A Comprehensive Review of Cashew By-Products in Animal Feed: Nutritional Potential, Processing, Safety, Microbiome Impacts, and Sustainability

Cashew by-products, including cashew nut shell (CNS), cashew apple, and cashew apple pomace, are underutilized resources that contribute to environmental pollution in cashew-producing regions. This review synthesizes studies (2015–2024) to evaluate their potential as sustainable animal feed resources for ruminants (cattle, goats, sheep), swine, and poultry (broilers). Processed CNS provides high fiber and energy, suitable for ruminants inclusion, while cashew apple and pomace offer carbohydrates and vitamin C for swine and poultry. Processing methods like roasting, ensiling, and fermentation reduce anti-nutritional factors, such as cashew nut shell liquid (CNSL) and tannins, improving safety and digestibility. Feeding trials show enhanced animal performance, gut microbiome health (increased Lactobacillus populations), and reduced methane emissions. Economically, feed costs decrease, and environmentally, carbon footprints are lowered. Challenges include CNSL toxicity, processing costs, and regulatory gaps. Long-term trials and cost-effective detoxification are needed for scalability in regions like India, Nigeria, Brazil, and Vietnam.