|Shields, Thomas - MISSISSIPPI STATE UNIV|
|Smith, Terry - MISSISSIPPI STATE UNIV|
|Althen, Tom - MISSISSIPPI STATE UNIV|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 1, 2004
Publication Date: April 17, 2004
Citation: Shields, T.H., Smith, T.R., Althen, T., Smith, D.J. The effect of ractopamine stereoisomers on lipolysis of bovine subcutaneous and intramuscular adipose tissue. [abstract]. Federation of American Societies for Experimental Biology Annual Meeting, April 17-24, 2004, Washington, DC. Abstract #8086. Technical Abstract: Beta-adrenergic agonists are leanness-enhancing agents, which direct dietary energy from adipose tissue into muscle. Use of beta-agonists in livestock species generally results in leaner carcasses relative to untreated animals. Recent FDA approval of ractopamine HCl for use in beef cattle should provide a tool to reduce subcutaneous fat in beef cattle. Few data are available to evaluate the effect of ractopamine HCl on intramuscular adipose tissue and its effect on meat quality. The objectives of this study were to evaluate the effect of ractopamine on subcutaneous and intramuscular adipose tissue depots from cattle. Isoproterenol (positive control) increased subcutaneous adipose tissue lipolysis (4174 vs. 9849 nMol/g/2h, nMol NEFA mobilized per gram of tissue in a two hour incubation; P <0.05) while not affecting intramuscular lipolysis (3584 vs. 4112 nMol/g/2h, P >0.05). The RR stereoisomer of ractopamine increased lipolysis in subcutaneous (5316 vs. 8707 nMol/g/2h; P <0.05) but not intramuscular adipose tissue (3651 vs. 4044 nMol/g/2h, P >0.05). The SS stereoisomer of ractopamine did not affect lipolysis (P >0.05) at either depot. These data indicate that use of a beta-agonist repartitioning agent in beef cattle could improve carcass yields without a negative impact on carcass quality.