Long-Term Physical Activity Modulates Lipid Metabolism and Gene Expression in Muscle and Fat Tissues of Alentejano Pigs

Abstract

This study examined the effect of long-term physical activity during the finishing period on meat and fat quality, and metabolic gene expression in obese Alentejano (AL) pigs. From 87.3 to 161.6 kg BW and for 130 days, eighteen pigs were assigned to either individual pens without an exercise area (NE, n = 9) or an outdoor park with an exercise area (WE, n = 9). Both groups received identical commercial diets at 85% ad libitum intake. Loin (Longissimus lumborum—LL), tenderloin (Psoas major—PM), and dorsal subcutaneous fat samples were obtained at slaughter, and analyzed for fatty acid composition and gene expression. Physical activity modulated the fatty acid profile and key metabolic genes in muscle and fat tissues. WE pigs showed higher palmitoleic (p = 0.031) and linolenic (p = 0.022) acids in LL, while Fatty acid synthase and Leptin in LL were downregulated (p = 0.071 and p = 0.018, respectively); Fatty acid binding protein 4 was downregulated (p = 0.003) and Stearoyl-CoA desaturase upregulated (p = 0.020) in the PM of WE pigs, indicating changes in lipid metabolism. Also, Myosin heavy chain 7 was upregulated (p = 0.016) in LL, suggesting oxidative muscle remodeling. These findings suggest that moderate, long-term physical activity during finishing induces modest but favorable metabolic adaptations in muscle and fat tissues without compromising meat quality in AL pigs, supporting its use in traditional rearing systems aimed at balancing animal welfare and product quality in local breeds.