From waste to feed: enhancing sustainability in ruminant nutrition through cashew apple utilization

Growing global demand for livestock products has intensified the need for sustainable feed resources in ruminant nutrition, particularly in developing regions. With feed costs comprising up to 75% of production expenses, exploring alternative feed sources can offer both economic and environmental benefits. This study explored the potential of cashew apple (CA) as a novel and sustainable by-product for ruminants by reviewing relevant articles from databases such as Scopus, Web of Science, PubMed, and Google Scholar. CA has an average proximate composition (dry matter basis) of 130 g/kg crude protein, 71.7 g/kg crude fibre, 61.2 g/kg ether extract, 49.3 g/kg ash, 640 g/kg nitrogen free extract, and 2973 kcal/kg metabolizable energy, making it a valuable addition to ruminant diets. It can reduce reliance on traditional and high-cost feed sources and mitigate environmental pollution by reducing waste and contributing to circular agricultural practices. However, limitations such as high moisture content in fresh cashew fruit, seasonal availability, and rapid spoilage necessitate effective processing methods. There is a knowledge gap on the use of CA in ruminant diets, and there is a need to assess its impact on ruminal pH, short-chain fatty acids production, ammonia production, other rumen fermentation profiles, and animal performance. Based on the quantitative data of this study about the proximate composition of CA and some animal studies, it could be a viable and eco-friendly supplement to the ruminant diets. Addressing its storage and preservation challenges can unlock its potential in diversified, eco-friendly ruminant systems.