抄録
Two experiments were conducted to find out if the occurrence of color abnormality and malformation in larval Japanese flounder could be prevented when enriching Artemia nauplii with vitamin A (VA) and its precursor. Ten-day-old larval flounder were chosen as the experimental fish and fed different strains of Artemia, Utahstrain in the first experiment and Tien-tsin strain in the second experiment.
Growth and VA content of larval flounder were almost the same in both experiments, except those fed Artemia enriched with 100×103 IU VA in a 10 l medium which showed retarded growth and malformation. No abnormal coloration was observed in thefirst experiment. However, in the second experiment, color abnormality was recognized in all the groups, probably on feeding the Tien-tsin Artemia, and the percentage occurrence was effectively reduced by feeding the Artemia containing about 1, 000 IU VA. However, bone deformity of a higher degree, such as central fusion, abnormalbone formation in caudal fin, and abnormal formation of pterigiophores wasobserved in the fish fedthis level of VA.
These results suggest that VA seems to be effective in preventing the abnormal coloration caused by Tien-tsin Artemia, but the excess amount of this vitamin can exert ill effects on normal growth of flounder.
