Formulação com aminoácidos totais ou digestíveis em rações com níveis decrescentes de proteína bruta para frangos de corte de 21 a 42 dias de idade

Abstract

RESUMO -Foram realizados dois experimentos para avaliar a formulação de rações para frangos de corte com redução do nível de proteína bruta (PB) e suplementadas com aminoácidos sintéticos, formuladas com base nos aminoácidos totais -AAT (experimento 1) ou digestíveis -AAD (experimento 2). Os experimentos foram conduzidos no período de 3 a 6 semanas de idade das aves. Em ambos os experimentos, os quatros níveis de PB foram: 20,8; 19,7; 18,6 e 17,5% PB. No experimento 2, também foram testados outros dois tratamentos com rações contendo 20,8 e 17,5% de PB e alta digestibilidade (ADig), à base de milho, farelo de soja, amido de milho e proteína isolada de soja. Nos dois experimentos, o consumo de ração não foi afetado pela redução de PB. No experimento 1, o ganho de peso (GP), a conversão alimentar (CA) e os rendimentos de peito e de coxa foram afetados negativamente pela redução dos níveis de PB, enquanto, no experimento 2 estas variáveis não foram influenciadas. No entanto, em ambos os experimentos, na semana de 21 a 28 dias, o GP e a CA foram influenciados negativamente pela redução dos níveis de PB na ração. Com o decréscimo no nível de PB, a digestibilidade da matéria seca (MS) e da matéria orgânica (MO) aumentou no experimento 2, em virtude da menor inclusão de farelo de soja. Em ambos os experimentos, a retenção relativa de proteína foi superior para rações com baixos níveis de PB. No experimento 2, apesar de os níveis de PB não terem influenciado o desempenho, a ração de ADig proporcionou maior digestibilidade da MO e tendência à maior digestibilidade da MS. As rações com 17,5% PB e ADig promoveram balanço mais positivo e maior retenção relativa de proteína em comparação às de digestibilidade padrão. Considerando todos os resultados, a formulação de rações com AAD mostrou vantagens em relação aos AAT.Palavras-chave: aves, metabolismo, proteína ideal, proteína isolada de soja Total and digestible amino acids formulation in diets with decreasing levels of crude protein for broilers from 21 to 42 days of age ABSTRACT -Two experiments (Exp) were carried out to evaluate diets for broilers formulated with reducing crude protein (CP) level, supplemented with synthetic amino acids, formulated based on total amino acids (TAA) (Exp 1) or digestible AA (DAA) (Exp 2). The experiments conducted in the period from 3 to 6 weeks of age of the birds. In both experiments, the four levels of CP were: 20.8, 19.7, 18.6 and 17.5% CP. In the Experiment 2, two other treatments were added: diets containing 20.8 and 17.5% CP and high digestibility (HD), based on corn, soybean meal, corn starch and soy protein isolate. In both experiments, the feed intake was not affected by CP decreasing. In Exp1, weight gain (WG), feed conversion (FC), breast and drumstick yield were negatively affected by CP reduction, meanwhile in Exp 2 those variables were not affected. However, in both experiments, in the week from 21 to 28 days of age, WG and FC were negatively influenced by CP decrease. As the CP levels decrease, the dry matter (DM) and organi...

Effect of different dietary concentrations of Amino Acids on the performance of two different Broiler Strains

“…Using data of six experiments, a reduction of more than 3% CP, even when corrected for the main limiting AA, resulted in worse performance (Dean, 2006). Reducing CP (20.8, 19.7 and 17.5%) of diets supplemented with synthetic AA had a negative effect on broiler WG and FCR between 21 and 28 days, indicating that, at this age, protein requirement may be higher than usual (20% CP) due to a higher rate of lean tissue accretion (Viola et al, 2008). It was clear that the increase in AA concentrations in the starter and growing periods improved performance.…”

Performance, nutrient digestibility, and muscular evaluation of female broiler chickens fed different dietary protein levels and slaughtered at 38 or 46 days

“…The results found for performance in the present study are in agreement with nutrient digestibility and diet energy values. Reduced nutritional levels in a diet improves nutrient digestibility for broiler chickens (Viola et al, 2008); however, the lack of standardization of the nutritional matrix of corn gluten meal (Santos, 2004) and higher inclusion of soybean meal may have worsened DMDC for the 21E treatment, which was similar to that of 19E and lower than the others. The amount and quality of carbohydrates, proteins, and fats contained in different diets can alter the retention time of digestion and thus influence the efficiency of digestion and absorption of nutrients (Soares et al, 2020).…”

Threonine-to-lysine ratio in laying hens: physiological parameters and organ weight

“…It is essential to know the performance of strains of egg-producing birds subjected to different levels of these nutrients, trying to determine the most suitable levels to minimize production costs (Ribeiro, Matos Júnior, Queiroz, Lara, & Baião, 2013). On the other hand, synthetic amino acids' availability allows nutritionists to formulate poultry feeds based on the crude protein requirement adjusted with respect to the amino acid requirements (Viola, Ribeiro, Beretta Neto, & Kessler, 2008).…”