Interactive effect of ractopamine and dietary fat source on quality characteristics of fresh pork bellies1

Abstract

Crossbred pigs (n = 216) were used to test the interaction, if any, of ractopamine (RAC) and dietary fat source on the characteristics of fresh pork bellies. Pigs were blocked by BW (77.6 +/- 6.5 kg) and allotted randomly to pens (6 pigs/pen). After receiving a common diet devoid of RAC for 2 wk, pens within blocks were assigned randomly to 1 of 4 treatments arranged in a 2 x 2 factorial design, with 5% fat (beef tallow vs. soybean oil) and RAC (0 vs. 10 mg/kg). At the conclusion of the 35-d feeding period, pigs were slaughtered at a commercial pork packing plant (average BW of 108.8 +/- 0.6 kg), and fresh bellies were captured during carcass fabrication. Neither RAC (P = 0.362) nor fat source (P = 0.247) affected belly thickness. Subjective (bar-suspension) or objective (compression test) measures of belly firmness were not (P > or = 0.148) affected by the inclusion of RAC in the diet; however, bellies from pigs fed soybean oil (SBO) were softer than those from pigs fed beef tallow (BT), as indicated by perpendicular (P < or = 0.005) and parallel (P < 0.001) suspensions. Moreover, bellies from BT-fed pigs required more (P = 0.096) force to compress 50% of their thickness than bellies from SBO-fed pigs (52.29 vs. 43.51 kg). Color (L*, a*, and b* values) of the belly lean and fat was not (P > or = 0.131) affected by RAC, and lean color was similar (P > or = 0.262) between fat sources; however, belly fat from BT-fed pigs was lighter (P = 0.030) and redder (P = 0.013) in color than belly fat from SBO-fed pigs. Bellies of SBO-fed pigs had greater (P < 0.001) proportions of PUFA and lower (P < 0.001) proportions of SFA and MUFA than belly fat from pigs fed BT. Regardless of the RAC inclusion level, PUFA:SFA and iodine values were lower in belly fat from pigs fed BT than SBO; however, within SBO-fed pigs, PUFA:SFA and iodine values were further increased by feeding RAC (RAC x fat source, P < 0.001). As expected, dietary fat source altered the fatty acid composition of fresh pork bellies, which subsequently impacted fresh belly firmness. Interestingly, including RAC in swine finishing diets exacerbated the effect of feeding SBO on pork fat polyunsaturation.

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).…”

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

“…Essa inibição da expressão gênica da leptina pelo uso da ractopamina pode ter ocorrido com os animais utilizados neste trabalho, justificando, assim, a ausência de redução no consumo alimentar. Entretanto, os diversos fatores abordados anteriormente para explicar o consumo alimentar estão em desacordo com outras pesquisas, pois o uso da ractopamina na dieta reduz o consumo de alimento (APPLE et al, 2007), mas não influencia o ganho de peso (MIMBS et al, 2005). Esta redução no consumo estaria relacionada à maior densidade energética das dietas, as quais não alteram o ganho médio diário, mas deprimem o consumo de alimentos (WEBER et al, 2006).…”

Effects of feeding high protein or conventional canola meal on dry cured and conventionally cured bacon

“…There was a tendency for a linear increase (P = 0.10) in total MUFA as inclusion of CM-CV increased. Decreased pork fat firmness has been associated with high levels of MUFA and PUFA in pork bellies (Apple et al, 2007;Eggert, Belury, Kempa-Steczko, Mills, & Schinckel, 2001). Pigs fed diets high in MUFA and PUFA have been shown to have bellies with high levels of unsaturated fatty acids (Apple et al, 2007Leick et al, 2010.…”