VITAMIN-C REQUIREMENT OF THE MEXICAN NATIVE CICHLID CICHLASOMA-UROPHTHALMUS (GUNTHER)

The dietary vitamin C requirement was determined for Cichlasoma urophthalmus, a particularly important Mexican native cichlid. Fry with initial weight of 160 to 170 mg were fed on diets containing 10 different levels of vitamin C ranging from 0 to 10 240 mg/kg of diet for 90 days. Fish fed the diet without vitamin C showed high mortality and significantly reduced growth (P<0.01) as compared to the other treatments. Fish fed diets containing 0,40 and 78 mg vitamin C/kg of diet showed an external pathological appearance which was not observed with fish fed diets containing higher levels of vitamin C. The external signs of deficiency observed were dark coloration, short operculae, hemorrhages in the eyes, head and fins, erosion of the skin and fins, loss of scales, exophthalmia, swollen abdomen, iritis, scoliosis and changes in the head bones. The minimum level of vitamin C required for normal growth was 40 mg/kg diet, and the minimum level required to ensure healthy fish was 110 mg/kg. © 1990.