The greater efficiency of ractopamine is associated with nutritional diet adjustments due to the gradual increased need for nutrients to support the increased deposition of muscle protein. Some research shows that fats improve the use of energy and digestibility of other components of the diet for as yet unknown interactions. The survey was conducted by verifying the qualitative assessment of the flesh of pigs fed diets containing different levels of net energy and supplemented with ractopamine (10ppm). A total of 100 pigs, high genetic potential, with average initial weight of 70kg and average final weight of 100kg were used in the study. The experimental design is a randomized block with a 5x2 (factorial arrangement with five levels of net energy: 2.300; 2.425; 2.550; 2.675; 2.800kcal/kg diet and two levels of dietary ractopamine: 0 e 10 ppm). Samples were taken up to the 12th rib, being subjected to slow freezing and subsequent cooling. Thawing was performed at refrigerator temperature. Not observed interaction between the net energy levels of ractopamine supplementation and dietary variables for shear force, water holding capacity, oxidation, pH and colour. Net energy and levels of ractopamine not change the shear force, holding capacity of water, oxidation, staining and pH of pig meat.
β-adrenergic; nutrition; oxidation; shear force; staining