Abstract
ABSTRACT The pirarucu, Arapaima gigas is a native, carnivorous fish species from the Amazon basin. As carnivorous fish have low amylase activity, exogenous enzymes can improve the digestibility of carbohydrates in aquaculture feeds. We evaluated the digestibility of increasing levels of an enzymatic complex in diets of pirarucu juveniles (65.2 ± 0.4 g). The experimental design was randomized with four treatments [diets containing 0.25, 0.50, 0.75, and 1 g kg-1 on-top inclusion of an enzyme complex (Allzyme® SSF®, USA), and a control, with three replications at a density of 5 fish per unit, and a 30-day duration. We quantified apparent digestibility of dry matter, crude protein, and crude energy through nutrient and chromium oxide content in diets and feces. Enzymatic activity, hepatic glycogen and total protein were determined in liver and anterior intestine samples. The diet with 1 g kg-1 of enzyme-complex resulted in an increase in apparent digestibility of crude protein, gross energy, and dry matter, hepatic glycogen, total proteins in liver and in intestine, showing the efficiency of the enzyme complex in pirarucu feeding. A higher accumulation of dry matter, crude energy, and ethereal extract in the carcass indicated weight increase in the fish treated with enzymatic complex. A decrease in the endogenous enzymatic activity (protease, lipase and amylase) suggested an improved efficacy of the digestive process. Our results indicate that the inclusion of 1 g kg-1 enzyme complex in the diet of juvenile pirarucu can be recommended to achieve greater digestibility of nutrients and improvement in productive performance.
Highlights
Arapaima gigas (Schinz 1822), popularly known in Brazil as pirarucu, is a carnivorous fish native to the Amazon basin (Ituassú et al 2005)
There was better apparent digestibility in pirarucus fed with diets, including the enzymatic complex
Percentages of dry matter, crude energy, and ether extract in the carcasses varied significantly among the experimental diets (Table 4), but the percentage of crude protein in the carcass did not vary significantly
Summary
Arapaima gigas (Schinz 1822), popularly known in Brazil as pirarucu, is a carnivorous fish native to the Amazon basin (Ituassú et al 2005). The inclusion of vegetable protein in fish feed has been evaluated for several species, including pirarucu (Ayhan et al 2008; Booth et al 2013; Souza et al 2014; Cipriano et al 2016; Dalsgaard et al 2012, 2016). This ingredient allows the use of food industry by-products, reducing production costs. The use of additives in the diet of carnivorous fish can increase digestibility coefficients, mainly those of vegetable components, and improve the productive performance of farmed animals, as the nutritional quality of the diet depends on the animals’ ability to digest and absorb nutrients
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
