Digestibility of nutrients and energy of cultivars of forage palm for growing Nile tilapia

Abstract

The objective was to evaluate the apparent digestibility coefficients of nutrients and energy of five cultivars of forage palm (orelha de onça, miúda, gigante, IPA 20 and comum) for growing Nile tilapia (110.02±16.17 g). The study design was completely randomized with five treatments, three replicates of eight fish per experimental unit. The diets were composed of 300 g/kg of each cultivar of the palm and 700 g/kg of the basal diet. Masculinized fish were distributed in circular feed tanks (150 L) and kept in closed circulation of water and constant aeration. The digestibility was estimated by indirect method, using 1.0 g/kg chromic oxide as an indicator of the diet and the feces was collected the day after the last feed in digestibility aquariums. The cultivars comum and onça presented the best values for dry matter digestibility (53.5%). The lowest value for crude protein digestibility was obtained to cultivar gigante (60%) and all cultivars tested showed gross energy digestibility below 50%. Nile tilapia has limitation on the digestibility of dry matter, gross energy, crude protein and amino acids of the cultivars of forage palm IPA 20, miúda, gigante, comum and orelha de onça.