Rainbow trout weighing 0.15g on the average were fed with purified diets containing different amounts of L-ascorbic acid for 20 weeks. Dietary ascorbic acid levels did not affect the appetite, growth, and movement of the fish until the appearance of the symptoms of scurvy. The occurrence of vertebral curvature and exophthalmus were recognized only in the fish which received the ascorbic acid-free diet for 15 to 20 weeks.
The values for the ratio of hydroxyproline to proline content of collagen fraction ofthe skin and bone were significantly lower in the fish groups receiving low ascorbic acid diets (0 to 2mg ascorbic acid /100g diet) for 11 weeks, whereas this value was not so low in th fish group fed with diet containing 5mg ascorbic acid per 100g diet, when compared with the control fish.
The results indicate that an underhydroxylated collagen is formed and accumulated in the tissues of the fish which are fed with ascorbic acid deficient diets. This trend seems to be continued until the ascorbic acid levelof the diet reachs 5mg per 100g deit. The minimum dietary ascorbic acid requirement to maintain a normal collagen formation in the tissues of the experimental fish was estimated to be 5 to 10mg per 100g diet.