High stocking density and water salinity levels influence haematological and serum protein profiles in mullet Mugil cephalus, Linnaeus, 1758

In this study, the effect of high stocking density and high salinity levels on haematological and serum protein profile of 65 Mugil cephalus was evaluated. After acclimation, fish were divided into three groups. The group A (n = 15), representing the control, was transferred into a 800 L tank at a density of 3.4 kg.m-3 (low density) and it was maintained to 35 of salinity. Group B (n = 35) was placed into 800 L tank at a density of 8.4 kg.m-3 (high density) and it was maintained to 35 of salinity. Group C (n = 15) was transferred into 800 L tank at a density of 3.4 kg.m-3 (low density) and subjected to 45 of salinity. Haematological and protein profiles were determined following blood sampling. Both experimental conditions influenced the values of red blood cells, haemoglobin, haematocrit, white blood cells, thrombocytes, serum total protein, albumin , α-globulins (P < 0.05). The values of β-globulins statistically changed (P < 0.05) under high salinity levels condition. In group B, the disappearance of prealbumin and γ-globulin fraction occurred. Statistical lower levels of prealbumin and γ-globulins (P < 0.05) were found in group C than control group. These results highlighted that high stocking density and salinity levels represent stressful conditions that lead to many physiological perturbations in mullet resulting in an impairment of mullet's oxygen-carrying capacity and immunity.