Fig 1.
Organ-to-body weight ratios and qPCR Ct values in broiler chickens experimentally infected with FAdV-8a at 21 days post-infection (dpi).
(A) Liver, spleen, and heart weights normalized to body weight in infected and control birds. The organ-to-body weight ratios were significantly higher in infected birds for both the liver (p = 0.0129) and spleen (p = 0.0252), whereas no significant difference was observed for the heart (p = 0.5422). Data are presented as mean ± SD (n = 7 per group). (B) Ct values obtained by qPCR targeting the hexon gene in liver, spleen, and heart tissues. The liver exhibited the lowest Ct values, indicating the highest viral load, whereas the spleen and heart showed comparatively higher Ct values. Statistical analysis using one-way ANOVA followed by Tukey’s multiple-comparison test did not reveal significant differences among the examined organs within the infected group (p > 0.05). Data are presented as mean ± SD (n = 5).
Fig 2.
Gross lesions observed in broiler chickens infected with FAdV-8a at 21 dpi.
(A) Liver of an infected bird showing enlargement and pale discoloration with scattered mottling. (B) Heart displaying mild pericardial congestion with a slightly opaque epicardium. (C) Kidney with diffuse enlargement, pale cortex, and a coarse reticulated appearance. (D) Spleen showing marked splenomegaly with a dark red congested appearance. Yellow arrows indicate the main areas of pathological change. (E–H) Corresponding organs from control birds showing normal size, shape, and coloration with no visible lesions.
Fig 3.
Histopathological lesions in broilers infected with FAdV-8a at 21 dpi.
Hematoxylin and eosin–stained sections from infected (A–D) and control (E–H) birds. (A) Liver showing multifocal hepatocellular degeneration and necrosis with mononuclear inflammatory infiltration. (B) Heart showing slight separation of myocardial fibers and interstitial edema. (C) Kidney showing focal congestion and tubular epithelial degeneration. (D) Spleen showing lymphoid depletion and multifocal congestion. (E–H) Representative tissues from control birds with normal histological architecture. The images highlight the characteristic morphological changes observed in organs infected with FAdV-8a. Scale bars = 200 µm.
Fig 4.
Quantitative detection of FAdV-8a DNA in liver, spleen, and heart tissues at 21 days post-inoculation.
(A) Ct values obtained by qPCR analysis. Viral DNA was clearly detected in infected tissues, with significantly lower Ct values in the liver, spleen, and heart compared individually with the control group (p < 0.0001 for all comparisons; one-way ANOVA followed by Dunnett’s multiple comparison test). No statistical comparisons were performed among infected organs. Data are presented as mean ± SD (n = 5). (B) Viral genome copy numbers calculated from the qPCR standard curve. The liver contained the highest viral load (~1.7 × 10⁵ copies g ⁻ ¹ tissue), followed by the spleen (~6.03 × 10⁴ copies g ⁻ ¹), whereas only minimal viral DNA was detected in the heart (~2.54 × 10³ copies g ⁻ ¹). Data are shown as mean ± SD (n = 5).