The inclusion of biological silage from chicken intestines and blood in the feed for Nilotic tilapia Oreochromis niloticus, substituting 80% of the protein content of fishmeal, was evaluated. The silages were made with 70% waste, 15% energy source (14% molasses and 1% sugar) and 15% yogurt (lactic acid bacteria). The pH and acidity were determined for 180 days, and the chemical analysis was done using standard methods. The base diet was formulated with the minimum cost equation, and considering the nutritional requirements for tilapia, inclusion levels and cost of inputs. A control diet and two with silages were used. The fingerlings (n=270) with an initial weight of 5.17 ± 0.18 g were randomly distributed in nine aquariums (3 per diet). The fish were fed three times a day and evaluated monthly. A significant difference (p<0.05) was found in the final weight and biomass averages betw...