Efeito da restrição alimentar e do grupo genético sobre a microbiota do trato gastrintestinal, a expressão gênica hepática e a deposição de lipídeos na carcaça de frangos de corte
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Data
2016-02-16
Autores
Lunedo, Raquel [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A hipótese testada neste projeto é que a restrição alimentar altera a composição da microbiota intestinal e a expressão gênica hepática em frangos de corte, e estas alterações podem influenciar a deposição tecidual das aves. Outra hipótese, é que a genética do frango influencia estas variáveis, e pode alterar a sua resposta frente a restrição alimentar. Os objetivos específicos foram analisar a resposta de duas linhagens de frangos de corte (crescimento rápido – Cobb – ou lento – Label Rouge) a dois programas de restrição alimentar (quantitativa ou energética) sobre: 1) o desempenho zootécnico; 2) a deposição tecidual; 3) a microbiota de íleo e ceco; 4) a expressão de genes relacionados ao metabolismo hepático. Para tal, dois experimentos foram conduzidos, sendo que no experimento I foram utilizados 480 frangos de corte, machos, da linhagem comercial Cobb500TM e no experimento II foram utilizados 480 frangos de corte, machos, da linhagem Label Rouge. Até os 21 dias as aves receberam mesma dieta e foram criadas em temperatura termoneutra. Aos 22 dias, oito grupos de 20 aves foram distribuídos dentro de cada um dos três tratamentos experimentais: 1. Controle (ad libitum – 3,176 Mcal/kg de EM e 19% PB); 2. Restrição energética (2,224 Mcal/kg EM e 19% PB) até os 43 dias de idade, com consumo equiparado ao controle; 3. Restrição quantitativa (restrição de 70%, ou seja, as aves restritas ingeriram apenas 30% da quantidade de ração consumida pelo grupo controle – 3,176 Mcal/kg EM e 19% PB) durante 7 dias, seguido de realimentação ad libitum até os 43 dias de idade. A restrição alimentar energética diminuiu o ganho de peso e o peso da carcaça e piorou a conversão alimentar em ambas as linhagens; diminuiu as contagens do grupo Lactobacillus e aumentou as contagens de Enterococcus e Enterobacteriaceae nas aves de crescimento rápido; favoreceu a proliferação de Lactobacillus, e diminuiu as populações de Enterococcus e Enterobacteriaceae nos cecos dos frangos de crescimento lento; induziu a expressão gênica das enzimas ACACA e FASN nas aves de crescimento lento e da enzima CPT1-A nas aves de crescimento rápido; e reduziu a massa de gordura corporal nas aves de crescimento rápido. Durante a semana de restrição alimentar quantitativa, não foi verificado ganho de peso em ambas as linhagens. A restrição levou a: diminuição das contagens do grupo Lactobacillus e aumento de Enterococcus e Enterobacteriaceae nas aves de crescimento rápido; indução da expressão gênica de ACACA, FASN e SREBP- 1 e repressão da expressão de CPT1-A nas duas linhagens. No período de realimentação, foi observado comportamento hiperfágico, melhor ganho de peso e melhor conversão alimentar nas aves restritas. O ganho compensatório não foi suficiente para alcançar o mesmo peso vivo. Nos frangos de crescimento rápido, a deposição tecidual foi semelhante ao controle, porém nas aves de crescimento lento ocorreu maior deposição de gordura e menor deposição de proteína corporal nas aves restritas. Em conclusão, apesar da resposta das variáveis ganho de peso e conversão alimentar aos programas de restrição alimentar ter sido semelhante nos dois grupos genéticos, a composição e a estabilidade da microbiota intestinal de frangos de corte foram dependentes da linhagem. Adicionalmente, encontramos evidências sobre a relação entre expressão de genes lipogênicos hepáticos e a deposição de lipídeos na carcaça de frangos de corte, além de demonstrar modificações no padrão de deposição tecidual em função da velocidade de crescimento da linhagem.
The hypothesis of this project is that feed restriction alters the composition of gut microbiota and hepatic gene expression in broilers, and these changes can influence the tissue deposition of birds. The second hypothesis is that the broiler genetics influence on these variables, and can change the response in front of feed restriction. The specific objectives were investigated the response of broilers (fast – Cobb – or slow-growing – Label Rouge – strains), in front of two feed restriction programs (energetic or quantitative), on: 1) growth performance; 2) tissue deposition; 3) ileal and cecal microbiota; 4) expression of genes related to hepatic metabolism. For this, two experiments were conducted. In the experiment I, were used 480 male Cobb500TM broilers, and in the experiment II, were used 480 male Label Rouge broilers. Up to 21 days of age, the birds received the same diet and were created in thermoneutral temperature. At 22 days of age, birds were divided into 3 experimental treatments (8 replicates of 20 birds): T1. Control (ad libitum – 3.176 Mcal/kg ME and 19% CP); T2. Energetic restriction (2.224 Mcal/kg ME and 19% CP) up to 42 days with consumption equivalent to control; T3. Quantitative restriction (70% restriction, i. e., restricted broilers ingested only 30% of the quantity consumed by the control group – 3.176 Mcal/kg ME and 19% CP) for 7 days, followed by refeeding ad libitum until 42 days. Energetic restriction reduces body weight gain and carcass weight and increased feed conversion ratio in both strains; reduced the Lactobacillus and increased the Enterococcus and Enterobacteriaceae copies in fast-growing broilers; promoted the Lactobacillus proliferation and reduced Enterococcus and Enterobacteriaceae populations in ceca of slow-growing broilers; induced the gene expression of ACACA and FASN in slow-growing, and CPT1-A in fast-growing broilers; and reduced the fat mass in fast-growing broilers. During the quantitative feed restriction period, was not verified body weight gain, independently of strain. The restriction leads to: reduction in Lactobacillus and increase in Enterococcus and Enterobacteriaceae copies in fast-growing broilers; induction of ACACA, FASN and SREBP-1 and reduction in CPT1-A gene expression in both strains. During the refeeding period, was observed hyperphagic behavior, better body weight gain and lower feed conversion ratio in restricted birds. The compensatory growth was not sufficient to achieve the same 42d body weight than the control treatment. For slowgrowing broilers, there was greater fat deposition and lower protein deposition after refeeding, whereas for fast-growing broilers, no difference between control and restricted birds were found. In conclusion, although the body weight gain and feed conversion ratio response of two genetic groups in front of feed restriction programs is similar, the composition and stability of the intestinal microbiota are strongly dependent on host. Additionally, the present data provide evidence on the relationship between hepatic lipogenic gene expression and lipids deposition in broilers carcass, and demonstrated that changes in the tissue deposition is directly related to growth rate in broilers.
The hypothesis of this project is that feed restriction alters the composition of gut microbiota and hepatic gene expression in broilers, and these changes can influence the tissue deposition of birds. The second hypothesis is that the broiler genetics influence on these variables, and can change the response in front of feed restriction. The specific objectives were investigated the response of broilers (fast – Cobb – or slow-growing – Label Rouge – strains), in front of two feed restriction programs (energetic or quantitative), on: 1) growth performance; 2) tissue deposition; 3) ileal and cecal microbiota; 4) expression of genes related to hepatic metabolism. For this, two experiments were conducted. In the experiment I, were used 480 male Cobb500TM broilers, and in the experiment II, were used 480 male Label Rouge broilers. Up to 21 days of age, the birds received the same diet and were created in thermoneutral temperature. At 22 days of age, birds were divided into 3 experimental treatments (8 replicates of 20 birds): T1. Control (ad libitum – 3.176 Mcal/kg ME and 19% CP); T2. Energetic restriction (2.224 Mcal/kg ME and 19% CP) up to 42 days with consumption equivalent to control; T3. Quantitative restriction (70% restriction, i. e., restricted broilers ingested only 30% of the quantity consumed by the control group – 3.176 Mcal/kg ME and 19% CP) for 7 days, followed by refeeding ad libitum until 42 days. Energetic restriction reduces body weight gain and carcass weight and increased feed conversion ratio in both strains; reduced the Lactobacillus and increased the Enterococcus and Enterobacteriaceae copies in fast-growing broilers; promoted the Lactobacillus proliferation and reduced Enterococcus and Enterobacteriaceae populations in ceca of slow-growing broilers; induced the gene expression of ACACA and FASN in slow-growing, and CPT1-A in fast-growing broilers; and reduced the fat mass in fast-growing broilers. During the quantitative feed restriction period, was not verified body weight gain, independently of strain. The restriction leads to: reduction in Lactobacillus and increase in Enterococcus and Enterobacteriaceae copies in fast-growing broilers; induction of ACACA, FASN and SREBP-1 and reduction in CPT1-A gene expression in both strains. During the refeeding period, was observed hyperphagic behavior, better body weight gain and lower feed conversion ratio in restricted birds. The compensatory growth was not sufficient to achieve the same 42d body weight than the control treatment. For slowgrowing broilers, there was greater fat deposition and lower protein deposition after refeeding, whereas for fast-growing broilers, no difference between control and restricted birds were found. In conclusion, although the body weight gain and feed conversion ratio response of two genetic groups in front of feed restriction programs is similar, the composition and stability of the intestinal microbiota are strongly dependent on host. Additionally, the present data provide evidence on the relationship between hepatic lipogenic gene expression and lipids deposition in broilers carcass, and demonstrated that changes in the tissue deposition is directly related to growth rate in broilers.
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Palavras-chave
Ácido graxo sintase, Bacteroidales, Cobb, Composição corporal, Hiperfagia, Label Rouge, Body composition, Fat acid synthase, Hyperphagia