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Abstract

ABSTRACT:The study assessed the effect of phytase on the digestibility of alternative plant feed ingredients Brazil nut (Bertholletia excelsa) and leucaena (Leucaena leucocephala) leaf meal fed to tambaqui (Colossoma macropomum) and on fish growth. Five treatments were used: UPI denoted the negative control diet with unfermented plant ingredients; UPIP was positive control diet with unfermented plant ingredient supplemented with 3 g/kg phosphorus (NaH 2 PO 4 ); FPI indicated diet with fermented plant ingredients; FPIPT1 denoted diet with fermented plant ingredients supplemented with phytase 4000 U/kg; and FPIPT2 was diet with plant ingredients fermented together with phytase 4000 U/kg. Chromic oxide was added to the diets as inert marker for digestibility study. The diets were fed to juveniles of tambaqui (70.0 ± 6.3 g) to satiation twice daily in recirculation systems for 56 days. Results indicated high and better digestibility of protein and lipid by fish fed diet with phytase, which resulted in a corresponding better fish growth. Growth rate of the fish was high and increased from initial weight of 70 g to 132 g almost doubling the initial weight. No significant differences were found in weight gain, specific growth rate, and feed conversion ration, but performance was better in fish fed diets with phytase. The fish grew well in low dissolved oxygen levels of 4.23-4.34 mg/l, pH of 5.80-5.91 and high ammonia concentration of 1.76-2.17 mg/l without compromising growth and physiological functions.

South American fish species suitable for aquaponics: a review

“…As reported for jundia, the investigations carried out with tambaqui used RAS as an experimental system to evaluate other productive management systems or parameters, and they were not specifically designed to evaluate the growth performance of tambaqui in such systems. These studies mainly focused on nutrition (Paulino et al 2018;Júnior et al 2017;Nwanna et al 2008), reproduction (Gallego et al 2017;Maria et al 2015), management (Dantas et al 2020;da Costa et al 2019), behaviour (Reis et al 2019;Barbosa et al 2009), genetics (Ariede et al 2020;da Silva et al 2019) and health (Barbas et al 2020;Paz et al 2019). Lima et al (2019) evaluated different stocking densities of tambaqui juveniles in RAS.…”