Inclusion effect of jack mackerel, Trachurus japonicus , meal in the diet of rockfish, Sebastes schlegeli , on growth, feed utilization, biochemical composition, and innate immune responses

Dietary inclusion effects of various levels of jack mackerel meal (JMM) on growth, feed utilization, biochemical composition, and innate immune response of rockfish were determined. The control (Con) diet included 550 g/kg fish meal (FM). Ten, 30, 50, 100, 200, 400, 600, and 1000 g/kg of JMM were included in the Con diet, referred to as the JMM 10 , JMM 30 , JMM 50 , JMM 100 , JMM 200 , JMM 400 , JMM 600 , and JMM 1000 diets, respectively. Eight hundred and ten fish (initial mean weight of 2.3 g) were distributed into 27 flow‐through tanks. The experimental diets were assigned to triplicate groups of fish. Fish were hand‐fed for 8 weeks. Weight gain of fish fed the JMM 400 diet was statistically better than that of fish fed the Con, JMM 10 , JMM 30 , JMM 50 , JMM 100 , and JMM 200 diets. Feed consumption of fish fed the JMM 400 diet was statistically higher than that of fish fed the Con, JMM 10 , JMM 30 , and JMM 50 diets. Dietary inclusion of JMM did not influence feed utilization, biochemical composition, and innate immune responses of fish. In conclusion, inclusion of JMM up to 400 g/kg of FM in diet improved growth and feed consumption of rockfish, and dietary optimum inclusion levels of JMM were estimated to be 396.7 and 403.1 g/kg based on regression analysis of weight gain and feed consumption, respectively.