The cherry and the leaves contain caffeine, an alkaloid that is a psychoactive stimulant drug, as well as tannins, polyphenols and high amounts of potassium (Bressani, 1982). The presence of these factors contributes to the antinutritional and antiphysiological activity of coffee by-products, as observed in both monogastrics and ruminants, such as low palatability, feed intake, protein digestibility and nitrogen retention. Physical (percolation), chemical (alcohol extraction) or microbiological (fermentation) methods may help reduce caffeine content and enhance animal performances (Brand et al., 2000; Peñaloza et al., 1985; Molina et al., 1974).
Fungi may develop on coffee by-products, which produce toxins harmful to the animal (Bressani, 1991).