Hidrolisados proteicos na alimentação de juvenis de dourado <i>Salminus brasiliensis</i>

Abstract

Protein hydrolysates in diets for juvenile dourado, Saminus brasiliensis Carnivorous fish diets strongly depend on fish meal (FM), a high-cost, scarce feedstuff, given the need for palatable protein and high nutritious value. Animal by-product hydrolysates are high-quality feedstuff that can substitute FM in fish diets. This study evaluated digestibility of hydrolysates from tilapia residue [TR], tuna head [TH], swine liver [SL] and poultry liver [PL], and the profile of digestive enzymes in the stomachs, pyloric cecum and intestines of juvenile (39,73 ± 5,30 g) dourado, Salminus brasiliensis, a carnivorous Characin fed diets containing graded levels of hydrolysates, and the performance of juvenile dourado (4,57 ± 1,25 g) fed diets containing increasing levels of FSU (0, 70, 140, 210 and 280 g kg-1). The addition of hydrolysates to diets lowered the pH of feed, but did not alter feed intake by fish. Higher digestibility coefficients of nutrients were recorded for fish fed diets containing TR and SL, and the lower for those fed diets containing TH. Protease and lipase activity in the fish's stomach was higher, especially for those fed diets containing SL. Amylase activity was higher in pyloric caeca, while in the intestines the higher activity was registered for fish fed control and TR diets. Animal byproduct hydrolysates were highly digestible for dourado, and enzymatic profile of fish depended on nutrients of diets. In the second trial, the lowest values of daily intake were recorded for fish fed diet without inclusion of hydrolysate. However, the lowest weight gain, final weight and specific growth rate, protein and energy efficiency, and protein retention rates were recorded for fish fed diet with 280 g kg-1 of swine hydrolysate. The large proportion of free amino acids and small peptides in the diets with inclusions above 140 g kg-1 of the product apparently reduced the protein synthesis by fish. Health status of fish was not significantly affected by dietary hydrolysates, but apparently, fish fed diets containing more than 140 g kg-1 had better immunohematological indices.

Attractiveness and palatability of liquid hydrolysates for Dourado ( Salminus brasiliensis ) fingerlings

“…Even with increased production and generation of data in aquaculture‐related studies, native species are little studied in Brasil. According to Cyrino and Fracalossi (2012), there has been an increased production of native species from the 90s, from the number of sports fishing, but recently, other qualities of these species have been evidenced, such as quality of the carcass, acceptance by the consumer and market price (Lorenz, 2017; Weingartner & Zaniboni‐Filho, 2013).…”