In order to examine the effect of hitherto unutilized materials for young carp feeding, four kinds of artifficially mixed food were made.
A. The basic food (40% of fishmeal, 40% of Gammarus and 20% of Ricebran.)
B. 40% of mulbery leaves was added to 60% of A.
C. 40% of walnut leaves added to 60% of A.
D. 40% of spiked water milfoil was added to 60% of A.
They were used for feeding young carps, of almost the same size reared in the four experimental ponds of the same size and under the same condition, for fourty four days, July 29 September 10, 1948.
The result was as follws:
On the average, the carps fed with A grow most quickly, then come those fed with B, those fed with C, and lastly come those fed with D, and they increased the weight of body 24.1%, 13.6% 7.4% and 6.2% respectively.
But regarding the total sum of the fish production, due to the survival rate of fish, B is the best, C is the 2 nd, D is the 3 rd and A is the last; the survival rates are at 90%, 75%, 70% and 60% respectively.
According to the above result, the food value in fish culture must be concluded not only on the growth rate of individual fish, but also on the survival rate of rearing fish or on the total sum of fish production.
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