Dry biomass of Aspergillus niger in commercial diets for juveniles of Nile tilapia (Oreochromis niloticus) in the intermediate growth phase (15 to 70g)

The objective of the present study was to evaluate different inclusion levels of drymass of the yeast Aspergillus niger (0; 0.125; 0.250; 0.500; 1.00; 2.00; 4.00 and 8.00%) in commercial diets for juveniles of Nile tilapia (16.11 ± 1.74g) in a water recirculation system. The productive performance, organosomatic indexes and carcass composition of these animals were evaluated after 58 days of experiment. A total of 192 juveniles were distributed among 32 tanks made up of eight treatments with four repetitions. A significant difference was observed for the hepatosomatic index at 2.00% of inclusion, which was similar to the other treatments except for the 0.125% inclusion level. The inclusion of A. niger had no negative impacts on performance when compared with the control diet. Since it is a by-product, the use of A. niger can be an alternative in the formulation of diets for tilapia in the initial stages (15-70g).