Impact of dietary energy level and ractopamine on growth performance, carcass characteristics, and meat quality of finishing pigs

Abstract

A total of 54 finishing barrows (initial BW = 99.8 ± 5.1 kg; PIC C22 × 337) reared in individual pens were allotted to 1 of 6 dietary treatments in a 2 × 3 factorial arrangement of treatments with 2 levels of ractopamine (0 and 7.4 mg/kg) and 3 levels of dietary energy (high, 3,537; medium, 3,369; and low, 3,317 kcal of ME/kg) to determine the effects of dietary ractopamine and various energy levels on growth performance, carcass characteristics, and meat quality of finishing pigs. High-energy diets were corn-soybean-meal-based with 4% added fat; medium-energy diets were corn-soybean meal based with 0.5% added fat; and low-energy diets were corn-soybean meal based with 0.5% added fat and 15% wheat middlings. Diets within each ractopamine level were formulated to contain the same standardized ileal digestible Lys:ME (0 mg/kg, 1.82; and 7.4 mg/kg, 2.65 g/Mcal of ME). Individual pig BW and feed disappearance were recorded at the beginning and conclusion (d 21) of the study. On d 21, pigs were slaughtered for determination of carcass characteristics and meat quality. No ractopamine × energy level interactions (P > 0.10) were observed for any response criteria. Final BW (125.2 vs. 121.1 kg), ADG (1.2 vs. 1.0 kg/d), and G:F (0.31 vs. 0.40) were improved (P < 0.001) with feeding of ractopamine diets. Feeding of the low-energy diet reduced (P = 0.001) final BW and ADG compared with the high- and medium-energy diets. Gain:feed was reduced (P = 0.005) when the medium-energy diets were fed compared with the high-energy diets. Additionally, G:F was reduced (P = 0.002) when the low-energy diets were compared with the high- and medium-energy diets. Feeding ractopamine diets increased (P < 0.05) HCW (93.6 vs. 89.9 kg) and LM area (51.2 vs. 44.2 cm(2)). The LM pH decline was reduced (P ≤ 0.05) by feeding ractopamine diets. The feeding of low-energy diets reduced (P = 0.001) HCW when compared with the high- and medium-energy diets and reduced (P = 0.024) 10th-rib backfat when compared with the high- and medium-energy diet. These data indicate that feeding ractopamine diets improved growth performance and carcass characteristics, while having little or no detrimental effect on meat quality. Reductions in energy content of the diet by adding 15% wheat middlings resulted in impaired ADG, G:F, and 10th-rib backfat. There were no ractopamine × energy level interactions in this trial, which indicates that the improvements resulting from feeding ractopamine were present regardless of the dietary energy levels.

Qualidade da carcaça e rendimento de cortes suínos com o uso de ractopamina

“…As medidas de pH foram realizadas em 1 e 24h após o abate (BRIDI et al, 2003;HINSON et al, 2011), a partir de amostra de pernil (Semimembranosus), utilizando pHmetro com eletrodo de inserção (pH 320/Ste-1, WTW). Foram realizadas 5 coletas e a análise realizada em triplicata para cada tratamento.…”

“…O pH mais elevado, observado no tratamento com Ractopamina, pode estar relacionado à redução das reservas de glicogênio do animal, devido à agitação e estresse dos suínos na propriedade em momento anterior ao abate (visto que o transporte de todos os animais foi realizado sob as mesmas normas), estando de acordo com os dados publicados por POLETTO et al (2010), HINSON et al (2011), quando foi constatado que suínos alimentados com ractopamina se tornam mais agressivos, o que pode ser a causa de estresse na propriedade.…”

“…A cor obtida para ambos os tratamentos realizados neste estudo encontra-se dentro da faixa considerada normal na carne suína, que, segundo BRIDI et al (2003), é igual a três, que corresponde à cor rosa acinzentado (NPPC, 1989). HINSON et al (2011) observou impacto significativo do uso de ractopamina (7,4ppm) (P<0,05) sobre a cor, em que o tratamento apresentou escores menores para a cor (média 2,54 pontos em escala de 1 a 5) e o tratamento sem o aditivo apresentou média 2,89. Valores similares ao observado na avaliação do marmoreio do presente trabalho foram observados por GONZALEZ et al (2010), quando ocorreu redução significativa no marmoreio das carcaças tratadas com ractopamina frente ao controle sem o aditivo.…”

Net energy and ractopamine levels for barrows weighing 70 to 100kg

“…This absence of effect may be related to the range of body weights (70-100kg) in the experimental period, as prior research has demonstrated the benefits of ractopamine addition to the diets of pigs weighing over 100kg at slaughter time, particularly in terms of weight gain (CORASSA et al, 2009) and feed conversion (ALMEIDA et al, 2010). Genotypic features may be another reason why ractopamine did not affect performance, since variability in the genetic materials employed in different studies may affect the variables evaluated (HINSON et al, 2011).…”

Efeito da adição de ractopamina e da imunocastração na carne <i>in natura</i> de suínos

“…No caso de intervenções ante mortem, o fornecimento de ractopamina nas dietas e sua relação no post mortem com a redução ou aumento das perdas de água por exsudação (drip loss e cocção) na qualidade da carne foi demonstrada em investigações científicas (UTTARO et al, 1993;HINSON et al, 2014;JEONG et al, 2011;LEAL et al, 2014).…”