Physical Activity Effects on Blood Parameters, Growth, Carcass, and Meat and Fat Composition of Portuguese Alentejano Pigs

SIMPLE SUMMARY: Outdoor farming systems are associated with health, animal welfare, sustainability, and food security, making them highly desirable for consumers. In this trial, it was possible to confirm that pig physical activity, a major factor in the traditional and extensive production systems of the Alentejano pig, influences animal welfare and the results of biochemical and zootechnical parameters. In this perspective, breeding pig breeds that perform spontaneous physical activity has greater advantages for producers, as pigs can reach the same slaughter weight in less time and with lower feed costs than animals reared in individual pens. Based on these results, the negative impacts that system intensification (with the consequent reduction in the vital space of each animal and the physical activity performed) may have on animal welfare, animal performance and on the quality of the meat obtained, should be considered. ABSTRACT: This study evaluated the effects of physical activity on blood, growth, carcass, and meat quality of finishing Alentejano (AL) pigs. Pigs, reared from ~87 to 160 kg in individual pens (no exercise area, NE group, n = 9) or in an outdoor park (with exercise area, WE group, n = 9), were fed commercial diets (85% ad libitum). WE pigs were in a park (~400 m(2)) with a feeding area separated from the drinking area with an automatic waterer, forcing pigs to walk at least 800 m daily. Blood samples were obtained during the trial (weeks 2, 11, and 18) and at slaughter. The left-side carcass was submitted to commercial cuts, and samples from loin, tenderloin, and dorsal subcutaneous fat (DSF) were analyzed. Plasma urea in WE pigs was higher in weeks 2 and 11, while cholesterol, LDL-cholesterol, cholesterol to HDL-cholesterol and LDL- to HDL-cholesterol ratios, and cortisol were lower in weeks 11 and 18. Final weight and average daily gain were higher and feed conversion ratio lower in WE pigs. DSF thickness and carcass weight were higher in WE pigs, leading to higher carcass yield. Finally, loin and tenderloin from WE pigs presented higher total protein content. These data show that allowing physical activity affects metabolism, growth, and carcass and meat quality of AL pigs.