Avaliação de danos genotóxicos, estresse oxidativo e alterações histopatológicas em robalos juvenis (Centropomus undecimalis) expostos à dieta contendo pó de policloreto de vinila (PVC)

Studies show that the ingestion of microplastics in the marine environment can cause physical damage to specimens and represents a vehicle for the introduction of chemical pollutants into the food chain. Therefore, it becomes necessary to acquire knowledge about the ingestion of plastic debris and its effects on fish, especially those valued for human consumption. The objective of the present study was to evaluate possible genotoxic damage, oxidative stress and histopathological changes in juvenile fish of Centropomus undecimalis (common snook) exposed for 7 days to PVC (polyvinyl chloride) powder added to the diet. Two types of diet were used: a standard ration and a ration rich in PVC. The standard ration was prepared from commercial fish feed which was first ground, then reconstituted in water and then air dried to form pellets. To produce the PVC-rich feed, PVC powder was mixed with the identical ground fish feed (50% g / g) and again reconstituted in water and air dried to form pellets. The choice of the proportion of PVC in the diet was based on an environmentally realistic concentration level. Thirty-six fish were distributed in 9 aquariums (4 fish / aquarium) and were separated into 3 groups: Control group (TRC), Treated group 1 (TRA1) and Treated group 2 (TRA2). All groups were fed 3 times daily for 7 days. The Control group received 150 mg / day of standard feed. The TRA1 group received 150 mg / day of PVC rich ration. Every day, the TRA2 group received 150 mg of PVC-rich ration plus 75 mg of standard ration, in order to match the nutritional value of the Control group, thus isolating the effect of PVC. After 7 days the animals were euthanized. Measurement of food intake and biometry were performed, and blood, liver and digestive tract samples were taken. The quantitative data were evaluated using ANOVA and the Tukey post-test. Our results showed that the animals exposed to PVC showed a significant increase in food consumption, besides the presence of tissue degeneration in the lumen, alteration in the villi cytoarchitecture and inflammatory infiltration in the posterior intestine. There was no significant difference between the groups regarding the condition factor, frequency of nuclear abnormalities and micronuclei in erythrocytes, lipid peroxidation or DNA damage in the liver. Our results show that the PVC powder added to the diet of juvenile sea bass caused histopathological changes in the posterior segment of the intestine, with a change in the feeding behavior of the specimens. The 7-day exposure time to the diet appears X to have not caused genotoxic damage, oxidative stress, or any change in the fish condition factor.