抄録
The starfish, Asterias amurensis Lütken, propagated suddenly in Tokoy Bay, from October 1953 to March 1954, and gave severe damage to the clam culture. Since that time, our attention has been directed to the possibilities of utilization of this species or others of Asteroid for feed-stuffs, not only on account of its abundance but because it must be exterminated, if possible, in order to protect the clam from the starfish attacks.
As the starfish contains much more calcium than fish, it is necessary to exclude the greater part of the calcium from starfish for the purpose of preparing feed-stuffs rich in pro- tein (Tables 2, 3). We attempt to separate the calcium from starfish by digesting it by protease.
The protease process ?? adopted was as follows;
To 1 part of raw stasfish is added 1 part of water and 0.02 part of a commercial bacterium protease “Bioprase, ”* and the mixture is warmed to 50 ?? 55°C for 1 ?? 2 hours while continuously stirred. Owing to this enzymic digestion, the body wall of starfish is crushed to white pieces of calcium carbonate and precipitated (Table 5; Figs. 1, 2). The precipitated calcium is filtered. The filtrate contains favourably small amount of calcium and considerable amount of various vitamins (Table 6). In place of “Bioprase”, animal internal organ, e.g. liver of blue crab can be used for the starfish digestion (Table 7). The filtrate (the starfish solubles) is evaporated in an open iron pot until the moisture is less than 50 per cent. In the condensation of starfish solubles, the loss of vitamins are very little (Table 8).
That the concentrated starfish solubles has no toxicity is proved by feeding experiment with rats (Tables 10, 11, 12; Fig. 3).
