Supra dietary levels of vitamins C and E enhance antibody production and immune memory in juvenile milkfish, Chanos chanos (Forsskal) to formalin-killed Vibrio vulnificus

Juveniles of milkfish, Chanos chanos (Forsskal), were fed two independent supra dietary levels of vitamins C (500 and 1500 mg kg(-1) feed, T1 and T2) and E (50 and 150 mg kg(-1), T3 and T4). Milkfish fed diets with supra (in addition to the vitamins present in the control diet) and normal levels (T5 containing 90 and 1.2 mg of vitamins C and E, respectively, kg-1 of feed) of vitamins were immunized (ip) with formalin-killed Vibrio vulnificus (FKVV). Priming and booster antibody responses to the injected bacterin were significantly (P < 0.05) better in the milkfish juveniles fed supra dietary levels. Survival response of the experimental fish fed supra. dietary levels of vitamins (T1, T2 and T3) was significantly (P < 0.01) better than that of the control set. Protective response against virulent bacterial challenge of the vaccinated fish fed vitamin-supplemented diets (T2 and T3) was better than the control (T5) and T I and T4. Memory factor reflecting immunological memory was superior in the fish fed vitamin-supplemented diets. Diets supplemented with either 1500 mg of Vitamin C or 50 mg of Vitamin E kg(-1) produced the best antibody responses, final survival and protective response upon challenge. No conclusive inferences could be drawn on the growth responses from the experiment. (c) 2006 Elsevier Ltd. All rights reserved.