Fish meal (FM) has long been considered an essential ingredient for the formulation of shrimp feeds. Until recently, 12%FM was considered a minimum amount, below which weight gain would become reduced due to a reduction in feed intake. In order to test this perceived minimum value, an experiment was conducted on a long-term basis with 4 replicates. Four practical isonitrogenous and isoenergetic diets were formulated for Litopenaeus vannamei juveniles. Survival, weight gain, feed conversion ratio (FCR) and protein efficiency ratio were determined for 0, 6, 10 and 15% FM diets and a reference diet. Shrimp survival ranged from 84 to 86.5%. Shrimp fed a diet with 0% FM showed lower average weight and SGR compared to the other treatments (P < 0.05). FCR of shrimp fed the reference diet was significantly lower compared to the other treatments. Short-term energy budget did not differ in recovered energy (RE). Variations in RE according to FM level were expected, however, it remained low (0.12 kJ prawn − 1 day − 1) and it was not possible to discriminate among dietary treatments. Data indicate that RE was similar as evidenced by an absence of difference in weight gain among 6, 10 and 15% FM diets and the reference diet (0.98 g/wk). Growth results obtained over a long-term period and in clear water indicated the possibility for FM replacement with soybean plus canola meals.

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