Substitution levels of fish meal by Arthrospira (=Spirulina) maxima meal in experimental diets for red tilapia fingerlings (Oreochromis sp.)

The high international demand and cost of protein ingredients have led to the increasing need to meet nutritional requirements of animals with national resources. Objective: the objective of th is study was to evaluate three levels of substitution (10, 20, and 30%) of fish meal with Spirulina maxima meal as a protein source in experimental diets for red tilapia fingerlings (Oreochromis sp.). Methods: masculinized fry (average weight: 2.5 ± 0.10 g) were randomly distributed in aerated aquaria with daily water exchange. Four diets were formulated replacing increasing levels of fish meal with Spirulina maxima meal, as follows: 10 (A), 20 (B), 30 (C) and 0% (D, control diet). A commercial diet (E) was also used. All diets were isoproteic (28%) and isocaloric (400 kcal/100 g). Fish were fed two daily rations during 90 days. Weight gain (GP), feed efficiency (EA), protein-efficiency ratio (REP), and feed conversion (FCA) were measured every two weeks. Results were assesses by ANOVA at the end of the test. Results: no significant differences (p>0.05) were observed for GP, EA and REP, indicating a similar efficiency in all diets (A, B, C, D, and E). Treatment C had the best FCA (p