Health status of wild and cultured sea bass in the northern Adriatic Sea

Abstract

A complex survey has been conducted in the northern Adriatic Sea over a period of one year that included comparative parasitological, bacteriological, virological, histological and biochemical studies of the cultured and wild sea bass (Dicentrarchus labrax L.). The results show that parasite infestations were due mainly to ectoparasitic monogenea Diplectanum sp. in both cultured and wild sea bass. Philometra sp. and Lernaea sp. were detected in wild sea bass while Triaenophorus sp. and Eimeria sp. were found in reared sea bass. Bacterial pathogens isolated from both reared and wild sea bass belong to Pseudomonadaceae (Pseudomonas sp., P. fluorescens) and unknown Gram-negative bacteria. Moraxellaceae (Acinetobacter sp.), Vibrionaceae (Shewanella putrefaciens), Enterobacteriaceae (Pantoea agglomerans) and Flavobacterium sp. were isolated from reared fish only. Virological examinations were negative. Histological analysis revealed “fatty liver” (fatty infiltration and degeneration) in the cultured fish. Triglyceride, cholesterol and glucose levels were higher in cultured sea bass (2.55 ± 1.77 mmol/l, 3.68 ± 1.43 mmol/l and 9.97 ± 3.33 mmol/l, respectively) than in wild fish (0.80 ± 0.57 mmol/l, 2.95 ± 0.77 mmol/l and 4.79 ± 3.29 mmol/l, respectively). The present paper contributes to establishing a relationship between disease and pathophysiological conditions in wild and cultured fish.