Nephrocalcinosis and kidney stones in Rachycentron canadum

Abstract

Nephrocalcinosis cases have been reported in fish, with different causes attributed for calcium deposition in the kidneys. We report the diagnosis of nephrocalcinosis an the presence of kidney stones in cobia, describing the main changes caused by the diases. On gross examination, an increase in kidney size was observed, with the presence of several grouped stones in the renal parenchyma. Microscopically, interstitial fibrosis and tubular dilation with basophil granules due to calcium deposits in the lumen were observed. By infrared spectroscopy, the stones were found to be composed of pure calcium (65%), oxalate (15%), calcium phosphate (16%) and non-specific salts (4%).This report of nephrocalcinosis and kidney stones is the first reported case of the disease occurrence in aquatic cultivation environments, it was not possible to identify the real cause of the emergence of lesions in the fish necessitating the study of the predisposing factors.