As espécies de Nematoda e a histopatologia do tubo digestivo de Auchenipterus nuchalis (Spix & Agassiz, 1829) (Siluriformes: Auchenipteridae) de lagos de várzea da Amazônia

Abstract

Forty-four Auchenipterus nuchalis were caught in four expeditions in September, October, November and December 2018, at the Catalão lakes complex, in the municipality of Iranduba, Amazonas, on the left bank of the Solimões River and to the right of the Negro River. The fish measured, on average, 11.8 - 18 (15.1 ± 1.35) cm of standard length and weighed 30.1 - 71.0 (47 ± 10.66) g. For the parasitological studies 38 fish were examined and 31 were parasitized. Eighty-eight specimens of Nematoda were collected: 53 Procamallanus (Spirocamallanus) inopinatus larvae L4 and adults in the intestine and stomach; 18 Spinitectus rodolphiheringi larvae L3, L4 and adults in the intestine and stomach, and 17 Contracaecum sp. larvae L3 in the stomach. For the anatomical and histological studies, six A. nuchalis were used. The morphological, anatomical and histological characteristics showed that the structure and arrangement of the digestive tract of A. nuchalis is in accordance with the general basic pattern described for the other teleost fishes. It was observed the division into: buccopharyngeal cavity, esophagus, stomach and intestine and, histologically, the wall of the tube consists of the mucosa, submucosa, muscular and serous layers. The attachment of Nematoda species to the digestive tract of A. nuchalis did not cause aggressive or even visible mechanical lesions along the evaluated mucosa.