Fishmeal substitution with Arthrospira (Spirulina platensis) in a practical diet for Litopenaeus vannamei: Effects on growth and immunological parameters

The use of fishmeal (FM) and fish oil in aquafeeds is a major challenge in the development of aquaculture. The discovery of alternative ingredients for aquaculture feedstuffs will allow for the sustainable growth of this activity. The cyanobacteria Arthrospira (Spirulina platensis) contains high quality protein and also immune-stimulatory properties that have been tested in mammals, fish and crustaceans. The purpose of this work was to evaluate the growth and immunological parameters of the white shrimp Litopenaeus vannamei when it was fed experimental isonitrogenous diets (~ 35% protein), containing 0%, 25%, 50%, 75% and 100% cyanobacteria A. platensis replacing fishmeal for 50 days. At the end of the experiment, there were no significant differences (p < 0.05) in growth performance among the shrimp fed diets with up to 75% fishmeal replacement. The immunological parameters differed significantly in the percentage of hyaline and granular hemocytes in the shrimp fed the diets with at least 25% fishmeal replacement. The apoptotic index also showed highly significant differences, but only in those shrimp fed a diet consisting of 100% fishmeal replacement. The results showed that up to 75% of fishmeal could be replaced by A. platensis without affecting survival or creating a growth depression. Moreover, the smaller substitution level (25%) promoted an enhancement of the tested immunological parameters.