Dietary inclusion of Schizochytrium limacinum meal can maintain key productive parameters of pink cusk-eel (Genypterus blacodes) juveniles with a reduction in fish oil

Abstract

The pink cusk-eel (Genypterus blacodes) is a promising new candidate species to diversify cold-water aquaculture further. However, there are several knowledge gaps to establish a commercial-scale cultivation strategy, with optimum feed formulation being one of the main remaining challenges. This study aimed to assess the dietary inclusion of Schizochytrium limacinum heterotrophic microalgae meal as a sustainable source of docosahexaenoic acid on fish growth and the condition status of pink cusk-eel juveniles. Three extruded diets were formulated to contain 0, 5 and 10% of dried algae and fed to duplicate groups of fish twice daily until apparent satiation during the 12-week trial. On termination of the feeding trial period, the average live weight gain did not show statistically significant differences between the three groups of juvenile fish, achieving an increase in weight of about two times at the end of the trial. Similarly, the protein efficiency and feed conversion ratios did not show significant differences among the experimental diets. On the contrary, a significant reduction in feed intake was observed as the dietary inclusion of microalgae meal increased. These results indicate that S. limacinum meal is a sustainable alternative ingredient for the dietary substitution of fish oil in commercial feed for G. blacodes at limited inclusion.