Influence of Raising System and Dietary Olive Cake Supplementation on the Physicochemical Composition of Bísaro Pork Loins: A Comparative Analysis

This study aimed to: (1) evaluate and compare the effects of two rearing sys-tems—intensive and extensive —on the quality characteristics of loins from Bísaro pigs, a traditional Portuguese breed, and (2) assess the influence of dietary supple-mentation with olive cake, a by-product of olive oil production, on the physicochemi-cal composition of pork loins. Muscle samples from the Longissimus thoracis et lumborum joint were collected from Bísaro pig carcasses raised on farms in the Trás-os-Montes region of northern Portugal. The slaughter and carcass cutting were standardized and performed at the Bragança municipal slaughterhouse, to ensure consistency in sample processing and preparation for laboratory analyses. Compre-hensive physicochemical evaluation showed that ash content was the only parameter exhibiting a statistically significant difference (p = 0.007) between rearing systems, suggesting that production conditions may affect the mineral content of the meat. No significant differences (p > 0.05) were observed between rearing systems for moisture, protein or total fat content. Similarly, dietary inclusion of olive cake in the animals’ di-et, irrespective of the rearing system, did not significantly affect any of these physico-chemical traits. The fatty acid profile - including saturated (SFA), monounsaturated (MUFA), and polyunsaturated fatty acids (PUFA) – also showed no statistically signif-icant differences (P > 0.05) in relation to either rearing system or dietary treatment. Overall, the evidence indicates that olive cake is a sustainable and practical option for Bísaro pork production, without compromising meat quality.