Effects of alpha-tocopherol and dietary oxidized fish oil on the immune response of sea bass Dicentrarchus labrax

Abstract

Sea bass weighing about 35 g were reared on 6 experimental diets differing in the level of alpha-tocopherol (vitamin E) supplementation (0, 40 or 300 mg kg-') and fish oil quality (fresh or oxidized). After 35 wk, group comparisons of haematological parameters were made and alpha-tocopherol levels in anterior kidney, spleen, and thymus were assessed in pooled samples. Non-specific immune factors assayed were: (1) plasma lysozyme and complement activ~ties, (2) natural haemolysis of sheep red blood cells (SRBC), and (3) chemiluminescence (CL) response of head kidney phagocytes. Humoral antibody production was also assessed for each group after immunisation with Vibrio anguillarurn 408. Res~stance to bacterial infection was assessed comparatively according to diet. The levels of alphatocopherol in the different tissues were a funct~on of the dietary vitamin E concentrations and were lower when oxidized flsh oil was added to the diet. Erythrocyte fragility was raised in vitamin E depleted groups as well as in fish fed diets containing oxidized oil. Disease resistance, antibody response to V anguillarum antigen, and haemolytic activity of sera were not affected by dietary treatment. Plasma lysozyme activity was lower in groups fed diets containing oxidized oil or not supplemented with vitamin E, and complement activity was higher in the fish that were fed the diet containing fresh oil and 300 mg vitamin E kg-'. One month after vaccination, the CL peak response of head kidney phagocytes, stimulated by opsonized zymosan, was significantly lower in the fish that were fed the diet containing oxidized oil and not supplemented with vitamin E.

Increased activities of hepatic antioxidant defence enzymes in juvenile gilthead sea bream (Sparus aurata L.) fed dietary oxidised oil: attenuation by dietary vitamin E

“…The growth of fish fed fresh oil was not increased by elevated dietary vitamin E. The level of vitamin E in the livers of catfish fed the oxidised oil was greatly reduced (Baker and Davies, 1997). This effect had been observed previously in sea bass (Dicentrarchus labrax) where tissue α-tocopherol levels were reduced in fish fed diets containing oxidised fish oil (Obach et al, 1993). In the present study, the level of hepatic α-tocopherol was reduced in sea bream fed the diets without supplemental vitamin E, consistent with the previous data.…”

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“…Our finding is in contrast with previous findings. Decrease in serum lysozyme activity in sea bass plasma was recorded when fish fed by OFO and α-tochopherol (Obach, Quentel, & Baudin Laurencin, 1993). Similar results had been recorded in Japanese sea bass, Lateolabrax japonicas fed by OFO and palm oil (Han et al, 2012).…”

“…Macrophages are the site of production of some of the complement proteins suggests that an alteration of macrophage function caused by peroxidation of the membrane phospholipid fatty acids may alter the synthesis of some of these proteins (Obach et al, 1993). IgM level is determined for evaluation of the humoral immune responses, low levels of IgM related to immunodeficiency (Buckley, 1986), while higher IgM values is associated with inflammatory and pathological conditions (Redman, 1979).…”

Influence of Stress and Dietary Natural‐Source Vitamin E on Nonspecific Immunocompetence, Tissue Tocopherol Composition, and Postslaughter Fillet Oxidative Stability in Sunshine Bass

“…Plasma lysozyme activity was estimated with a M. lysodeiktus lysis assay based on the spectrophotometric method of Obach et al (1993) modified for microplate wells. Aliquots (10 lL) of whole plasma were added to wells containing 190 lL of M. lysodeiktus stock culture.…”