Innovative strategies in feeding ruminants to improve product quality and reduce environmental impact of farming

The aim of this PhD thesis was to find "green" solutions by valorizing agro industrial by- products or alternative feeds, particularly those derived from olive oil production (olive cake), combined with linseeds, in the feeding of young podolian bulls, evaluating their effects on growth performance, oxidative stability (shelf life), and meat quality. Due to their significant properties, olive cake and linseeds were used in the following experimental trial conducted on thirty-six young podolian bulls, divided into 4 groups: Control Group (CTRL), Olive cake Group (OC), Linseeds Group (EL), and olive cake + linseeds Group (OCEL), to evaluate animal performance and meat quality. Podolian bulls, a rustic breed typical of Italy's mountainous regions, are traditionally fed a diet based primarily on mountain forage, such as grasses and hay, which reflects their adaptive nature to poor and challenging environments. However, the introduction of agricultural by-products such as olive cake and linseeds into the diet of these animals represents an innovative practice that, in addition to improving nutrition and the quality of animal products, also contributes to the sustainability of agricultural practices. Olive cake is the solid residue obtained from the crushing of olives during the olive oil extraction process and contains polyphenols, antioxidant compounds that may have positive effects on the health of cattle. Polyphenols are known for their anti inflammatory and immunomodulatory properties, which could enhance the animals' immune response, increasing their resistance to diseases and improving their overall health. However, the high oil content in olive cake can pose a challenge. If not properly processed, olive cake can be difficult for cattle to digest, potentially leading to digestive disorders. Therefore, to optimize its use, olive cake must be treated, either by drying or oil extraction, to reduce its lipid content and improve digestibility. Additionally, the amount of olive cake fed to the animals must be carefully monitored to prevent excessive caloric intake. Linseeds are another valuable source of nutrition for podolian bulls. These seeds are particularly rich in polyunsaturated fatty acids, specifically alpha-linolenic acid (ALA), a type of Omega-3 fatty acid that can improve the quality of fats in meat, providing animal products with a higher amount of healthy fats. Therefore, the use of olive cake and linseeds represents an opportunity to supplement the diets of podolian bulls with healthy, nutrient-dense, and sustainable feeds. With careful and balanced management, these resources can significantly contribute to improving the quality of animal products and promoting more ecological and efficient agricultural practices.