The effect of artificial feed on blood biochemistry profile and liver histology of wild saddled bream, Oblada melanura (Sparidae)

Floating fish farms attract a great number of wild fish species, changing their behaviour and physiology. The saddled bream, Oblada melanura, sampled from populations aggregated around the Adriatic fish farm and from natural/control populations, were analysed for differences in eleven blood biochemistry parameters and liver histomorphology. The levels of lactate dehydrogenase (LDH), alkaline phosphatase (ALKP) and urea (URE) in cage-associated saddled bream (428.00 ± SD 321.56 U/L, 86.13 ± SD 39.87 U/L and 0.05 ± SD 0.16 mmol/L, respectively) were significantly lower than those observed in the control specimens (1047.06 ± SD 505.56 U/L, 125.75 ± SD 34.70 U/L and 1.99 ± SD 0.73 mmol/L, respectively). In contrast to that, concentrations of aspartate aminotransferase (AST) in cage-associated fish (87.63 ± SD 132.34 U/L) were higher than values noted for the control population (6.55 ± SD 5.90 U/L). URE and AST presented the main variables contributing to the discrimination between two analysed populations. One-way ANOSIM based on the blood parameters showed significant difference between saddled bream that fed around cages and those from the remote waters ( R = 0.697; P