Influence of outdoor rearing and indoor temperature on growth performance, carcass, adipose tissue and muscle traits in pigs, and on the technological and eating quality of dry-cured hams

Abstract

The effects of restricted outdoor rearing during winter (W) or summer (S), and the influence of indoor ambient temperature [17 °C (I17) vs. 24 °C (I24), the latter being considered as control] on pig growth performance, carcass, muscular and adipose tissue traits, and technological and eating quality of dry-cured hams were evaluated. I17 pigs exhibited higher, whereas W had similar and S lower growth rates than the controls ( P<0.001). Carcass traits were not different between groups, except in lower back fat weights of S and W pigs ( P<0.01). Decrease in environmental temperature affected the fatty acid composition of the back fat leading to higher MUFA and lower SFA and PUFA contents ( P<0.001) in I17 and W pigs, whereas S pigs exhibited higher PUFA levels ( P<0.001) and fat firmness ( P<0.01) than the controls. Rearing system did not significantly influence the intramuscular fat content of Semimembranosus ( P=0.08), and had no effect on ultimate pH. In the Longissimus lumborum, percentage and relative area of αR fibers increased in W pigs ( P<0.05), but citrate synthase activity did not differ between groups. I17 and W hams exhibited higher processing yields of dry-cured hams than controls ( P<0.05). Sensory analyses showed that pig rearing conditions influenced the product appearance, the I17 and W hams exhibiting lower homogeneity ( P<0.01) and intensity ( P<0.05) of colour, and higher marbling scores ( P<0.01) than I24 hams, but had no influence on texture or flavour.