Effects of the addition of pure glycerin supplementation in the drinking water on the performance of broilers submitted to heat stress and feed restriction

The experiment was conducted to study the effect of pure glycerin supplementation (GLYC) in the drinking water of broilers subjected to heat stress and feed restriction. Water with 0, 1, or 2% glycerin was provided ad libitum to broilers in six hours of feed restriction. The birds were housed in two environments: thermoneutral (TN) - 25 ° C, and cyclic heat stress (HS) - 12h with 250C, 6h with 320C, 3h of 250 to 320C and 3h of 320 to 250C. The experimental design was randomized in a factorial arrangement of 2 x 3 + 2, with three GLYC levels, two environments and one control group with ad libitum feeding each environment. When submitted to HS, broiler receiving 2% glycerin presented higher weight gain (WG), water consumption (WC), feed intake (FI) and energy consumption (EI) than those in the other treatments, contrarily to birds in TN, where increasing GLYC levels decreased those responses. Broilers submitted to feed restriction presented reduced FI, but better feed conversion (FCR), independently of rearing environment or GLYC levels. Broilers under HS submitted to feed restriction and receiving 2% GLYC presented higher WC (p < 0.05) and similar WG as the controls, differently from the restricted-fed broilers under TN receiving 2% GLYC, which WC and WG were lower than the controls. The inclusion of 2% pure glycerin in the drinking water may compensate the negative effects on performance caused by feed restriction in broilers submitted to heat stress.

Effects of the addition of pure glycerin supplementation in the drinking water on the performance of broilers submitted to heat stress and feed restriction

The experiment was conducted to study the effect of pure glycerin supplementation (GLYC) in the drinking water of broilers subjected to heat stress and feed restriction. Water with 0, 1, or 2% glycerin was provided ad libitum to broilers in six hours of feed restriction. The birds were housed in two environments: thermoneutral (TN) - 25 ° C, and cyclic heat stress (HS) - 12h with 250C, 6h with 320C, 3h of 250 to 320C and 3h of 320 to 250C. The experimental design was randomized in a factorial arrangement of 2 x 3 + 2, with three GLYC levels, two environments and one control group with ad libitum feeding each environment. When submitted to HS, broiler receiving 2% glycerin presented higher weight gain (WG), water consumption (WC), feed intake (FI) and energy consumption (EI) than those in the other treatments, contrarily to birds in TN, where increasing GLYC levels decreased those responses. Broilers submitted to feed restriction presented reduced FI, but better feed conversion (FCR), independently of rearing environment or GLYC levels. Broilers under HS submitted to feed restriction and receiving 2% GLYC presented higher WC (p < 0.05) and similar WG as the controls, differently from the restricted-fed broilers under TN receiving 2% GLYC, which WC and WG were lower than the controls. The inclusion of 2% pure glycerin in the drinking water may compensate the negative effects on performance caused by feed restriction in broilers submitted to heat stress.(AU)

Efeitos do fornecimento de dietas pré-desmame para leitões: uma revisão / Effects of providing preweaning diets to piglets: a review of the literature

O fornecimento de alimento complementar ao leite da porca durante a lactação (creep feed) é um manejo comumente recomendado para produtores. A prática foi introduzida como estratégia para minimizar os efeitos deletérios do desmame abrupto e precoce, bem como para uniformizar as leitegadas a serem desmamadas, aumentar o peso ao desmame e acelerar a adaptação do trato gastrintestinal dos leitões a dietas sólidas. As dietas creep feed são formuladas buscando-se altos níveis de digestibilidade e palatabilidade e incluem ingredientes de alta qualidade e alto custo. No entanto, resultados de pesquisas que indiquem que a simples oferta de creep feed é eficiente para minimizar os efeitos deletérios do desmame ou para facilitar a adaptação dos leitões a dietas iniciais ainda são escassos e pouco consolidados. O objetivo desse trabalho foi revisar os fatores que influenciam o consumo de creep feed, os efeitos do consumo dessas dietas sobre o desempenho durante a lactação, bem como as possíveis influências sobre o desenvolvimento enzimático, a ocorrência de diarreias e o desempenho pós-desmame de leitões desmamados entre 21 e 28 dias de idade. Os resultados encontrados indicam que leitões lactentes não apresentam maturidade intestinal suficiente para que estas dietas sejam voluntariamente consumidas e adequadamente digeridas. Mesmo os animais dispostos ao consumo não o fazem em quantidade suficiente para promover a adaptação enzimática ou melhorar o desempenho pós-desmame. Ao contrário do esperado, o consumo de creep feed, especialmente se em baixas quantidades, pode estar associado a sensibilização do trato gastrintestinal, que resulta em reações de hipersensibilidade e diarreia pós-desmame. Concluiu-se que a simples oferta de creep feed não é eficiente para promoção do crescimento na lactação e no pós-desmame, ou para facilitar a adaptação de leitões desmamados precocemente a dietas sólidas. Portanto, destaca-se a necessidade de pesquisas na área, visando...

Providing a solid diet in addition to sow milk during lactation (creep feed) is a management commonly recommended to producers. This practice was introduced as a strategy to minimize the deleterious effects of abrupt and early weaning, as well as to standardize the litters to be weaned, to increase weaning weight, and to accelerate the adaptation of the gastrointestinal tract of piglets to solid diets. Creep feeds are formulated to present high levels of digestibility and palatability and to contain high-quality and high-cost ingredients. However, the results of studies indicating that the simple offer of creep feed is efficient in minimizing the deleterious effects of weaning or in facilitating the adaptation of piglets to early diets are still sparse and poorly consolidated. The objective of this study was to review factors that influence the consumption of creep feed and the effects of consumption of these diets on performance during lactation, as well as possible effects on enzyme production, occurrence of diarrhea episodes and postweaning performance of piglets weaned at 21 to 28 days of age. The results indicate that the intestinal maturity of suckling piglets is not sufficient to permit voluntary consumption and adequate digestion of the diets. Even animals ready for consumption did not ingest sufficient amounts to promote enzymatic adaptation or to improve postweaning performance. Contrary to expectations, the consumption of creep feed, especially in low amounts, may be associated with sensitization of the gastrointestinal tract which results in hypersensitivity reactions and postweaning diarrhea. It can be concluded that the simple offer of creep feed is not efficient in promoting growth during lactation and postweaning, nor does it facilitate the early adaptation of weaned piglets to solid diets. Studies in this area are therefore necessary to develop techniques that can effectively minimize losses resulting from the practice of early weaning...

Efeitos do fornecimento de dietas pré-desmame para leitões: uma revisão / Effects of providing preweaning diets to piglets: a review of the literature

O fornecimento de alimento complementar ao leite da porca durante a lactação (creep feed) é um manejo comumente recomendado para produtores. A prática foi introduzida como estratégia para minimizar os efeitos deletérios do desmame abrupto e precoce, bem como para uniformizar as leitegadas a serem desmamadas, aumentar o peso ao desmame e acelerar a adaptação do trato gastrintestinal dos leitões a dietas sólidas. As dietas creep feed são formuladas buscando-se altos níveis de digestibilidade e palatabilidade e incluem ingredientes de alta qualidade e alto custo. No entanto, resultados de pesquisas que indiquem que a simples oferta de creep feed é eficiente para minimizar os efeitos deletérios do desmame ou para facilitar a adaptação dos leitões a dietas iniciais ainda são escassos e pouco consolidados. O objetivo desse trabalho foi revisar os fatores que influenciam o consumo de creep feed, os efeitos do consumo dessas dietas sobre o desempenho durante a lactação, bem como as possíveis influências sobre o desenvolvimento enzimático, a ocorrência de diarreias e o desempenho pós-desmame de leitões desmamados entre 21 e 28 dias de idade. Os resultados encontrados indicam que leitões lactentes não apresentam maturidade intestinal suficiente para que estas dietas sejam voluntariamente consumidas e adequadamente digeridas. Mesmo os animais dispostos ao consumo não o fazem em quantidade suficiente para promover a adaptação enzimática ou melhorar o desempenho pós-desmame. Ao contrário do esperado, o consumo de creep feed, especialmente se em baixas quantidades, pode estar associado a sensibilização do trato gastrintestinal, que resulta em reações de hipersensibilidade e diarreia pós-desmame. Concluiu-se que a simples oferta de creep feed não é eficiente para promoção do crescimento na lactação e no pós-desmame, ou para facilitar a adaptação de leitões desmamados precocemente a dietas sólidas. Portanto, destaca-se a necessidade de pesquisas na área, visando...(AU)

Providing a solid diet in addition to sow milk during lactation (creep feed) is a management commonly recommended to producers. This practice was introduced as a strategy to minimize the deleterious effects of abrupt and early weaning, as well as to standardize the litters to be weaned, to increase weaning weight, and to accelerate the adaptation of the gastrointestinal tract of piglets to solid diets. Creep feeds are formulated to present high levels of digestibility and palatability and to contain high-quality and high-cost ingredients. However, the results of studies indicating that the simple offer of creep feed is efficient in minimizing the deleterious effects of weaning or in facilitating the adaptation of piglets to early diets are still sparse and poorly consolidated. The objective of this study was to review factors that influence the consumption of creep feed and the effects of consumption of these diets on performance during lactation, as well as possible effects on enzyme production, occurrence of diarrhea episodes and postweaning performance of piglets weaned at 21 to 28 days of age. The results indicate that the intestinal maturity of suckling piglets is not sufficient to permit voluntary consumption and adequate digestion of the diets. Even animals ready for consumption did not ingest sufficient amounts to promote enzymatic adaptation or to improve postweaning performance. Contrary to expectations, the consumption of creep feed, especially in low amounts, may be associated with sensitization of the gastrointestinal tract which results in hypersensitivity reactions and postweaning diarrhea. It can be concluded that the simple offer of creep feed is not efficient in promoting growth during lactation and postweaning, nor does it facilitate the early adaptation of weaned piglets to solid diets. Studies in this area are therefore necessary to develop techniques that can effectively minimize losses resulting from the practice of early weaning...(AU)

Pendulous Crop in Broilers

Pendulous crop is a physiological disorder, which etiology is still unknown and it is characterized by abnormal dilation of the crop of poultry. This article aims at reporting a case of high incidence of pendulous crop in male and female broilers Cobb 500, as well as to discuss its possible causes and consequences. In an experiment with broilers performed at the experimental facilities of Laboratório de Ensino Zootécnico of UFRGS, a high incidence (9.5%) of pendulous crop was observed. Genetic predisposition is the most frequently documented and accepted cause of that condition. Despite presenting the same live weight as normal broilers, birds with pendulous crop had lower carcass weight due to dehydration and malnourishment, and should be culled after diagnosis. Therefore, further studies on the origin and control of this physiological disorder are warranted.(AU)

Pendulous Crop in Broilers

Pendulous crop is a physiological disorder, which etiology is still unknown and it is characterized by abnormal dilation of the crop of poultry. This article aims at reporting a case of high incidence of pendulous crop in male and female broilers Cobb 500, as well as to discuss its possible causes and consequences. In an experiment with broilers performed at the experimental facilities of Laboratório de Ensino Zootécnico of UFRGS, a high incidence (9.5%) of pendulous crop was observed. Genetic predisposition is the most frequently documented and accepted cause of that condition. Despite presenting the same live weight as normal broilers, birds with pendulous crop had lower carcass weight due to dehydration and malnourishment, and should be culled after diagnosis. Therefore, further studies on the origin and control of this physiological disorder are warranted.

Development and Performance of a Mechanical Egg Collection System Versus the Hand-Operated Dutch Nest

The aim of this study was to design a new mechanical nesting system based on scientific works on the behavior of laying hens, and to compare its performance with that of a hand-operated Dutch nest. The equipment was assessed in two poultry houses; in the first one, the eggs were collected manually, whereas in the second one, the newly designed mechanical nest was used for the collection. A total of 7,800 hens and 800 males were housed in each poultry house, and the percentages of eggs produced, nest dirty eggs, floor eggs, and cracked and discarded eggs were determined between weeks 25 and 52. The percentage of eggs with microcracks, infertility, embryo mortality, bacterial contamination, fungal contamination, chicks with stunting syndrome and hatching from both types of nest was assessed in the hatchery on a fortnightly basis. The mechanical nest designed herein proved to be a good alternative to the hand-operated Dutch nest, but it still has to be improved in order to have the same performance, especially with regard to reduction in the incidence of floor eggs.

Development and Performance of a Mechanical Egg Collection System Versus the Hand-Operated Dutch Nest

The aim of this study was to design a new mechanical nesting system based on scientific works on the behavior of laying hens, and to compare its performance with that of a hand-operated Dutch nest. The equipment was assessed in two poultry houses; in the first one, the eggs were collected manually, whereas in the second one, the newly designed mechanical nest was used for the collection. A total of 7,800 hens and 800 males were housed in each poultry house, and the percentages of eggs produced, nest dirty eggs, floor eggs, and cracked and discarded eggs were determined between weeks 25 and 52. The percentage of eggs with microcracks, infertility, embryo mortality, bacterial contamination, fungal contamination, chicks with stunting syndrome and hatching from both types of nest was assessed in the hatchery on a fortnightly basis. The mechanical nest designed herein proved to be a good alternative to the hand-operated Dutch nest, but it still has to be improved in order to have the same performance, especially with regard to reduction in the incidence of floor eggs.(AU)

Comparison between linear and nonlinear systems of feed formulation for broilers

Two experiments were simultaneously carried out to compare feed formulation models: a linear model for minimum cost with a nonlinear model for maximum profitability for one-to 42-d-old broilers. One-d-old male or female Cobb 500 broilers (n=2368) were allocated to one of the two trials according to sex. The experiments were performed simultaneously in an experimental poultry farm. Two housing densities were used: high density (HDH), with 14 birds/m2, and low density (LDH), with 10 birds/m2. The following treatments were evaluated: linear feed formulation and LDH (LF10); nonlinear formulation and LDH (NF10); linear formulation and HDH (LF14); and nonlinear formulation and HDH (NF14). A completely randomized design with four treatments of eight replicates each was applied. Performance and cost per kg of poultry were evaluated. Both formulation systems promoted similar broiler performance. However, the high-density feed using linear formulation reduced body weight in 42-d-old males, but not when nonlinear formulation was used. The NF10 treatment yielded the worst feed conversion ratio (p 0.05) and the lowest cost/kg broiler (p 0.05) for both sexes. The results demonstrate that the nutritional program that yields the best performance is not always the most economical one.(AU)

Effect of an Enzyme Blend on the Performance, Diet Metabolizability, Phosphorous Retention, and Bone Mineralization of Broilers Fed Diets Containing Defatted Rice Bran

An experiment was conducted to evaluate the effect of an enzyme blend (EB) on the performance, diet metabolizability, phosphorus (P) retention, and bone mineralization of broilers fed diets containing 10% defatted rice bran (DRB). In total, 432 one- to 38-d-old male Cobb broilers were evaluated according to a completely randomized experimental design in 3 x 2 factorial arrangement. Three diets were tested with two nutrient reductions (NR) in the matrix (standard diet; NR I of 75 kcal/kg ME, 0.1% Ca and 0.1% available P; and NR II of 100 kcal/kg ME, 0.1% Ca and 0.1% available P) with or without the addition of an EB (200 g/t). The coefficients of total tract apparent retention (CTTAR) of the diets and P retention were determined by collecting excreta during two periods (14 to 17 and 28 to 31 d). As expected, birds fed the standard diet had higher BW, BW gain, and G:F compared to birds on the NR diets. The EB did not show any positive effects on CTTAR or on performance; however, birds fed the EB retained 6.58% more P from d 14 to 17 (p 0.07) and 8.55% from d 28 to 31 (p 0.05). Tibiotarsus ash percentage also increased by 2.45% (p 0.06) on d 38. In diets containing 10% DRB, the enzyme blend showed biological activity improving P retention and tibiotarsus mineralization.(AU)

Utilization of Different Corn Fractions by Broilers

This study was conducted to evaluate the nutritional values of fractions of damaged corn. One hundred and eighty 22-d-old Cobb 500 male broilers were distributed in batteries according to a completely randomized design with six treatments of six replicates each. The treatments consisted of diets containing five corn fractions, classified as sound, fermented, insect-damaged, mold-damaged, or reference corn. The test diets consisted of 60% of reference diet + 40% of each corn fraction. Only the reference corn fraction included all the fractions at different proportions (0.8% fermented, 0.05% insect-damaged, 3.3% mold-damaged, and 95.85% sound grains). The method of total excreta collection was used to determine AMEn values and metabolizability coefficients of dry matter (MDM), crude protein (MCP), ether extract (MEE), and gross energy (MGE) of the reference corn and its fractions. The density values of the corn fractions were used to calculate the correlations among the evaluated parameters. The evaluated corn fractions presented different compositions values. The insect-damaged and mold-damaged grains presented higher CP level, lower density, and MDM and MCP coefficients compared with the other fractions. However, calculated AMEn values were not significantly different (p>0.05) among corn fractions. A low correlation between density and AMEn content (r 0.5), and a high correlation between density and MCP (r>0.8) were calculated. Although the evaluated corn fractions presented different nutritional values, there were no marked differences in their utilization by broilers.(AU)

Comparison between linear and nonlinear systems of feed formulation for broilers

Two experiments were simultaneously carried out to compare feed formulation models: a linear model for minimum cost with a nonlinear model for maximum profitability for one-to 42-d-old broilers. One-d-old male or female Cobb 500 broilers (n=2368) were allocated to one of the two trials according to sex. The experiments were performed simultaneously in an experimental poultry farm. Two housing densities were used: high density (HDH), with 14 birds/m2, and low density (LDH), with 10 birds/m2. The following treatments were evaluated: linear feed formulation and LDH (LF10); nonlinear formulation and LDH (NF10); linear formulation and HDH (LF14); and nonlinear formulation and HDH (NF14). A completely randomized design with four treatments of eight replicates each was applied. Performance and cost per kg of poultry were evaluated. Both formulation systems promoted similar broiler performance. However, the high-density feed using linear formulation reduced body weight in 42-d-old males, but not when nonlinear formulation was used. The NF10 treatment yielded the worst feed conversion ratio (p 0.05) and the lowest cost/kg broiler (p 0.05) for both sexes. The results demonstrate that the nutritional program that yields the best performance is not always the most economical one.

Effect of an Enzyme Blend on the Performance, Diet Metabolizability, Phosphorous Retention, and Bone Mineralization of Broilers Fed Diets Containing Defatted Rice Bran

An experiment was conducted to evaluate the effect of an enzyme blend (EB) on the performance, diet metabolizability, phosphorus (P) retention, and bone mineralization of broilers fed diets containing 10% defatted rice bran (DRB). In total, 432 one- to 38-d-old male Cobb broilers were evaluated according to a completely randomized experimental design in 3 x 2 factorial arrangement. Three diets were tested with two nutrient reductions (NR) in the matrix (standard diet; NR I of 75 kcal/kg ME, 0.1% Ca and 0.1% available P; and NR II of 100 kcal/kg ME, 0.1% Ca and 0.1% available P) with or without the addition of an EB (200 g/t). The coefficients of total tract apparent retention (CTTAR) of the diets and P retention were determined by collecting excreta during two periods (14 to 17 and 28 to 31 d). As expected, birds fed the standard diet had higher BW, BW gain, and G:F compared to birds on the NR diets. The EB did not show any positive effects on CTTAR or on performance; however, birds fed the EB retained 6.58% more P from d 14 to 17 (p 0.07) and 8.55% from d 28 to 31 (p 0.05). Tibiotarsus ash percentage also increased by 2.45% (p 0.06) on d 38. In diets containing 10% DRB, the enzyme blend showed biological activity improving P retention and tibiotarsus mineralization.

Utilization of Different Corn Fractions by Broilers

This study was conducted to evaluate the nutritional values of fractions of damaged corn. One hundred and eighty 22-d-old Cobb 500 male broilers were distributed in batteries according to a completely randomized design with six treatments of six replicates each. The treatments consisted of diets containing five corn fractions, classified as sound, fermented, insect-damaged, mold-damaged, or reference corn. The test diets consisted of 60% of reference diet + 40% of each corn fraction. Only the reference corn fraction included all the fractions at different proportions (0.8% fermented, 0.05% insect-damaged, 3.3% mold-damaged, and 95.85% sound grains). The method of total excreta collection was used to determine AMEn values and metabolizability coefficients of dry matter (MDM), crude protein (MCP), ether extract (MEE), and gross energy (MGE) of the reference corn and its fractions. The density values of the corn fractions were used to calculate the correlations among the evaluated parameters. The evaluated corn fractions presented different compositions values. The insect-damaged and mold-damaged grains presented higher CP level, lower density, and MDM and MCP coefficients compared with the other fractions. However, calculated AMEn values were not significantly different (p>0.05) among corn fractions. A low correlation between density and AMEn content (r 0.5), and a high correlation between density and MCP (r>0.8) were calculated. Although the evaluated corn fractions presented different nutritional values, there were no marked differences in their utilization by broilers.

Quality assessment of corn batches received at a feed mill in the brazilian cerrado

This study aimed at investigating factors that contribute to changes in the quality of corn used in compound poultry feeds. Samples were collected from 6488 bulk cargos received at a feed mill located close to Brasília, Brazil. The parameters studied were divided into two groups: those related to corn chemical composition, including crude protein (% CP), ether extract (% EE), crude fiber (% CF), nitrogen-free extract (% NFE), and estimated metabolizable energy (ME), and corn physical characteristics, including density, moisture, and grain physical damage. High coefficients of determination (R²) and low coefficients of variation (CV) were determined for the chemical and physical parameters. The analysis of variance showed low to medium R². Month, year, supplier, and their interactions influenced (p 0.05) all chemical properties, as well as density, moisture, and ME. Physical characteristics were less affected by those factors, except for quantity of damaged grains. The principal component analysis separated the physical and chemical factors. The coefficients of the first component explained 54% of the total variation between variables. The first principal component showed that NFE and ME increased as humidity decreased. The second component also showed a decrease of physical problems due to reduction in humidity. Results indicate that the feed mills should take preventive measures when selecting suppliers, and diets should be formulated according to the differences in chemical and physical composition of corn supplied in different months and years.(AU)

Growth and deposition of body components of intermediate and high performance broilers

The objectives of the present study were to determine the parameters of Gompertz equations and to determine curves and growth rate, feed intake and body component deposition, as well as allometric coefficients of body water, protein, and fat relative to live weight of male and female broilers of intermediate performance (C44) and high performance (Cobb-500) genetic strains. In total, 384 one-d-old chicks were distributed into four treatments: male Cobb 500, male C44, female Cobb 500, and female C44, with six replicates of 16 birds, according to a completely randomized experimental design. Average body weight, weight gain, and feed intake were weekly determined, and six birds, representing the average weight of each treatment, were sacrificed to determine body composition. Growth curves were built applying Gompertz function, with excellent fit, and growth, feed intake, and tissue deposition rates were obtained by its derivatives. Superior growth rate was obtained for Cobb 500 male broilers. This genetic strain has higher feed intake capacity, which is achieved earlier than in the C44 strain. Protein and fat deposition maturity was reached earlier in males than in females in Cobb 500. The allometric coefficients showed earlier maturity for body water in C44 and females. In terms of body protein, male Cobb 500 broilers reached maturity earlier than females and C44. Body fat deposition maturity was reached earlier in Cobb 500 than in C44. The Gompertz equations obtained in the present study efficiently described body growth, feed intake, and deposition of body components, with a coefficient of determination higher than 0.99.(AU)

Effect of dietary fiber, genetic strain and age on the digestive metabolism of broiler chickens

In this study, 360 male broilers, out of which 240 of a fast-growing strain (Cobb500), and 120 of a slow-growing strain (Label Rouge), were used to evaluate the effect of dietary fiber on digesta transit time and digestive metabolism during the period of 1 to 42 days of age. A completely randomized experimental design with a 3x2 factorial arrangement was applied, consisting of three groups of birds (slow-growing - SG; fast-growing fed ad libitum - FGAL; and fast-growing pair-fed with SG broilers - FGPF) and two iso-protein diets (a 3100 kcal ME/kg low-fiber diet - LFD- and a 2800 kcal ME/kg high-fiber diet - HFD- with 14% wheat bran and 4% oat hulls). HFD-fed birds presented lower ME retention (p < 0.001) and lower dry matter metabolizability (DMM) (p < 0.001), which is possibly related to the shorter digesta transit time observed in these birds (p < 0.001). DMM was reduced with age, whereas metabolizable energy remained almost constant (p < 0.001) independently of strain. This may be related to the increase in feed intake as birds age. The slow-growing strain did not present better utilization of the high-fiber diet as compared to the fast-growing strain in none of the analyzed ages, even though showing a significant better use of fiber and dietary energy from 31 days of age.(AU)

Effect of different dietary concentrations of Amino Acids on the performance of two different Broiler Strains

Four Nutritional Programs (NP) used in the Brazilian poultry industry were tested in two broiler strains (Cobb 500 and Ross 308). NP varied in the concentrations of their main essential amino acids (AA) and were classified as Low, Regular, High and Mixed (high AA concentrations up to 21 days and regular concentrations after that). Minimum digestible Met+Cys/Lys, Thr/Lys, Arg/Lys, Ile/Lys, and Val/Lys ratios were 0.74, 0.64, 1.05, 0.65 and 0.75, respectively, in all NP, and no minimum amount of CP was fixed. There were no interactions between strain and NP for any of the evaluated responses. From 1 to 47 days of age, birds fed the Low NP presented lower average body weight and body weight gain (BWG). The high NP allowed for better feed conversion ratio (FCR), followed by the Regular and the Mixed NP. Ross 308 broilers were heavier, presenting worse FCR due to higher FI. Birds fed the High NP had lower carcass yield than those fed the Low NP. The Low and Regular NP had lower costs per WG when compared with the High NP. Low and Regular NP presented higher gross margin returns compared with the High NP. The Regular and Mixed NP are the most recommended, presenting intermediate performance and higher economic returns.

Effect of different dietary concentrations of Amino Acids on the performance of two different Broiler Strains

Four Nutritional Programs (NP) used in the Brazilian poultry industry were tested in two broiler strains (Cobb 500 and Ross 308). NP varied in the concentrations of their main essential amino acids (AA) and were classified as Low, Regular, High and Mixed (high AA concentrations up to 21 days and regular concentrations after that). Minimum digestible Met+Cys/Lys, Thr/Lys, Arg/Lys, Ile/Lys, and Val/Lys ratios were 0.74, 0.64, 1.05, 0.65 and 0.75, respectively, in all NP, and no minimum amount of CP was fixed. There were no interactions between strain and NP for any of the evaluated responses. From 1 to 47 days of age, birds fed the Low NP presented lower average body weight and body weight gain (BWG). The high NP allowed for better feed conversion ratio (FCR), followed by the Regular and the Mixed NP. Ross 308 broilers were heavier, presenting worse FCR due to higher FI. Birds fed the High NP had lower carcass yield than those fed the Low NP. The Low and Regular NP had lower costs per WG when compared with the High NP. Low and Regular NP presented higher gross margin returns compared with the High NP. The Regular and Mixed NP are the most recommended, presenting intermediate performance and higher economic returns.(AU)

Respostas fisiológicas e de desempenho de leitões suplementados com B-glucanos e desafiados imunologicamente / Phisiologial responses and growth performance of immune challenged piglets supplemented with B-glucans

O estudo buscou avaliar as respostas fisiológicas e de desempenho à adição de diferentes níveis de β-glucanos na dieta de leitões recém-desmamados. Foram utilizados 30 machos de linhagem comercial, com 34 dias de idade e peso de 10,9±0,63kg, alojados em gaiolas individuais, durante 14 dias. Os tratamentos variaram somente nos níveis de β-glucanos que foram de 35, 70, 140 e 280g/T. No final desse período, em metade dos animais foram injetados 2,7mg de lipopolissacarídeo (LPS) em 1mL de solução (PBS)/leitão, e nos demais 1mL/leitão de PBS. Foram avaliadas temperatura retal (TR), frequência respiratória (FR), perfil bioquímico sanguíneo e sinais clínicos aos 30, 90, 120 e 390 minutos seguintes à injeção. As respostas de desempenho não foram afetadas pelos níveis de β-glucanos. Foi observado o aumento de TR, tanto em função do LPS como em função da hora em que a temperatura foi medida. No entanto, os animais LPS-injetados, que receberam 280g/T de β-glucanos, tiveram a mesma TR daqueles LPS-não injetados. Os sinais clínicos foram compatíveis com um quadro de inflamação aguda e foram observados, nos animais LPS-injetados, vômito, prostração e diarreia, sendo que a inclusão de β-glucanos não conseguiu reverter esses sintomas. O uso de β-glucanos por 14 dias na dieta de leitões recém-desmamados mostrou um efeito anti-inflamatório em situação de desafio agudo. Para reverter o desafio imunológico utilizado, o nível de 280g/T de β-glucanos mostrou-se o mais recomendado.

This study was done to evaluate immunological responses and performance of weaning piglets receiving diets with different levels of β-glucans. Thirty males from a commercial line with 34 days of age and 10.9±0,6kg initial weight were housed in individual metabolic cages during 14 days. The treatments only differed in β-glucans levels: 35; 70; 140 and 280g/T. On the 14th day, half of the pigs were inoculated with 2.7mg LPS (lipopolysaccharide)/mL of solution (PBS)/pig and the other half received 1mL PBS/pig. Rectal temperature (RT), respiratory frequency (RF), biochemical profile and animal behavior (120 and 390 minutes after LPS inoculation) were evaluated. As the experiment was conducted, performance was not affected by β-glucans. An RT increase was observed due to LPS and time of temperature measurement. LPS-injected animals receiving 280g/T of β-glucans had the same RT as the LPS- non injected group. Clinical signs were near the expectation for acute inflammation. LPS-injected presented prostration, diarrhea and vomit and the β-glucans did not reverse this situation. The use of β-glucans in weaning pigs for fourteen days showed an anti-inflammatory action. To revert the immunologic challenge, the level of 280g/T of β-glucans was the most recommended.