| Abstract: | Avian amyloid A (AA) amyloidosis is commonly observed in adult birds with chronic
inflammation, such as that caused by bacterial infection. We previously described
vaccine-associated AA amyloidosis in juvenile chickens. In this study, the prevalence of
amyloid deposition was measured in mature healthy chickens that survived a previous
outbreak of avian AA amyloidosis while they were juveniles. Herein, we analyzed the
amyloid deposition in mature chickens and compared the prevalence of amyloid deposition
with juvenile chickens obtained in our previous study (Murakami et al.,
2013). We found that: 1) amyloid deposition in the liver was absent in mature chickens,
while juvenile chickens had a rate of 24%; 2) amyloid deposition in the spleen was
observed in 36% of juvenile chickens and in 40% of mature chickens; 3) amyloid deposition
in the pectoral muscle of mature chickens (43.75%) was approximately half that of juvenile
chickens (88%). These results suggest that additional amyloid deposition in chickens
previously exposed to AA amyloidosis may not worsen with age. Further, amyloid deposition
in chickens may tend to regress when causative factors, such as vaccinations and/or
chronic inflammation, are absent. |
