Respostas de frangos de corte ao estresse térmico agudo ou crônico
Carregando...
Arquivos
Data
2016-06-03
Autores
Sandre, Danilo Gualberto de [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Dois experimentos envolvendo 1280 pintos machos Cobb 500, foram conduzidos para avaliar as possíveis interações entre condicionamento termo precoce e balanço eletrolítico da dieta sobre o desempenho de frangos de corte, bem como estudar os efeitos do estresse térmico agudo e crônico. No d 8, as aves foram transferidas para 32 boxes, com raspas de madeira e resíduo desidratado de acerola (proporção ½ a ½ ) como cama, mantendo os mesmos tratamentos com oito repetições cada. Os dados da Exp. 1 (stress agudo) e 2 (stress crónico) foram combinados num arranjo fatorial 2x2x2 (com e sem condicionamento térmico precoce (CTP); dieta com e sem equilíbrio eletrolítico (EE); e estresse térmico agudo ou crônico. A dieta com EE foi calculada como mEq / kg para a Na + K-Cl e o valor da relação (K + Cl) / Na, com 300 mEq / kg e uma proporção de 3: 1, respectivamente. As aves foram alimentadas com: (1) uma dieta tradicional (176 mEq / kg e a relação de 3,36: 1) sem CTP; (2) dieta tradicional com CTP; (3) dieta com EE e sem CTP e (4) dieta com EE e CTP. Ração e água foram fornecidas ad libitum. Metade das aves foram expostas a 36 °C durante 24 horas com a idade de 5, enquanto que a outra metade não foi exposto a CTP. Na idade de 38 d, metade dos pintos foram termicamente desafiados por estresse térmico agudo de 36 °C durante 6h e com a idade de 35 a 39 d, outra metade dos pintos foram termicamente desafiado por um estresse térmico crônico de 32 °C por 6h. O consumo de ração, peso corporal (PC), a umidade das fezes e deposição de gordura abdominal foram determinadas a 46 d de idade e taxa de conversão alimentar ajustado foi calculado através da inclusão de PC da mortalidade. Coordenadas tricromáticas (L*, a*, e b*) foram medidos no músculo do peito, às 24h. Nenhum efeito de interação foi encontrado com nenhum dos parâmetros avaliados. Assim, não existe sinergismo para qualquer um dos traços. Houve aumento expressivo da mortalidade [(3,06-65,62%) / P <0,0001] de estresse agudo. O EE aumentou a umidade nas fezes (P = 0,0202). Os conteúdos de lipídios dos tecidos abdominais foram afetados pela exposição ao calor e diminuiu significativamente (P <0,0001) para crônica (53.9g) versus estresse agudo (127.5g). Além disso, um efeito significativo (P <0,0001) valores mais elevados foi encontrado em carne para aguda (66,4 e 23,2) versus o estresse crônico (57,6 e 17,6), em L* e b*, respectivamente. Os resultados sugerem que as aves submetidas a estresse agudo estão sujeitos a síndrome do músculo pálida aves.
Two experiments involving 1280 male Cobb 500 chicks were conducted to evaluate the possible interactions between early thermal conditioning and electrolyte balance of the diet on the performance of broiler chickens, as well as studying the effects of acute and chronic heat stress. On d 8, the broilers were transferred to 32 floor pens with wood shavings as litter while maintaining the same treatments with eight replicates each. The data from Exp. 1 (acute stress) and 2 (chronic stress) were combined in a 2x2x2 factorial arrangement [with and without early thermal conditioning (ETC)]; diet with and without electrolyte balance (EB); and acute or chronic heat stress. The diet with EB was calculated as mEq/kg for Na+K-Cl and the value the ratio (K+Cl)/Na, with 300 mEq/kg and a ratio the 3:1, respectively. The birds were fed: (1) a traditional diet (176 mEq/kg and a ratio the 3.36:1) without ETC; (2) traditional diet with ETC; (3) diet with EB and without ETC and (4) diet with EB and ETC. Feed and water were supplied ad libitum. Half of birds were exposed to 36°C for 24h at the age of 5, whereas the remaining half was not exposed to ETC. At the age of 38 d, half chicks were thermally challenged by an acute heat stress of 36°C for 6h or at the age of 35 to 39 d, another half chicks were thermally challenged by a chronic heat stress of 32°C for 6h. Feed intake, body weight (BW), moisture of feces and abdominal fat deposition were determined at 46 d of age and adjusted feed conversion ratio was calculated by including BW of mortality. Trichromatic coordinates (L*, a*, and b*) were measured on the breast muscle at 24h. No interaction effects were found for any of the parameters evaluated. Thus, there is no synergism for any of the traits. There was expressive increase of mortality [(3.06 to 65.62%) / P<0.0001] from acute stress. The EB increased moisture of feces (P=0.0202). Lipid contents of abdominal tissues was affected by heat exposure with significantly decreased (P<0.0001) to chronic (53.9g) versus acute stress (127.5g). Also, a significant effect (P<0.0001) values higher was found in meat for acute (66.4 and 23.2) versus chronic stress (57.6 and 17.6) on L* and b*, respectively. The results suggest that birds submitted to acute stress are subject to pale poultry muscle syndrome.
Two experiments involving 1280 male Cobb 500 chicks were conducted to evaluate the possible interactions between early thermal conditioning and electrolyte balance of the diet on the performance of broiler chickens, as well as studying the effects of acute and chronic heat stress. On d 8, the broilers were transferred to 32 floor pens with wood shavings as litter while maintaining the same treatments with eight replicates each. The data from Exp. 1 (acute stress) and 2 (chronic stress) were combined in a 2x2x2 factorial arrangement [with and without early thermal conditioning (ETC)]; diet with and without electrolyte balance (EB); and acute or chronic heat stress. The diet with EB was calculated as mEq/kg for Na+K-Cl and the value the ratio (K+Cl)/Na, with 300 mEq/kg and a ratio the 3:1, respectively. The birds were fed: (1) a traditional diet (176 mEq/kg and a ratio the 3.36:1) without ETC; (2) traditional diet with ETC; (3) diet with EB and without ETC and (4) diet with EB and ETC. Feed and water were supplied ad libitum. Half of birds were exposed to 36°C for 24h at the age of 5, whereas the remaining half was not exposed to ETC. At the age of 38 d, half chicks were thermally challenged by an acute heat stress of 36°C for 6h or at the age of 35 to 39 d, another half chicks were thermally challenged by a chronic heat stress of 32°C for 6h. Feed intake, body weight (BW), moisture of feces and abdominal fat deposition were determined at 46 d of age and adjusted feed conversion ratio was calculated by including BW of mortality. Trichromatic coordinates (L*, a*, and b*) were measured on the breast muscle at 24h. No interaction effects were found for any of the parameters evaluated. Thus, there is no synergism for any of the traits. There was expressive increase of mortality [(3.06 to 65.62%) / P<0.0001] from acute stress. The EB increased moisture of feces (P=0.0202). Lipid contents of abdominal tissues was affected by heat exposure with significantly decreased (P<0.0001) to chronic (53.9g) versus acute stress (127.5g). Also, a significant effect (P<0.0001) values higher was found in meat for acute (66.4 and 23.2) versus chronic stress (57.6 and 17.6) on L* and b*, respectively. The results suggest that birds submitted to acute stress are subject to pale poultry muscle syndrome.
Descrição
Palavras-chave
Síndrome musculo pálido frangos, Balanço eletrolítico ânion-cátion, Condicionamento térmico precoce, Pale poultry muscle syndrome, Dietary anion-cation balance, Early thermal conditioning