anatidae obtained from the archives of the Diagnostic Center for Population and Animal Health at Michigan State University. These cases were grouped based on the primary disease process found at necropsy, including inanition, septicemia, renal disease, hepatic disease, and alimentary disease. Birds that died from traumatic injury or had no postmortem signs of disease were used as controls. Koilin was graded based on the following parameters: epithelial cell retention, hemorrhage, inflammation, vacuolation, structural organization, luminal surface defects, thickness, and the presence of microorganisms. For most of the parameters evaluated, there were no statistically significant differences between the koilin of control birds and that of diseased birds. Additionally, the Anatidae koilin showed a higher degree pathologic changes overall than the Phasianidae and Psittacidae koilin. There were few statistically significant differences between the Phasianidae and Psittacidae koilin.
The authors would like to thank the Morris Animal Foundation and the Graduate School at Michigan State University for funding this study, the histopathology laboratory at the Diagnostic Center for Population and Animal Health at Michigan State University for their assistance in trimming and staining samples, and Paul Coe and Christopher Hamm for statistical consultation.
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2. Novoa-Garrido M, Larsen S, Kaldhusal M. Association between gizzard lesions and increased caecal Clostridium perfringens counts in broiler chickens. Avian Pathology. 2006;35:367–372.