Nutritional support plays an important role in promoting high cellular and humoral innate immunity activity and in preventing outbreaks of disease. The effects of β-glucan Leiber(®)Beta-S dietary supplementation on selected nonspecific immune parameters in juvenile European eel (Anguilla anguilla) in an intensive culture system were studied. The fish were fed commercial pellets containing either 0 (control group) or 200 mg Leiber(®)Beta-S kg-1 of feed (glucan-fed group). After four and eight weeks of feeding, the levels of the following immunological parameters were measured: phagocyte respiratory burst activity, phagocyte potential killing activity, lymphocyte proliferation stimulated by concanavaline A or lipopolysaccharide, serum lysozyme activity, and total immunoglobulin (Ig) serum levels. After four and eight weeks of feeding 200 mg Leiber(®)Beta-S kg feed-1 the levels of all immune parameters were statistically significantly higher (p < 0.05) in the glucan-treated group than in the control group. After eight weeks of feeding the fish 200 mg Leiber(®)Beta-S kg feed-1 and after an additional eight weeks in ponds, the levels of all immune parameters, excluding lymphocyte proliferation stimulated by concanavaline A, were statistically significantly higher (p < 0.05) in the glucan-fed group than in the control group. These data suggest that feeding juvenile eel Leiber(®)Beta-S for four and eight weeks might improve innate immunity.
Keywords: eel; immunostimulant; innate immunity; β-glucan.