Histopathological changes in surubim Pseudoplatystoma coruscans subjected to high levels of vitamin C

Abstract

This study evaluated the supplementation of vitamin C in diets for Pseudoplatystoma coruscans (surubim) juveniles. The effects of high concentrations of vitamin C were evaluated through the histological skin alterations regarding the structure of epidermis and collagen deposition. Ascorbic polyphosphate (AP) was used as a source of vitamin C in the diet of the surubim juveniles at concentrations of 500, 1000, 1500, 2000 and 2500 mg of AP/kg diet added to a basic diet (control; 0 mg AP/kg diet). After 90 days, six animals per treatment were euthanized and fragments of skin were sampled. The histological cuts were stained with hematoxilin - eosin (HE), Masson tricromic (TM), and Periodic acid Schiff (PAS). The epidermis showed disarrangement of the club cells in fish from control group and in fish fed with the 2000 and 2500 mg of AP/kg of diet. The treatment with 2500 mg of AP/kg of diet also caused the lowest epidermis height. However, no morphological skin alterations were observed on treatments 500, 1000, and 1500 mg of AP/kg of diet. Thus, decreases in epidermis height and changes in club cells arrangement can be recognized as new clinical signs of hypervitaminosis C in that fish, hindering skin development.