Comparative study of Chronic Ulcerative Dermatopathy in cultured meagre, Argyrosomus regius

Chronic Ulcerative Dermatopathy (CUD) is a disease that affects all cultured meagre when reared in facilities supplied with borehole water, resulting in ulceration of the skin overlying the lateral line canals. The aims of this study were (i) to describe the morphogenesis of the cephalic lateral line, (ii) to investigate the effect of the use of borehole water vs natural seawater in the development of the disease, (iii) to assess the recovery of the lesions and (iv) to evaluate the effect of CO2 and pH on the development of CUD. The development of the lateral line canals in the head was completed by day 28 post hatching when fish were 19.3 mm in total length, while the source of the water did not affect the developmental process. The characteristic lesions of CUD were induced when meagre were reared in borehole water, while the lesions were resolved when fish were transferred to natural seawater. Lesions were macroscopically visible by day 56 post hatching. Moreover, significant differences in the expression of genes regulating osteoclast's activity were observed between healthy and CUD-affected fish, while neither pH nor CO2 were involved in the development of the disease. Finally, higher concentrations of heavy metals were found in the heads of CUD-affected meagres reared in borehole water compared to healthy fish reared in natural seawater.