(1) Effect of dietary vitamin C on the disease susceptibility and inflammatory response of mrigal, Cirrhinus mrigala (Hamilton) to experimental infection of Aeromonas hydrophila. Sobhana, K. S.; Mohan, C. V.; Shankar, K. M. College of Fisheries, Department of Aquaculture, Fish Pathology and Biotechnology Laboratory, University of Agricultural Sciences, Mangalore, India. Aquaculture (2002), 207(3-4), 225-238. Publisher: Elsevier Science B.V.

Abstract

Two groups of 3-day-old hatchlings of Cirrhinus mrigala were fed with vitamin C supplemented (at 1000 mg vitamin C/kg diet) and non-supplemented practical diet for a period of 4 mo. At the end of the feeding period, fishes were examd. for their disease susceptibility and inflammatory response to a virulent strain of Aeromonas hydrophila. Mortality curves were clearly distinct and the vitamin C non-supplemented (VNS) group showed significantly higher mortality rates compared to the vitamin C supplemented (VS) group. While studying the inflammatory response to A. hydrophila, it was found that in the VS group, the infiltration of phagocytic cells was quicker with very limited lesion development at the injection site and there was complete resoln. by day 9 post-injection. In the VNS group, the bacterium was able to produce necrotic lesions clin. and histol. typical of a disease condition.

(2) Optimization of dietary vitamin C in fish and crustacean larvae: a review. Merchie, G.; Lavens, P.; Sorgeloos, P. Laboratory for Aquaculture and Artemia Reference Center, University of Ghent, Rozier 44, Ghent, Belg. Aquaculture (1997), 155(1-4), 165-181. Publisher: Elsevier

Abstract

A review with 64 refs. HPLC techniques have been adapted and standardized for quantification of ascorbic acid (AA) and its derivs. in both diets and target organisms. To assess the dietary needs for AA at the start of exogenous feeding, the AA content in the various live diets currently used in aquaculture (algae, rotifers, Artemia) was analyzed. Application of techniques for boosting vitamin C using ascorbyl palmitate as the source enabled the transfer of elevated levels (up to 2500 g AA/g DW) of bioactive vitamin C. Larvae of fish (Clarias gariepinus, Dicentrarchus labrax, Scophthalmus maximus), white shrimp (Penaeus vannamei) and prawn (Macrobrachium rosenbergii) are enriched via the live food chain. This vitamin C enrichment procedure has proven to be a valuable technique for the evaluation of the effects of high levels of dietary vitamin C on stress resistance. However, in most of the species examd., the initial level of AA in Brachionus and Artemia impaired the detn. of the AA requirements for optimal growth and survival. Formulated diets contg. variable levels of stable AA-phosphate esters were used for the detn. of minimal requirements for AA in the early post-weaning stage of marine fish species (D. labrax, S. maximus) and the postlarval stage of penaeid shrimp (Penaeus monodon, P. vannamei). For both fish species, results indicated that, within the concn. range tested, 20 mg AA/kg diet is sufficient for normal growth and survival. For prodn. of postlarval shrimp, this level amts. to a min. 20 and 130 mg AA/kg diet for P. monodon and P. vannamei, resp., while a level of 2000 mg AA/kg diet is needed to enhance the resistance of shrimp postlarvae to stress conditions and bacterial infections.