Sustainable Valorization of Oil Palm Coproducts: Physicochemical Characterization and Potential Use in Insect Bioconversion

The oil palm production chain generates coproducts whose sustainable valorization remains a challenge. This study tested the hypothesis that partial replacement of the conventional substrate with oil palm coproducts could maintain the productive performance of Zophobas atratus larvae and generate value-added biomass. Mesocarp fiber (MF), palm oil mill effluent (POME), and palm kernel cake (PKC) were characterized in terms of physicochemical composition, carotenoids, and antioxidant capacity and examined as partial substitutes for wheat bran in six diets for Z. atratus. PKC demonstrated higher levels of protein (15.27%), carbohydrates (65.68%), neutral detergent fiber (68.35%), acid detergent fiber (37.70%), and saturated fatty acids (83.06%) and greater antioxidant capacity associated with phenolic compounds. MF showed the highest carotenoid content (138.27 mg/100 g), and POME had the highest lipid content (17.69%). Diet containing 50% PKC-supplemented wheat bran promoted higher feed conversion efficiency (78.99%), lower feed conversion ratio (0.90%), and higher larval protein content (39.14%) and maintained performance similar to that of the control. Larvae fed on 50% MF exhibited carotenoid bioaccumulation, with >190% increase compared with the control. Although the coproducts demonstrate potential as substrates, mortality restricts their technical feasibility. Their use depends on an adequate protein/energy balance and the digestibility of the fibrous fraction for strategic supplementation.