Effect of shark by‑product meal as an alternative to fish meal on growth and phosphorus loading to the environment in juvenile yellowtail, Seriola quinqueradiata

Abstract

The shark by-product meal (SM) was used to replace fish meal (FM) in the diet of juvenile Japanese yellowtail, Seriola quinqueradiata, to investigate its effect on growth and phosphorus (P) load in the ecosystem. The control diet (C) was composed of FM as the protein source, and 25%, 50%, 75%, and 100% of FM protein from diet C were replaced with SM-based protein to formulate the diets SM25, SM50, SM75, and SM100, respectively. A group of 25 fish (mean weight 18.01±0.09 g) were loaded into each 500 L tank in triplicate for each treatment and fed twice daily until apparent satiation for 6 weeks. There were no significant differences in growth parameters among fish fed diets C, SM25, SM50, and SM75, although SM100 produced a significantly lower performance than the other diets. The P productive value increased significantly with increasing levels of SM in the diets, resulting in a significantly lower P load per kilogram weight gain from the SM-based diets than that in the control diet. There were no significant differences in plasma constituents, except triglycerides, blood urea nitrogen, and ammonia levels. In conclusion, the results suggest that 75% of FM protein can be replaced by SM-based protein without compromising growth performance and health and that a significant ecological benefit can be achieved by reducing P loading by using an SM-based diet in yellowtail juvenile.