378 Growth responses and antioxidant status of finishing pigs fed low-energy, low-phosphorus, low-calcium and low-trace mineral diets added with exogenous enzymes

Abstract The objective of the study was to evaluate the productivity parameters and the antioxidant responses in the meat in finishing pigs fed diets reduced in metabolizable energy (ME), Ca, P and trace minerals added with the exogenous enzymes phytase, xylanase and pectinase. Pigs (n = 48) were randomly distributed into 4 treatments: 1) A Sorghum/soybean meal diet formulated to meet all the nutrient requirements, with a mineral premix based on sulfates (Control); 2) Same as 1) but reduced in ME, Ca and P, added with phytase, xylanase and pectinase, the same mineral premix; 3) Same as 2) but with reduction of 33.3 % of the mineral premix; or 4) Same as 2) but reduction of 66.6% of the mineral premix. Pigs were housed in an open building, with natural ventilation in individual pens with solid concrete floor. The feeding program consisted of 2 phases, the first for 28 d and the second for 25 d. All diets were offered in meal form. Pigs were weighed individually at the beginning and end of the experiment, to estimate daily body weight gain. The daily feed consumption was registered. Feed efficiency was estimated as body weight gain based on feed consumption. At the end of the study, the depth of fat and loin muscle were measured at the 10th and the last rib. Pigs were transported to a slaughter facility. Samples of the loin and psoas major muscle were taken to determine the antioxidant status. Data were analyzed for a completely randomized design using the GLM, MEANS, MIXED, and UNIVARIATE procedures of SAS. No statistical differences were found on the productive responses, the depth of fat and loin muscle, fat-free lean tissue and carcass yield. The luminosity in the loin muscle increased (58.89 vs 59.85; P < 0.042), the antioxidant power of ferric radicals tended to be less (3.25 vs 2.90 mg Eq. Trolox/g; P < 0.052) and the thiobarbituric acid reactive substances tended to be greater (0.15 vs 0.21 mg MDA/kg; P < 0.063) in the loin muscle of pigs fed diet 4) reduced by 66.6% in mineral premix compared with that of pigs fed the control diet (1). The thiobarbituric acid reactive substances were greater (0.18 vs 0.25 mg MDA/kg; P < 0.023) and the drip loss tended to be greater (1.1 vs 1.4%; P < 0.056) in the psoas major muscle of pigs fed diet 4) reduced by 66.6% in mineral premix compared with that of pigs fed the control diet 1). Finishing pigs fed diets reduced in ME, Ca, P and trace minerals by 66.6% and added with exogenous enzymes did not show detrimental effects on productivity, but it reduced the antioxidant capacity of the loin and psoas major muscles.