Silicon in broiler drinking water promotes bone development in broiler chickens.

Skeletal abnormalities, bone deformities and fractures cause significant losses in broiler production during both rearing and processing. Silicon is an essential mineral for bone and connective tissue synthesis and for calcium absorption during the early stages of bone formation. Performance was not affected by the addition of silicon. However, broilers receiving silicon showed a significant increase of phosphorus, zinc, copper, manganese and ash in the tibia. In conclusion, broiler performance was not impaired by adding the tested silicon product to the drinking water. In addition, bone development improved, as demonstrated by higher mineral and ash content. Further studies are required to determine the optimal concentration of silicon, including heat stress simulations, to better understand the effects of silicon on bone development.

Reduced Nutrient Excretion and Environmental Microbial Load with the Addition of a Combination of Enzymes and Direct-Fed Microbials to the Diet of Broiler Chickens

This study evaluated the effects of the dietary inclusion of an enzyme blend and a direct-fed microbials in broiler diets on litter production and quality. In total, 900 Cobb 500(r) broiler chicks were distributed according to a completely randomized design into 4 treatments and 9 replicates of 25 birds each. Broilers were reared from 1 to 42 days of age. The treatments consisted of the following diets: NC: negative control; DFM: NC + 500 ppm of direct-fed microbials product (DFM), containing Bacillus subtilis and Bacillus licheniformis; ENZ: diet formulated with an enzyme blend (20 ppm phytase, 200 ppm protease and 200 ppm of xylanase); DFM+E: ENZ + DFM. Birds and litter were weighed at the start and end of the rearing period, for litter production and waste ratio (Rw) determination. Litter samples were analyzed for dry matter (DM) content, total and thermotolerant coliform counts, nutrient composition (nitrogen (N), phosphorous (P) and potassium (K)), and fiber fraction (neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin). The dietary inclusion of the evaluated additivesdid not influence litter production or Rw; however, ADF (%), NDF (kg and kg/kg DM litter), and total and thermotolerant coliform counts were reduced, and N content increased in the litter. The diets containing enzymes (ENZ and DFM+E) reduced litter P content. The addition of exogenous enzymes and their combination with a DFM based on Bacillus spp .Did not affect waste production, and reduced litter microbial load, and the contents of P and insoluble fiber in the litter.(AU)

Reduced Nutrient Excretion and Environmental Microbial Load with the Addition of a Combination of Enzymes and Direct-Fed Microbials to the Diet of Broiler Chickens

This study evaluated the effects of the dietary inclusion of an enzyme blend and a direct-fed microbials in broiler diets on litter production and quality. In total, 900 Cobb 500(r) broiler chicks were distributed according to a completely randomized design into 4 treatments and 9 replicates of 25 birds each. Broilers were reared from 1 to 42 days of age. The treatments consisted of the following diets: NC: negative control; DFM: NC + 500 ppm of direct-fed microbials product (DFM), containing Bacillus subtilis and Bacillus licheniformis; ENZ: diet formulated with an enzyme blend (20 ppm phytase, 200 ppm protease and 200 ppm of xylanase); DFM+E: ENZ + DFM. Birds and litter were weighed at the start and end of the rearing period, for litter production and waste ratio (Rw) determination. Litter samples were analyzed for dry matter (DM) content, total and thermotolerant coliform counts, nutrient composition (nitrogen (N), phosphorous (P) and potassium (K)), and fiber fraction (neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin). The dietary inclusion of the evaluated additivesdid not influence litter production or Rw; however, ADF (%), NDF (kg and kg/kg DM litter), and total and thermotolerant coliform counts were reduced, and N content increased in the litter. The diets containing enzymes (ENZ and DFM+E) reduced litter P content. The addition of exogenous enzymes and their combination with a DFM based on Bacillus spp .Did not affect waste production, and reduced litter microbial load, and the contents of P and insoluble fiber in the litter.

Effects of Ascorbic Acid Injection in Incubated Eggs Submitted to Heat Stress on Incubation Parameters and Chick Quality

Dose-dependent positive effects on hatchability and hatchling weight have been attributed to ascorbic acid (AA) when eggs were submitted or not to intermittent heat stress during incubation. Fertile breeder (Cobb(r)) eggs were used to determine if the pre-incubation injection of AA in ovo affects the incubation and hatchling quality of egg incubated under thermoneutral or intermittent heat stress conditions. Eggs were not injected or injected with 0, 2,4, or 6% AA/100µL water and incubated at continuous thermoneutral (37.5ºC) or hot (39.0ºC) temperature. Eggshell temperature (EST) increased in the second half of the incubation period in all experimental groups. The EST of non-injected eggs and of those injected with water was higher when incubated at 39°C than at 37.5°C, but EST was not different among eggs injected with AA. Egg mass loss and eggshell conductance were higher in the eggs incubated at 39°C than at 37.5°C.Hatchability was lower in the eggs injected with AA. Liver and yolk sac weights were higher, whereas heart and liver weights were lower in hatchlings from eggs incubated at 39°C; however, hatchling weight was not affected by incubation temperature. The results showed that AA doses affected egg conductive heat loss and hatchability, and that they did not minimize the effects of high incubation temperature on liver and heart development.(AU)

Effects of Ascorbic Acid Injection in Incubated Eggs Submitted to Heat Stress on Incubation Parameters and Chick Quality

Dose-dependent positive effects on hatchability and hatchling weight have been attributed to ascorbic acid (AA) when eggs were submitted or not to intermittent heat stress during incubation. Fertile breeder (Cobb(r)) eggs were used to determine if the pre-incubation injection of AA in ovo affects the incubation and hatchling quality of egg incubated under thermoneutral or intermittent heat stress conditions. Eggs were not injected or injected with 0, 2,4, or 6% AA/100µL water and incubated at continuous thermoneutral (37.5ºC) or hot (39.0ºC) temperature. Eggshell temperature (EST) increased in the second half of the incubation period in all experimental groups. The EST of non-injected eggs and of those injected with water was higher when incubated at 39°C than at 37.5°C, but EST was not different among eggs injected with AA. Egg mass loss and eggshell conductance were higher in the eggs incubated at 39°C than at 37.5°C.Hatchability was lower in the eggs injected with AA. Liver and yolk sac weights were higher, whereas heart and liver weights were lower in hatchlings from eggs incubated at 39°C; however, hatchling weight was not affected by incubation temperature. The results showed that AA doses affected egg conductive heat loss and hatchability, and that they did not minimize the effects of high incubation temperature on liver and heart development.

High-fiber diets with reduced crude protein for commercial layers

This study aimed at evaluating diets containing different fiber sources and two crude protein levels on the performance, egg quality, and nitrogen metabolism of commercial layers. In total, 392 48-wk-old Isa Brown layers were distributed according to a completely randomized experimental design in a 3x2+1 (control) factorial arrangement, resulting in seven treatments with seven replicates of eight birds each. Treatments consisted of three fiber feedstuffs (cottonseed hulls, soybean hulls, and rice hulls) and two dietary crude protein levels (12% and 16%). Cottonseed hulls associated with the high crude protein level (16%) resulted in the worst feed conversion ratio per dozen eggs. Diets with 16% crude protein resulted in the highest feed intake, egg production, egg weight, egg mass values, and improved feed conversion ratio (kg eggs/kg feed). The dietary inclusion of soybean hulls determined low yolk pigmentation, and of rice hulls, low egg specific gravity. The 16% crude protein diet with rice hulls promoted the best feed conversion ratio. Hens fed the reference diet presented higher egg mass and better feed conversion ratio per kg eggs and per dozen eggs. Hens fed the diets with low crude protein level (12%) had reduced nitrogen excretion, but presented worse egg production.(AU)

Use of nicarbazin, salinomycin and zinc oxide as alternative molting methods for commercial laying hens

An experiment was carried out to evaluate the performance, egg quality and morphometry of the reproductive tract, liver, pancreas and tongue of laying hens submitted to different molting methods. Two hundred and eighty eight 72-week-old Isa brown layers were distributed according to a completely randomized design with six treatments (molting methods) and six replicates of eight birds each. Layers were fed diets containing 3000 ppm zinc oxide, 60 ppm or 120 ppm nicarbazin, 30 ppm or 60 ppm salinomycin, or were submitted to feed fasting. Data were submitted to analysis of variance and means were compared by the test of Tukey at 5% probability level. Molting methods alternative to feed fasting were effective to induce molting in layer and provided good performance results in the second laying cycle.(AU)

High-fiber diets with reduced crude protein for commercial layers

This study aimed at evaluating diets containing different fiber sources and two crude protein levels on the performance, egg quality, and nitrogen metabolism of commercial layers. In total, 392 48-wk-old Isa Brown layers were distributed according to a completely randomized experimental design in a 3x2+1 (control) factorial arrangement, resulting in seven treatments with seven replicates of eight birds each. Treatments consisted of three fiber feedstuffs (cottonseed hulls, soybean hulls, and rice hulls) and two dietary crude protein levels (12% and 16%). Cottonseed hulls associated with the high crude protein level (16%) resulted in the worst feed conversion ratio per dozen eggs. Diets with 16% crude protein resulted in the highest feed intake, egg production, egg weight, egg mass values, and improved feed conversion ratio (kg eggs/kg feed). The dietary inclusion of soybean hulls determined low yolk pigmentation, and of rice hulls, low egg specific gravity. The 16% crude protein diet with rice hulls promoted the best feed conversion ratio. Hens fed the reference diet presented higher egg mass and better feed conversion ratio per kg eggs and per dozen eggs. Hens fed the diets with low crude protein level (12%) had reduced nitrogen excretion, but presented worse egg production.

Use of nicarbazin, salinomycin and zinc oxide as alternative molting methods for commercial laying hens

An experiment was carried out to evaluate the performance, egg quality and morphometry of the reproductive tract, liver, pancreas and tongue of laying hens submitted to different molting methods. Two hundred and eighty eight 72-week-old Isa brown layers were distributed according to a completely randomized design with six treatments (molting methods) and six replicates of eight birds each. Layers were fed diets containing 3000 ppm zinc oxide, 60 ppm or 120 ppm nicarbazin, 30 ppm or 60 ppm salinomycin, or were submitted to feed fasting. Data were submitted to analysis of variance and means were compared by the test of Tukey at 5% probability level. Molting methods alternative to feed fasting were effective to induce molting in layer and provided good performance results in the second laying cycle.

Performance, carcass traits, and body composition of broilers fed different linseed oil levels between 21 and 56 days of age

This study was carried out to evaluate the effect of the inclusion of different linseed oil levels (0.0, 3.3, 6.6, or 9.9%) in iso-energy diets fed during the period of 21 to 56 days of age on the performance, carcass traits, and body composition of broilers. A total of 1,600 broilers were distributed according to a completely randomized experimental design consisting of four treatments with eight replicates of 40 birds per experimental unit. In the period of 21-42 days of age, weight gain increased, feed and calorie conversion ratios quadratically improved, and feed and metabolizable energy intakes linearly increased as dietary linseed oil level increased. Considering the entire experimental period, dietary linseed oil linearly increased weight gain and feed and energy intakes, and feed and calorie conversion ratios in a quadratic manner. On days 42 and 56, abdominal fat percentage and carcass yield were quadratically influenced by dietary linseed oil. Total body fat content at 56 days of age was quadratically influenced by dietary linseed levels.(AU)

Efeito de níveis de silício na água de bebida sobre o desempenho, rendimento de carcaça, excreção de minerais e perfil de ácidos graxos no músculo peitoral de frangos de corte / Effect of levels of silicon in drink water of broiler on performance, carcass yield, excretion of minerals and fatty acid profile

O objetivo do estudo foi avaliar o efeito de níveis de silício na água de bebida de frangos de corte sobre o desempenho, o rendimento de carcaça, o metabolismo do cálcio, fósforo e nitrogênio e o perfil de ácidos graxos no músculo peitoral de frangos de corte. Foram utilizadas 1.120 pintos machos de um dia de idade da linhagem Cobb, distribuídas em um delineamento inteiramente casualisado, com quatro níveis de silício na água de bebida (0; 0,5mg; 1,0mg e 1,5mg do produto/100 kg de peso/dia), totalizando quatro tratamentos com oito repetições e 35 aves por parcela. A análise estatística dos dados foi realizada pelo método da análise de variância com o auxílio do procedimento GLM do SAS® e em caso de significância, os níveis de inclusão de silício foram estimados por intermédio dos modelos de regressão polinomial. A suplementação de silício via água de bebida promoveu efeito quadrático sobre a coxa+sobrecoxa com valor máximo de rendimento estimado em 28,87%. Com relação aos perfis de ácidos graxos observou - se efeito linear para os ácidos graxos vacênico, γ-linolênico, araquidico e palmítico e efeito quadrático para os ácidos graxos mirístico, miristoleico, palmitoleico e eicosadienoico. O silício modificou o perfil de ácidos graxos no músculo peitoral, bem como o rendimento de coxa+sobrecoxa das aves aos 49 dias de idade, podendo ser uma ferramenta importante a ser utilizada para a nutrição das aves.(AU)

The aim of this study was evaluate different levels of silicon in the drinking water of broilers on performance, carcass yield, metabolism of calcium, phosphorus and nitrogen and fatty acid profiles of pectoral muscle of broilers. A total of 1,120 one-day-old male Cobb chicks were used, distributed in a completely randomized design within four levels of silicon in the drinking water (0, 0.5 mg, 1.0 mg and 1.5 mg of silicon/100 kg/day), and eight replicates of 35 birds each . The data were analysed by the PROC GLM procedure of SAS® and in case of significance polynomial regressions were performed. Silicon supplementation in the drinking water promoted quadratic effect on thigh and drumstick with maximum yield estimated of 28.87%. For fatty acid profiles were observed linear effect for γ - linolenic, vaccenic, arachidonic and palmitic, and quadratic effect for myristic, myristoleic, palmitoleic and eicosadienoic. Silicon modified the fatty acid profiles of pectoral muscle as well as yield of thigh and drumstick of 49 days old birds, and could be an important tool to be used for poultry nutrition.(AU)

EFEITO DE NÍVEIS DE SILÍCIO NA ÁGUA DE BEBIDA SOBRE O DESEMPENHO, RENDIMENTO DE CARCAÇA, EXCREÇÃO DE MINERAIS E PERFIL DE ÁCIDOS GRAXOS NO MÚSCULO PEITORAL DE FRANGOS DE CORTE.

O objetivo do estudo foi avaliar o efeito de níveis de silício na água de bebida de frangos de corte sobre o desempenho, o rendimento de carcaça, o metabolismo do cálcio, fósforo e nitrogênio e o perfil de ácidos graxos no músculo peitoral de frangos de corte. Foram utilizadas 1.120 pintos machos de um dia de idade da linhagem Cobb, distribuídas em um delineamento inteiramente casualisado, com quatro níveis de silício na água de bebida (0; 0,5mg; 1,0mg e 1,5mg do produto/100 kg de peso/dia), totalizando quatro tratamentos com oito repetições e 35 aves por parcela. A análise estatística dos dados foi realizada pelo método da análise de variância com o auxílio do procedimento GLM do SAS® e em caso de significância, os níveis de inclusão de silício foram estimados por intermédio dos modelos de regressão polinomial. A suplementação de silício via água de bebida promoveu efeito quadrático sobre a coxa+sobrecoxa com valor máximo de rendimento estimado em 28,87%. Com relação aos perfis de ác

Performance, carcass traits, and body composition of broilers fed different linseed oil levels between 21 and 56 days of age

This study was carried out to evaluate the effect of the inclusion of different linseed oil levels (0.0, 3.3, 6.6, or 9.9%) in iso-energy diets fed during the period of 21 to 56 days of age on the performance, carcass traits, and body composition of broilers. A total of 1,600 broilers were distributed according to a completely randomized experimental design consisting of four treatments with eight replicates of 40 birds per experimental unit. In the period of 21-42 days of age, weight gain increased, feed and calorie conversion ratios quadratically improved, and feed and metabolizable energy intakes linearly increased as dietary linseed oil level increased. Considering the entire experimental period, dietary linseed oil linearly increased weight gain and feed and energy intakes, and feed and calorie conversion ratios in a quadratic manner. On days 42 and 56, abdominal fat percentage and carcass yield were quadratically influenced by dietary linseed oil. Total body fat content at 56 days of age was quadratically influenced by dietary linseed levels.

Efeito de níveis de silício na água de bebida sobre o desempenho, rendimento de carcaça, excreção de minerais e perfil de ácidos graxos no músculo peitoral de frangos de corte / Effect of levels of silicon in drink water of broiler on performance, carcass yield, excretion of minerals and fatty acid profile

O objetivo do estudo foi avaliar o efeito de níveis de silício na água de bebida de frangos de corte sobre o desempenho, o rendimento de carcaça, o metabolismo do cálcio, fósforo e nitrogênio e o perfil de ácidos graxos no músculo peitoral de frangos de corte. Foram utilizadas 1.120 pintos machos de um dia de idade da linhagem Cobb, distribuídas em um delineamento inteiramente casualisado, com quatro níveis de silício na água de bebida (0; 0,5mg; 1,0mg e 1,5mg do produto/100 kg de peso/dia), totalizando quatro tratamentos com oito repetições e 35 aves por parcela. A análise estatística dos dados foi realizada pelo método da análise de variância com o auxílio do procedimento GLM do SAS® e em caso de significância, os níveis de inclusão de silício foram estimados por intermédio dos modelos de regressão polinomial. A suplementação de silício via água de bebida promoveu efeito quadrático sobre a coxa+sobrecoxa com valor máximo de rendimento estimado em 28,87%. Com relação aos perfis de ácidos graxos observou - se efeito linear para os ácidos graxos vacênico, γ-linolênico, araquidico e palmítico e efeito quadrático para os ácidos graxos mirístico, miristoleico, palmitoleico e eicosadienoico. O silício modificou o perfil de ácidos graxos no músculo peitoral, bem como o rendimento de coxa+sobrecoxa das aves aos 49 dias de idade, podendo ser uma ferramenta importante a ser utilizada para a nutrição das aves.

The aim of this study was evaluate different levels of silicon in the drinking water of broilers on performance, carcass yield, metabolism of calcium, phosphorus and nitrogen and fatty acid profiles of pectoral muscle of broilers. A total of 1,120 one-day-old male Cobb chicks were used, distributed in a completely randomized design within four levels of silicon in the drinking water (0, 0.5 mg, 1.0 mg and 1.5 mg of silicon/100 kg/day), and eight replicates of 35 birds each . The data were analysed by the PROC GLM procedure of SAS® and in case of significance polynomial regressions were performed. Silicon supplementation in the drinking water promoted quadratic effect on thigh and drumstick with maximum yield estimated of 28.87%. For fatty acid profiles were observed linear effect for γ - linolenic, vaccenic, arachidonic and palmitic, and quadratic effect for myristic, myristoleic, palmitoleic and eicosadienoic. Silicon modified the fatty acid profiles of pectoral muscle as well as yield of thigh and drumstick of 49 days old birds, and could be an important tool to be used for poultry nutrition.

Dietary fiber inclusion as an alternative to Feed Fasting to induce molting in Commercial Layers

The objective of the present experiment was to compare the performance, egg quality and organ morphometrics of commercial layers submitted to alternative forced molting methods using dietary fibers. The experimental period included the phases of molting, rest, and second laying cycle (six periods of 28 days each). In the trial, 320 commercial Isa Brown layers with 72 weeks of age were distributed, according to a completely randomized experimental design into five treatments with eight replicates of eight birds each, totaling 40 experimental units. Molting was induced by feeding diets with the inclusion of alfalfa or soybean husks at 80% and 60% or feed fasting. Treatments were applied for 14 days. Performance and egg quality parameters were evaluated for the second laying cycle and organ morphometrics (liver, gizzard, proventriculus, reproductive apparatus) in two different slaughter dates. The obtained data were submitted to analysis of variance using the General Linear Model (GLM) procedure of SAS statistical package (SAS Institute, 2002). Alternative molting methods promoted similar performance and egg quality results after molting were similar to those obtained by the conventional fasting method. Feeding fiber produced the expected effects in terms of organ weight regression and recovery and may be used to induce molting in commercial layers.(AU)

Dietary fiber inclusion as an alternative to Feed Fasting to induce molting in Commercial Layers

The objective of the present experiment was to compare the performance, egg quality and organ morphometrics of commercial layers submitted to alternative forced molting methods using dietary fibers. The experimental period included the phases of molting, rest, and second laying cycle (six periods of 28 days each). In the trial, 320 commercial Isa Brown layers with 72 weeks of age were distributed, according to a completely randomized experimental design into five treatments with eight replicates of eight birds each, totaling 40 experimental units. Molting was induced by feeding diets with the inclusion of alfalfa or soybean husks at 80% and 60% or feed fasting. Treatments were applied for 14 days. Performance and egg quality parameters were evaluated for the second laying cycle and organ morphometrics (liver, gizzard, proventriculus, reproductive apparatus) in two different slaughter dates. The obtained data were submitted to analysis of variance using the General Linear Model (GLM) procedure of SAS statistical package (SAS Institute, 2002). Alternative molting methods promoted similar performance and egg quality results after molting were similar to those obtained by the conventional fasting method. Feeding fiber produced the expected effects in terms of organ weight regression and recovery and may be used to induce molting in commercial layers.

Effect of forced-molting methods and rearing temperatures on the performance and organ biometrics of laying hens

An experiment was conducted to evaluate the biometrics of organs (ovary, oviduct, liver, proventriculus and gizzard) of laying hens submitted to different forced-molting methods of molt and maintained at three different temperature. Organs were evaluated after molting and resting period. Six hundred birds were distributed according to a completely randomized experimental design in a 5x3 factorial arrangement (forced-molting methods x environmental temperatures) into 15 treatments with 5 replicates of 8 birds each. The molting methods applied were the dietary inclusion of 90%, 70%, 50% of alfalfa, 2,800 ppm zinc oxide, or total feed restriction. Birds were kept at ±20 ºC, ±27 ºC, or ±35 ºC. Data were submitted to analysis of variance and means were compared by orthogonal and polynomial contrasts. The traditional forced-molting method (feed fasting) resulted in adequate performance. However, as the aim of the present study was to find an alternative method to feed fasting, the highest dietary alfafa inclusion level (90%) was shown to be efficient compared with other methods, particularly when hens were kept at high temperature. Therefore, this alternative forced-molting may be applied, especially when bird welfare is taken into consideration.(AU)

Effect of forced-molting methods and rearing temperatures on the performance and organ biometrics of laying hens

An experiment was conducted to evaluate the biometrics of organs (ovary, oviduct, liver, proventriculus and gizzard) of laying hens submitted to different forced-molting methods of molt and maintained at three different temperature. Organs were evaluated after molting and resting period. Six hundred birds were distributed according to a completely randomized experimental design in a 5x3 factorial arrangement (forced-molting methods x environmental temperatures) into 15 treatments with 5 replicates of 8 birds each. The molting methods applied were the dietary inclusion of 90%, 70%, 50% of alfalfa, 2,800 ppm zinc oxide, or total feed restriction. Birds were kept at ±20 ºC, ±27 ºC, or ±35 ºC. Data were submitted to analysis of variance and means were compared by orthogonal and polynomial contrasts. The traditional forced-molting method (feed fasting) resulted in adequate performance. However, as the aim of the present study was to find an alternative method to feed fasting, the highest dietary alfafa inclusion level (90%) was shown to be efficient compared with other methods, particularly when hens were kept at high temperature. Therefore, this alternative forced-molting may be applied, especially when bird welfare is taken into consideration.

EFFECT OF ASCORBIC ACID INJECTED IN PRE-INCUBATION EGG ON INCUBATION AND RESPIRATORY HEMATOLOGICAL PARAMETERS/Injeção de ácido ascórbico in ovo pré-incubação sobre parâmetros de incubação e hematológicos respiratórios

O presente estudo teve como objetivo verificar o efeito da injeção de ácido ascórbico em ovos férteis sobre parâmetros de incubação e sanguíneos. Oitocentos ovos férteis de matrizes de frango de corte (Cobb®) com 36 semanas de idade foram pesados e distribuídos homogeneamente em quatro incubadoras, com controle automático de temperatura, giro e umidade. Durante o período de incubação utilizou-se uma temperatura de 37,5ºC e 60% de umidade relativa até a transferência (19 dias de incubação) e 70% de umidade relativa nos dois últimos dias de incubação. O delineamento utilizado foi o inteiramente casualizado, com cinco tratamentos aplicados antes da incubação: ovos não perfurados e, portanto não injetados; ovos injetados com 100 µl de água no albúmem, com as seguintes concentrações: 0, 2, 4 e 6% de ácido ascórbico. As análises estatísticas foram realizadas pelo programa SAS ®. Os dados mostraram que os tratamentos utilizados não prejudicaram o desenvolvimento in ovo sob c

DIET MANAGEMENT ASSOCIATED WITH DIFFERENT TEMPERATURES FOR INDUCING MOLT IN LAYING HENS/Manipulação da dieta associada a diferentes temperaturas para aves de postura em muda forçada

O objetivo do estudo foi avaliar o desempenho de poedeiras comerciais durante a muda forçada submetidas a diferentes dietas e temperaturas. As aves foram distribuídas em um delineamento inteiramente ao acaso, em esquema fatorial 5x3 (dietas x temperaturas), com cinco repetições de oito aves cada. As dietas testados consistiram de inclusão de alfafa, em 90%, 70% e 50%, dieta com 2.800 ppm de zinco e o controle jejum alimentar. As temperaturas utilizadas foram: 20 ºC, 27 ºC e 35 ºC. As deitas foram fornecidas durante 14 dias. Durante o processo de muda e descanso, foram avaliadas as características de desempenho das aves. Os dados obtidos foram submetidos à análise de variância pelo programa SAS ® e as médias comparadas por meio de contrastes ortogonais e polinomiais. Os resultados indicaram que dietas com a inclusão de alfafa induziram o processo de muda em poedeiras comerciais em 3,85 dias após o fornecimento. As aves arraçoadas com alfafa apresentaram perda de peso corporal para induzir a muda de 26,88%, enquanto que para o controle (jejum alimentar) a perda de peso corporal foi de 30,26%. Aves mantidas em temperatura termoneutra, durante a muda, cessaram a produção de ovos em 2,73