Efeito da proteína balanceada sobre a otimização biológica e econômica de frangos de corte e matrizes pesadas
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Data
2020-10-22
Autores
Azevedo, Jefferson Moraes [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo do estudo é avaliar as respostas de frangos de corte e matrizes pesadas submetidos a diferentes níveis de proteína balanceada de acordo com o conceito de proteína ideal e, baseado nestas respostas, propor uma abordagem para otimização econômica, avaliando os impactos entre as estratégias nutricionais que se fundamentam no máximo desempenho biológico em comparação a uma que busque máximo retorno econômico. Para isso, dois experimentos foram realizados. No primeiro experimento, foi avaliado a resposta de frangos de corte das linhagens Ross e Cobb em função de diferentes concentrações proteína balanceada na dieta e, divididas em quatro fases de alimentação (Inicial) 1 a 14; (Crescimento) 15 a 28; (Final I) 29 a 42 e (Final II) 43 a 56 dias de idade. Foram utilizados seis tratamentos (concentrações de proteína balanceada na ração), arranjados em esquema fatorial (6 níveis de proteína balanceada x 2 linhagens x 2 sexos) perfazendo 24 tratamentos com quatro repetições de 26 aves, totalizando 2.496 aves distribuídas em 96 parcelas experimentais. As rações foram produzidas utilizando a técnica da diluição, onde uma ração com alto conteúdo proteico (A=283 g/kg) foi diluída com uma ração de baixo conteúdo de proteína (B=117g/kg), produzindo os seis níveis crescentes de proteína balanceada para cada fase. As duas dietas foram elaboradas para conter igual teor de energia metabolizável (EMAn), atendendo as exigências de vitaminas, minerais e a relação ideal dos aminoácidos. Foram avaliadas as variáveis de desempenho (peso corporal, ganho de peso, consumo de ração e ingestão de proteína), composição química (água, proteína, gordura e cinzas), rendimento de cortes (carcaça, peito, pernas (coxa+sobrecoxa), asas e restante). O consumo de ração em todos os períodos, em ambas as linhagens e sexos, aumentou à medida que o nível de proteína na dieta diminuiu e, em seguida, diminuiu acentuadamente nos níveis mais baixos de proteína. Somente aos 14 dias o consumo de ração diferiu entre as linhagens e os sexos, apresentando assim interação significativa; em todos os outros casos, as O consumo de ração diferiu apenas entre os sexos. Aos 14 dias, a resposta no peso corporal diferiu entre as linhagens e o sexo, enquanto em todas as outras amostragens eles diferiram apenas entre os sexos. A resposta na produção de carcaça, peito e asa aos 14 dias foi a mesma para ambas as linhagens e sexos, mas diferiu entre linhagens e sexos aos 28 dias. Aos 42 e 56 dias, a resposta diferiu apenas entre os sexos. A resposta no peso da perna (coxa mais sobrecoxa) aos 14 dias foi a mesma para ambas as linhagens e sexos, mas depois disso diferiu apenas entre os sexos. O conteúdo de lipídios corporais aumentou linearmente inicialmente e depois quadraticamente conforme o conteúdo de proteína da dieta foi reduzido. A análise econômica identificou que, usando como base os valores de marcado atuais, o conteúdo de proteína da dieta que maximizou a margem sobre o custo da ração foi sempre maior para machos do que para fêmeas e para aves vendidas processadas em relação àquelas vendidas vivas. Usando lisina como aminoácido de referência, o ótimo econômico no período inicial para machos vendidos vivos foi obtido com uma concentração de 12,1 g lisina/kg sendo 14,1 g/kg quando essas aves são vendidas abatidas; para as fêmeas os valores equivalentes foram 11,3 e 13,7 g/kg, respectivamente. Quando o custo dos ingredientes que contêm proteína foi aumentado em 25%, ou a receita gerada com a venda do produto reduzida em 25%, o nível econômico ideal de proteína dietética aumentou em comparação com o valor do preço base, sendo este aumento maior para as aves vendido vivas. O oposto ocorreu quando os custos foram aumentados ou as receitas diminuíram 25%. Em síntese, a análise econômica identificou que, dependendo de o cenário econômico, preconizar o máximo desempenho poderá originar perdas econômicas, e que buscar ajustar os níveis de proteína da dieta de acordo com as mudanças do cenário econômico parece ser a estratégia mais viável para o aumento da rentabilidade de um sistema de produção de frangos de corte. No segundo experimento, foi avaliado o desempenho produtivo e composição corporal de matrizes pesadas submetidas a 5 níveis de proteína balanceada em duas quantidades diárias de oferta de ração. Para isso um total de 200 de aves reprodutoras (Ross 308) com 55 semanas de idade foram distribuídas aleatoriamente em gaiolas individuais. Os tratamentos foram constituídos por cinco diferentes concentrações de proteína balanceada ofertadas em duas quantidades diárias (150 a 170 g/dias) perfazendo um delineamento inteiramente casualisado alocado em arranjo fatorial com 10 tratamentos de 20 repetições. Não houve interação (p> 0,05) entre a quantidade de ração ofertada (FA) e a proteína balanceada da dieta (BP) para nenhuma variável avaliada. A produção de ovos (EP) não foi influenciada (p> 0,05) pelos tratamentos, mas o peso dos ovos (EW) e a massa de ovo (EO) aumentaram com os níveis de BP, mas não foram afetados pela FA. O ganho de peso corporal (BWG) e a retenção de proteína corporal (BPR) também aumentaram com a BP, mas não foram afetados pela FA, enquanto a retenção de gordura corporal (BFG) teve um incremento apenas com a FA. Consequentemente, a energia total retida no corpo (BPRt) aumentou tanto com PA quanto AF, enquanto a energia corporal retida como proteína (BPRp) e gordura (BPRg) foram influenciadas apenas pela BP e FA, respectivamente. A energia total retida (TER) também aumentou com os dois fatores, enquanto a produção total de calor (THP) reduziu com a BP e aumentou com a FA. Mesmo no final da vida produtiva, as matrizes de corte são capazes de manter seu desempenho reprodutivo alterando a composição corporal e consequentemente afetando a partição de energia.
ABSTRACT - The objective of the study is to evaluate the responses of broiler chickens and broiler breeders subjected to different levels of balanced protein according to the ideal protein concept and, based on these responses, to propose an approach for economic optimization, evaluating the impacts between the nutritional strategies that are based on maximum biological performance compared to one that seeks maximum economic return. For this, two experiments were carried out. In the first one, the response of broilers from Ross and Cobb strains was evaluated according to different concentrations of balanced protein in the diet and divided into four feeding phases (Initial) 1 to 14; (Growth) 15 to 28; (Final I) 29 to 42 and (Final II) 43 to 56 days of age. Six treatments (balanced protein concentrations in the ration) were used, arranged in a (6 balanced protein levels x 2 strains x 2 sexes) factorial scheme, making 24 treatments with four replications of 26 birds, totaling 2,496 birds distributed in 96 experimental plots. The diets were produced using the dilution technique, where a diet with a high protein content (A = 283 g / kg) was diluted with a diet with a low protein content (B = 117g / kg), producing the six increasing levels of protein balanced for each phase. Both diets were designed to contain an equal content of metabolizable energy (AMEn), meeting the requirements of vitamins, minerals and the ideal ratio among amino acids. The performance variables (body weight, weight gain, feed intake and protein intake), chemical composition (water, protein, fat and ash), cut-up performance (carcass, breast, legs (thigh + drumstick), wings and remainder). Feed intake in all periods, in both strains and sexes, increased as the level of protein in the diet decreased and then decreased markedly at the lowest levels of protein. Only at 14 days did feed consumption differ between strains and sexes, thus showing significant interaction; in all other cases, feed consumption differed only between the sexes. At 14 days, the response in body weight differed between strain and sex, while in all other samples they differed only between sexes. The response in carcass, breast and wing production at 14 days was the same for both strains and sexes, but differed between strains and sexes at 28 days. At 42 and 56 days, the response differed only between the sexes. The response in the weight of the leg (thigh plus thigh) at 14 days was the same for both strains and sexes, but after that it differed only between the sexes. The body lipid content increased linearly initially and then quadratically as the protein content of the diet was reduced. The economic analysis identified that, based on the current labelled values, the protein content of the diet that maximized the margin over feeding cost was always higher for males than for females and for poultry sold processed in relation to those sold alive. Using lysine as a reference amino acid, the optimum economic in the initial period for males sold live was obtained with a concentration of 12.1 g lysine/kg, and 14.1 g/kg when these birds are sold slaughtered; for females, the equivalent values were 11.3 and 13.7 g/kg, respectively. When the cost of protein-containing ingredients was increased by 25%, or the revenue generated by selling the product reduced by 25%, the ideal economic level of dietary protein increased compared to the base price, this increase being greater for the birds sold alive. The opposite occurred when costs were increased or revenues decreased by 25%. In summary, the economic analysis identified that, depending on the economic scenario, supporting maximum performance may result in economic losses, and that seeking to adjust the dietary protein levels according to the changes in the economic scenario seems to be the most viable strategy for the increased profitability of a broiler production system. In the second experiment, the productive performance and body composition of broiler breeders subjected to 5 levels of balanced protein in two daily amounts of feed offer were evaluated. For this, a total of 200 broiler breeder hens (Ross 308) at 55 weeks of age were randomly assigned to individual cages. The treatments consisted of five different concentrations of balanced protein offered in two daily quantities (150 or 170 g/days) making a completely randomized design allocated in a factorial arrangement with 10 treatments of 20 replicates. There was no interaction (p> 0.05) between the amount of feed offered (FA) and the balanced diet protein (BP) for any variable evaluated. Egg production (EP) was not influenced (p>0.05) by treatments, but egg weight (EW) and egg mass (EO) increased with BP levels, but were not affected by FA. Body weight gain (BWG) and body protein retention (BPR) also increased with BP, but were not affected by FA, while body fat retention (BFR) increased only with FA. Consequently, the total energy retained in the body (BER) increased with both BP and FA, while the body energy retained as protein (BERp) and fat (BERf) were influenced only by BP and FA, respectively. Total retained energy (TER) also increased with both factors, while total heat production (THP) decreased with BP and increased with FA. Even at the end of the productive life, the broiler breeders are able to maintain their reproductive performance by changing the body composition and consequently affecting the energy partition.
ABSTRACT - The objective of the study is to evaluate the responses of broiler chickens and broiler breeders subjected to different levels of balanced protein according to the ideal protein concept and, based on these responses, to propose an approach for economic optimization, evaluating the impacts between the nutritional strategies that are based on maximum biological performance compared to one that seeks maximum economic return. For this, two experiments were carried out. In the first one, the response of broilers from Ross and Cobb strains was evaluated according to different concentrations of balanced protein in the diet and divided into four feeding phases (Initial) 1 to 14; (Growth) 15 to 28; (Final I) 29 to 42 and (Final II) 43 to 56 days of age. Six treatments (balanced protein concentrations in the ration) were used, arranged in a (6 balanced protein levels x 2 strains x 2 sexes) factorial scheme, making 24 treatments with four replications of 26 birds, totaling 2,496 birds distributed in 96 experimental plots. The diets were produced using the dilution technique, where a diet with a high protein content (A = 283 g / kg) was diluted with a diet with a low protein content (B = 117g / kg), producing the six increasing levels of protein balanced for each phase. Both diets were designed to contain an equal content of metabolizable energy (AMEn), meeting the requirements of vitamins, minerals and the ideal ratio among amino acids. The performance variables (body weight, weight gain, feed intake and protein intake), chemical composition (water, protein, fat and ash), cut-up performance (carcass, breast, legs (thigh + drumstick), wings and remainder). Feed intake in all periods, in both strains and sexes, increased as the level of protein in the diet decreased and then decreased markedly at the lowest levels of protein. Only at 14 days did feed consumption differ between strains and sexes, thus showing significant interaction; in all other cases, feed consumption differed only between the sexes. At 14 days, the response in body weight differed between strain and sex, while in all other samples they differed only between sexes. The response in carcass, breast and wing production at 14 days was the same for both strains and sexes, but differed between strains and sexes at 28 days. At 42 and 56 days, the response differed only between the sexes. The response in the weight of the leg (thigh plus thigh) at 14 days was the same for both strains and sexes, but after that it differed only between the sexes. The body lipid content increased linearly initially and then quadratically as the protein content of the diet was reduced. The economic analysis identified that, based on the current labelled values, the protein content of the diet that maximized the margin over feeding cost was always higher for males than for females and for poultry sold processed in relation to those sold alive. Using lysine as a reference amino acid, the optimum economic in the initial period for males sold live was obtained with a concentration of 12.1 g lysine/kg, and 14.1 g/kg when these birds are sold slaughtered; for females, the equivalent values were 11.3 and 13.7 g/kg, respectively. When the cost of protein-containing ingredients was increased by 25%, or the revenue generated by selling the product reduced by 25%, the ideal economic level of dietary protein increased compared to the base price, this increase being greater for the birds sold alive. The opposite occurred when costs were increased or revenues decreased by 25%. In summary, the economic analysis identified that, depending on the economic scenario, supporting maximum performance may result in economic losses, and that seeking to adjust the dietary protein levels according to the changes in the economic scenario seems to be the most viable strategy for the increased profitability of a broiler production system. In the second experiment, the productive performance and body composition of broiler breeders subjected to 5 levels of balanced protein in two daily amounts of feed offer were evaluated. For this, a total of 200 broiler breeder hens (Ross 308) at 55 weeks of age were randomly assigned to individual cages. The treatments consisted of five different concentrations of balanced protein offered in two daily quantities (150 or 170 g/days) making a completely randomized design allocated in a factorial arrangement with 10 treatments of 20 replicates. There was no interaction (p> 0.05) between the amount of feed offered (FA) and the balanced diet protein (BP) for any variable evaluated. Egg production (EP) was not influenced (p>0.05) by treatments, but egg weight (EW) and egg mass (EO) increased with BP levels, but were not affected by FA. Body weight gain (BWG) and body protein retention (BPR) also increased with BP, but were not affected by FA, while body fat retention (BFR) increased only with FA. Consequently, the total energy retained in the body (BER) increased with both BP and FA, while the body energy retained as protein (BERp) and fat (BERf) were influenced only by BP and FA, respectively. Total retained energy (TER) also increased with both factors, while total heat production (THP) decreased with BP and increased with FA. Even at the end of the productive life, the broiler breeders are able to maintain their reproductive performance by changing the body composition and consequently affecting the energy partition.
Descrição
Palavras-chave
Aminoácidos na nutrição, Aves domésticas alimentação e rações, Nutrição animal, Amino acids in nutrition, Poultry food and feed, Animal nutrition