Forage Potential of Faba Bean By-Products: A Comprehensive Analysis of Proximate Nutrients, Mineral Content, Bioactive Components, and Antioxidant Activities

The global feed gap, driven by seasonal shortages and climate change, highlights the need for novel forage resources. Vicia faba (Faba bean) produces substantial above-ground biomass as residue after fresh pod harvest, which remains underutilized. This study comprehensively evaluated the forage potential of faba bean leaves and stems across three growth stages: flowering (S1), pod development (S2), and ripening (S3). Dry matter content peaked at S2 in both tissues, while crude protein and fat content were highest at S1; carbohydrate levels increased progressively with maturation. Significant mineral concentrations, particularly K, Ca, and Mg, were detected, with leaves at S2 showing higher ash (i.e., mineral) content. Bioactive compounds (L-dopa, flavonols, total phenolics, and flavonoids) and antioxidant activities were most abundant at S1, with strong positive correlations between phenolics and antioxidant activities. Overall, faba bean residues offer proximate nutritional profiles comparable to traditional forages such as alfalfa and clover, while providing superior antioxidant potential. Their incorporation into animal feed systems before S3 could help mitigate seasonal forage shortages and enhance the nutritional quality of livestock diets.