Replacement of fish oil with a DHA-richSchizochytriummeal on growth performance, activities of digestive enzyme and fatty acid profile of Pacific white shrimp (Litopenaeus vannamei) larvae

This trial was conducted to evaluate the effects of replacing dietary fish oil with Schizochytrium meal for Pacific white shrimp (Litopenaeus vannamei) larvae (initial body weight 4.21 ± 0.10 mg). Six test microdiets were formulated using Schizochytrium meal to replace 0 g/kg, 250 g/kg, 500 g/kg, 750 g/kg, 1000 g/kg or 1500 g/kg fish oil DHA. No significant differences were observed in survival, growth, final body length and activities of digestive enzyme among shrimp fed different diets (p > .05). No significant differences were observed in C20:5n-3 (EPA) in muscle samples (p > .05). C18:3n-3 and C20:4n-6 in muscle increased as Schizochytrium meal replacement level increased (p < .05). No significant differences were observed in C22:6n-3 (DHA) and n-3 fatty acids among shrimp fed diets that algae meal replaced 0 g/kg - 1000 g/kg of fish oil. Shrimp fed diet R150 had higher DHA content than other groups and had higher n-3 fatty acids than that of shrimp fed diets R50, R75 and R100 (p < .05). C18:2n-6, PUFA and n-6 fatty acids in muscle increased, while n-3/n-6 ratio decreased with increasing algae meal replacement level from 0 g/kg to 1000 g/kg (p < .05). In conclusion, Schizochytrium meal could replace 1500 g/kg fish oil DHA in the microdiets without negatively affecting shrimp larvae survival, growth and activities of digestive enzyme.