Efeito de dietas com baixo teor protéico, formuladas usando o conceito de proteína ideal, para frangos de corte criados em temperaturas fria, termoneutra e quente
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Data
2003-02
Autores
Faria Filho, Daniel Emygdio de [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Foram conduzidos dois experimentos com o objetivo de avaliar a utilização de dietas com baixo teor protéico, formuladas usando o conceito de proteína ideal, para frangos de corte de 7 a 21 dias (experimento 1) e de 21 a 42 dias (experimento 2) criados em diferentes temperaturas. Foram utilizados 900 e 720 frangos machos para os experimentos 01 e 02 respectivamente, da linhagem Cobb-500, distribuídos em um delineamento inteiramente ao acaso em esquema fatorial 3 x 3, com os fatores: níveis de proteína bruta (uma dieta controle e duas com redução protéica de 1,5 e 3,0% em relação a dieta controle) e temperaturas ambiente (fria, termoneutra e quente), totalizando nove tratamentos com quatro repetições cada. Foram avaliados o desempenho, rendimento de carcaça e de cortes comerciais, percentagem de gordura abdominal, temperaturas superficiais e cloacal e a perda de calor por radiação. No experimento 1 a redução do teor protéico prejudicou o desempenho dos frangos independente da temperatura, enquanto que no experimento 2 a redução da proteína bruta foi prejudicial somente para a temperatura quente. O desempenho foi reduzido pelas temperaturas quente e fria (experimento 1) e quente (experimento 2). A redução protéica aumentou a deposição de gordura abdominal das aves em ambos os experimentos. A temperatura quente proporcionou maior rendimento de carcaça, de coxa+sobrecoxa e de asas, enquanto o rendimento de peito foi reduzido. A gordura abdominal aumentou com a elevação da temperatura somente no experimento 1. Nos dois experimentos, as temperaturas superficial e cloacal aumentaram com a elevação da temperatura ambiente, e a perda de calor por radiação diminuiu, enquanto que os níveis de proteína não afetaram a homeostase térmica das aves.
Two experiments were carried out to evaluate the use of low-protein diets, formulated on ideal protein concept, for broilers from 7 to 21 days (experiment 1), and from 21 to 42 days (experiment 2) reared under different environmental temperatures. Nine hundred (experiment 1), and seventy hundred and twenty (experiment 2) male broilers of Cobb-500 strain were randomly housed in a 3 x 3 factorial arrangement: crude protein levels (a control diet, and two other diets with reductions of 1,5 and 3,0% of the protein level from control diet), and environmental temperatures (cold, thermoneutral, and hot) resulting in nine treatments with four replicates each. Performance, carcass and part yields, abdominal fat deposition, surface and cloacal temperatures, and heat loss by radiation were evaluated. Low-protein diets impaired broiler performance irrespective the environment temperature in experiment 1, while the performance was reduced only when low-protein diets were fed at hot temperature in experiment 2. Performance was reduced by cold and hot temperature (experiment 1) and hot temperature (experiment 2). Low-protein diets increased the abdominal fat deposition in both experiments. Hot temperatures improved carcass, thigh+drumstick, and wing yields, while breast yield was reduced. Abdominal fat (experiment 1), and surface and cloacal temperatures (experiments 1 e 2) increased as environmental temperature was increased, while heat loss by radiation decreased. There was no effect of protein levels on thermal homeostasis of broilers.
Two experiments were carried out to evaluate the use of low-protein diets, formulated on ideal protein concept, for broilers from 7 to 21 days (experiment 1), and from 21 to 42 days (experiment 2) reared under different environmental temperatures. Nine hundred (experiment 1), and seventy hundred and twenty (experiment 2) male broilers of Cobb-500 strain were randomly housed in a 3 x 3 factorial arrangement: crude protein levels (a control diet, and two other diets with reductions of 1,5 and 3,0% of the protein level from control diet), and environmental temperatures (cold, thermoneutral, and hot) resulting in nine treatments with four replicates each. Performance, carcass and part yields, abdominal fat deposition, surface and cloacal temperatures, and heat loss by radiation were evaluated. Low-protein diets impaired broiler performance irrespective the environment temperature in experiment 1, while the performance was reduced only when low-protein diets were fed at hot temperature in experiment 2. Performance was reduced by cold and hot temperature (experiment 1) and hot temperature (experiment 2). Low-protein diets increased the abdominal fat deposition in both experiments. Hot temperatures improved carcass, thigh+drumstick, and wing yields, while breast yield was reduced. Abdominal fat (experiment 1), and surface and cloacal temperatures (experiments 1 e 2) increased as environmental temperature was increased, while heat loss by radiation decreased. There was no effect of protein levels on thermal homeostasis of broilers.
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Palavras-chave
Frango de corte - Nutrição, Temperatura, Homeostase, Aminoacidos na nutrição animal, Amino acids, Thermal homeostasis
Como citar
FARIA FILHO, Daniel Emygdio de. Efeito de dietas com baixo teor protéico, formuladas usando o conceito de proteína ideal, para frangos de corte criados em temperaturas fria, termoneutra e quente. 2003. xiii, 85 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2003.