Replacement of fish oil with a DHA-rich<i>Schizochytrium</i>meal on growth performance, activities of digestive enzyme and fatty acid profile of Pacific white shrimp (<i>Litopenaeus vannamei</i>) larvae

Abstract

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.