Valorization of Algerian food by-products in animal feed

Introduction. The valorization of food by-products in animal feed has emerged as a pivotal strategy. This innovative approach not only addresses the challenge of food waste management but also contributes to the optimization of resources in animal nutrition. Objective. To characterize food waste (carob molasses residue, carob seeds, bitter orange peels and brown chicken eggshells) with a view to their use as a value-added food supplement for animals based on their biologically active compounds. Materials and methods. In this study, several food by-products were utilized, including carob molasses residue, orange peels and eggshells. The biological material was collected in Boumerdès, Algeria, during 2021, according to the ripening period of the plant material (August for carob and December for oranges). For the characterization of the different components of the biological material, phytochemical tests based on color reactions, high-performance liquid chromatography (HPLC), atomic absorption spectrophotometry and solubility in solvents were employed. Results. The by-products were found to be low in fat and protein, and moderately high in sugar. Orange peel constitutes a reservoir of vitamin C, carotenoids and phenolic compounds. The mineralogical study showed a predominance of calcium, magnesium and phosphorus in the eggshells. The comparison of by-products shows that carob seeds are the least rich in crude fiber and therefore supply more available carbohydrates, providing more assimilable energy compared to other by-products. Conclusions. These food by-products provide bioactive compounds, including vitamin C, carotenoids, phenolic compounds, as well as some minerals, and offer more available energy. The combination of these by-products constitutes a value-added food supplement for livestock feed.