Circular economy in aquaculture: formulation of feed from agricultural by products and wasts to improuve growth, metabolism and immunity system of Red Tilapia.

Abstract

With the growing need for sustainable aquaculture, this study explores the use of locally available agro-industrial by-products as alternatives to commercial feeds for red tilapia (Oreochromis sp.). The objective was to assess the effects of four experimental diets—three based on natural ingredients (carob, grape pomace, spirulina, moringa) and one commercial feed (ONAB) on growth performance, hematological parameters, biochemical markers, and innate immunity. The carob-based diet (Diet 1) significantly enhanced growth (WG = 192 g, DWG = 5.65 g/day), improved feed conversion (FCR = 2.66; FE = 0.38), and elevated key blood markers such as plasma protein (45.52 g/L), glucose (67.38 mg/dL), and lysozyme activity (6.11 U/mL). In contrast, the grape pomace-based diet (Diet 2) showed the lowest performance, likely due to its high tannin and fiber content, which reduced digestibility and nutrient absorption. The spirulina-moringa-based diet (Diet 3) offered intermediate benefits. Future research should focus on histological analysis, gut microbiota profiling, gene expression of immune markers, and economic feasibility under semi-industrial conditions to validate the practical application of these alternative feeds