The influence of ascorbic acid (vitamin C) on non-specific immunity in the turbot (Scophthalmus maximus L.)

Immunomodulation by dietary vitamin C and glucan in rainbow trout (Oncorhynchus mykiss)

“…The results of the e#ect of dietary vitamin C on enhancing lysozyme levels in non-vaccinated fish showed an enhancement of this parameter in Atlantic salmon (Waagbø et al, 1993), in turbot (Roberts et al, 1995) while no significant variations were observed in rainbow trout (Verlhac et al, , 1996. Results of Verlhac et al (1996) on lysozyme level measured in rainbow trout fed glucan and vitamin C in graded doses from 150 to 4000 ppm showed an increase in plasma lysozyme with increasing levels of vitamin C but the variations were not considered to be significant due to high individual variations.…”

“…An e#ect of a high dietary dose of vitamin C has been demonstrated on the production of either O 2 or other ROS by rainbow trout macrophages (Verlhac & Gabaudan, 1992, 1994 while Hardie et al (1991) did not find any significant variation in O 2 production measured via the reduction of nitroblue tetrazolium. Ingestion of latex beads (Blazer, 1982;Verlhac et al, 1993) and phagocytosis of yeast cells (Roberts et al, 1995) were also enhanced by dietary vitamin C. The beneficial e#ect of beta-1,3/1,6 yeast glucan on macrophage activities, especially their bactericidal and phagocytic properties has been clearly demonstrated when this substance was delivered by injection (Jørgensen et al, 1993a,b;Noya et al, 1995) but the results on the capacity of this substance to enhance IMMUNOMODULATION BY DIETARY VITAMIN C macrophage activities when administered orally are less clear. Noya et al (1995) observed no variations in the erythrophagocytosis by peritoneal macrophages of gilthead seabream fed beta-1,3/1,6 yeast glucan for 3 weeks.…”

In vitro manipulations of vitamin C and vitamin E concentrations alter intracellular O−2 production of hybrid striped bass (Morone chrysops×Morone saxatilis) head-kidney cells

“…However, the benefit of dietary supplementation of vitamin C and vitamin E, above minimum requirements for growth, on phagocytic cell function is not clear. Some researchers have observed increased phagocytosis [8,9] and production of superoxide anions or hydrogen peroxide [10][11][12] in response to elevated dietary supplementation with vitamins C or E, however, others have observed no beneficial e#ects [6,7,[13][14][15].…”

Natural cytotoxic activity in seabream (Sparus aurata L.) and its modulation by vitamin C

“…Lysozyme activity was increased by dietary vitamin C intake in Atlantic salmon and turbot [10,30]. In rainbow trout, di#erences in lysozyme levels were reported due to specimen deviations [30,31].…”

“…In rainbow trout, di#erences in lysozyme levels were reported due to specimen deviations [30,31]. However, statistically significant di#erences in lysozyme activity were found when 1 g of vitamin C kg 1 was administered for 2 weeks [9].…”