Crude protein level and dry yeast in diet combined with organic fertilizer in Nile tilapia (Oreochromis niloticus ) fingerling rearing

摘要

Aiming to evaluate the use of crude protein (CP) levels and dry yeast (DY) combined with organic fertilizer in Nile tilapia fingerling culture, 480 fishes (2.190.29g) were distributed in an entirely randomized block design with twelve treatments with four replications. The diets had 27, 30, and 33% of CP with or without DY (6%) and applied in tanks with or without manure. Fishes that received diets with 30 and 33% of CP without DY and the diet with 33% of CP with DY in tanks fertilized showed better final weight values than those feed with 27 and 30% of CP with or no DY in no fertilized tanks. Fishes that received diets with 30 and 33% of CP without DY had better feed conversion index than those that received diets with 27% of CP in no fertilized tanks. The treatments that have diets with 27 or 30% of CP in fertilized tanks promoted similar values of final weight and feed/gain ratio conversion than treatments with 33% of CP at no fertilized tanks. There was a linear increase of final weight and efficiency protein rate values by the levels of PB in diets in fertilized tanks and without manure. The use of manure with diets with the same PB levels showed better values of final weight, feed/gain and efficiency protein rate. The final weight, feed: gain ratio and efficiency protein rate of fishes were better at the fertilized tanks. Therefore these parameters were no affect by the DY in diets. It may be concluded that the use of manure make possible a reduction in the dietary protein level in Nile tilapia fingerlings.