The objective of this study was to evaluate the effect of heat stress and methionine supplementation on the gene expression of insulin-like growth factor I (IGF-I), growth hormone receptor (GHR), phosphatidylinositol 3-kinase, and regulatory 1 (PI3KR1) in the liver, as well as the expression of the atrogin 1 and cathepsin L2 (CTSL2) genes in the breast muscle of broilers. Broilers from 1–21 and 22–42 days of age were divided into three treatments related to methionine supplementation as follows: without methionine supplementation (MD), recommended level of methionine (DL1), and excess supplementation of methionine (DL2). The animals were either maintained at a thermal comfort temperature or exposed to heat stress (HS) (38°C for 24 hours, starting on day 20 or day 41 for experiments 1 and 2, respectively). The heat stress increased the body temperature at both ages. Starter period: The HS animals presented increased plasma creatinine content (P<0.0001) and the highest CTSL2 gene expression (P<0.0001). The methionine supplementation increased the IGF-I (P = 0.0144) and GHR (P = 0.0011) gene expression and decreased the CTSL2 (P = 0.0004) and atrogin 1 (P = 0.0012) gene expression. Grower period: Significant effects for the interaction between supplementation and environment were observed for GHR (P = 0.0252) and CTSL2 (P = 0.0011) gene expression. The highest GHR expression was observed in animals that remained in thermal comfort on the DL2 diet, and the lowest expression occurred in the HS animals fed the MD diet. For CTSL2, the HS animals fed the MD diet presented the highest CTSL2 gene expression, and the lowest expression was observed in the animals maintained at thermal comfort on DL1 and DL2 diets. Only methionine supplementation had effect on atrogin-1 gene expression (P<0.0001), with higher methionine content in the diet lower atrogin-1 gene expression was observed. Our results suggest that heat stress induces greater protein degradation and that methionine supplementation could induce protein deposition because methionine increased the expression of genes related to protein synthesis and decreased the expression of genes related to protein breakdown.

The aim of the present study was to evaluate the effects of heat stress (HS) and methionine supplementation on the markers of stress and on the gene expression levels of uncoupling proteins (UCP), betaine -homocysteine methyltransferase (BHMT), cystathionine b-synthase (CBS), glutathione synthetase (GSS) and glutathione peroxidase 7 (GPx7). Broilers from 1 to 21 d and from 22 to 42 d of age were divided into three treatment groups related to methionine supplementation: without methionine supplementation (MD); recommended level of methionine supplementation (DL1); excess methionine supplementation (DL2). The broilers were either kept at a comfortable thermal temperature or exposed to HS (388C for 24 h). During the starter period, we observed the effects of the interaction between diet and environment on the gene expression levels of UCP, BHMT and GSS. Higher gene expression levels of UCP and BHMT were observed in broilers that were maintained at thermal comfort conditions and received the MD diet. HS broilers fed the DL1 and DL2 diets had the highest expression level of GSS. The expression levels of the CBS and GPx7 genes were influenced by both the environment and methionine supplementation. During the grower period, the gene expression levels of BHMT, CBS, GSS and GPx7 were affected by the diet £ environment interaction. A higher expression level of BHMT was observed in broilers maintained at thermal comfort conditions and on the MD diet. HS induced higher expression levels of CBS, GSS and GPx7 in broilers that received the DL1 and DL2 diets. The present results suggest that under HS conditions, methionine supplementation could mitigate the effects of stress, since methionine contributed to the increased expression levels of genes related to antioxidant activity.

The aims of the present study were to evaluate the possible effects of heat stress (HS) on H2O2 production and to evaluate whether methionine supplementation (MS) could mitigate the deleterious effects on cell metabolism and the redox state induced by oxidative stress. Meat quails (Coturnix coturnix coturnix) were fed a diet that either met the nutritional demands for methionine or did not meet this demand (methionine deficient [MD] diet) for 7 d. The animals were either kept at a thermal comfort temperature (25°C) or exposed to HS (38°C for 24 h, starting on the sixth day). Heat stress induced decreased food intake (P = 0.0140), decreased daily weight gain (P < 0.0001), and increased water intake (P = 0.0211). A higher rate of H2O2 production was observed in HS animals (0.0802 vs. 0.0692 nmol of reactive oxygen species [ROS] produced per minute per milligram of protein; P = 0.0042) and in animals fed with the MD diet (0.0808 vs. 0.0686 nmol of ROS produced per minute per milligram of protein; P = 0.0020). We observed effects of the interaction between diet and the environment on the activities of glutathione peroxidase (GP-x) and catalase (P = 0.0392 and P < 0.0001, respectively). Heat stress induced higher levels of GP-x activity in animals on the MS diet and higher catalase activity in animals on the MD diet. Glutathione (GSH) levels were higher in animals on the MS diet (P = 0.0273) and in animals that were kept in thermal comfort (P = 0.0018). The thiobarbituric acid reactive substances level was higher in HS animals fed with the MD diet (P = 0.0386). Significant effects of the interaction between supplementation and environment were observed on uric acid concentration levels, which were higher in HS animals fed the MS diet (P = 0.008), and on creatine kinase activity levels, which were lower in HS animals fed the MD diet (1,620.33 units/L; P = 0.0442). Our results suggest that under HS conditions, in which H2O2 production is increased, MS was able to mitigate ROS-induced damage, possibly by increasing the activities of antioxidant elements such as GSH, GPx activity, and uric acid concentration, which were present in higher levels in animals that were subjected to HS and fed the MS diet.

A automatização total dos aviários e as inovações tecnológicas nas instalações de frangos de corte têm sido geradas ao logo dos anos, e vários modelos de galpões podem ser encontrados a campo com diferentes finalidades. Por ser um dos seguimentos mais modernos da criação animal a avicultura de corte cresce a cada ano e também a busca por melhorias nas instalações para acomodação das aves. Entretanto, para cada região devem ser observados os fatores meteorológicos que podem prejudicar a produção das aves, e a partir disso escolher o tipo de criação e posteriormente o tipo de galpão que atende as condições daquela região. Nesta revisão o intuito é trazer informações sobre os sistemas de criação e acondicionamento térmico em instalações para frangos, bem como o impacto destes sobre o bem-estar e a produção de carne. Aliando ao melhoramento genético, o manejo, a sanidade e a nutrição adequada para as aves, as instalações possuem importância significativa principalmente no quesito do conforto animal, tendo em vista que em situações que geram estresse o animal tem muita dificuldade em expressar todo seu potencial genético. Neste contexto, uma instalação adequada é essencial para trazer um retorno da produção, devem-se tomar como preocupação principal as condições ambientais dentro das instalações para as aves, por meio do controle da temperatura, da umidade relativa do ar, da radiação solar e da velocidade e qualidade do ar, esses fatores estão intimamente ligados com o bom desempenho do lote, assim, o controle do ambiente é uma das características preponderantes para garantir o conforto e bem-estar das aves e melhorar a qualidade do produto final. O objetivo desta revisão é reunir informações sobre o acondicionamento térmico para frangos de corte, possibilitando assim ter uma noção do que é importante para um bem-estar ideal.

-An experiment was conducted to estimate the parameters of the Gompertz, Brody, Logistic, and Von Bertalanffy equations through Bayesian inference and evaluate the potential for growth in terms of weight and body composition of laying female quail (Coturnix coturnix japonica). The weights and body compositions of the birds were obtained weekly (1-119 days), allowing the adjustment of the four equations by Bayesian inference. The parameters mature weight (β1), integration constant (β2), maturity rate (β3), and their credibility intervals in four models on body weight and body components were properly estimated by Bayesian inference to describe the body growth in laying quail. The inflection point was determined by the 1st and 2nd derivatives of the Gompertz equation for body weight and body components (fat, protein, ash, and water). Based on Deviance Information Criterion (DIC) for the studied and analyzed variables, there is a model that fits best as a result of its better performance to achieve the DIC value. The Von Bertalanffy model proved to be very versatile, not obtaining good fit of data only for fat. The study shows that other models can also be used in several data sets as an alternative to Gompertz, which, due to its adequate biological interpretation and desirable characteristics in a curve growth, is generally the most used.

1. The objective of this study was to estimate growth parameters of carcass components (wing, thighs and drumsticks, back and breast) and organs (heart, liver, gizzard and gut) in males and females of one meat-type quail strain (Coturnix coturnix coturnix) and two laying strains (Coturnix coturnix japonica) designated either yellow or red. 2. A total of 1350 quail from 1 to 42 d old were distributed in a completely randomised design, with 5 replicates of each strain. The carcass component weights and body organs were analysed weekly and evaluated using the Gompertz function; growth rates were evaluated through derivative equations. 3. The meat-type strain presented the highest growth rates in carcass components and organs. Across strains, females showed the highest weight of internal organs at maturity compared to males. 4. Females had greater growth potential in breast, wings and back than males for both yellow and red laying quail.

No abstract

The aim of this study was to assess the goodness of fit for nonlinear models, using the best model to describe body growth curves, comparing the parameters obtained for gender and one meat-type (Coturnix coturnix coturnix) and two laying (Coturnix coturnix japonica) quail strains, as well as nesting via MCMC (Markov chain Monte Carlo processes) methods under a Bayesian approach. A total of 1,350 one-day-old mixed quail were used: 400 of meat-type, 450 of yellow laying, and 500 of red laying strains distributed in a completely randomized design with three treatments (each treatment corresponded to one strain) and five replications. The experimental period consisted of 1 to 42 days of age. At 21 days of age, quail sexing was performed by means of sexual dimorphism, being individually identified at one day of age with numbered rings, allowing determining growth curves by gender. Birds were reared in a conventional system, fed ad libitum with diets formulated to meet nutritional requirements. Body weight was determined weekly and assessed using nonlinear models: Logistic, Brody, Von Bertalanffy, and Gompertz. DIC (Deviance Information Criterion) criterion was used to select the best nonlinear model, i.e. the lower the DIC value is, the better the model goodness of fit to the data. Gompertz model was better adjusted to the data regardless the gender or strain. Meat-type quail had the highest asymptotic weights and the highest age at which growth rate was maximum, followed by red and yellow strains. All nestings presented significant differences (p < 0.05) between gender for contrasted parameters. Meat-type, yellow, and red females presented values significantly (p < 0.05) higher for asymptotic weight (370, 203, and 215 g, respectively) when compared to males (274, 131, and 143 g, respectively), which were earlier in body growth. Key words: Deviance information criterion. Gompertz equation. Nonlinear models. Body weight. ResumoO objetivo deste trabalho foi avaliar a qualidade de ajuste dos modelos não lineares aos dados, utilizando o melhor modelo para descrever as curvas de crescimento corporal, comparando os parâmetros obtidos para gênero e uma linhagem de codornas de corte (Coturnix coturnix coturnix) e duas de postura (Coturnix coturnix japonica), bem como o aninhamento, via método MCMC (Cadeias de Markov em processos de Monte Carlo), sob o enfoque Bayesiano. Foram utilizadas 1.350 codornas mistas, com um dia de idade, sendo: 400 da linhagem de corte, 450 de postura amarela e 500 de postura vermelha, distribuídas por um delineamento inteiramente casualizado, com três tratamentos (cada tratamento corresponde a uma linhagem) e cinco repetições. O período experimental foi de 1 a 42 dias de idade. Aos 21 dias de idade foi realizada a sexagem por dimorfismo sexual, sendo que elas foram identificadas individualmente com um dia com anilhas numeradas, possibilitando a determinação das curvas de crescimento por gênero. As aves foram criadas em um sistema convencional, alimentadas ad libitum com rações formuladas p...