42 巻 (1976) 5 号 p. 571-576
In order to determine the requirements of prawn Penaeus japonicus for ascorbic acid and inositol, the effects of dietary levels of dietary levels of these two vitamins on growth and feed efficiency were examined by using a purified test diet devised by the authors.
1) Growth depression occurred as the dietary level of ascorbic acid increased within the range tested from 0 to 1.0%, the best growth resulting when the diet contained no ascorbic acid. The amount of food ingested by the prawn also decreased with increasing ascorbic acid in the diet. Feed efficiency, however, remained almost constant among the test diets. On the other hand, the diets either lacking or containing 0.1% ascorbic acid produced high mortalities at a high water temperature of 28-30°C and particular signs such as decolorization and development of a greyish-white color on the margin of the carapace, the lower part of the abdomen and on the tips of walking legs.
2) Within the range from 0 to 0.4%, higher levels of dietary inositol resulted in higher growth rates. The prawns fed diets lacking or containing 0.04% inositol developed loss of appetite, poor growth, low feed efficiency and high mortality. Most of the prawn on these two diets died just after molting.
3) Adequate levels of these two vitamins in the test diet were assumed to be about 0.3% for ascorbic acid and about 0.4% for inositol.