Simple SummaryNew sources of feeds are of high priority in modern animal production systems. In the present study, a novel silage created from Greek olive, winery, and feta cheese waste by-products, was evaluated as a feed ingredient at different inclusion rates (0%, 5% or 10%) for weaned pigs. The effects of this supplementation on the performance, health and meat quality parameters of the pigs were evaluated. The results showed no negative effects on the performance of the pigs. Some intestinal microbial populations were affected. The oxidative stability and the fatty acid profile of the meat was positively affected.AbstractNew sustainable sources of feeds, which can enhance the health and welfare of farm animals, lower feeding costs, and lead to safer products, are of high priority in modern animal production systems. In the present study, a novel silage created from Greek olive, winery, and feta cheese waste by-products, was evaluated as a feed ingredient at different inclusion rates (0%, 5% or 10%) in 34-day-old weaned pigs. The potential beneficial effects on performance, health and intestinal digesta microflora balance of the pigs were evaluated. Additionally, chemical, microbiological and quality analysis of the meat was carried out. Results showed no detrimental effects (p> 0.05) on the pigs’ performance and no significant changes (p> 0.05) in meat pH, color and chemical analysis. Ileum and cecum microflora populations (total anaerobes, Lactobacillaceae) were positively affected (p≤ 0.05) by the dietary usage of the silage. The microbial populations (Clostridiumspp.) of belly meat cuts were positively modified (p≤ 0.01). The concentration of total phenols in the meat cuts were increased (p≤ 0.05) and their resistance to oxidation was improved (p≤ 0.05). In addition, the fatty acid profile of the meat lipids (polyunsaturated and n-3 fatty acids) was positively modified (p≤ 0.001).