High vs. low human edible input diets: Effects on meat quality and sustainability in dairy beef

Twenty-four Belgian Blue × Holstein heifers (205 kg ± 34) were equally subdivided into two dietary treatments for 8 months: a conventional cereals-based diet (CTRL), and a low human edible input diet (EXP) composed of hay and a concentrate including agri-food by-products (hazelnut peel, spelt bran, corn germ, and wheat middlings) and faba bean var. minor. The effects on animal performance, meat quality, economic and sustainability indicators were evaluated. Both diets provided similar energy and crude protein, but the EXP diet was lower in starch and greater in fiber and lipids than the CTRL diet. The EXP diet reduce human-edible feed intake and input per kg of carcass gain without detriments of animal performance and carcass traits. Similarly, the EXP diet reduced feeding costs and improved the material circularity index. EXP meat showed higher proportions of trans-18:1 fatty acids and PUFA n-3 as well as lower 18:1 t10/t11 and PUFA n-6/n-3 ratios, suggesting a modulation of biohydrogenation, reliably driven by the greater intake of fiber and phenols. Moreover, meat from the EXP group exhibited greater antioxidant capacity than the CTRL meat. This study indicates that the inclusion of agri-food by-products and forages in place of conventional ingredients, such as cereals and soybean meal, in the diet for dairy-beef allows to reduce feeding cost, feed-to-food competition while maintaining animal performance and partially improving meat quality. Overall, the results support the use of alternative feed resources as reliable strategy to enhance the quality and the sustainability of beef meat from dairy systems.