Feed Deprivation effects on Bactericidal an Immunological activity of Blood and skin mucus, and on blood Chemistry of Gilthead Seabream (Sparus aurata)

Abstract

Aquaculture needs to optimize production and nutrition of fish. The effects caused by 1, 2, 4 and 20 days of starvation on humoral immunity and bactericidal activity, against Vibrio anguillarum, in blood and skin mucus of gilthead seabream (Sparus aurata) were determined. In addition, several blood biochemical parameters were also analysed in order to test the general health status of the fish and also in an attempt to correlate the physiological changes due to starvation with the changes observed in the immune parameters. Significant decreases in IgM level and protease activity (P-value < 0.05), as well as significant increases in peroxidase and bactericidal activity were obtained in the mucus of the fish after short periods of starvation (from 1 to 4 days), compared to the fed fish. However, it was impossible to determine similar conditions in fish subjected to 20 days of starvation, since all the parameters studied in this group showed very similar values to those obtained for control fish (fed). This could be due to the necessity for fish to recover their homeostasis in order to survive, even when maintained under starvation conditions. The possible relationships between the nutritional state and humoral immunity in fish is discussed.