The effects of ractopamine hydrochloride on lean carcass yields and pork quality characteristics1

Abstract

One hundred eighty barrows were evaluated to determine the effects of ractopamine hydrochloride (RAC) on lean carcass yields and pork quality. The pens were blocked by weight (six pens per block) with starting block weights of 69.0, 70.7, 73.8, 76.6, 78.4, and 84.3 kg. Pens within a block were assigned randomly to one of three RAC treatments so each treatment in a block was replicated twice. Treatments (as-fed basis) included control diet, 10 ppm of RAC added (R10), and 20 ppm of RAC added (R20) and ranged from 25 to 41 d depending on block. Pigs were slaughtered by blocks when block average live weights were 109 kg. Gain and feed efficiency were improved (P < 0.05) with increasing dietary concentrations of RAC, but feed intake did not differ (P > 0.05). Dressing percentage was higher (P < 0.05) for RAC-treated pigs. Subjective color, firmness, marbling scores, and Minolta L* reflection of the LM were not different (P > 0.05) among treatments. Carcass weights were heavier (P < 0.05) for pigs treated with RAC compared with control pigs and were higher for R20 than for R10. The RAC-fed pigs had greater (P < 0.05) yields (actual and percentage of HCW) of the following Institutional Meat Purchase Specification (IMPS) cuts than control pigs: trimmed, boneless ham (IMPS-402C and IMPS-402G), loin (IMPS-414), sirloin, and Boston butt (IMPS-406A). Pigs treated with RAC had a greater (P < 0.05) percentage of fat-free lean trimmings (IMPS-418) than did control pigs. Pigs treated with the R20 concentration had increased (P < 0.05) water-holding capacity compared with control pigs. Purge loss decreased linearly (P < 0.05) with increasing RAC compared with control for 14-d aged, non-enhanced loins. Warner-Bratzler shear (WBS) force values measured for nonenhanced chops were greater for RAC-treated pigs than for control pigs with a low dose response (P = 0.001). Enhanced chop (salt and phosphate injection) WBS values did not differ (P > 0.05) among dietary treatments. Trained sensory evaluation panel results for tenderness decreased in a low-dose plateau response fashion for nonenhanced chops (P = 0.004). Tenderness of enhanced chops decreased linearly (P = 0.04) with increasing RAC concentrations. No differences (P > 0.05) were found in juiciness or flavor of enhanced or nonenhanced chops. Feeding RAC to late-finishing swine resulted in faster growing, more efficient animals with increased boneless subprimal yields, and it had little effect on pork juiciness and flavor.

The effect of ractopamine supplementation at 5 ppm of swine finishing diets on growth performance, carcass composition and ultimate pork quality

“…In general, not enhanced chops were considered by the panel to be slightly to moderately tender, while enhanced chops were moderately to very tender. As expected, enhancement resulted in significantly more tender and juicy pork (Carr et al 2005a). However, unlike the present study, Carr et al (2005a) found that differences in tenderness and shear values due to RAC were less when moisture enhancement was applied.…”

Effects of ractopamine hydrochloride and immunological castration in pigs. Part 2: belly quality characteristics and fatty acid composition

“…Similar results to this study were obtained by Apple et al (2007), who found no significant difference in meat color and fat color in the bellies of pigs receiving 0 and 10 ppm of ractopamine in the diet. Leick et al (2010), analyzing bellies from pigs that received 0 and 5 ppm of ractopamine, did not observe any changes in the fat color parameters L *, a * and b * with the addition of ractopamine; similar results were also found by Carr et al (2005).…”

“…For the color of belly meat as influenced by gender (Table 1), it was observed that bellies of physically castrated and immunocastrated pigs showed lower values for the meat color parameter a* compared to the belly from gilts, a fact which, according to Carr et al (2005), indicates low levels of oxymyoglobin present in the bellies, possibly due to the dilution effect caused by hypertrophy of muscle fibers. The color of the belly fat from physically castrated animals that did not receive ractopamine in the diet showed the lowest L* value, therefore darker compared to gilts; however, the belly fat color of immunocastrated animals did not differ from barrows and gilts).…”

Alimentação de suínos em terminação com dietas contendo ractopamina e extratos cítricos: desempenho e características de carcaça

“…Estes resultados de desempenho para animais suplementados com ractopamina são condizentes com outro estudo (MIMBS et al, 2005). Porém, outro trabalho demonstrou que a ractopamina melhora o desempenho animal (CARR et al, 2005). Essas respostas divergentes são comuns na literatura e podem ser explicadas pela utilização de diferentes populações genéticas, nível de inclusão do agonista, período de fornecimento, nível de lisina e relação lisina/energia metabolizável (SMITH et al, 1995).…”