An Integrated Approach to Evaluate the Influence of Dietary Olea europaea L. Polyphenols on Physiological Stress, Intestinal Morphofunctional Traits, and Meat Quality in Neroametà Pigs: A Preliminary Study

The use of olive by-products in livestock farming is a valuable resource, given their high levels of bioactive compounds with antioxidant and health-promoting properties. This preliminary study adopted an integrated approach to evaluate the influence of dietary Olea europaea L. polyphenols on animal welfare, physiological stress response, intestinal morphofunctional traits, and meat quality in Neroametà finishing pigs, a novel Casertana × Large White genetic line (Neroametà). Thirty pigs reared under extensive farming conditions were randomly allocated to two groups (n = 15): a control group fed a standard diet (C) and a treatment group (OL) supplemented with 300 mg/head/day of olive polyphenolic extract for 90 days. The study focused on the systemic correlation between host health and product quality. Meat composition, rheological properties, meat antioxidant activity, stress parameters, and fatty acid profiles of the longissimus lumborum and psoas major muscles were analyzed. Results showed that the OL diet significantly modulated the HPA axis, as evidenced by a marked reduction in plasma ACTH and cortisol levels, alongside improved antioxidant status. These physiological changes were positively associated with a trophic effect on the intestinal mucosa, characterized by increased villus height and a more favorable villus/crypt ratio. Regarding meat quality, the OL group exhibited superior oxidative stability, optimized pH decline, and an improved intramuscular fatty acid profile (increased MUFA and n-3 PUFA, reduced SFA). Despite the pilot scale of 30 animals, these findings provide a solid foundation for characterizing the Neroametà breed. In conclusion, Olea europaea L. polyphenols act as a multi-level modulator, enhancing physiological resilience and meat quality, offering a sustainable strategy for high-quality pork production in line with circular economy and One Health principles.