The research on alternative and sustainable feed ingredients is a challenge to reduce the feed-food competition between humans and monogastrics, in particular pigs. Former food products (FFPs) drop out from the industrial production of food such as pasta, bread, snacks and chips. They have a high nutritional and energetic value and represent an alternative and sustainable feed ingredient. The aim of this study was to apply label-free quantitative peptidomics to assess the impact of the inclusion of FFPs on serum peptidome.