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Efficient meat production is crucial in addressing global market demands and sustainability goals. Modeling production systems has gained worldwide attention, offering valuable insights for predicting outcomes and optimizing economic returns. In the poultry industry, researchers have developed mathematical models to predict animal performance and maximize profits. These models incorporate theories to explain real-world processes and enable future event predictions. One such model is the Broiler Growth Model (BGM), which serves as a predictive tool for estimating feed intake, growth, and body composition of broilers. The BGM takes into account the genetic potential of the broilers, the feed they are provided, and several constraining factors that may prevent the animal from achieving their genetic potential. To evaluate the BGM, a series of simulations were performed: (i) model behavior was evaluated by simulating the response of males and females from 22 to 35 d to feeds differing in dietary protein content and nutrient density; (ii) model prediction was evaluated using the results of a protein response trial conducted at UNESP in which six dietary protein levels were fed to male and female broilers over a 56 d period; and (iii) model optimization was used to maximize economic returns in the above trial. The model behaved as expected when feeds differing in protein content were fed, with feed intake per kg of BW increasing as protein level was decreased, resulting in lower gains and higher body lipid contents. Increasing nutrient density resulted in higher feed intake in the second level, followed by a reduction in feed intake in the highest nutrient feed. The simulated response to nutrient density resulted in increasing body lipid deposition as the nutrient density increased. In comparing the simulated and actual results of the protein response trial, the overall error of prediction was up to 15% for feed intake, BW, and body protein. The optimization routine allows the simulation of different economic scenarios, helping in decision-making. The Broiler Growth Model emerges as a valuable tool for the poultry industry, offering predictive capabilities and economic optimization potential. While minor discrepancies between simulated and actual results exist, the BGM holds significant promise for enhancing efficiency and profitability in broiler production, contributing to the broader goals of sustainable broiler meat production.

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This study evaluates the removal of COD and nitrogen from poultry wastewater in photobioreactors. Cell growth, the effect of light intensity (3200, 9800, and 12000 lux) and air flow (1.6, 3.2, and 4.8 L min-1) as a source of CO2 in bold basal medium and wastewater with different concentrations of COD were evaluated. The growth kinetics were modeled by using the Gompertz model and logistic model for both culture media. COD removals of up to 95% were achieved, and poultry wastewater was found to be a viable growing medium for Chlorella vulgaris. Finally, the wastewater met Mexican standards, and biomass was obtained with products valued as lipids (3.2 g lipid/100 g biomass) and proteins (342.94 mg L-1). The culture was found to have a dilatory behavior, and the rheological models of Ostwald de Waele, Ostwald de Waele linealized and Herschel Bulkley were utilized, showing a laminar behavior.

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Feathers make up 7% of the total weight of adult chickens and keratin protein makes up 85% of the feathers. Today, the keratinase enzymes of some Bacillus strains are used to degrade and process raw keratin waste for animal and poultry feed. According to various studies, the probiotic properties of some spore-shaped Bacillus have also been proven. The study aimed to isolation of the keratinolytic Bacillus bacteria that they have probiotic properties for using in the livestock and poultry feed industry. We were able to isolate 8 strains of Bacillus licheniformis with kreatin degrading properties from the soil of Baharan chicken slaughterhouse (Qom city, Iran) applying heat shock, alcohol- and keratin-rich culture medium, and after microscopic and biochemical analysis, 16S rDNA gene was isolated. The measurement results of keratinase activity showed that the three strains of Bacillus licheniformis pvkr6, pvkr 15, and pvkr41 had the highest activity with 124.08, 101.1, and 100.18 U/ml. The results of probiotic properties evaluation also revealed that among all the isolates, only Bacillus licheniformis pvkr15 and Bacillus licheniformis PTCC 1595 (positive control) were γ-hemolytic strains. The percentage of surface hydrophobicity of the strains was obtained from 3.27 to 30.57. It was also shown that, on average, all the strains had acceptable susceptibility to the tested antibiotics except penicillin G. Bacillus licheniformis pvkr15 with highest keratinase activity (101.1U/ml) was considered an optional probiotics due to its abilities such as (biofilm formation, being safe cause of γ-hemolytic activity, high susceptibility to antibiotics such as streptomycin, gentamicin, cefixime, amoxicillin, tetracycline, vancomycin, erythromycin and having a moderate hydrophilic (hydrophobicity: 19.09%), high survivability in pH 2, 2.5 and 3, strong resistance to bile salts and moderate antagonistic activity against pathogenic bacterium like Proteus mirabilis and the ability to grow under anaerobic conditions). By using this strain, after hydrolysis of keratin protein in the feather structure, to replace part of the protein of livestock and poultry feed, not only is no need to separate bacteria from the feed, but also the strain play role of an useful and effective additive in animal growth.

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The present study proposes a Gaussian process regression (GPR) approach to develop a model to predict true metabolizable energy corrected for nitrogen (TMEn) content of corn samples (as model output) for poultry given levels of feed chemical compositions of crude protein, ether extract, crude fiber, and ash (as model inputs). A 30 corn samples obtained from 5 origins [Brazil (n = 9), China (n = 5), Iran (n = 7), and Ukraine (n = 9)] were assayed to determine chemical composition and TMEn content using chemical analyses and bioassay technique. In addition to GPR model, data were also analyzed by multiple linear regression (MLR) model. Results revealed that corn samples of different origins differ in their gross energy and chemical composition of crude protein, crude fiber, and ash, but no differences were observed for their ether extract and TMEn contents. Based on model evaluation criteria of R2 and root mean square error (RMSE), the GPR model showed satisfactory performance (R2 = 0.92 and RMSE = 33.68 kcal/kg DM) in predicting TMEn and produced relatively better prediction values than those produce by MLR (R2 = 0.23 and RMSE = 104.85 kcal/kg DM). The GPR model may be capable of improving our aptitude and capacity to precisely predict energy contents of feed ingredients to formulate optimal diets for poultry.

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Aflatoxin B1 aldehyde reductase (AFAR) enzyme activity has been associated to a higher resistance to the aflatoxin B1 (AFB1) toxicity in ethoxyquin-fed rats. However, no studies about AFAR activity and its relationship with tolerance to AFB1 have been conducted in poultry. To determine the role of AFAR in poultry tolerance, the hepatic in vitro enzymatic activity of AFAR was investigated in liver cytosol from four commercial poultry species (chicken, quail, turkey and duck). Specifically, the kinetic parameters Vmax, Km and intrinsic clearance (CLint) were determined for AFB1 dialdehyde reductase (AFB1-monoalcohol production) and AFB1 monoalcohol reductase (AFB1-dialcohol production). In all cases, AFB1 monoalcohol reductase activity saturated at the highest aflatoxin B1 dialdehyde concentration tested (66.4 µM), whereas AFB1 dialdehyde reductase did not. Both activities were highly and significantly correlated and therefore are most likely catalyzed by the same AFAR enzyme. However, it appears that production of the AFB1 monoalcohol is favored over the AFB1 dialcohol. The production of alcohols from aflatoxin dialdehyde showed the highest enzymatic efficiency (highest CLint value) in chickens, a species resistant to AFB1; however, it was also high in the turkey, a species with intermediate sensitivity; further, CLint values were lowest in another tolerant species (quail) and in the most sensitive poultry species (the duck). These results suggest that AFAR activity is related to resistance to the acute toxic effects of AFB1 only in chickens and ducks. Genetic selection of ducks for high AFAR activity could be a means to control aflatoxin sensitivity in this poultry species.

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The present study reports the in vitro studies with furafylline and troleandomycin (TAO) as specific inhibitors of activities 7-methoxyresorufin-O-demethylase (MROD) and nifedipine oxidase, catalyzed by cytochrome P450 1 A2 (CYP1 A2) and 3A4 human enzymes, respectively, in hepatic microsomes of quail, duck, turkey and chicken. The results suggest that in chicken and quail the MROD activity is carried out by orthologs CYP1 A4 and 1 A5, meanwhile in duck and turkey by a CYP1 A5 ortholog. The nifedipine oxidase activity is carried out by orthologs of the CYP3A family in the four bird species. The use of furafylline and TAO significantly decreased these activities (P < 0.05) and suggested that the biotransformation of resorufin methyl ether (RME) may be related to more than one avian ortholog.

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Dietary inclusion of lipid sources has been one of the methods adopted by nutritionists aiming at better energy balancing. However, alternative energy feedstuffs have been sought in an attempt to reduce production costs. In this regard, lipid sources that can replace conventional ones, such as beef tallow, cottonseed oil, and sunflower oil have been investigated. The objective of this study was to examine the effects of different lipid sources on the performance, egg quality, biometrics of digestive organs, and bone quality of white-egg commercial layers in the first production cycle. A total of 216 Hy-Line White layers at 70 weeks of age, weighing 1.701 ± 0.103 kg, were used in a completely randomized design with four treatments and six replicates. The diets provided to them contained equal amounts of protein, calories, and amino acids, with only the lipid source varying - soybean oil (control), cottonseed oil, beef tallow, and sunflower oil. No significant effect of lipid sources was observed on any of the performance or egg-quality variables assessed (p>0.05). Biometric variables were not influenced by lipid sources, except for abdominal fat, which was highest in the birds receiving the beef-tallow treatments and lowest in birds fed the sunflower-oil diets (p 0.05). Except for mineral matter, bone traits were not influenced by the treatments; this variable was highest in the control treatments and lowest in the beef-tallow treatments. In conclusion, cottonseed and sunflower oils can be used to fully replace soybean oil in diets for white-egg commercial layers.(AU)

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Dietary inclusion of lipid sources has been one of the methods adopted by nutritionists aiming at better energy balancing. However, alternative energy feedstuffs have been sought in an attempt to reduce production costs. In this regard, lipid sources that can replace conventional ones, such as beef tallow, cottonseed oil, and sunflower oil have been investigated. The objective of this study was to examine the effects of different lipid sources on the performance, egg quality, biometrics of digestive organs, and bone quality of white-egg commercial layers in the first production cycle. A total of 216 Hy-Line White layers at 70 weeks of age, weighing 1.701 ± 0.103 kg, were used in a completely randomized design with four treatments and six replicates. The diets provided to them contained equal amounts of protein, calories, and amino acids, with only the lipid source varying - soybean oil (control), cottonseed oil, beef tallow, and sunflower oil. No significant effect of lipid sources was observed on any of the performance or egg-quality variables assessed (p>0.05). Biometric variables were not influenced by lipid sources, except for abdominal fat, which was highest in the birds receiving the beef-tallow treatments and lowest in birds fed the sunflower-oil diets (p 0.05). Except for mineral matter, bone traits were not influenced by the treatments; this variable was highest in the control treatments and lowest in the beef-tallow treatments. In conclusion, cottonseed and sunflower oils can be used to fully replace soybean oil in diets for white-egg commercial layers.

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A study was designed with the objective, to evaluate the effect of dietary lysine (Lys) regimens on growth performance and meat composition of Aseel chicken. In total, 540 day old chicks, 180 from each variety, were randomly assigned to 9 experimental groups in a 3 (Varieties: Mianwali (MW), Peshawari (PW), and Lakha (LK)) × 3 (Lys regimens: L1, L2 and L3:1.35, 1.30 and 1.25%) factorial arrangement under randomized complete block design (RCBD) with sex as block. Each experimental group was replicated 6 times with 10 birds in each with average weight of 29 gram. Feed intake (FI), weight gain (WG) and feed:gain ratio (F:G) parameters of growth performance and Dry Matter (DM), Ash, Crude Protein (CP) and Ether Extract (EE) parameters of meat composition were evaluated. The results indicated better (p=0.0006) WG and (p=0.0006) F:G was observed in MW verities. Among different Lys regimens, higher and medium level in the diet improved WG (p<.0001), F:G (p<.0001) and reduced (p=0.0001) FI. Similarly increased (p<.0001; 0.0150) ash content in thigh and breast due to increased level of lysine in the early life period. Dry matter was found to be higher (p=0.0036) only in medium Lys regimen, whereas meat CP was observed to be higher (p=0.0064) in control diet. It was concluded that, 1.30% digestible Lys level regimen can be used to improve the early growth rate of Aseel chicken. Similarly, Mianwali variety due to its better early growth can be used as a meat type chicken.(AU)

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An experiment was designed to study the efficacy of Zinc and or creatine monohydrate (CMH) supplementation, either alone or in combination, on improving growth performance of Balady chicks. A total number of 144 Balady chicks were randomly divided into four equal groups. The first treatment was fed the basal diet and served as control, while groups 2, 3, and 4 were given the basal diet and supplemented drinking water with, 0.6 mg/ml (zinc sulphat); 0.45 mg/ml (CMH); 0.6 mg/ml (zinc sulphat) + 0.45 mg/ml (CMH), respectively. The results indicated that the live body weight, weekly body weight gain and feed efficiency were significantly (p≤0.05) improved in all treated groups compared with the control. Also, significant decrease (p≤0.05) has been recorded in water consumption values of treated groups compared to control. Moreover, significant increase was recorded in carcass yield, kidney, spleen, bursa, thymus and intestine density (weight/length) with treated groups as compared to control group. On the other hand, serum total protein, globulin, total lipids, total antioxidant, thyroxine hormone level were significantly higher in treated groups than the control. Furthermore, Red and white blood cell counts, hemoglobin level, hematocrit values and antibody titres against Newcastle disease virus, were significantly improved in all treated groups. Therefore, it can be concluded that Zn and or CMH supplementation improved the physiological, productive traits of Balady chicks. The best significant results of performance were recorded for group the supplemented with Zn and CMH in combination compared with those of other treatments.(AU)

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Feed costs are the main limiting factors in poultry industry and alternative sources of food and/or feed supplements to optimize the bird´s life cycle and to extend their production period need to be explored. This study evaluated morphometric parameters of the small intestine and gonadotropin transcript levels in Isa Brown laying hens supplemented with glutamine + glutamic acid (Aminogut®) during a second production cycle. Molting was induced and groups of 100 hens each, were supplemented with 0, 0.8, 1.6 or 2.4% Aminogut® in their diet. At the end of the experimental period, tissue sections from duodenum, jejunum and ileum were processed by the Hematoxylin-Eosin technique and samples from hypothalamus and hypophysis were collected for RT-PCR analysis of GnRH and GnRHR transcript levels. As results, the height of the intestinal villi of the duodenum and ileum was significantly (p<0.05) higher in hens supplemented with 0.8% and 1.6% Aminogut®, while in the jejunum, no significant differences were found. Hens treated with increased doses of Aminogut® tended to increase GnRH transcripts levels, whereas those of GnRHR tended to decrease proportionally. It is concluded that supplementation of Isa Brown laying hens during a second production cycle with Aminogut® developed increased villus height in duodenum and ileum that may promote better absorption of nutrients and potentially to increase the egg production. This study shows the importance of molecular techniques such as RT-PCR to support the biological effects of nutritional compounds on morphological parameters and hen productivity.(AU)

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Birds fed with vegetable diets rely on the endogenous synthesis of creatine, which requires amino acids, some of which, for example arginine (Arg), are considered essential for several physiological and metabolic functions. Creatine is limited to high energy expenditure cells, particularly muscle cells. The objective of this study was to evaluate the inclusion of guanidinoacetic acid and arginine (as precursors of creatine) in vegetable diets, on the performance, quality, and yield of broiler chickens. The treatments consisted of diets based on corn and soybean meal (T1); corn, soybean meal + 3% meat meal (T2); corn, soybean meal + 0.08% guanidinoacetic acid (T3); and corn, soybean meal + 0.08% L-arginine (T4). The productive performance of the birds aged 7-, 21-, and 42-days-old was determined. Eighteen 7-day-old birds were sacrificed per treatment to evaluate breast and leg yield, and breast muscle fibers,and eighteen 42-day-old birds were sampled per treatment to determine serum uric acid, urea, creatine,lactate, and glucose concentrations. The same birds were slaughtered to calculate carcass yield in relation to live weight and commercial cut yield. The right pectoralis major muscle of each bird was used to test pH, color (luminosity L*, red index a*, and yellow index b*), and loss of water by pressure analysis, and the left side was used to analyze losses by defrosting and cooking. The data were analyzed using the software SAS. Diets to which meat or vegetable meal plus guanidinoacetic acid or L-Arginine were added resulted in higher live weight and breast meat percentage at 7 days old. Feed conversion was affected for a total period of 1 to 42 days of age (P < 0.0002).[...](AU)

Aves alimentadas com dietas vegetais dependem da síntese endógena de creatina, que requer a participação de aminoácidos, alguns deles considerados essenciais para diversas funções fisiológicas e metabólicas, como a arginina (Arg). A creatina limita-se a células de alto gasto energético, em particular as células musculares. O objetivo foi avaliar a inclusão do ácido guanidinoacético e de arginina como precursor da creatina em dietas vegetais sobre o desempenho, a qualidade e o rendimento de carcaça de frangos de corte. Os tratamentos consistiram em dietas baseadas em milho e farelo de soja (T1); dieta a base de milho, farelo de soja + 3% de farinha de carne (T2); dieta a base de milho e farelo de soja +0,08% de ácido guanidinoacético (T3) e dieta a base de milho e farelo de soja +0,08% de L-arginina(T4). O desempenho produtivo das aves foi determinado aos 7, 21 e 42 dias de idade. Aos sete dias de idade, 18 aves/tratamento foram sacrificadas para avaliação do rendimento de peito e pernas e parafibras musculares do peito. Aos 42 dias de idade foi coletado sangue de 18 aves/tratamento para a determinação das concentrações séricas de ácido úrico, uréia, creatina, lactato e glicose. As mesmas aves foram abatidas, para o cálculo de rendimento de carcaça em relação ao peso vivo e rendimento de cortes nobres. O músculo Pectoralis major direito de cada ave foi utilizado para as análises de pH,cor (luminosidade L*, índice de vermellho a* e índice de amarelo b*) e a perda de água por pressão e o lado esquerdo para as análises de perdas por descongelamento e por cozimento. Os dados foram analisados pelo software SAS. As dietas com adição de farinha de carne ou vegetais acrescidas de ácido guanidionacético ou L-Arginina resultaram em maior peso vivo e percentual de carne de peito aos sete dias. Para o período total de 1 a 42 dias de idade, observou-se efeito (P<0,0002) sobre a conversão alimentar.[...](AU)

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Feed costs are the main limiting factors in poultry industry and alternative sources of food and/or feed supplements to optimize the bird´s life cycle and to extend their production period need to be explored. This study evaluated morphometric parameters of the small intestine and gonadotropin transcript levels in Isa Brown laying hens supplemented with glutamine + glutamic acid (Aminogut®) during a second production cycle. Molting was induced and groups of 100 hens each, were supplemented with 0, 0.8, 1.6 or 2.4% Aminogut® in their diet. At the end of the experimental period, tissue sections from duodenum, jejunum and ileum were processed by the Hematoxylin-Eosin technique and samples from hypothalamus and hypophysis were collected for RT-PCR analysis of GnRH and GnRHR transcript levels. As results, the height of the intestinal villi of the duodenum and ileum was significantly (p<0.05) higher in hens supplemented with 0.8% and 1.6% Aminogut®, while in the jejunum, no significant differences were found. Hens treated with increased doses of Aminogut® tended to increase GnRH transcripts levels, whereas those of GnRHR tended to decrease proportionally. It is concluded that supplementation of Isa Brown laying hens during a second production cycle with Aminogut® developed increased villus height in duodenum and ileum that may promote better absorption of nutrients and potentially to increase the egg production. This study shows the importance of molecular techniques such as RT-PCR to support the biological effects of nutritional compounds on morphological parameters and hen productivity.

Assuntos

RESUMO

An experiment was designed to study the efficacy of Zinc and or creatine monohydrate (CMH) supplementation, either alone or in combination, on improving growth performance of Balady chicks. A total number of 144 Balady chicks were randomly divided into four equal groups. The first treatment was fed the basal diet and served as control, while groups 2, 3, and 4 were given the basal diet and supplemented drinking water with, 0.6 mg/ml (zinc sulphat); 0.45 mg/ml (CMH); 0.6 mg/ml (zinc sulphat) + 0.45 mg/ml (CMH), respectively. The results indicated that the live body weight, weekly body weight gain and feed efficiency were significantly (p≤0.05) improved in all treated groups compared with the control. Also, significant decrease (p≤0.05) has been recorded in water consumption values of treated groups compared to control. Moreover, significant increase was recorded in carcass yield, kidney, spleen, bursa, thymus and intestine density (weight/length) with treated groups as compared to control group. On the other hand, serum total protein, globulin, total lipids, total antioxidant, thyroxine hormone level were significantly higher in treated groups than the control. Furthermore, Red and white blood cell counts, hemoglobin level, hematocrit values and antibody titres against Newcastle disease virus, were significantly improved in all treated groups. Therefore, it can be concluded that Zn and or CMH supplementation improved the physiological, productive traits of Balady chicks. The best significant results of performance were recorded for group the supplemented with Zn and CMH in combination compared with those of other treatments.

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A study was designed with the objective, to evaluate the effect of dietary lysine (Lys) regimens on growth performance and meat composition of Aseel chicken. In total, 540 day old chicks, 180 from each variety, were randomly assigned to 9 experimental groups in a 3 (Varieties: Mianwali (MW), Peshawari (PW), and Lakha (LK)) × 3 (Lys regimens: L1, L2 and L3:1.35, 1.30 and 1.25%) factorial arrangement under randomized complete block design (RCBD) with sex as block. Each experimental group was replicated 6 times with 10 birds in each with average weight of 29 gram. Feed intake (FI), weight gain (WG) and feed:gain ratio (F:G) parameters of growth performance and Dry Matter (DM), Ash, Crude Protein (CP) and Ether Extract (EE) parameters of meat composition were evaluated. The results indicated better (p=0.0006) WG and (p=0.0006) F:G was observed in MW verities. Among different Lys regimens, higher and medium level in the diet improved WG (p<.0001), F:G (p<.0001) and reduced (p=0.0001) FI. Similarly increased (p<.0001; 0.0150) ash content in thigh and breast due to increased level of lysine in the early life period. Dry matter was found to be higher (p=0.0036) only in medium Lys regimen, whereas meat CP was observed to be higher (p=0.0064) in control diet. It was concluded that, 1.30% digestible Lys level regimen can be used to improve the early growth rate of Aseel chicken. Similarly, Mianwali variety due to its better early growth can be used as a meat type chicken.

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The aim of this study was to evaluate the effect of supplemental copaiba or sucupira oils on broiler performance and intestinal health. A total of 600 one-day old Cobb 500 male broilers were distributed in a completely randomized design with four treatments and six replicates with 25 broilers each. To increase the health challenge, the broilers were reared on reused litter. The treatments consisted of: control diet; diet with a performance enhancing antibiotic (avilamycin); diet with 2,000 mg/kg copaiba oil and a diet with 500 mg/kg sucupira oil. Data were submitted to analysis of variance and Tukey test (5%). The addition of sucupira oil at 500 mg/kg decreased broiler performance at 21, 33, and 40 days of age, whereas the addition of copaiba oil resulted in similar performance relative to the antibiotic. Dietary supplementation of copaiba or sucupira oils did not change the intestinal epithelium of broilers. The addition of sucupira oil negatively affected broiler performance. Copaiba oil can be used in broiler diets as a performance enhancer.

Objetivou-se avaliar a utilização de óleo de copaíba ou sucupira na ração de frangos de corte, sobre o desempenho e saúde intestinal. Foram utilizados 600 pintos de corte machos, da linhagem Cobb500 com um dia de idade, distribuídos em delineamento inteiramente casualizado, com quatro tratamentos e seis repetições com 25 aves cada. Com o objetivo de aumentar o desafio, as aves foram criadas sobre cama reutilizada. Os tratamentos consistiram de: ração controle; ração com antibiótico melhorador de desempenho avilamicina; ração com 2.000 mg/kg de óleo de copaíba e ração com 500 mg/kg de óleo sucupira. Os dados foram submetidos à análise de variância e teste Tukey (5%). A adição de 500 mg/kg do óleo de sucupira resultou em queda do desempenho das aves no período de 21, 33 e 40 dias de idade, já a adição do óleo de copaíba proporcionou resultados de desempenho semelhantes ao antibiótico. A suplementação com óleo de copaíba ou sucupira não promoveu alterações no epitélio intestinal dos frangos avaliados. A adição do óleo de sucupira foi prejudicial ao desempenho das aves. O óleo de copaíba pode ser utilizado em dietas para frangos como melhorador de desempenho.

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The performance and breast skin color of slow-growing broilers from 30 to 90 days old fed diets with different inclusions of cassava bagasse and annatto colorific were evaluated. 308 slow-growing broilers were used in a completely randomized experimental design, in a factorial scheme with an additional treatment 3 X 2 + 1, with three levels of annatto colorific as a pigmentant agent (1%, 2% and 3%), two levels of cassava bagasse (10% and 20%) and an additional treatment (control diet), totaling seven treatments, four replicates and 11 broilers per experimental unit. Feed intake and feed conversion were affected by treatments, with interaction. The weight gain and final weight were influenced by the treatments and the best results were found for the inclusion of 10% cassava bagasse and 2% annatto colorific. There was no effect of treatment and no interaction on carcass yield. The color parameters L*, a* and b* were not influenced by treatments. The inclusion of 10% cassava bagasse and 1% annatto colorific for slow-growing broilers from 30 to 90 days of age is recommended. However, the use of these ingredients proved to be economically unfeasible.

Foram avaliados o desempenho e a cor da pele de frangos de corte de crescimento lento no período de 30 a 90 dias, alimentados com dietas com diferentes inclusões de bagaço de mandioca e colorífico de urucum. 308 frangos de corte de crescimento lento foram utilizados em um delineamento experimental inteiramente casualizado, em esquema fatorial com tratamento adicional 3 X 2 + 1, sendo três níveis de colorífico de urucum como agente pigmentante (1%, 2% e 3%), dois níveis de bagaço de mandioca (10% e 20%) e um tratamento adicional (dieta de controle), totalizando sete tratamentos, quatro repetições e 11 frangos de corte por unidade experimental. O consumo de ração e a conversão alimentar foram influenciados pelos tratamentos, com interação. O ganho de peso e o peso final foram influenciados pelos tratamentos (p<0,001) e os melhores resultados foram encontrados para a inclusão de 10% de bagaço de mandioca e 2% de colorífico de urucum. Não houve efeito dos tratamento e nenhuma interação sobre o rendimento da carcaça. Os parâmetros de cor L *, a * e b * não foram influenciados pelos tratamentos. É recomendável a inclusão de bagaço de mandioca a 10% e 1% de colorífico de urucum para frangos de crescimento lento de 30 a 90 dias de idade. No entanto, o uso desses ingredientes provou ser economicamente inviável.

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A total of 120 one-day-old broiler chicks (Ross 308) were randomly assigned to 12 pens of 10 birds in a completely randomized design (CRD). In four experimental diets, soya bean meal was replaced with a maggot meal at the rate of 0, 40, 50 and 60% designated as group A, B, C and D respectively. Body weight was significantly higher (p<0.05), whereas feed intake and feed conversion ratio (FCR) were significantly lower in group D than group A and B. Dressing percentage and apparent metabolizable energy were significantly (p<0.05) higher in group D than group A, B and C. Digestibility of dry matter, crude protein, ether extract and ash were significantly (p<0.05) higher, and crude fiber was significantly (p<0.05) lower in group D than group A. It was concluded that 60% soybean meal could be safely replaced by a maggot meal in broiler ration during the starter phase.(AU)

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The aim of this study was to compare the effects of beak trimming by hot blade or infrared radiation on production indicators and plasma levels of corticosterone in pullets. During the rearing phase, an entirely random delineation was used a 2 x 3 factorial design (two different techniques for beak trimming x 3 strains), a total of six treatments with six repetitions of 20 hens. In the growing phase, the previous treatments were divided into 12, with eight repetitions with seven hens. These treatments were then distributed in a factorial design of 2 x 3 x 2 (two methodologies for beak trimming during rearing phase x three strains x with or without beak trimming at ten weeks of age). In the rearing phase the birds treated by infrared radiation had a lower total consumption and a longer beak length. In the growing phase, the execution of beak trimming at ten weeks of age, led to a lower total consumption and a lower body weight, but a better food conversion, when compared to those hens that did not have beak treatment. Beak trimming at ten weeks did not change the plasmatic levels of corticosterone.(AU)

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This study was conducted to determine the total lysine requirement for female broiler breeders from days 14 to 42. Two-hundred and ten female broiler breeders were used in a completely randomized design with 6 replicates per treatment and 5 chicks per pen under restricted feeding. The contents of total lysine used in this experiment were 0.68, 0.72, 0.76, 0.80, 0.84, 0.88 and 0.92% in the diet. A basal diet was formulated to meet or to exceed the Ross 308 female broiler breeders nutrient specifications except for the lysine. Body weight and feed intake were measured to calculate feed efficiency, and body weight uniformity was defined on a weekly basis. One chick per pen was randomly selected to collect blood samples, organ and an abundance of sexual maturity associated miRNAs (miR-21, mi-26a and mi-375) in the plasma was measured on day 42. Increasing total lysine contents in the diet improved body weight gain and feed conversion ratio from days 14 to 42. The combined values from the two models for BW, average daily gain and feed efficiency were estimated at 1.04, 1.00 and 1.21% total lysine, respectively. Total lysine contents did not affect the ovary weight, serum estradiol-17b, serum progesterone and plasma urea nitrogen or the expression levels of the three miRNAs on day 42. Therefore, the results from the current study indicated that female broiler breeders fed on 0.68% total lysine could achieve the recommended BW, suggested by field practice when data were fitted into the overlapped point of linear-, and quadratic-plateau models.(AU)

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