From the environmental point of view, aquaculture diets must be, avoiding the use of marine resources, increasing diet efficiency to improve production management. For this to happened, it is crucial the increase of unused by-products. For this reason, it is essential the fish oil (FO) and fish meal (FM) replacement by using protein and oil sources from recycle by-products such as terrestrial proteins and fats from husbandry animals. California yellowtail Seriola dorsalis, is a promising fish species to be culture. In fact, several Seriola spp. fish species are already produced in around the world with great success. However, being a carnivore species, a high demand of FM is needed. Therefore, the study to replace FM is crucial.
This study aimed to evaluate the effect of partial to total replacement of fish meal (FM) and fish oil (FO) from diets formulated to yellowtail (Seriola dorsalis ) using poultry by-product meal (PBM) using beef tallow supplemented with DHA. Four experimental diets were formulated to be isoproteic and isolipidic , based on the yellowtail nutritional requirements. Cholesterol was added to compensate its content in the FO. S. dorsalis juveniles (14.54g ± 0.19 g, mean ± SE) were randomly distributed into 12 tanks, with 500L each, connected into a recirculation system. After 48 days experimentation procedure, no significant differences were observed in performance for the PBM in replacement of FM. Significant differences were observed in the fatty acid profile of muscle tissue among treatments. Saturated fatty acids were less retained indicating a major use as energy source. It was observed a lower DHA level in fish from T-Low compared those from T-Med.
It is concluded that PBM can efficiently replace FM and FO in diets for Seriola dorsalis without any negative impact. However, more experiments are needed to find better fatty acid combination to improve the protein sparing effect .