Horticultural wastes as sustainable alternative feed resources for livestock: processing technologies, nutritional value, and animal performance.

The rapid expansion of the horticulture sector has resulted in the generation of substantial quantities of fruit and vegetable waste, posing environmental and waste disposal challenges. The improper disposal of these residues may contribute to greenhouse gas emissions, environmental pollution, and loss of potentially valuable nutrients. Concurrently, the rising cost and increasing demand for conventional feed resources have intensified the exploration of sustainable and economical alternatives for livestock and poultry feeding systems. This review examines the potential of horticultural waste and by-products as alternative feed resources in livestock and poultry production systems, with emphasis on their nutritional characteristics, processing technologies, dietary inclusion levels, and effects on animal performance and health. Fruit and vegetable by-products such as avocado residues, mango residues, tomato pomace, watermelon rinds, cabbage, carrots, cauliflower, cucumbers, potato residues, mushroom waste and pumpkin seed meal have been evaluated as feed ingredients at different inclusion levels and through different processing approaches. The reported effects vary considerably depending on the animal species, by-product type and composition, processing technique, dietary formulation and inclusion level. While several studies have reported improvements or no adverse effects on growth performance, feed efficiency, milk production, nutrient digestibility, rumen fermentation and gut health at appropriate inclusion levels, other studies have reported reduced drymatter intake, average daily gain, digestibility, body weight or carcass characteristics at higher or unsuitable inclusion levels. Processing methods such as drying, ensiling, fermentation and pelleting can improve storage characteristics and may modify nutrient availability, but their effectiveness is also material and process specific. Therefore, the use of horticultural by-products requires careful consideration of species-specific responses, nutritional composition, processing conditions, inclusion limits and feed safety risks. Overall, horticultural waste represents a promising complementary feed resource with potential environmental and economic benefits, although its practical utilization should be guided by evidence based, species and diet specific inclusion strategies.