84 Effect of Dietary Ractopamine Supplementation on Growth Performance, Meat Quality, Carcass Characteristics and Fecal Score in Finishing Pigs.

Abstract

Ractopamine has been the focus of widespread research over the last 20 years and has been shown to give substantial improvements in average daily gain, feed conversion efficiency, dressing percent and carcass lean content. It has been approved for use in finishing swine weighing from 68 to 109 kg in the United States since December of 1999 and was recently given approval by the Food Drug Administration (FDA), in May of 2006 to be fed at levels ranging from 5 to 10 ppm to finishing swine for the last 20.4 to 40.8 kg of gain prior to harvest. This study was conducted to determine the effect of dietary Ractopamine supplementation on growth performance, meat quality, carcass characteristics and fecal score in finishing pigs. A total of 96 finishing pigs [(Yorkshire× Landrace) × Duroc] with an average BW of 73.1 ± 2.5 kg were used in a 6-wk study. Pigs were randomly allotted to 1 of 2 dietary treatments: 1) CON, basal diet, 2) CON + 1% Ractopamine with 12 replicate pens per treatment and 2 barrows and 2 gilts per pen. The diets were formulated to meet or exceed NRC (1998) nutrient requirements. All experimental data were analyzed using the GLM Procedure as a randomized complete block design (SAS Inst. Inc., Cary, NC). The pen was used as the experimental unit. Differences among treatment means were determined using the Tukey’s range test. Individual pig BW and pen feed consumption were recorded at the end of wk 6 to calculate ADG, ADFI, and G: F. During the overall study, pigs fed the Ractopamine supplementation diets had a higher (56.7% and 54.6%) lean meat percentage at the final period of the experiment (P < 0.05) than pigs fed the CON diet. In regards to sensory evaluation color (2.02 and 1.91) and firmness (1.98 and 1.89) of meat were higher in control diet than Ractopamine supplemented diet. Drip loss was higher (5.93% and 11.24%) in Ractopamaine fed diet compared to control diet at day 1. Additionally longissimus muscle (45.22 and 48.91) was improved in Ractopamine treated diet than in control diet. There were no significant differences on growth performance, fecal score, and carcass weight and grade. In conclusion, Ractopamine supplementation improved leanness and meat quality of finishing pigs.