Use of Glutamine in Post-Hatch Feed for Broiler Chicks

Post-hatch delayed placement damages, physical and physiological development of broiler chicks. The objective of this study was to ascertain adequate levels of glutamine inclusion in post-hatch and pre-starter feed, in order to minimize the negative effects of post-hatch delayed placement on broiler chicks. The birds were distributed in a completely randomized design, with four treatments and five replicates of ten birds each. Four levels of glutamine supplementation (0, 1, 2 and 3%) were used in the pre-starter feed, which was given to the chicks in the transportation box and during the pre-starter phase. After 24 hours of access to this feed, and at 7 days of age, the chicks performance, yolk sac retraction, plasma glucose concentration, weight and small-intestine histomorphometry were evaluated. From seven to ten days of age, a metabolizability assay was performed. Glutamine supplementation tended to increase the use of the yolk sac, the concentration of plasma glucose (p 0.10) and the depth of the crypt in the ileum after 24 hours of life (p 0.05). There was no statistical difference between the glutamine supplementation levels, in relation to glucose, histomorphometry or metabolizability in the pre-starter phase. Glutamine concentrations did not differ in relation to performance, histomorphometry of the small intestine or metabolizability of nutrients in the pre-starter phase.(AU)

Use of Glutamine in Post-Hatch Feed for Broiler Chicks

Post-hatch delayed placement damages, physical and physiological development of broiler chicks. The objective of this study was to ascertain adequate levels of glutamine inclusion in post-hatch and pre-starter feed, in order to minimize the negative effects of post-hatch delayed placement on broiler chicks. The birds were distributed in a completely randomized design, with four treatments and five replicates of ten birds each. Four levels of glutamine supplementation (0, 1, 2 and 3%) were used in the pre-starter feed, which was given to the chicks in the transportation box and during the pre-starter phase. After 24 hours of access to this feed, and at 7 days of age, the chicks performance, yolk sac retraction, plasma glucose concentration, weight and small-intestine histomorphometry were evaluated. From seven to ten days of age, a metabolizability assay was performed. Glutamine supplementation tended to increase the use of the yolk sac, the concentration of plasma glucose (p 0.10) and the depth of the crypt in the ileum after 24 hours of life (p 0.05). There was no statistical difference between the glutamine supplementation levels, in relation to glucose, histomorphometry or metabolizability in the pre-starter phase. Glutamine concentrations did not differ in relation to performance, histomorphometry of the small intestine or metabolizability of nutrients in the pre-starter phase.

Sodium butyrate in post-hatch feed for broiler chicks / [Uso de butirato de sódio em rações pós-eclosão para pintos de corte]

This study was designed to determine adequate levels for sodium butyrate inclusion in pre-hatching and pre-starter feed in order to minimize the negative effects of post-hatch delayed placement on broiler chicks. Newly-hatched chicks were allotted in a completely randomized design, with five treatments, each comprising five replicates of ten birds each. Five dietetic levels of sodium butyrate (control, 0.050, 0.075, 0.100 and 0.200%) were used in the pre-starter feed offered to the chicks in the transporting box and during the pre-starter phase. Performance, yolk sac retraction, plasma glucose concentration, weight and histomorphometry of the small intestine were evaluated after 24 hours of feed access and at 7 days of age. A metabolic trial was performed when the chicks were seven to ten days of age. Supplementation of 0.1% sodium butyrate increased the development of broiler chicks' intestinal villi at seven days of age but was not able to improve performance in the pre-starter phase. Supplementation with sodium butyrate in a diet offered in the transportation box does not improve broiler performance in the pre-starter phase. Supplementation of up to 0.16% is recommended, in order to improve the metabolizability of the ether extract for broilers at seven days of age.(AU)

Objetivou-se, com este estudo, encontrar níveis adequados de inclusão de butirato de sódio em ração pós-eclosão e pré-inicial, buscando minimizar os efeitos negativos do jejum de pintos de corte. Os animais foram distribuídos em delineamento inteiramente ao acaso, com cinco tratamentos e cinco repetições de 10 aves cada. Foram utilizadas cinco suplementações de butirato de sódio (controle; 0,05; 0,075; 0,100 e 0,200%) na ração pré-inicial, fornecidas aos pintos na caixa de transporte e durante a fase pré-inicial. Após 24 horas de acesso ao alimento e aos sete dias de idade, foram avaliados desempenho, retração do saco vitelino, concentração de glicose plasmática, peso e histomorfometria do intestino delgado. De sete a 10 dias de idade, realizou-se ensaio de metabolizabilidade. A suplementação de 0,10% de butirato de sódio aumentou o desenvolvimento das vilosidades intestinais dos pintos de corte aos sete dias de idade, mas não foi capaz de melhorar o desempenho na fase pré-inicial. A suplementação com butirato de sódio em dieta oferecida na caixa de transporte não melhora o desempenho dos frangos na fase pré-inicial. Recomenda-se suplementação de até 0,16%, a fim de melhorar a metabolizabilidade do extrato etéreo para frangos de corte aos sete dias de idade.(AU)

Use of Betaine in Post-Hatch Feed for Broiler Chicks

Post-hatch delayed placement damages the physical and physiological development of broiler chicks. This study was designed to find adequate levels of betaine inclusion in pre-hatching and pre-starter feed, in order to minimize the negative effects of post-hatch delayed placement on broiler chicks. Newly-hatched chicks were allotted in a completely randomized design, with five treatments, five replicates of ten birds each. Five dietetic levels of betaine (control, 0.070, 0.130, 0.200 and 0.260%) were used in the pre-starter ration, offered to the chicks in the transporting box and during the pre-starter phase. Performance, yolk sac retraction, plasma glucose concentration, weight and histomorphometry of the small intestine were evaluated, after 24 hours of feed access and at 7 days of age. A metabolic trial was performed from seven to ten days of age. Betaine supplementation linearly influenced the chicks ileum crypt depth after 24 hours in the transportation box. There was a quadratic effect, with an increase in feed intake up to 0.152% betaine supplementation. There was an improvement in the quality of the jejunum with betaine supplementation above 0.1%. The metabolizable coefficient of the ether extract was improved until reaching 0.163% of betaine supplementation. Betaine supplementation around 0.150% increases feed intake, the use of ether extract and interferes with the intestinal villi of chicks at seven days of age.(AU)

Use of Betaine in Post-Hatch Feed for Broiler Chicks

Post-hatch delayed placement damages the physical and physiological development of broiler chicks. This study was designed to find adequate levels of betaine inclusion in pre-hatching and pre-starter feed, in order to minimize the negative effects of post-hatch delayed placement on broiler chicks. Newly-hatched chicks were allotted in a completely randomized design, with five treatments, five replicates of ten birds each. Five dietetic levels of betaine (control, 0.070, 0.130, 0.200 and 0.260%) were used in the pre-starter ration, offered to the chicks in the transporting box and during the pre-starter phase. Performance, yolk sac retraction, plasma glucose concentration, weight and histomorphometry of the small intestine were evaluated, after 24 hours of feed access and at 7 days of age. A metabolic trial was performed from seven to ten days of age. Betaine supplementation linearly influenced the chicks ileum crypt depth after 24 hours in the transportation box. There was a quadratic effect, with an increase in feed intake up to 0.152% betaine supplementation. There was an improvement in the quality of the jejunum with betaine supplementation above 0.1%. The metabolizable coefficient of the ether extract was improved until reaching 0.163% of betaine supplementation. Betaine supplementation around 0.150% increases feed intake, the use of ether extract and interferes with the intestinal villi of chicks at seven days of age.

Use of Soy Protein Concentrate in Pre-Starter and Starter Diets for Broilers

Two experiments were carried out to evaluate the effect of using soy protein concentrate (SPC) in pre-starter and starter diets for broilers. In the first experiment, 600 male Cobb broilers, between one and 40 days of age, were distributed in a completely randomized design, with four treatments and six replications of 25 birds each. Treatments were ofered to broilers in the pre-starter and starter diets and consisted of inclusion of soy protein concentrate (0,3,6 and 9%) in diets. The parameters evaluated were: body weight gain, feed conversion ratio, consumption of ration, enzyme production in the pancreas, villus: crypt ratio, leukocyte count and immunoglobulin A (IgA) dosage. Aimed to determine the coefficient of nutrient metabolization of feeds, 144 male Cobb chicks were distributed, between 14 and 21 days of age, with four treatments and six replications of six birds per experimental unit. Treatments were the same as in the first experiment. The use of 3 and 9% of SPC did not affect weight gain, feed intake, feed conversion or viability of the poultry. The use of 6% of SPC provided an increase in trypsin activity, villi length and crypt depth; the coefficient of dry matter metabolization increased linearly; but no differences were observed in performance or immunological parameters.(AU)

Use of Soy Protein Concentrate in Pre-Starter and Starter Diets for Broilers

Two experiments were carried out to evaluate the effect of using soy protein concentrate (SPC) in pre-starter and starter diets for broilers. In the first experiment, 600 male Cobb broilers, between one and 40 days of age, were distributed in a completely randomized design, with four treatments and six replications of 25 birds each. Treatments were ofered to broilers in the pre-starter and starter diets and consisted of inclusion of soy protein concentrate (0,3,6 and 9%) in diets. The parameters evaluated were: body weight gain, feed conversion ratio, consumption of ration, enzyme production in the pancreas, villus: crypt ratio, leukocyte count and immunoglobulin A (IgA) dosage. Aimed to determine the coefficient of nutrient metabolization of feeds, 144 male Cobb chicks were distributed, between 14 and 21 days of age, with four treatments and six replications of six birds per experimental unit. Treatments were the same as in the first experiment. The use of 3 and 9% of SPC did not affect weight gain, feed intake, feed conversion or viability of the poultry. The use of 6% of SPC provided an increase in trypsin activity, villi length and crypt depth; the coefficient of dry matter metabolization increased linearly; but no differences were observed in performance or immunological parameters.

Detection of Salmonella spp. by Conventional Bacteriology and by Quantitative Polymerase-Chain Reaction in Commercial Egg Structures

Conventional bacteriology techniques and quantitative polymerase-chain reaction (qPCR) were applied to the eggshell, albumen, and yolk of washed and unwashed commercial white and brown eggs, to detect Salmonella spp. Pooled samples of eggshells, albumen, and yolk of white and brown eggs were collected at the poultry house and at the egg-storage room. Salmonella spp. was detected by conventional bacteriology in 5.4% (21/387) of analyzed samples and in 16% (68/387) by qPCR. In the 114 unwashed white eggs samples of eggshell, albumen and yolk, the bacterium was identified in 2.6% of the eggs (3/114) by conventional bacteriology and in 13.2% (15/114) by qPCR. In the 90 samples of washed eggs, 6.7% (6/90) were contaminated as detected by conventional bacteriology and 10.0% (9/90) by qPCR. In the 81 samples of unwashed brown eggs, Salmonella spp. was detected in 6.1% of the eggs (5/81) by conventional bacteriology and 27.2% (22/81) by qPCR. In the 102 samples of brown washed eggs, 6.9% (7/102) where positive by conventional bacteriology and 35.3% (16/102) by qPCR. All samples detected as positive by conventional bacteriology were also positive by qPCR. Salmonella Agona represented 18.2% (4/22) of identified serovars, Salmonella enterica subs. enterica O: 4.5 18.2% (4/22), Salmonella Schwarzengrund 18.2% (4/22), Salmonella Cerro 13.6% (3/22), Salmonella Anatum 13.6% (3/22), Salmonella Enteritidis 9.1% (2/22), Salmonella Johannesburg 4.5% (1/22), and Salmonella Corvallis 4.5% (1/22). The qPCR method provided better detection of Salmonella spp. in commercial eggs than conventional bacteriology. The conventional egg washing and disinfection procedures are not efficient to eliminate Salmonella.

Detection of Salmonella spp. by Conventional Bacteriology and by Quantitative Polymerase-Chain Reaction in Commercial Egg Structures

Conventional bacteriology techniques and quantitative polymerase-chain reaction (qPCR) were applied to the eggshell, albumen, and yolk of washed and unwashed commercial white and brown eggs, to detect Salmonella spp. Pooled samples of eggshells, albumen, and yolk of white and brown eggs were collected at the poultry house and at the egg-storage room. Salmonella spp. was detected by conventional bacteriology in 5.4% (21/387) of analyzed samples and in 16% (68/387) by qPCR. In the 114 unwashed white eggs samples of eggshell, albumen and yolk, the bacterium was identified in 2.6% of the eggs (3/114) by conventional bacteriology and in 13.2% (15/114) by qPCR. In the 90 samples of washed eggs, 6.7% (6/90) were contaminated as detected by conventional bacteriology and 10.0% (9/90) by qPCR. In the 81 samples of unwashed brown eggs, Salmonella spp. was detected in 6.1% of the eggs (5/81) by conventional bacteriology and 27.2% (22/81) by qPCR. In the 102 samples of brown washed eggs, 6.9% (7/102) where positive by conventional bacteriology and 35.3% (16/102) by qPCR. All samples detected as positive by conventional bacteriology were also positive by qPCR. Salmonella Agona represented 18.2% (4/22) of identified serovars, Salmonella enterica subs. enterica O: 4.5 18.2% (4/22), Salmonella Schwarzengrund 18.2% (4/22), Salmonella Cerro 13.6% (3/22), Salmonella Anatum 13.6% (3/22), Salmonella Enteritidis 9.1% (2/22), Salmonella Johannesburg 4.5% (1/22), and Salmonella Corvallis 4.5% (1/22). The qPCR method provided better detection of Salmonella spp. in commercial eggs than conventional bacteriology. The conventional egg washing and disinfection procedures are not efficient to eliminate Salmonella.(AU)

Dietary supplementation of barbatimão (stryphnodendron adstringens) and pacari (lafoensia pacari) extracts on the oxidative stability and quality of chicken meat

In order to evaluate the antioxidant effects of barbatimão (BAR) or pacari (PAC) on chicken meat oxidative stability and quality, seven dietary treatments containing in three different BAR and PAC concentrations (200, 400 and 600ppm) plus a negative control (CONT) were fed to 350 broilers from 1 to 41 days of age. Ten birds per treatment were slaughtered to collect breast and thigh meat to evaluate pH, color (L*, a*, b*), cooking weight loss (CWL), and shear force (SF) 24 hours postmortem, and TBARS levels in precooked meatballs stored chilled for 8days. The dietary supplementation with BAR and PAC extracts did not affect pH and color, but reduced (p 0.05) SF in breast meat compared with CONT suggesting improved tenderness. PAC200 increased (p 0.05) L* and protected (p 0.05) yellow pigments (b* values) of thigh meat from degradation compared with the CONT diet. At the end of the chilled storage period, BAR600 and PAC600 significantly reduced (p 0.06) MDA concentrations in breast meatballs compared to the CONT. The dietary supplementation of BAR and PAC improved (p 0.03) oxidative stability of thigh meatballs, except for BAR200. In conclusion, the dietary addition of BAR and PAC extracts may improve meat quality and prevent lipid oxidation in white and dark precooked and chilled chicken meatballs.

Addition of amylase from aspergillus awamori to the diet of broiler chickens

Two experiments were performed to evaluate the hematological and blood biochemistry parameters, biometry of digestive organs, enzyme activities, protein content and absolute weight of the pancreas of broilers fed pre-starter and pre-starter diets supplemented or not with amylase from Aspergillus awamori. In total, 120 male Cobb chicks were housed in heated cages in each experiment. A completely randomized experimental design, with two treatments (feed with and without amylase) and six replicates per treatment of 10 birds each was applied. The data were subjected to analysis of variance using the F-test at 5% probability level. The dietary amylase addition did not affect hematological and blood biochemistry parameters and the biometry of the gastrointestinal tract of 7- and 21-d-old broilers, nor the absolute weight, enzyme activities or protein concentration of the pancreas of 7-d-old broilers. However, the inclusion of amylase in the diet reduced amylase activity and pancreatic protein concentration in 21-d-old broilers. The application of amylase to broiler chicken pre-starter and starter feeds is not justified given the pancreatic amylase activity and protein concentrations.

Addition of amylase from aspergillus awamori to the diet of broiler chickens

Two experiments were performed to evaluate the hematological and blood biochemistry parameters, biometry of digestive organs, enzyme activities, protein content and absolute weight of the pancreas of broilers fed pre-starter and pre-starter diets supplemented or not with amylase from Aspergillus awamori. In total, 120 male Cobb chicks were housed in heated cages in each experiment. A completely randomized experimental design, with two treatments (feed with and without amylase) and six replicates per treatment of 10 birds each was applied. The data were subjected to analysis of variance using the F-test at 5% probability level. The dietary amylase addition did not affect hematological and blood biochemistry parameters and the biometry of the gastrointestinal tract of 7- and 21-d-old broilers, nor the absolute weight, enzyme activities or protein concentration of the pancreas of 7-d-old broilers. However, the inclusion of amylase in the diet reduced amylase activity and pancreatic protein concentration in 21-d-old broilers. The application of amylase to broiler chicken pre-starter and starter feeds is not justified given the pancreatic amylase activity and protein concentrations.(AU)

Dietary supplementation of barbatimão (stryphnodendron adstringens) and pacari (lafoensia pacari) extracts on the oxidative stability and quality of chicken meat

In order to evaluate the antioxidant effects of barbatimão (BAR) or pacari (PAC) on chicken meat oxidative stability and quality, seven dietary treatments containing in three different BAR and PAC concentrations (200, 400 and 600ppm) plus a negative control (CONT) were fed to 350 broilers from 1 to 41 days of age. Ten birds per treatment were slaughtered to collect breast and thigh meat to evaluate pH, color (L*, a*, b*), cooking weight loss (CWL), and shear force (SF) 24 hours postmortem, and TBARS levels in precooked meatballs stored chilled for 8days. The dietary supplementation with BAR and PAC extracts did not affect pH and color, but reduced (p 0.05) SF in breast meat compared with CONT suggesting improved tenderness. PAC200 increased (p 0.05) L* and protected (p 0.05) yellow pigments (b* values) of thigh meat from degradation compared with the CONT diet. At the end of the chilled storage period, BAR600 and PAC600 significantly reduced (p 0.06) MDA concentrations in breast meatballs compared to the CONT. The dietary supplementation of BAR and PAC improved (p 0.03) oxidative stability of thigh meatballs, except for BAR200. In conclusion, the dietary addition of BAR and PAC extracts may improve meat quality and prevent lipid oxidation in white and dark precooked and chilled chicken meatballs.(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)

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.

Values of Metabolizable Energy and Metabolization of Nutrients for Slow- and Fast-growing Birds at Different Ages

Two trials were performed to determine apparent metabolizable energy (AME) and AME corrected for zero nitrogen balance (AMEn) values and coefficients of apparent metabolizability of nitrogen (CAMN) and of ether extract (CAMEE) of slow- and fast-growing broilers (Isa label and Cobb, respectively) fed four different diets between 10 to 17 days or 28 to 35 days of age. The method of total excreta collection was applied. The tested feedstuffs were corn, whole corn germ (WCG), sorghum, and soybean meal (SBM). A randomized block experimental design was applied, with two treatments (breeds) and four replicates of ten animals each in the first trial, and four replicates of six animals each in the second trial. No differences in CAMN values were observed between the breeds; however, Isa Label birds presented higher CAMEE for all tested feedstuffs. The AME and AMEn values obtained in Isa Label chickens fed the corn diet were 5.75 and 3.44% higher relative tothe Cobb birds, respectively. Breed did not influence AME and AMEn values of the other tested feedstuffs. Independently of breed, age influenced the AME and AMEn values of WCG, sorghum and SBM, suggesting that birds become utilize feed more efficiently as they age.

Values of Metabolizable Energy and Metabolization of Nutrients for Slow- and Fast-growing Birds at Different Ages

Two trials were performed to determine apparent metabolizable energy (AME) and AME corrected for zero nitrogen balance (AMEn) values and coefficients of apparent metabolizability of nitrogen (CAMN) and of ether extract (CAMEE) of slow- and fast-growing broilers (Isa label and Cobb, respectively) fed four different diets between 10 to 17 days or 28 to 35 days of age. The method of total excreta collection was applied. The tested feedstuffs were corn, whole corn germ (WCG), sorghum, and soybean meal (SBM). A randomized block experimental design was applied, with two treatments (breeds) and four replicates of ten animals each in the first trial, and four replicates of six animals each in the second trial. No differences in CAMN values were observed between the breeds; however, Isa Label birds presented higher CAMEE for all tested feedstuffs. The AME and AMEn values obtained in Isa Label chickens fed the corn diet were 5.75 and 3.44% higher relative tothe Cobb birds, respectively. Breed did not influence AME and AMEn values of the other tested feedstuffs. Independently of breed, age influenced the AME and AMEn values of WCG, sorghum and SBM, suggesting that birds become utilize feed more efficiently as they age.(AU)

Egg quality of hens fed different digestible lysine and arginine levels

This experiment aimed at evaluating the influence of the supplementation of digestible lysine and digestible arginine at different ratios in the diet fed to layers between 24 to 44 weeks of age on egg quality. In total,320 Lohmann LSL laying hens were allotted according to a completely randomized design in a 2 x 4factorial arrangement, consisting of two digestible lysine levels (700 or 900 mg/kg of diet) and four digestible arginine levels (700, 800, 900,or 1000 mg/kg of diet). Diets contained, therefore, digestible Lys:Arg ratios of 100, 114, 128, and 142 when the diet contained 700 mg digestible lysine per kg of diet, and 78, 89, 100, and 111 when 900 mg digestible lysine per kg was supplemented. The data obtained with digestible arginine levels were fitted to polynomial regression equations, and with digestible lysine, the F test (5% probability) was used to compare the means. The following variables were evaluated: egg weight; internal egg quality (yolk percentage and index, albumen percentage, Haugh units), eggshell quality (specific gravity andeggshell percentage); and whole egg, albumen, and yolk solids content. Digestible lysine and arginine interaction did not affect egg quality. Increasing levels of digestible lysine and arginine reduced eggshell quality and albumen solids, respectively. The levels of these amino acids suggested to improveegg quality are 700 mg digestible lysine and 700 mg digestible arginine/kg of feed at a Dig Lys: Dig Arg ratio of 100.

Digestible Threonine Levels in the Starter Diet of Broilers Derived from Breeders of Different Ages

The aim of this study was to evaluate the effect of digestible threonine supplementation in the starter diet on the performance, intestinal parameters, and nutrient metabolism of broilers derived from breeders of different ages. In total, 480 one-day-old Cobb chicks, derived from 38-or 49-week-oldbreeders, were housed in experimental battery cages until 21 days of age and fed four different threonine levels (800, 900, 1,000, or 1,100 mg/kg) in the starter feed. A completely randomized experimental design in a 2x4 factorial arrangement (breeder age x threonine levels) was applied, totaling eight treatments with five replicates of 12 birds each. Broilers from older breeders fed 800 mg digestible threonine/kg of diet presented higher weight gain, with a positive linear effect. There was also an interaction between breeder age and threonine levels for the weight gain of 21-d-old broilers supplemented at maximum level of 1,003 mg Thr/kg diet during the starter phase. There was no effect of breeder age or threonine levels on nutrient metabolism during the period of 17-21 days. There was no influence of breeder age or threonine levels in the starter diet on intestinal morphometric measurements, absorption area, or percentage of goblet cells.

Digestible Threonine Levels in the Starter Diet of Broilers Derived from Breeders of Different Ages

The aim of this study was to evaluate the effect of digestible threonine supplementation in the starter diet on the performance, intestinal parameters, and nutrient metabolism of broilers derived from breeders of different ages. In total, 480 one-day-old Cobb chicks, derived from 38-or 49-week-oldbreeders, were housed in experimental battery cages until 21 days of age and fed four different threonine levels (800, 900, 1,000, or 1,100 mg/kg) in the starter feed. A completely randomized experimental design in a 2x4 factorial arrangement (breeder age x threonine levels) was applied, totaling eight treatments with five replicates of 12 birds each. Broilers from older breeders fed 800 mg digestible threonine/kg of diet presented higher weight gain, with a positive linear effect. There was also an interaction between breeder age and threonine levels for the weight gain of 21-d-old broilers supplemented at maximum level of 1,003 mg Thr/kg diet during the starter phase. There was no effect of breeder age or threonine levels on nutrient metabolism during the period of 17-21 days. There was no influence of breeder age or threonine levels in the starter diet on intestinal morphometric measurements, absorption area, or percentage of goblet cells.(AU)