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Keywords
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Bacterial flora, Cortisol, Fe-Nanoparticles, Histology, Starry sturgeon
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Abstract
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Regarding the important role of iron in the physiological process in fish bodies and the presence
of iron nanoparticles (Fe-NPS) in the aquatic environment, this study was designed to evaluate the
effects of Fe-NPS on the intestinal bacterial flora and histology of the intestine and kidney in a stellate
sturgeon (Acipenser stellatus Pallas, 1771). Juvenile stellate sturgeon, averaging 182.09±9.05 g, were
fed with diets containing varying doses of Fe-NPs: 0 (T0), 25 (T1), 50 (T2), and 100 (T3) mg∙kg-1 of
food for 60 days. Based on the glucose and cortisol levels in different treatments, it seems that the
best dose of Fe-NPs for stellate sturgeon was 50 mg∙kg-1 food (T2) under experimental conditions.
The most important histological changes observed in the intestine were the shortening of the intestinal
villi, a high number of mucus-secreting cells, and mucosal secretions within the intestinal tract. These
changes in the kidney were shrinkage of renal glomeruli, increasing Bowman’s capsule space, mild
degeneration of renal tubules, and infiltration of white blood cells into the kidney tissue. The most
effective dose of Fe-NPs was 50 mg∙kg-1 Fe-NPs with a less negative effect on fish intestine and kidney
histology. Fe-NPs led to a significant increase in the mean total count of aerobic bacteria and lactic
acid bacteria. Generally, the fish food supplemented with 50 mg∙kg-1 Fe-NPs led to the least stress and
histological damage in the kidney and intestine and the highest number of intestinal bacterial flora in the
stellate sturgeon.
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