Ingestion rates of the juvenile O. marmoratus on different treatments of TS pellet with the test substance concentration level at 0.1 M
Considering the highest ingestion rate of INO and IMP•Na2 in the juvenile O. marmoratus, these chemical substances were further tested on the fish with the lower concentrations (0.01 and 0.001 M) to detect their threshold to the fish. Figure 2 shows the fish ingestion rates of TS pellets with different concentrations of INO and IMP•Na2. The ingestion rates of IMP•Na2 at 0.001 and 0.01 M were 2 and 78 %, respectively; these values were significantly lower (P < 0.05) than that of the 0.1 M IMP-Na2 (100 %). On the other hand, the ingestion rates of INO at 0.001 and 0.01 M were all 100 %, similar with that of the 0.1 M INO. These results suggested that INO was more effective or suitable than IMP•Na2 to be used as a feeding stimulant for juvenile O. marmoratus in term of their functional dosage. Such results were in agreement with those reported on the marbled rockfish Sebasticus marmoratus by Takaoka et al. (1990).