Availability of squid viscera meal with cadmium removal treatment as a feed ingredient for fingerling black rockfish Sebastes schlegeli

Abstract

Two 12-week feeding experiments were conducted to evaluate the nutritional value of squid viscera meal with cadmium removal treatment (dCSVM), which contained 1.5–2.0 mg/kg cadmium, as an alternative protein source to sardine meal in diets for fingerling black rockfish Sebastes schlegeli. Initial mean body weights in experiments 1 and 2 were 23.0 and 6.4 g, and the replacement rates of sardine meal with dCSVM in the test diets were 20–80 % and 30–60 %, respectively. In experiment 1, inclusion of dCSVM at 40 % and higher replacement rates of sardine meal retarded the growth of fish due partly to inferior dCSVM protein digestibility. The cadmium (Cd) concentrations in fish muscle of all treatment groups were below the detection limit (<0.1 mg/dry matter). In experiment 2 using dCSVM containing Cd at a lower level and having a higher protein digestibility than in experiment 1, no significant differences were observed in the growth between the control and 60 % replacement groups, although feed efficiency gradually decreased with the increase of dCSVM inclusion. These results show that dCSVM is safe and useful as an alternative protein source and could replace up to 60 % of sardine meal in fingerling black rockfish diets.