Introduction: Iron storage disease which majorly resembles idiopathic (hereditary) hemochromatosis in human beings is a common and life-threatening condition in various species of captive ornamental birds, including the common mynah (Acridotheres tristis). Despite its prevalence, many aspects of the disease, particularly its etiology, pathophysiology, diagnosis, and even treatment, remain unclear and challenging. The aim of the present study was to experimentally induce iron storage disease in common mynahs and to evaluate the effects of oral administration of Escherichia coli Nissle and a commercial synbiotic product containing Lactobacillus spp. on clinical signs, necropsy findings, and hepatic changes with a focus on radiographic and ultrasonographic parameters.
Methods: A total of 20 clinically healthy mynahs were used in this study. The birds underwent a one-week acclimatization period and were fed a commercial mynah-specific diet with a defined iron content. At the end of this period, body weights were recorded and liver length was measured via ultrasonography. Additionally, two plain radiographs (lateral and dorsoventral views) were obtained for each bird. This procedure was repeated at the end of the study. Then, the birds were randomly assigned to four equal groups (n=5 per group) and treated for 30 days as follows: Negative Control Group: Received the standard commercial diet. Positive Control Group: Received the standard diet supplemented with ferrous sulfate to induce iron storage disease. Synbiotic Treatment Group: Received the high-iron diet along with a commercial synbiotic administered at a dose of 1 g per bird per day in drinking water, as per manufacturer instructions. Probiotic (E. coli Nissle) Treatment Group: Received the high-iron diet and were administered E. coli Nissle (10 9 CFU/bird) daily via drinking water.
Results: At the end of the experimental period, no clinical or necropsy abnormalities were observed in the negative control group, and no clinical signs were noted during the trial. In the positive control group, hepatomegaly was observed in all birds during clinical examination. In two birds, distinct dark iron deposits were seen in the caudal region of the right liver lobe, and the liver color had changed from normal reddish-brown to brownish-golden. However, no overt clinical signs were observed during the study period. In both the synbiotic and E. coli treatment groups, no distinct clinical signs were observed. In the E. coli group, hepatomegaly was detected in three birds, and necropsy revealed clear iron deposits in the caudal lobe of the liver in one bird. In the synbiotic group, mild liver discoloration was observed in four birds upon necropsy, and mild hepatomegaly was noted during clinical examination. Statistical analysis showed no significant differences in body weight changes between the negative control and the treatment groups (synbiotic and E. coli) compared to the positive control group (P > 0.05). However, food and water consumption in the E. coli group was significantly higher than in the positive control group. The liver-to-body weight ratio was significantly higher in the positive control group compared to the negative control group. This parameter did not significantly differ between the positive control and the bacterial treatment groups, although it was elevated in the synbiotic group compared to the negative control. Ultrasonographic liver length measurements before and after the trial did not show significant differences among groups. Regarding liver echogenicity, the number of birds with normal versus hyperechoic liver patterns did not differ significantly among groups. Additionally, no statistically significant differences were found between groups in terms of radiographic liver size changes. However, qualitative radiographic liver alterations were more frequently observed in the E. coli group compared to the other groups.
Conclusion: Overall, the findings suggest that radiographic and ultrasonographic techniques may have limited utility in detecting hepatic lesions associated with iron storage disease in mynahs, particularly in the absence of overt clinical signs. Nevertheless, radiographic findings may offer more informative insights than ultrasonography. However, clinical examination and necropsy remain more definitive for diagnosis. Moreover, synbiotic supplementation appeared to mildly mitigate clinical and pathological signs associated with hepatic iron accumulation.
Keywords: Common mynah, iron storage disease, microbiota, imaging, clinical signs