Agricultural by-products such as cereal straws, which are available in large quantities, represent an important source of feed for ruminants. Known for their high fiber content, these feeds can limit the digestive utilization of feed rations. With the progress of biotechnology, and following the success of incorporating enzyme additives into monogastric feed rations, the possibility of using these enzyme products in ruminants to improve their zootechnical performance has attracted the attention of researchers. The use of exogenous fibrolytic enzymes can improve the digestive utilization of these fibers, enabling more efficient use of agricultural co-products as a feed source for ruminants. This can lead to reduced costs for feed producers, as well as a reduction in agricultural waste and a more sustainable use of resources. In short, adding value to agricultural co-products by supplementing them with fibrolytic enzymes can contribute to more sustainable agriculture and more efficient animal nutrition.