The objective of this study was to evaluate the effects of ractopamine and enzyme phytase on the performance and carcass characteristics of finishing pigs. Three hundred and fifty-four commercial type barrows were used from a single source with 94.1 ± 5.7 kg initial body weight in a randomized complete block design, with six treatments and five replications with 11 or 12 animals per experimental unit evaluated. The following feeds were: control diet based on tables of nutritional requirements; (A) diet control with nutritional adjustment for ractopamine; (FIT) diet A with phytase; (RAC) diet A with ractopamine; (RAC+FIT) diet A with ractopamine and phytase; and (RAC+FITe) diet A with ractopamine and phytase with part of the demands for calcium and available phosphorus met by the enzyme. The experiment lasted 21 days and at the end the animals were slaughtered for carcass evaluation. The results were compared by orthogonal contrasts. Feed intake was not influenced by the diets. The diet with adjusted protein and amino acid levels and without ractopamine did not improve performance compared with the control diet. There was effect of ractopamine on daily gain and feed conversion at the end of the 21-day period, and also on the pre-slaughter weight, hot carcass weight, carcass dressing, total fat-free lean and payment index. Phytase inclusion in diets containing ractopamin for calcium and phosphorus available levels above the finishing pigs´ requirements did not effect the weight gain, feed conversion and carcass traits. Ractopamine improved performance and carcass traits. The use of phytase in diets containing ractopamine in partial substitution of inorganic mineral sources made possibly to maintain performance and carcass traits.
addictives; β-adrenergic; carcass; enzyme; phytate
