Effect of breed and dietary protein and lysine levels on pork quality traits

摘要

Pork is the most consumed meat all over the world. Intramuscular fat (IMF) has been shown to be positively related to quality of meat. Hence, the production of pork with higher amounts of IMF, without an increase in subcutaneous fat, would be highly desirable for the pig industry. This study was designed in order to investigate the effect of breed (Alentejano purebred vs. Large White x Landrace x Retrain crossbred) and protein level (normal vs. reduced) with or without correction for lysine on meat quality, IMF, instrumental tenderness and optical measurements in pork longissimus dorsi muscle. Sixty intact male pigs with an initial and final average live weight of 60 ± 2 and 93 ± 2 kg, respectively, were used in this experiment. The IMF was extracted according to the Soxhlet method with previous acid hydrolysis. Loin pH and temperature were measured at 45 min and 24 h postmortem and colour lightness, redness and yellowness (L,~* a~* and b~* values) at 24 h postmortem. Results showed a significant interaction (P<0.05) between breed and diet for IMF content (2.2-5.8 g/100 g muscle). Breed had a significant effect on pH and shear force (P<0.01), initial temperature (P<0.05) as well as on L~* (P<0.001) and a~* (P<0.01) values, while dietary protein and lysine levels had no influence. The relationship between IMF, shear force and meat colour are further discussed.