Influence of Sex on Meat and Fat Quality from Heavy Alentejano Pigs Finished Outdoors on Commercial and High Fiber Diets

SIMPLE SUMMARY: A growing consumer focus on animal welfare, high-quality meat, and product traceability has led to an increased demand for meat from ancient local breeds reared outdoors. Traditionally, these systems involve the slaughter of heavy and fat pigs, which are castrated to mitigate boar taint, an off odor and flavor rejected by consumers when detected. A more welfare-friendly approach involves rearing and slaughtering young intact pigs, leaner and with limited boar taint content in meat and fat. This goal can potentially be achieved through diet manipulation, a strategy that has proven effective in lean industrial breeds but remains unexplored in fatty local breeds like the Portuguese Alentejano pig. In this trial, we studied the influence of gender on meat and fat quality in Alentejano pigs reared outdoors that were fed both commercial and experimental diets during fattening. The results revealed that outdoor finished intact Alentejano pigs produced meat and fat with higher leanness and lower levels of saturation than castrated ones. The LL muscle of intact pigs presented a lower antioxidant activity compared to castrated ones, but this did not affect the lipid oxidative stability of cooked meat between the experimental groups. The experimental diet, with no negative effects on growth, did not influence boar taint compounds, which remained below the threshold values for consumer detection on all Alentejano pigs. ABSTRACT: This work aimed to examine the effects of sex on meat and fat quality traits from thirty Portuguese Alentejano (AL) pigs reared in outdoor conditions. These pigs were divided into three groups and fed ad libitum. From ~40 to 130 kg LW, castrated (C group) and intact animals (I and IExp) consumed commercial diets. Until slaughter (~160 kg), C and I pigs remained on commercial diets, and IExp changed to a more sustainable experimental diet with locally produced pulses and byproducts. Samples were collected from the Longissimus lumborum (LL), Psoas major (PM), and dorsal subcutaneous fat (DSF). At ~160 kg, the PM muscle of intact pigs presented lower intramuscular fat content than that of C pigs, while total collagen was higher. Additionally, PM myoglobin was lower and lightness (L*) was higher in intact pigs. Regarding DSF, moisture and total protein contents were higher and total lipids were lower in intact than in castrated pigs, while color parameters were not significantly different. Finally, antioxidant capacity measured in the LL muscle showed an overall lower value in intact pigs. However, lipid oxidation values were not significantly different between the experimental groups and only increased with storage time. Outdoor-reared intact AL pigs produced leaner and less saturated pork and fat compared to castrated ones. Despite the lower antioxidant activity observed in the LL muscles of intact pigs, the lipid oxidative stability of cooked meat was not different among the experimental groups.