THE EFFECT OF BETA-CAROTENE AND VITAMIN-A ENRICHED ARTEMIA NAUPLII ONTHE MALFORMATION AND COLOR ABNORMALITY OF LARVAL JAPANESE FLOUNDER

Two experiments were conducted to find out if the occurrence of color abnormality and malformation in larval Japanese flounder could be prev ented when enriching Artemia nauplii with vitamin A (VA) and its precu rsor. Ten-day-old larval flounder were chosen as the experimental fish and fed different strains of Artemia, Utah strain in the first experi ment and Tien-tsin strain in the second experiment. Growth and VA cont ent of larval flounder were almost the same in both experiments, excep t those fed Artemia enriched with 100 x 10(3) IU VA in a 10l medium wh ich showed retarded growth and malformation. No abnormal coloration wa s observed in the first experiment. However, in the second experiment, color abnormality was recognized in all the groups, probably on feedi ng the Tien-tsin Artemia, and the percentage occurrence was effectivel y reduced by feeding the Artemia containing about 1,000 IU VA. However , bone deformity of a higher degree, such as central fusion, abnormal bone formation in caudal fin, and abnormal formation of pterigiophores was observed in the fish fed this level of VA. These results suggest that VA seems to be effective in preventing the abnormal coloration ca used by Tien-tsin Artemia, but the excess amount of this vitamin can e xert ill effects on normal growth of flounder.