The effect of dietary ractopamine concentration and duration of feeding on growth performance, carcass characteristics, and meat quality of finishing pigs

Abstract

A total of 400 barrows from Dekalb EB and 83 terminal sires mated to 43 and 45 maternal lines were used to evaluate the effects of dietary ractopamine (RAC; Paylean, Elanco Animal Health, Greenfield, IN) concentrations (0, 5, 10, or 20 ppm; as-fed basis) and feeding durations (6 to 34 d) on growth, efficiency, carcass, and meat quality characteristics of finishing pigs. Barrows were weighed and sorted into five weight blocks, each block consisting of 16 pens (five pigs per pen). Weight blocks were allocated to feeding duration treatments and assigned consecutively by weight from lightest to heaviest to represent 34, 27, 20, 13, and 6 d on test, respectively. The lightest and heaviest blocks averaged 79.8 and 103.8 kg, respectively, at the start of the test. Within a weight block, pens (four per treatment) were randomly assigned to one of four dietary concentrations of RAC in a basal diet containing 18.5% CP and 1.13% lysine. The experiment-wide target slaughter weight was 109 kg, and pigs and feeders were weighed weekly. Weight blocks (80 barrows per block) were slaughtered at a commercial packing plant after 6, 13, 20, 27, or 34 d on test. Overall, RAC supplementation improved (P < 0.05) ADG; however, ADG was not different (P > 0.08) from controls for pigs fed 5, 10, and 20 ppm RAC for 27, 34, and 6 d, respectively. During each feeding period, RAC-fed pigs had improved (P < 0.05) G:F, and, after 20, 27, and 34 d on test, pigs fed 20 ppm RAC had greater (P < 0.05) G:F compared with those fed 0 or 5 ppm RAC. Hot carcass weight was increased (P < 0.05) by RAC feeding after 13 and 27 d of feeding, and by feeding 10 and 20 ppm RAC after 20 d of feeding. After 34 d, pigs fed 20 ppm RAC had heavier (P < 0.05) hot carcass weight than pigs fed 10 ppm RAC. Fat-free lean estimates and the 10th-rib LM area were increased (P < 0.05) by feeding 10 and 20 ppm RAC after 27 d, and by feeding 20 ppm RAC after 34 d compared with controls. Japanese and American color scores, as well as L*, a*, and b* values of the LM, were not affected (P > 0.11) by 5 and 10 ppm RAC compared with controls during each feeding period. Visual marbling score for the LM was decreased (P < 0.05) when RAC was fed at 10 and 20 ppm compared with 0 ppm RAC when fed for 34 d. Dietary RAC improved growth performance at all feeding durations, whereas carcass composition was improved at longer feeding durations. In addition, 5 and 10 ppm RAC did not affect objective and subjective measures of pork quality.

Relação da ractopamina com componentes nutricionais e desempenho em suínos: um estudo meta-analítico

“…Assim, atuando no metabolismo dos animais como um particionador de nutrientes para funções desejáveis, a ractopamina pode melhorar as taxas de crescimento e a eficiência alimentar de suínos (ARMSTRONG et al, 2004).…”

“…Os aditivos ß-adrenérgicos são uma alternativa nutricional comumente utilizada na produção animal como particionadores de nutrientes, melhorando a retenção de nitrogênio, as taxas de crescimento e a deposição de tecido muscular em detrimento de gordura (ARMSTRONG et al, 2004). Apesar do amplo uso em nutrição animal, pouco é conhecido sobre as implicações da ractopamina como aditivo melhorador de desempenho, especialmente no que diz respeito à sua interação com outros componentes nutricionais.…”

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

“…Some results indicate no effect of RAC on the visual assessment of marbling in the LM between the 10th and 11th ribs (Watkins et al 1990;Stites et al 1991;Crome et al 1996), or on the extractable lipid content of the LM (Stites et al 1994). Armstrong et al (2004) reported that the visual marbling score for the LM was decreased when RAC was fed for 34 d at 10 and 20 ppm compared with 0 ppm RAC. Conversely, Watkins et al (1990) and Aalhus et al (1990) reported that the LM from RAC-fed pigs received higher marbling scores than pork from control pigs, whereas several other studies observed similar marbling scores between RAC and control pigs (Adeola et al 1990;Crome et al 1996;Stoller et al 2003;Weber et al 2006).…”

“…The lower a* values may also be due to the shift of intermediate fibres (Type 2A) to white fibres (Type 2B) (McKeith et al 1988;Anderson et al 1991;Uttaro et al 1993). Armstrong et al (2004) reported that the effect of RAC on colour was dependent on its level and feeding period. They found that L*, a*, and b* values of the loin muscle were not affected by 5 and 10 ppm RAC compared with controls during each feeding period.…”

“…While RAC has been shown to improve carcass merit, the results in the literature have been inconsistent at the dose rate and time of feeding employed in this experiment. For example, Armstrong et al (2004) did not see an improvement in carcass leanness when RAC was fed at 5 ppm, and only saw an improvement in loin eye area when the feeding period was at least 27 days. Stites et al (1991) also saw no improvement in backfat thickness but did see an increase in loin eye area when RAC was fed at 5 ppm; however, in their experiment, amino acid levels were not increased.…”