Ocorrência de mixosporídeos em (Mylossoma duriventre) e possíveis implicações fisiológicas na região de Santarém-PA

Abstract

Mylossoma duriventre (pacu manteiga) is a species widely distributed in the Amazon Basin, of food and ornamental importance in the Northern region. This study aimed to characterize morphologically, histopathologically, and molecularly the myxosporidia that infect M. duriventre from the Santarém-PA region, evaluating their tissue distribution and possible physiopathological implications. One hundred and twenty specimens acquired at the Santarém-PA Fish Market between December 2024 and October 2025 were used, subjected to necropsy, histopathological, molecular, and phylogenetic analyses, as well as biometrics. The laboratory procedures were performed at the Laboratory of Morpho-molecular Integration and Technologies (LIMT) of the Federal Rural University of the Amazon (UFRA, Belém campus). Parasitized tissues were processed for histology, electron microscopy, and molecular biology. Based on spore morphology, representatives of the genera Sphaeromyxa, Myxobolus, Henneguya, and Ortholinea were identified, distributed in different organs, including the kidney, gills, and urinary bladder. Histological analyses revealed tissue alterations compatible with myxozoan infection, especially in the gills, suggesting potential local functional impairment. However, no parasitic structures or histopathological alterations were observed in the gonads of the analyzed individuals. Therefore, it is recommended that future studies include experimental designs and physiological biomarkers capable of directly and quantitatively evaluating possible interactions between parasitism and the reproductive performance of M. duriventre.