Ractopamine In Finishing Pig Performance, Carcass Quality And Metabolism Of Research

At approximately 65 kg live weight, crossbred barrows and guts (n=341) were administered 0, 4, 10, 16, 22, 40 ppm ractopamine桰ICl (RAC) and 4 ppm clenbuterol until about 100kg final live weight under the same nutrition condition (3.2OMcalDE/kg, 15%CP) to determine growth performance, carcass quality and some biochemistry parameters in serum and muscle. The results showed: (1) RAC improved growth performance and carcass characteristics. Pigs fed RAC had increased average daily gain (ADG) 12.54?1.78% and improved (p<0.Ol) efficiency of feed utilization 12. 36~?9. 78% compared with control group. Carcass lean ratio increased 4. 13?~-10. 03% and body fat decreased 10. 41---17. 93% in RAC treated pigs. With the dosage of RAC increased, growth performance varied in index curve line manner, the effects of per mg/kg on growth performance ware dreased. Meanwhile, RAC had not adverse effects on meat quality. (2) RAC increased activity of lipase in serum to accelerate fattic acid decomposition, meanwhile it decreased SUN (serum urea nitrogen) and increased skeletal muscle mRNA to enhance protein deposition and improve muscle growth. (3) Compared with controls, Cleributerol had no effect on ADG, reduced average daily feed intake (ADFI) 11.68% and decreased (p<0. 05) F/G 9.6%, moreover Clenbuterol maybe had some adverse 31 effects on meat quality. So the differences of RAC and Clenbuterol were in growth characteristics and meat quality. (4) The dosage of RAC is 16.5 ppm in 65挆lOOkg pigs according to growth performance. It is concluded that RAC increases protein synthesis at the expense of fat, thus improves growth performance, carcass quality and economic efficiency in finishing pigs.