Inclusão de Aspergillus niger em rações comerciais extrusadas para juvenis de tilápias do Nilo (Oreochromis niloticus)

Abstract

The production of fish has been growing significantly, in Brazil the main cultivated species is tilapia, but several factors still prevent a greater growth of this activity; one of them is the high cost of the rations. The use of fungus in animal feed has gained special attention given that Brazil is one of the major sugar cane and fruit producer in the world. This work aimed to evaluate the inclusion of Aspergillus niger biomass in commercial extruded feeds for Nile tilapia (Oreochromis niloticus). The experiment lasted 42 days, and parameters of zootechnical performance and organosomatic indexes were evaluated. There was no significant effect on length, feed intake, survival, condition factor, splenosomatic index and gonadosomatic index. However, there was a quadratic effect for final weight, weight gain, feed conversion, carcass yield, specific growth rate, somatic hepato index and visceral fat index, where optimal levels were between 3.7% and 4.1%. There was also a linear effect for the somatic digestive index. It is recommended the use of 4% of Aspergillus niger biomass in commercial extruded feeds for Nile tilapia, without losses in productive parameters.