Relação metionina mais cistina digestível: lisina digestível em dietas suplementadas com ractopamina para suínos em terminação

• Ano de defesa: 2007
• Autor(a) principal: Pena, Sérgio de Miranda
• Orientador(a): Lopes, Darci Clementino
• Banca de defesa: Silva, Francisco Carlos de Oliveira , Brustolini, Paulo César
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Zootecnia
• Departamento: Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul
• País: BR
• Palavras-chave em Português: Suíno; Nutrição; Aminoácidos sulfurados; Desempenho; Características de carcaça; Colesterol
• Palavras-chave em Inglês: Swine; Nutrition; Amino acids; Performance; Carcass characteristics; Cholesterol
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL
• Link de acesso: http://locus.ufv.br/handle/123456789/5847

The purpose of this study was to determine the digestible methionine plus cystine to digestible lysine ratio (Met+Cys/Lys) for barrows with high genetic potential for lean gain fed ractopamine (RAC) in finishing phase. Eighty barrows with an average initial body weight of 84.64±1.28 kg were allotted to dietary treatment on the basis of weight in randomized complete block design. Dietary treatments included a basal diet containing RAC (5 ppm) plus DL-Met, resulting in treatment diets containing Met+Cys/Lys of 0.54, 0.58, 0.62, 0.66 and a diet without RAC containing Met+Cys/Lys of 0.62, control (CONT). There were eight replications of barrows with two pigs per replicate during 28 days. Increasing the Met+Cys/Lys had no effects on average daily feed intake (ADFI), feed: gain ratio (F/G) and average daily gain (ADG) of pigs fed RAC. Barrows fed RAC and Met+Cys/Lys of 0.54 had the highest profitability index. The end weight of RAC-treated pigs was 2% higher compared to CONT pigs (by 2.3 kg). The RAC increased ADG by 10% and improved F/G by 13% compared to control pigs, but there were no differences in ADFI. Increasing the Met+Cys/Lys had no effects on fat depth (FD), fat-free lean mass (FFLM), carcass weight (CW), fat-free lean percentage (FFLP) and dressing (DR) for pigs fed RAC. The digestible methionine + cystine of the diet influenced in a quadratic way the cholesterol concentration, Y = -227,1900+ 9,6809X - 0,0837X², (R² = 0,99), being the Met+Cys/Lys of 0.66 for minimum cholesterol concentration, but the RAC had no effects on cholesterol concentration in muscle (Longissimus dorsi) and fat. The RAC increased FFLM by 6%, CW by 4% and DR by 2% compared to control pigs. However, the RAC had no effects on FD and FFLP of barrows. Thus, the optimum Met+Cys/Lys which will achieve maximal growth performance, carcass characteristics and economic return of finishing pigs (from 85 to 109 kg) fed RAC is 0.54. However, to minimize cholesterol concentration in muscle and fat the optimum Met+Cys/Lys is 0.66.