Effect of In Ovo Ascorbic Acid Injection and Thermal Manipulation During Incubation on Intestine Morphology of Broilers Reared under Cold and Heat Stress

It was investigated if pre-incubation ascorbic acid (AA) injection in fertile eggs incubated at high temperature impacts the performance, the yield of carcass and parts, and the intestine morphology of broilers reared under heat stress. Three thousand Cobb® fertile broiler eggs were randomly distributed according to weight into three incubations treatments (eggs not injected with AA and incubated at 37.5°C; eggs not injected with AA and incubated at 39°C; and eggs injected with 6 µg AA/100 µL water prior to incubation and incubated at 39ºC). The hatched birds were reared at thermoneutral, cold, and hot house temperatures. Broilers reared under hot temperature presented lower feed intake and weight gain than the broilers of the different rearing temperatures. Egg incubation at 39.0 ºC and 39.0 ºC + AA reduced broiler viability. Carcass and cut yields were not influenced by incubation and rearing procedures. Duodenal goblet cell count was lower in broilers from eggs of the treatment 39ºC + AA than in broilers from the other incubation treatments and in broiler rearing in hot temperature. In the jejunum, the goblet cell counts were higher in broilers that were reared under hot than thermoneutral temperatures. The incubation treatment of 39 ºC+AA increased the goblet cell counts in the ileum of broilers reared under cold temperatures. Rearing temperature influenced the duodenal villi counts, which were lower under cold rearing conditions than in the two other rearing temperatures. The results showed that egg incubation at 39°C, independently of ascorbic acid injection, did not produce an effective epigenetic heat adaptation in broilers.(AU)

Genetic and environmental effects on tonic immobility duration of red-winged tinamou applying survival analysis

Fear behavioral studies provide knowledge on animal welfare, and fearful behaviors can be used as selection criteria of individuals adapted to intensive rearing system. The survival analysis methodology was applied to estimate tonic immobility (TI) duration, as an indicator of fear, of red-winged tinamous (Rhynchotus rufescens) reared in captivity and to determine if TI is genetically influenced. A number of 539 birds born between 2006 and 2010 were evaluated. The exploratory data analysis was performed using the Kaplan-Meier estimate (KM), and the covariates were then fit to a Cox model, considering month of observation nested within year of birth and body weight as fixed effects and the random effect of sire as frailty term. In order to predict genetic values and to estimate heritability, the model of proportional hazards was applied, using a Weibull distribution as the baseline hazard. Birds born in the last year presented shorter TI duration than those born in the previous year, as shown by the survival KM curves, indicating a decline in fearfulness from one year to the next. The Cox analysis detected that hazard function was reduced as body weight increased. The frailty term was significant (p<0.05), showing that sires induced variation in the TI duration of the offspring. Heritability estimated as 0.37, indicating the influence of additive genes. These findings suggest that the selection of for short TI duration may allow reducing fearfulness of a red-winged tinamou population after some generations.(AU)

Genetic and environmental effects on tonic immobility duration of red-winged tinamou applying survival analysis

Fear behavioral studies provide knowledge on animal welfare, and fearful behaviors can be used as selection criteria of individuals adapted to intensive rearing system. The survival analysis methodology was applied to estimate tonic immobility (TI) duration, as an indicator of fear, of red-winged tinamous (Rhynchotus rufescens) reared in captivity and to determine if TI is genetically influenced. A number of 539 birds born between 2006 and 2010 were evaluated. The exploratory data analysis was performed using the Kaplan-Meier estimate (KM), and the covariates were then fit to a Cox model, considering month of observation nested within year of birth and body weight as fixed effects and the random effect of sire as frailty term. In order to predict genetic values and to estimate heritability, the model of proportional hazards was applied, using a Weibull distribution as the baseline hazard. Birds born in the last year presented shorter TI duration than those born in the previous year, as shown by the survival KM curves, indicating a decline in fearfulness from one year to the next. The Cox analysis detected that hazard function was reduced as body weight increased. The frailty term was significant (p<0.05), showing that sires induced variation in the TI duration of the offspring. Heritability estimated as 0.37, indicating the influence of additive genes. These findings suggest that the selection of for short TI duration may allow reducing fearfulness of a red-winged tinamou population after some generations.

Effect of Broiler Breeder Age and Glutamine Supplementation on the Development of the Intestinal Mucosa of 7-Day-Old Chicks

The aim of this study was to evaluate the possible effects of glutamine and broiler breeder age on the development of intestinal mucosa in broiler chicks during first week of age. For this purpose, 32 one-day-old broiler chicks were distributed according to a completely randomized experimental design in a 2 x 2 factorial arrangement. Treatments consisted of two broiler breeder ages (30 and 60 weeks) and two dietary glutamine supplementation levels (0% and 1%). The morphological development of intestinal mucosa, particularly villus height and crypt depth, was evaluated. The results showed that the supplementation with 1% of glutamine influenced the development of villus height in the duodenum (p=0.009), jejunum (p = 0.006), and ileum (p = 0.001), as well as crypt depth in the jejunum (p = 0.037) of 7-day-old broilers. These results suggest that the presence of glutamine influenced the development of intestinal mucosa during the first week of age, when these tissues are highly influenced by dietary components, especially by trophic agents. The results show that broiler breeder age (30 or 60 weeks) did not influence the evaluated parameters.

Poultry egg incubation: integrating and optimizing production efficiency

Due to its central position in the production chain, in-ovo development is influenced by pre-incubation factors that affect the quality of embryonated eggs and incubation conditions themselves, and both may influence egg hatchability and chick quality, as well as bird survival, growth performance, and phenotype in the field. The evolution of the incubation process over the years is characterized by significant scientific and technological development. Presently, the main current focuses of research are the manipulation of thermal incubation conditions, eggshell temperature, and the integrated effects of factors that influence incubation. In this context, one of the questions that needs to be asked is how effective are the current physical conditions of incubation to promote greater hatchability and better quality chicks, and higher survival and better performance in the field under adverse conditions or not. What are the new and future prospects for incubation? The purpose of this paper was to review the role of the physical agents of incubation, such as temperature, relative humidity, O2 and CO2 concentration, and egg turning and position from an integrated perspective, considering egg incubation as the transitional link between egg and poultry production.

Effect of broiler breeder age on the intestinal mucosa development of the embryos at 20 days of incubation

This study investigated the effect of broiler breeder age on the morphological development of the small intestine broiler embryos (villus height, crypt depth, microvillus height, and villus density) at 20 day of incubation. Eggs obtained from 30- and 60-wk-old broiler breeders were used. The results showed that embryos from older broiler breeders presented longer villi in the duodenum, jejunum, and ileum compared with younger broiler breeders. In addition, embryos from older broiler breeders presented deeper crypts in the jejunum and ileum, longer microvilli in jejunal enterocytes, and lower villus density (microvillus number/mm2) in the duodenum and ileum than younger breeders. These results suggest that breeder age influences the gut mucosa development of broiler embryos. Embryos from older broiler breeder showed greater development of the small intestine mucosa than those from younger broiler breeder.

Effect of broiler breeder age on the intestinal mucosa development of the embryos at 20 days of incubation

This study investigated the effect of broiler breeder age on the morphological development of the small intestine broiler embryos (villus height, crypt depth, microvillus height, and villus density) at 20 day of incubation. Eggs obtained from 30- and 60-wk-old broiler breeders were used. The results showed that embryos from older broiler breeders presented longer villi in the duodenum, jejunum, and ileum compared with younger broiler breeders. In addition, embryos from older broiler breeders presented deeper crypts in the jejunum and ileum, longer microvilli in jejunal enterocytes, and lower villus density (microvillus number/mm2) in the duodenum and ileum than younger breeders. These results suggest that breeder age influences the gut mucosa development of broiler embryos. Embryos from older broiler breeder showed greater development of the small intestine mucosa than those from younger broiler breeder.(AU)

Poultry egg incubation: integrating and optimizing production efficiency

Due to its central position in the production chain, in-ovo development is influenced by pre-incubation factors that affect the quality of embryonated eggs and incubation conditions themselves, and both may influence egg hatchability and chick quality, as well as bird survival, growth performance, and phenotype in the field. The evolution of the incubation process over the years is characterized by significant scientific and technological development. Presently, the main current focuses of research are the manipulation of thermal incubation conditions, eggshell temperature, and the integrated effects of factors that influence incubation. In this context, one of the questions that needs to be asked is how effective are the current physical conditions of incubation to promote greater hatchability and better quality chicks, and higher survival and better performance in the field under adverse conditions or not. What are the new and future prospects for incubation? The purpose of this paper was to review the role of the physical agents of incubation, such as temperature, relative humidity, O2 and CO2 concentration, and egg turning and position from an integrated perspective, considering egg incubation as the transitional link between egg and poultry production.(AU)

Effect of Broiler Breeder Age and Glutamine Supplementation on the Development of the Intestinal Mucosa of 7-Day-Old Chicks

The aim of this study was to evaluate the possible effects of glutamine and broiler breeder age on the development of intestinal mucosa in broiler chicks during first week of age. For this purpose, 32 one-day-old broiler chicks were distributed according to a completely randomized experimental design in a 2 x 2 factorial arrangement. Treatments consisted of two broiler breeder ages (30 and 60 weeks) and two dietary glutamine supplementation levels (0% and 1%). The morphological development of intestinal mucosa, particularly villus height and crypt depth, was evaluated. The results showed that the supplementation with 1% of glutamine influenced the development of villus height in the duodenum (p=0.009), jejunum (p = 0.006), and ileum (p = 0.001), as well as crypt depth in the jejunum (p = 0.037) of 7-day-old broilers. These results suggest that the presence of glutamine influenced the development of intestinal mucosa during the first week of age, when these tissues are highly influenced by dietary components, especially by trophic agents. The results show that broiler breeder age (30 or 60 weeks) did not influence the evaluated parameters.(AU)

Effect of In-Ovo Ascorbic Acid Injection on the Bone Development of Broiler Chickens Submitted to Heat Stress During Incubation and Rearing

This experiment was conducted to evaluate the effect of in-ovo ascorbic acid (AA) injection on the bone development of broilers submitted to heat stress during incubation and rearing. One thousand (1,000) Cobb(r)fertile broiler eggs were randomly distributed according to the weight into five incubators, with 200 eggs per incubator. The incubation treatments were: eggs not injected with AA and incubated at 37.5°C; eggs not injected with AA and incubated at 39°C; and eggs injected with 6 µg AA/100 µL water prior to incubation and incubated at 39ºC. The hatched birds were reared at three different house temperatures: cold, thermoneutral, or and hot. The high incubation temperature negatively influenced broilers' bone characteristics. The femur of the birds hatched from eggs incubated at 39°C and injected with AA presented lower shaft mineral density, lower maximum force and lower elongation at maximum force. Their tibia presented reduced mineral density at the proximal and distal epiphysis. In-ovo AA injection of eggs incubated at high temperature did not minimize the negative effects of high rearing temperature on the performance andbone development of broiler chickens reared until 42 days of age.

Effect of In-Ovo Ascorbic Acid Injection on the Bone Development of Broiler Chickens Submitted to Heat Stress During Incubation and Rearing

This experiment was conducted to evaluate the effect of in-ovo ascorbic acid (AA) injection on the bone development of broilers submitted to heat stress during incubation and rearing. One thousand (1,000) Cobb(r)fertile broiler eggs were randomly distributed according to the weight into five incubators, with 200 eggs per incubator. The incubation treatments were: eggs not injected with AA and incubated at 37.5°C; eggs not injected with AA and incubated at 39°C; and eggs injected with 6 µg AA/100 µL water prior to incubation and incubated at 39ºC. The hatched birds were reared at three different house temperatures: cold, thermoneutral, or and hot. The high incubation temperature negatively influenced broilers' bone characteristics. The femur of the birds hatched from eggs incubated at 39°C and injected with AA presented lower shaft mineral density, lower maximum force and lower elongation at maximum force. Their tibia presented reduced mineral density at the proximal and distal epiphysis. In-ovo AA injection of eggs incubated at high temperature did not minimize the negative effects of high rearing temperature on the performance andbone development of broiler chickens reared until 42 days of age.(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.(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.

Efeitos do espaço de alojamento e da idade sobre desenvolvimento, integridade e proteção da mucosa intestinal de frangos de corte / Effects of enclosure size and age on development, integrity and protection of the intestinal mucosa in broiler chickens

Foi avaliado se o espaço de alojamento influencia o desenvolvimento da mucosa do intestino delgado de frangos, sendo usado um esquema fatorial 4 x 2 (14, 28, 42, 55 dias de idade e alojamento pequeno: 0,11m²/ave e grande: 0,525m²/ave). Foram analisadas: altura, perímetro e número dos vilos, profundidade das criptas, número de células caliciformes e número de vilos sem e com perda de epitélio e exposição do conjuntivo. Em ambos os espaços de alojamento, o número de vilos diminuiu e a profundidade das criptas aumentou com a idade nas três regiões intestinais. A altura e o perímetro dos vilos aumentaram de 14 para 28 dias no jejuno e íleo, e o número de células caliciformes foi maior no duodeno e íleo a partir dos 42 dias. A perda de epitélio pelos vilos do íleo aumentou com a idade. Nas aves do alojamento grande, ocorreu aumento na altura e no perímetro dos vilos duodenais com a idade, possibilitado pelo aumento na profundidade das criptas, que resultou em vilos maiores nessas aves do que nas do alojamento pequeno aos 55 dias de idade. O número de células caliciformes diminuiu nas aves do alojamento pequeno aos 42 dias de idade. Os dados mostram que o tamanho do alojamento interferiu no modelo de desenvolvimento temporal da mucosa intestinal e que frangos apresentaram maior tamanho de vilo duodenal quando alojados em espaço maior.(AU)

This study evaluated if enclosure size and age influence the intestinal mucosa development of broiler chickens, using an experimental design in an 4x2 factorial arrangement (14, 18, 42 and 55 days of age and two enclosure spaces: small= 0.11m² /bird and large= 0.525m²/bird). Villous height, perimeter and number, and crypt depth, goblet cells number, and number of villous without and with epithelium loss and conjunctive tissue exposition were analyzed in duodenum, jejunum and ileum. Regardless of enclosure size, the villous number diminished and the crypt depth increased with the age in the three intestinal regions. From 14 to 28 days of age, villous height and perimeter increased in the jejunum and ileum. The number of goblet cells was greater from 42 days in duodenum and ileum, and epithelium loss increased until 42 days in the ileum. Broilers housed in small and large enclosures differed in the intestinal characteristics from 42 days. In broilers housed in large enclosure, duodenal villous height and perimeter increased with the age, with an increase in the crypt depth, reaching greater size at 55 days of age than duodenal villous of the broilers housed in a small enclosure. These later presented at 42 days a smaller number of goblet cells than the former. According these results, enclosure size influenced the temporal pattern of the intestinal mucosa development, and broilers presented major duodenal villous growth when housed in large enclosures.(AU)

Injeção de ácido ascórbico in ovo pré-incubação sobre parâmetros de incubação e hematológicos respiratórios / Effect of ascorbic acid injected in pre-incubation egg on incubation and respiratory hematological parameters

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 condições termoneutras, exceto a eclosão, a qual foi influenciada por falta de habilidade na execução da técnica de injeção. Além disso, a injeção de 6% de ácido ascórbico aumentou o teor de hemoglobina, com melhora no potencial de transporte de gases no sangue destes pintainhos.

The present study evaluates the effect of ascorbic acid injection into fertile eggs on incubation and blood parameters. Eight hundred fertile eggs from broiler (Cobb®) breeders aged 36 weeks were weighed and homogeneously distributed in four incubators with automatic control of temperature, humidity and turning. The eggs were incubated at 37.5°C while relative humidity was kept at 60% until transfer (19 days incubation) and, then, increased to 70% on the last two days of incubation. The experimental design was completely randomized with five treatments, applied before incubation: eggs without holes and therefore not injected; eggs injected in the albumen with 100 µL of water plus 0, 2, 4 and 6% ascorbic acid. Statistical analysis was performed by SAS®. The data shows that the treatments did not compromise the development in ovo under thermoneutral conditions, except for the hatching, which was influenced by lack of skill in performing the injection technique. Furthermore, injection of 6% ascorbic acid increased hemoglobin content, improving the transport of gases in the blood of these chicks.

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

Injeção de ácido ascórbico in ovo pré-incubação sobre parâmetros de incubação e hematológicos respiratórios / Effect of ascorbic acid injected in pre-incubation egg on incubation and respiratory hematological parameters

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 condições termoneutras, exceto a eclosão, a qual foi influenciada por falta de habilidade na execução da técnica de injeção. Além disso, a injeção de 6% de ácido ascórbico aumentou o teor de hemoglobina, com melhora no potencial de transporte de gases no sangue destes pintainhos.(AU)

The present study evaluates the effect of ascorbic acid injection into fertile eggs on incubation and blood parameters. Eight hundred fertile eggs from broiler (Cobb®) breeders aged 36 weeks were weighed and homogeneously distributed in four incubators with automatic control of temperature, humidity and turning. The eggs were incubated at 37.5°C while relative humidity was kept at 60% until transfer (19 days incubation) and, then, increased to 70% on the last two days of incubation. The experimental design was completely randomized with five treatments, applied before incubation: eggs without holes and therefore not injected; eggs injected in the albumen with 100 µL of water plus 0, 2, 4 and 6% ascorbic acid. Statistical analysis was performed by SAS®. The data shows that the treatments did not compromise the development in ovo under thermoneutral conditions, except for the hatching, which was influenced by lack of skill in performing the injection technique. Furthermore, injection of 6% ascorbic acid increased hemoglobin content, improving the transport of gases in the blood of these chicks.(AU)

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

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)

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.