Immunoglobulin levels in the teleost sea bass Dicentrarchus labrax (L.) in relation to age, season, and water oxygenation

Abstract

A monoclonal antibody DLIg3, against sea bass immunoglobulins, was employed in indirect quantitative ELISA to analyze the concentration of serum immunoglobulin in groups of fish at different ages (7 months, 2 years, 10 years), and farmed in non-hyperoxygenated water (<10 ppm/l of oxygen) and in hyperoxygenated sea water (10–13 ppm/l). The results showed that the immunoglobulin levels increased consistently with age and size, being 0.4±0.1 mg/ml at 7 months, 5.6±0.8 mg/ml at two years, and 11.3±0.9 mg/ml at ten years. Hyperoxygenation of sea water resulted in a two-fold increase of immunoglobulins, from 3.9±0.3 mg/ml in running seawater, to 7.1±0.5 mg/ml at 12 ppm O 2/l. The immunoglobulin levels from two year-old fish varied from spring (6.7±0.6 mg/ml) to summer (3.83±0.25 mg/ml), reaching the maximum in winter (7.8±0.7 mg/ml). This seasonal trend could also be related to the reproductive cycle of sea bass.