The protein levels in isocaloric diets for hybrid tilapia (II) Economical evoluation

Abstract

The research was set up in two experimental batches, in aquaria and brick layering ponds at the Aquiculture Center of UNESP, "Campus" Jaboticabal, São Paulo, Brazil, from September 1979 to March 1980, at 21^o 15' 22" Southern latitude and 595 m of altitude, aiming the determination of the optimum proteic dietary level that provides the best performance for hybrid tilapia (male Oreochromis hornorum x female O. niloticus) fingerlings. Three isocaloric rations (estimated 3100 kcal ME/kg) were formulated with 12, 18 and 24% crude protein leveIs. It was observed that only fishes that received the ration containing the lowest crude protein leveI differed from the other treatments (rations containing 18 and 24% protein) presenting the worst performance. Considering the data obtained in both experimental periods, the maximum growth of fishes could be expected with a diet formulated with the same ingredients containing 22.26% crude protein which is very similar to the economical proteic dietary leveI; estimated in 22.25% under the experimental conditions.