ABSTRACT
Dietary ractopamine improves pork leanness, whereas its effect on sarcoplasmic proteome has not been characterized. Therefore, the influence of ractopamine on sarcoplasmic proteome of post-mortem pork Longissimus thoracis muscle was examined. Longissimus thoracis samples were collected from carcasses (24 h post-mortem) of purebred Berkshire barrows (n=9) managed in mixed-sex pens and fed finishing diets containing ractopamine (RAC; 7.4 mg/kg for 14 days followed by 10.0 mg/kg for 14 days) or without ractopamine for 28 days (CON). Sarcoplasmic proteome was analyzed using two-dimensional electrophoresis and mass spectrometry. Nine protein spots were differentially abundant between RAC and CON groups. Glyceraldehyde-3-phosphate dehydrogenase and phosphoglucomutase-1 were over-abundant in CON, whereas serum albumin, carbonic anhydrase 3, L-lactate dehydrogenase A chain, fructose-bisphosphate aldolase A, and myosin light chain 1/3 were over-abundant in RAC. These results suggest that ractopamine influences the abundance of enzymes involved in glycolytic metabolism, and the differential abundance of glycolytic enzymes could potentially influence the conversion of muscle to meat.
Subject(s)
Adrenergic beta-Agonists/pharmacology , Glycolysis/drug effects , Muscle Proteins/metabolism , Paraspinal Muscles/metabolism , Phenethylamines/pharmacology , Proteome/metabolism , Red Meat/analysis , Animals , Body Weight/drug effects , Breeding , Diet , Growth Substances/pharmacology , Humans , Male , Myosin Light Chains/metabolism , Paraspinal Muscles/enzymology , Postmortem Changes , SwineABSTRACT
Our objective was to determine the effect of dietary ractopamine and immunocastration on the quality attributes of pork frankfurters. Gilts (GT), surgically castrated male pigs (SR) and immunologically castrated male pigs (IM) were fed diets containing 7.5 ppm ractopamine (RAC) or no ractopamine (CON) for 21 days prior to harvest. Deboned hams were manufactured into frankfurters, and physico-chemical parameters, instrumental color and texture, and sensory attributes were evaluated. Ractopamine increased (P<0.05) L* (lightness) in SR, whereas it decreased (P<0.05) lightness in IM and GT. While ractopamine increased (P<0.05) a* (redness) in GT, a reverse (P<0.05) trend was observed in SR. With respect to instrumental texture, ractopamine increased (P<0.05) hardness, resistance, and springiness in IM, cohesiveness and springiness in GT, and shear force in SR. These results indicated that ractopamine exerted sex-specific effects on frankfurter quality. Swine industry may adopt sex-specific dietary strategies to optimize the quality of further processed meat products.
