Potential of agricultural and fishery wastes as sustainable feed ingredients for Nile tilapia (Oreochromis niloticus)

Abstract

Abstract Soybean meal (SBM) is the most widely employed vegetable ingredient in aquafeeds, but its rising price and the negative environmental impacts of its cultivation open research efforts for its replacement. More sustainable aquaculture may be achieved by utilizing agricultural and fishery by-products; thus, this study aims to incorporate pea meal (PM) and shrimp protein hydrolysate (SH) as protein ingredients in tilapia juveniles’ feed. The presence of protease inhibitors and the in vitro digestion were evaluated for raw (PM0) and extruded pea meals (PM150), while SH characteristics were studied as well. The nutritional quality of alternative ingredients was assessed to formulate a diet that meets tilapia juveniles’ requirements, and its effects on growth were evaluated. Extrusion significantly reduced the PM inhibitory effect on tilapia proteases (from 5.4–1.9%). In vitro protein digestion of PM150 (7.8 ± 1.35%) did not differ from the control treatment with fish meal (FM; 11.8 ± 1.94%). Additionally, SH presented 41.6 ± 2.91% of DPPH radical scavenging activity. Tilapias fed with a diet where SBM was totally replaced by the dietary inclusion of 25% PM150 and 10% SH, presented comparable growth indicators to those exposed to the control diet. Extrusion reduced PM proteolytic inhibitory effect and improved protein digestibility. SH presented antioxidant effect, as well as, provided flavor enhancers and essential amino acids to the diet. It is feasible to achieve a sustainable dietary formulation for juvenile tilapia using the evaluated by-products without affecting its growth performance.