Digestibility and performance of juvenile Nile tilapia fed with diets containing forage palm

Abstract

Supplying the nutritional needs of animals in an economical way is essential to the success of any type of production. The forage palm is a cactaceae well-adapted to semiarid regions and commonly used in the feeding of ruminants. However, studies assessing its use in fishes are scarce. We aimed to evaluate the digestibility of bran from five different forage palm cultivars (Opuntia fícus) in juvenile Nile tilapia and the development of juveniles when receiving increasing levels of the cultivar with the best apparent digestibility coefficient of crude protein (ADCCP) (75.2%). We used 90 masculinized juvenile Nile tilapia (with an average weight of 6.02 ± 0.65 g) in the digestibility experiment to determine the apparent digestibility coefficients of dry matter (ADCDM), crude energy (ADCCP), and crude protein of the cultivars (Orelha de onça, Miúda, Gigante, Comum, and IPA 20). The experimental design was completely randomized (CRD) with five treatments and three repetitions. In the development experiment, 300 masculinized juvenile Nile tilapia (with average weight of 1.39 ± 0.12 g) received feed with different inclusion levels (0, 72, 144, and 216 g Kg-1) of IPA 20 palm bran in a CRD with four treatments and five repetitions. We observed significant differences (P < 0.05) for ADCDM and ADCCP between the treatments. The cultivars that presented the highest ADCDM were IPA 20 (41.75%), Orelha de onça (36.41%), and Gigante (32.59%). For ADCCP, the best cultivar was IPA 20 with 75.2%, followed by Orelha de onça (61.5%), and Miúda (56.1%). As for the performance, the inclusion of IPA 20 palm bran at a rate of 113 g/kg-1 provided the best values in terms of weight gain and final weight in juvenile Nile tilapia.