The aim of this study was to determine the effects of silver nanoparticles (AgNPs) on the morphology and enzymatic activity of butterfly splitfin (Ameca splendens). Individuals of both sexes, aged about five months, were exposed to AgNPs at concentrations of 0 (control group), 0.01, 0.1, and 1.0 mg/dm3 for 42 days. On the last day of the experiment, the fish were euthanized, subjected to standard histological processing (anterior intestine, liver, and gonads), and analysed for digestive enzyme activity in the anterior intestine and oxidative stress markers in the liver. Fish in the AgNP 0.01 and 0.1 groups had the lowest anterior intestinal fold and enterocyte height. However, there were no statistically significant changes in the digestive enzyme activity in the anterior intestine. Analysis of enzymatic activity in the liver showed an increase in superoxide dismutase activity in fish in the AgNP 0.1 group. Histological analyses showed that AgNPs inhibited meiotic divisions at prophase I in a non-linear manner in ovaries and testes. In the AgNP 0.1 and 1.0 groups, the area occupied by spermatocytes was lower compared to the other groups. These results indicate that exposure to AgNPs may lead to disturbances in morphology and enzymatic activity in the liver and intestine and may lead to disruption of reproduction in populations.
Keywords: Goodeidae fishes; enzymatic activity; histology; nanoecotoxicology; silver nanoparticles.