Levels of digestible lysine in nutricional plans for broilers in different thermal environments

Foram conduzidos dois experimentos para avaliar o efeito de diferentes planos nutricionais, com sequências de níveis de lisina digestível (Ld), no desempenho e nas características de carcaça de frangos de corte de 1 a 46 dias de idade mantidos em ambiente termoneutro e de estresse por calor. Em cada experimento foram utilizados 360 pintos de corte machos da linhagem Cobb, distribuídos em um delineamento inteiramente casualizado, com cinco tratamentos, representados pelos planos nutricionais (1,12-1,02-0,93-0,89; 1,17-1,07-0,98-0,94; 1,22-1,12-1,03-0,99; 1,27-1,17- 1,08-1,04 e 1,32-1,22-1,13-1,09% de Ld, respectivamente, para as fases de 1 a 10, 11 a 23, 24 a 40 e 41 a 46 dias), nove repetições e oito aves por unidade experimental. No experimento 1, as aves foram mantidas em câmaras climáticas com temperatura do ar e umidade relativa controladas de forma a caracterizar um ambiente de termoneutralidade, e no experimento 2 (ambiente de estresse por calor) a temperatura do ar e a umidade relativa nas câmaras foram, respectivamente, de 34,5 ± 1,01 ºC e 70 ± 5,5 %, de 1 a 23 dias, e de 31,7 ± 0,58 ºC e 67 ± 4,2 %, de 24 a 46 dias de idade. Durante todo o experimento, as aves receberam rações experimentais e água à vontade. As variáveis consumo de ração (CR), ganho de peso (GP) e conversão alimentar (CA) foram avaliadas no período de 1 a 23 e de 1 a 46 dias de idade das aves. Ao final do período experimental (46 dias), as aves foram abatidas e as carcaças foram evisceradas, pesadas e submetidas aos cortes. No experimento 1, não se observou efeito dos planos nutricionais no CR das aves em nenhum dos períodos avaliados. Os planos nutricionais influenciaram o GP e a CA das aves, sendo que os planos 4 e 5 proporcionaram os melhores resultados. Observou-se efeito dos planos nutricionais no peso absoluto da carcaça, do peito, da coxa e da sobrecoxa e no peso relativo da sobrecoxa, onde as melhores respostas foram também observadas nos frangos que receberam as rações correspondentes aos planos 4 e 5. No experimento 2, o CR das aves não variou entre os planos nutricionais no período de 1 a 23 dias, porém o GP e a CA dos frangos foram influenciados, sendo que os planos 4 e 5 proporcionaram os melhores resultados. No período de 1 a 46 dias, não foi constatado efeito significativo dos planos no CR, GP e CA das aves. Não se observou efeito dos planos nutricionais nos pesos absoluto e relativo da carcaça e no peso absoluto do peito, no entanto, o peso relativo do peito variou, sendo que os frangos de corte que receberam o plano 1 apresentaram o melhor resultado. Foi verificado efeito significativo dos planos nutricionais nos pesos absoluto e relativo da coxa e da sobrecoxa dos frangos, em que o plano 2 proporcionou resultados satisfatórios. Conclui-se que o plano nutricional 4 (1,27-1,17-1,08-1,04% de Ld) atendeu as exigências de lisina digestível para melhores resultados de desempenho, carcaça e cortes nobres de frangos de corte de 1 a 46 dias mantidos em ambiente termoneutro. No ambiente de estresse por calor, o plano nutricional 1 (1,12; 1,02; 0,93 e 0,89% de Ld) garantiu o atendimento das exigências nutricionais para desempenho e rendimento de carcaça e peito dos frangos, enquanto o plano nutricional 2 (1,17; 1,07; 0,98 e 0,94% de Ld) foi suficiente para otimizar a deposição muscular na coxa e sobrecoxa de frangos de corte de 1 a 46 dias de idade.Two experiments were conducted to evaluate the effect of different nutritional plans with sequences of digestible lysine levels on performance and on carcass characteristics of broilers from 1 to 46 days of age maintained in thermoneutral and heat stress environment. In each experiment, 360 male chicks Cobb were distributed in a completely randomized design with five treatments, represented by nutritional plans (1,12-1,02-0,93-0,89; 1,17-1,07-0,98-0,94; 1,22-1,12-1,03-0,99; 1,27-1,17-1,08-1,04 e 1,32-1,22-1,13-1,09% of digestible lysine, from 1 to 10, 11 to 23, 24 to 40 and 41 to 46 days, respectively), nine replicates and eight birds per experimental unit. In experiment 1, the birds were maintained in climatic chambers with controlled air temperature and relative humidity in order to characterize a thermoneutral environment and in experiment 2 (heat stress environment), the air temperature and relative umidity were 34,5 ± 1,01 ºC e 70 ± 5,5 %, from 1 to 23 days and of 31,7 ± 0,58 ºC e 67 ± 4,2 %, from 24 to 46 days, respectively. The birds received the experimental diets and water ad libitum throughout the experiment. The feed intake (FI), weight gain (WG) and feed conversion (FC) were evaluated in the period of 1 to 23 and 1 to 46 days of age of the birds. At the end of the experimental period (46 days), the birds were slaughter and the carcasses were eviscerated, weighed and subjected to cuts. In experiment 1 there was no effect of nutritional plans on FI of birds in any of the periods. The nutritional plans affected the WG and FC, whereas the plans 4 and 5 provided the best results. Effect was observed of nutritional plans on the absolute weight of carcass, breast, thigh and drumstick and on the relative weight of the drumstick, where the best responses were also observed in broilers that received the corresponding diets to plans 4 and 5. In experiment 2, there was no effect of nutritional plans on FI of birds from 1 to 23 days, but the WG and FC of broilers were influenced, whereas the plans 4 and 5 provided the best results. There was no effect on FI, WG and FC for broilers from 1 to 46 days. There was no effect of nutritional plans on absolute and relative weight of carcass and on absolute weight of breast, but the relative weight of breast varied, whereas the broilers that received the nutritional plan 1 showed the best results. Effect was observed of nutritional plans on the absolute and relative weight of thigh and drumstick of the broilers, in that the nutritional plan 2 provided satisfactory results. It was conclude that the nutritional plan 4 (1,27-1,17-1,08-1,04% of digestible lysine) meets the requirements of digestible lysine for best results of performance, carcass and prime cuts of broilers from 1 to 46 days old maintained in thermoneutral environment. In heat stress environment the nutritional plan 1 (1,12; 1,02; 0,93; 0,89% of digestible lysine) meet the nutricional requirements of performance and relative weight of carcass and breast of the birds, while the nutritional plan 2 (1,17; 1,07; 0,98 e 0,94% of digestible lysine) was sufficient to optimize muscle deposition in thigh and drumstick of broilers from 1 to 46 days old.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Digestible methionine + cysteine / digestible lysine ratio in diets for broilers under different thermal environments

Dois experimentos foram conduzidos no Departamento de Zootecnia da Universidade Federal de Viçosa para avaliar diferentes relações Metionina + Cistina/ Lisina digestíveis (Met+Cis/LisD) no desempenho, características de carcaça, concentração de malonaldeído (MDA) no peito e na avaliação da glutationa reduzida (GSH) no soro de frangos de corte, no período de 8 a 21 e de 8 a 42 dias de idade, criados em dois ambientes térmicos. Setecentos e vinte pintos de corte machos sexados da linhagem COBB 500 TM foram distribuídos em delineamento inteiramente casualizado constituído por cinco tratamentos, nove repetições e oito aves por unidade experimental. Os tratamentos consistiram de cinco relações Met+Cis/LisD (64, 68, 72, 76 e 80%) para as diferentes fases avaliadas. As aves foram mantidas em câmaras climáticas com temperatura do ar e umidade relativa controladas de forma a caracterizar um ambiente termoneutro de acordo com o manual da Cobb (Artigo 1) e de estresse por calor (Artigo 2). Durante ambos os experimentos, as aves receberam as rações e a água à vontade. No experimento 1, as relações Met+Cis/LisD da dieta influenciaram o peso final (PF) e o ganho de peso (GP) das aves de 8 a 21 dias de idade, que variaram de forma quadrática sendo estimado em 74% a relação que proporcionou os melhores valores. A conversão alimentar (CA) também foi influenciada pelas diferentes relações, melhorando até a relação de 73%. Com relação aos dados de 8 a 42 dias de idade, foi observado que o PF e o GP melhoraram até a relação de 73% A CA foi reduzida de forma linear de acordo com o aumento das relações Met+Cis/LisD. Não foi observada diferença significativa no consumo de ração dos frangos em nenhum dos períodos de avaliação. Observou-se resposta linear crescente das relações no peso absoluto da carcaça, do peito, da coxa e da sobrecoxa e no peso relativo da carcaça e do peito das aves. O peso relativo da coxa e da sobrecoxa dos frangos não foi influenciado pelos tratamentos. Não foi verificado efeito das relações Met+Cis/LisD na concentração de MDA no músculo do peito nem na concentração de GSH no soro das aves no experimento 1. Conclui- se que, em ambiente termoneutro, as relações Met+Cis/LisD que proporcionaram os melhores dados de desempenho nos períodos de 8 a 21 e de 8 a 42 dias e dos parâmetros de carcaça são 73 e 80%. No experimento 2, as relações Met+Cis/LisD da dieta influenciaram o peso final (PF) e o ganho de peso (GP) das aves de 8 a 21 dias de idade, que variaram de forma quadrática até a relação estimada de 73% que proporcionou os maiores valores. O consumo de ração dos frangos aumentou de forma quadrática até a relação estimada de 72%. A conversão alimentar (CA) foi influenciada pelas diferentes relações, melhorando até a relação de 74%. Com relação aos dados de 8 a 42 dias de idade das aves, foi observado que o PF e o GP foram melhorados de forma quadrática de acordo com o aumento das relações Met+Cis/LisD até a relação estimada em 73%. O consumo de ração dos frangos de 8 a 42 dias aumentou até a relação de 72%. A conversão alimentar reduziu de forma linear no período total de avaliação. Verificou-se resposta quadrática das diferentes relações no peso absoluto da carcaça e no peso absoluto e relativo do peito, que aumentaram até a relação de 73%. O peso absoluto da coxa melhorou até a relação de 72%. A concentração de GSH no soro das aves aumentou linearmente com o aumento das relações dos aminoácidos sulfurados com a lisina. Pode-se concluir que no ambiente de alta temperatura, a relação Met+Cis/LisD que proporcionou os melhores dados de desempenho no período de 8 a 21 dias foi estimada em 74%, enquanto que no período de 8 a 42 dias, a relação estimada de 80% promoveu a melhor conversão alimentar das aves deste estudo.Two experiments were conducted to evaluate different methionine + cystine / digestible lysine (Met + Cis/LisD) ratios in performance, carcass characteristics, malonaldehyde concentration (MDA) in the breast and serum reduced glutathione (GSH) of broiler chickens from 8 to 21 and from 8 to 42 days of age, raised in two thermal environments. Seven hundred and twenty male COBB chicks were distributed in a completely randomized design consisting of five treatments, nine replicates and eight birds per experimental unit. The treatments consisted in five Met + Cis/LisD ratios (64, 68, 72, 76 and 80%) for the different phases evaluated. The broilers were kept in climatic chambers with controlled air temperature and relative humidity in order to characterize a thermoneutral environment according to the Cobb management guide (Article 1) and heat stress environment (Article 2). Throughout the both of experiments, the broilers received the diets and water ad libitum. In experiment 1, the Met + Cis / LisD ratios of the diet influenced the final weight (FW) and the weight gain (WG) of birds from 8 to 21 days of age, which varied quadratically, estimating in 74% the ratio that provided the highest values. Feed conversion (FC) was also influenced by the different ratios, which improved up to the 73%. Regarding the 8 to 42 day old datas, it was observed that the FW and WG were improved until the ratio of 73% according to the increase of Met+Cis/LisD ratios. FC was linearly improved. There was no significant difference in broiler feed intake in any of the evaluation periods. There was increasing linear response of the different relationships in absolute weights of carcass, breast, thigh and drumstick and in relative weight of carcass and broiler breast. Relative weights of thigh and drumstic were not influenced by treatments. No significant effect of Met + Cys / LisD ratios on MDA concentration in breast muscle or on GSH concentration in poultry serum was observed. It was concluded that in the thermoneutral environment, the Met + Cys/ LisD ratios of 73 e 80% provided the best results of performance and carcass parameters for broilers from 8 to 21 and from 8 to 42 days, respectively. In experiment 2, the Met + Cis / LisD ratios of the diet influenced the final weight (FW) and the weight gain (WG) of birds from 8 to 21 days of age, which varied quadratically, estimating in 73% the ratio that provided the highest values. Feed intake was greater quadratically until the ratio of 72%. Feed conversion (FC) was also influenced by different ratios, which improved up to a 74% ratio. Regarding the 8 to 42 day old datas, it was observed that the FW and WG were improved quadratically according to the increase of the Met + Cis / LisD ratios up to the estimated ratio of 73%. Feed consumption of broilers from 8 to 42 days increased up to 72%. Feed conversion reduced linearly over the whole evaluation period. There was a quadratic response of the different ratios in the absolute carcass weight and in absolute and relative weight of breast, which increased up to 73%. The absolute weight of the thigh was also influenced by the treatments, improving up to 72%. No significant effect of Met + Cys / LisD ratios on MDA concentration was observed in the breast muscle. The concentration of GSH in the serum of the broilers increased linearly according to the increase of the evaluated ratios. It can be concluded that in heat stress environment the ratio Met+Cis/LisD of 74% meets the requirements for best performance for broiler from 8 to 21 days of age. To the phase from 8 to 42 days of age, the 80% ratio provided the best feed conversion for broilers ins this experiment

Non-phytate phosphorus requirement for broilers from 8 to 21 days of age under heat stress conditions

Two trials were conducted to determine the non-phytate phosphorus (nPP) requirement for broiler under heat stress. In both trials, birds were distributed in a completely randomized 4 × 2 factorial design with four nPP concentrations: 0.25, 0.35, 0.45, and 0.55%, and two Ca supply techniques: Ca fixed at 0.899% (CaF) or varying along with nPP aiming a 2:1 Ca to nPP ratio (CaV). Both trials had eight pens/treatment, with nine and five birds/pen for exp. 1 and exp. 2, respectively. nPP concentration had no effect on feed intake (FI), body weight gain (BWG), feed conversion ratio (FCR), nor fat deposition ratio (FDR). nPP levels showed a linear effect on protein deposition ratio (PDR) only for CaF diets. The nPP levels had a significant effect, regardless the technique adopted, on tibia phosphorus (TibP), which varied quadratically, on tibia calcium (TibCa) that increased quadratically and linearly, respectively, on CaF and CaV diets, and on tibia ash (TibAsh) that showed a quadratic effect for both. No effect was observed on Ca to P ratio in the tibia (TibCa:TibP). The nPP levels showed a linear increase effect over phosphorus intake (PI), phosphorus excreted (PE), and phosphorus retained (PR), and a linear decrease effect on phosphorus retention coefficient (PRC). Therefore, the nPP requirement for broilers from 8 to 21 days of age that provided better performance and bone variables were 0.250 and 0.484%, respectively, for CaF diets and 0.250 and 0.511%, respectively, for CaV diets

Glutamine for broilers from 21 to 42 days maintained in thermoneutral environment

This study was conducted to evaluate the effects of dietary glutamine levels on performance and carcass traits of broilers kept in thermoneutral environment from 21 to 42 days of age. Hundred sixty eight male broilers Cobb® with 21 days of age and initial body weight of 900 ± 4.71 g were allotted in a completely randomized design with four levels of glutamine (0.00, 0.50, 1.00 and 1.50%), seven replicates with six birds each. Performance, relative weights of carcass, breast, thigh and drumstick and mRNA expression of HSP70 were evaluated. Birds were housed in environmental chambers with temperature of 23.2 ± 1.77ºC and relative humidity of 70 ± 5.82% corresponding to a calculated BGHI of 72 ± 2.75, which characterize thermoneutral environment. There was no effect of glutamine on feed intake, weight gain, and feed conversion of broilers. Glutamine had no influence on absolute and relative weights of carcass, breast, thigh, and drumstick of birds. There was not effect of dietary glutamine on mRNA expression of HSP70. Dietary glutamine did not affect performance and carcass traits of broilers from 21 to 42 days of age maintained in thermoneutral environment

Available phosphorus levels in diets supplemented with phytase for male broilers aged 22 to 42 days kept in a high-temperature environment

ABSTRACT This study was conducted to evaluate the effect of reduction of the available phosphorus (avP) in diets supplemented with 500 FTU/kg phytase on performance, carcass characteristics, and bone mineralization of broilers aged 22 to 42 days kept in a high-temperature environment. A total of 336 Cobb broilers with an average initial weight of 0.883±0.005 kg were distributed in a completely randomized design with six treatments - a positive control (0.354 and 0.309% avP without addition of bacterial phytase for the phases of 22 to 33 and 34 to 42 days, respectively), and another five diets with inclusion of phytase (500 FTU) and reduction of the level of avP (0.354, 0.294, 0.233, 0.173, and 0.112%; and 0.309, 0.258, 0.207, 0.156, and 0.106% for the phases of 22 to 33 and 34 to 42 days, respectively) - eight replicates, and seven birds per cage. The experimental diets were formulated to meet all nutritional requirements, except for avP and calcium. Birds were kept in climatic chambers at a temperature of 32.2±0.4 °C and air humidity of 65.3±5.9%. Phytase acted by making the phytate P available in diets with reduction in the levels of avP, keeping feed intake, weight gain, feed:gain, and carcass characteristics unchanged. Treatments affected ash and calcium deposition and the Ca:P ratio in the bone; the group fed the diets with 0.112 and 0.106%, from 22 to 33 and 34 to 42 days of age, respectively, obtained the lowest values, although the phosphorus deposition in the bone was not affected. Diets supplemented with 500 FTU of phytase, with available phosphorus reduced to 0.173 and 0.156%, and a fixed Ca:avP ratio of 2.1:1, meet the requirements of broilers aged 22 to 33 and 34 to 42 days, respectively, reared in a high-temperature environment

Evaluation of soils under the influence of coal mining and a thermoelectric plant in the city of Candiota and vicinity, Brazil

Coal burning generates gases, particles, and condensation by-products that are harmful to soil, water, and to the atmosphere. The aim of this study was to characterize and identify the cytotoxic and mutagenic potential of soil samples from the cities of Aceguá, Bagé, Candiota and Pinheiro Machado, near a large coal-fired power plant. Our study describes soil characteristics and contributes to the evaluation of the genotoxic activity of coal mining and burning, using the Comet Assay and Micronucleus test in V79 cells, as well as mutagenicity assays with Salmonella typhimurium strains. Comet Assay results show that the winter soil samples of Candiota and Pinheiro Machado induced a significant increase of the Damage Index for cells, as well as for the Aceguá summer sample. The micronucleus test did not detect differences between cities and seasons. A component analysis indicates associations between results obtained in Comet Assay and Ti and phenanthene concentrations for Pinheiro Machado during the winter, and Al for Aceguá during the summer and Zn during the winter. Results of Salmonella/microsome assays were negative, only Candiota and Pinheiro Machado samples showed a statistical increase of his + colonies in TA102. Our work describes biological data on these cells exposed to coal-contaminated soil, confirming the sensitivity of the Comet Assay in V79 cells and Salmonella/microsome assay for the evaluation of the effects of complex mixtures. These findings help to understand the spatial distribution of contaminants in the local soil related to a power plant, which is important for planning public safety actions

Evaluation of the cytotoxic and genotoxic effects of Sida planicaulis Cav extract using human neuroblastoma cell line SH-SY5Y

Sida planicaulis is a weed thought to have originated in Brazil, where it is present in abundant quantities, but also this plant is also found in south-central Florida, Indian Ocean Islands, and the Pacific Islands. Sida planicaulis produces neurotoxicity that adversely affects livestock breeding with heavy animal losses and consequent negative impact on Brazil’s economy. The aim of this study was to determine the chemical profile, cytotoxic and genotoxic effects of ethanolic extracts of S. planicaulis collected in winter (leaf extract) and summer (leaf extract and leaf + flower extract) using an in vitro model of human neuroblastoma cell line SH-SY5Y. Phytochemical screening demonstrated the presence of alkaloids, flavonoids, and apolar compounds. Rutin, quercetin, and swainsonine were detected by HPLC and GC/MS, respectively. Phosphorus, potassium, iron, and zinc were the inorganic elements found. Extracts produced cytotoxicity at all concentrations tested (7–4,000 μg/ml) as evidenced by the colorimetric assay [3-(4,5-dimethyl-thiazol-2-yl) −2,5-diphenyltetrazolium bromide (MTT)]. Based upon the alkaline comet assay extracts were found to induce genotoxicity at concentrations ranging from 0.437 to 7 μg/ml. DNA damage produced by extracts was affirmed using a modified comet assay with the enzymes Endo III and FPG in a concentration dependent manner. Further, enzyme-modified comet assay showed both oxidized purines and pyrimidines, and consequently oxidative stress was related to genomic instability and cell death. Data suggest that low concentrations of ethanolic extracts of S. planicaulis (different seasons) induced increased DNA damage related to oxidative stress and chemical composition

Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care. We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care