Dietary inclusion effect of feed ingredients showing high feeding attractiveness to rockfish (Sebastes schlegeli Hilgendorf 1880) on the growth performance, feed utilization, condition factor and whole body composition of fish (II).

Dietary inclusion effect of feed ingredients showing high feeding attractiveness to rockfish on the growth, feed utilization, condition factor (CF) and whole body composition of fish was investigated. Three hundred sixty juvenile rockfish were randomly distributed into 18 50-L flow-through tanks (twenty fish per tank). Six experimental diets were prepared: the control (Con) diet containing 55% anchovy meal, and 5% anchovy meal in the Con diet was replaced with an equivalent amount of jack mackerel, sardine, Pollack, squid and shrimp meals, referred to as the JM, SM, PM, SQM and SHM diets, respectively. Each diet was assigned in triplicate and hand-fed to satiation twice daily for 8 weeks. Weight gain (20.7 ± 0.03), amount of feed supply (20.1 ± 0.05) and CF (1.50 ± 0.002) of rockfish fed the JM diet were greater than those of fish fed all other diets, followed by the SM (20.3 ± 0.04, 19.5 ± 0.08 and 1.48 ± 0.003), PM (19.9 ± 0.09, 19.2 ± 0.05 and 1.47 ± 0.003), SQM (19.5 ± 0.06, 18.8 ± 0.07 and 1.45 ± 0.002), SHM (19.0 ± 0.12, 18.3 ± 0.09 and 1.44 ± 0.001) and Con diets (17.8 ± 0.07, 17.2 ± 0.05 and 1.43 ± 0.005). However, feed efficiency, protein efficiency ratio and protein retention was not affected by the experimental diets. The proximate composition of the whole body of fish, except for ash content was not affected by the experimental diets. In conclusion, the greatest weight gain, amount of feed supply and CF of rockfish were obtained in the JM diet, followed by the SM, PM, SQM, SHM and Con diets, in order.