Hepatic iron assessment using pinch liver biopsies in Asian glossy starlings (Aplonis panayensis)

Abstract

Hepatic hemosiderosis is a common nutritional disease affecting numerous bird species. The aim of this study was to validate the use of pinch hepatic biopsies to quantify the hepatic iron in Asian glossy starlings (AGS) and compare clinical measures usable for antemortem disease monitoring. Following euthanasia, serum, liver pinch biopsies, and whole liver sections were sampled from 21 AGS. Liver biopsies and sections were stained with Perl's Prussian blue, and the area containing iron pigment was calculated by image analysis. The mean percent iron-stained area per whole hepatic section was 62.52% ± 21.81%, while the mean percent iron-stained area in biopsies was 71.47% ± 19.77%. Positive correlations were found between hepatic iron concentration and percentage iron in whole sections (r = 0.92; P < .0001), percentage iron in biopsies (r = 0.91; P < .0001), and other clinico-pathological features. Hemosiderin in hepatic biopsies was significantly higher than in whole hepatic section assessed by image analysis (P < .0001).

Keywords: antemortem diagnosis; hemosiderosis; iron quantification; passerine; postmortem diagnosis.

Figure 1.

Hepatic biopsy of an Asian glossy starling. (a) Hematoxylin and eosin. (b) Perl’s Prussian blue demonstrating iron distributed throughout the liver. (c) Visualization of the same image in (b) with an overlay of the trained image analysis model. Purple, background; yellow, iron; and green, non-iron tissue.

Figure 2.

Correlation between hepatic iron concentration (Fe µmol/kg dry matter) and the percentage of iron-stained tissue in (a) hepatic pinch biopsy, (b) whole hepatic section, (c) total serum iron (µmol/L), and (d) length of the liver silhouette (mm). Hepatic iron concentration was positively associated with all other 4 features. Correlations of iron concentration were very similar among the percentage of iron-stained tissue of whole hepatic section and in pinch biopsies.