Histological study as indicator of juveniles farmed turbot, Scophthalmus maximus L. health status

• Farmed turbot health status evaluation
• Histology based survey
• Histopathological scoring scheme

Several tools can be used to evaluate the health status of fish. Histology is one of them because it assesses pathological changes induced by environment, pathogens and/or nutritional factors. The histological condition of macroscopically healthy turbot juveniles in the beginning of the growing phase in an intensive fish farm was evaluated. The gill, skin, liver, kidney and intestine were histologically processed by standard techniques and their histological status determined semi-quantitatively. The skin, the gills and the liver of examined turbot were in a good overall condition or presented slight alterations frequently observed in farmed fish. The kidney and the intestine of some fish presented pronounced histological alterations caused mainly by the occurrence of nephrocalcinosis in the kidney, and necrotic areas in intestinal lamina propria of the mucosa. The possible causes of these findings are discussed.Statement of relevance“This is a very first histology based survey conducted in an intensive farm to evaluate the health status of turbot juveniles. The results showed that i) the histological analysis is a useful tool for assessing the fish health and, ii) most of the fish were in good health condition”