Resumo
The objective of this study was to evaluate the effects of dietary supplementation of purified lignin on the performance, relative organ weights, serum metabolites, and gene expression profiles of broiler chickens subjected to cyclic heat stress (HS). At 22 days old, 280 broilers were distributed in a completely randomized design with four treatments, ten repetitions, and seven birds per experimental unit. The birds were subjected to daily cyclic HS. A high temperature of 32±1 °C was maintained for 10 h/day (08:0018:00 h), while a temperature of 22±1 °C was maintained for the remaining time. Treatments were a basal diet or basal diet with the addition of 5, 10, or 15 g of purified lignin/kg of diet. Data were analyzed using one-way ANOVA and means were compared by Tukey's test at 0.05 significance. There was no effect of lignin supplementation on performance, carcass yield, relative weights of the bursa, spleen, and liver, or serum levels of glucose, triglycerides, uric acid, malondialdehyde, triiodothyronine, or tetraiodothyronine. The abundance of mRNA of heat shock protein 70, nuclear factor-κB, glutathione peroxidase, and Cu,Zn-superoxide dismutase in the liver was similarly unaffected by treatments. Purified lignin supplementation does not improve performance or the antioxidant response of broiler chickens subjected to HS.(AU)
Assuntos
Animais , Galinhas/fisiologia , Lignina/efeitos adversos , Antioxidantes/efeitos adversos , Transtornos de Estresse por Calor/veterináriaResumo
Investigaram-se os efeitos de diferentes tempos de exposição ao calor sobre o rendimento de carcaça, cortes e vísceras comestíveis e a composição química da carne de peito de frangos de corte de duas linhagens. Foram alojados 560 pintos de corte da linhagem Cobb 500 Slow® e 560 da Hubbard Flex® em 32 boxes. A partir do 14º dia, eles foram divididos nos ambientes térmicos: controle, uma hora, duas horas ou três horas diárias de estresse por calor. O rendimento de carcaça, peito sem osso, coxa e sobrecoxa com osso, asas, pés, fígado, moela e coração foi avaliado em seis aves de cada linhagem em cada ambiente térmico. Amostras foram obtidas para analisar matéria seca, extrato etéreo, proteína bruta e matéria mineral. O estresse cíclico por calor por até três horas diárias não influenciou o rendimento de carcaça, de peito sem osso, de coxa e sobrecoxa, de asa, de coração, de moela, de fígado e a composição química do peito. A linhagem Cobb 500 Slow® apresentou maior rendimento de peito. A Hubbard Flex® apresentou peito com maior percentual de matéria mineral e proteína. A linhagem Cobb é mais indicada à produção de peito, e a linhagem Hubbard à produção de frango inteiro.(AU)
The effects of different exposure periods under heat on the carcass yield, cuts and edible organs and breast chemical composition of broilers from two strains were investigated. Five hundred and sixty Cobb 500 Slow® and 560 Hubbard Flex® broiler chicks were housed in 32 pens and from the 14th day on, they were divided in thermal environments: control, 1 hour, 2 hours or 3 hours a day under heat stress. Carcass yield, boneless breast, thigh and drumstick with bone, wings, feet, liver, gizzard and heart were evaluated in six birds of each strain in each thermal environment. Samples were obtained to assess dry matter, ether extract, crude protein and mineral matter. The cyclic heat stress for up to three hours a day did not influence 33 the carcass yield, boneless breast, thigh and drumstick, wing, heart, gizzard, liver, and the breast chemical composition. Cobb 500 Slow® strain had higher breast yield. Hubbard Flex® had breast with higher percentage of mineral matter and protein. Cobb strain is best designed to breast production, and Hubbard is best for whole chicken production.(AU)
Assuntos
Animais , Galinhas/classificação , Galinhas/fisiologia , Carne/análise , Transtornos de Estresse por CalorResumo
Investigaram-se os efeitos de diferentes tempos de exposição ao calor sobre o rendimento de carcaça, cortes e vísceras comestíveis e a composição química da carne de peito de frangos de corte de duas linhagens. Foram alojados 560 pintos de corte da linhagem Cobb 500 Slow® e 560 da Hubbard Flex® em 32 boxes. A partir do 14º dia, eles foram divididos nos ambientes térmicos: controle, uma hora, duas horas ou três horas diárias de estresse por calor. O rendimento de carcaça, peito sem osso, coxa e sobrecoxa com osso, asas, pés, fígado, moela e coração foi avaliado em seis aves de cada linhagem em cada ambiente térmico. Amostras foram obtidas para analisar matéria seca, extrato etéreo, proteína bruta e matéria mineral. O estresse cíclico por calor por até três horas diárias não influenciou o rendimento de carcaça, de peito sem osso, de coxa e sobrecoxa, de asa, de coração, de moela, de fígado e a composição química do peito. A linhagem Cobb 500 Slow® apresentou maior rendimento de peito. A Hubbard Flex® apresentou peito com maior percentual de matéria mineral e proteína. A linhagem Cobb é mais indicada à produção de peito, e a linhagem Hubbard à produção de frango inteiro.(AU)
The effects of different exposure periods under heat on the carcass yield, cuts and edible organs and breast chemical composition of broilers from two strains were investigated. Five hundred and sixty Cobb 500 Slow® and 560 Hubbard Flex® broiler chicks were housed in 32 pens and from the 14th day on, they were divided in thermal environments: control, 1 hour, 2 hours or 3 hours a day under heat stress. Carcass yield, boneless breast, thigh and drumstick with bone, wings, feet, liver, gizzard and heart were evaluated in six birds of each strain in each thermal environment. Samples were obtained to assess dry matter, ether extract, crude protein and mineral matter. The cyclic heat stress for up to three hours a day did not influence 33 the carcass yield, boneless breast, thigh and drumstick, wing, heart, gizzard, liver, and the breast chemical composition. Cobb 500 Slow® strain had higher breast yield. Hubbard Flex® had breast with higher percentage of mineral matter and protein. Cobb strain is best designed to breast production, and Hubbard is best for whole chicken production.(AU)
Assuntos
Animais , Galinhas/classificação , Galinhas/fisiologia , Carne/análise , Transtornos de Estresse por CalorResumo
Background: The wellbeing and performance of calves may be impaired if raised in high temperature environments. Physiological and hematological variables serve as a tool to assess the welfare of cattle; therefore, the influence of seasons and age on physiological and hematological variables was evaluated of crossbred dairy calves in a tropical environment.Materials, Methods & Results: Forty-two male and female calves were evaluated from July 2016 to July 2017, when the calves were of 2, 15, 30, and 60 days of age. Respiratory (RR) and heart rates (HR) and rectal (RT) and body surface (BST) temperatures were quantified in the morning. Additionally, in the morning, dry bulb (Tdb) and wet bulb (Twb) temperatures were measured, and then, relative humidity (RH) and a temperature-humidity index (THI) were calculated. Blood was collected to perform hemogram. The day before the calves were evaluated, thermal environment data were collected to verify whether there were cyclic periods of heat stress. The mean air temperature ranged from 19°C to 22.1°C, and the highest THI value of 68 occurred in the summer mornings. In the afternoon, the maximum air temperature ranged from 27.5°C to 29.7°C. In autumn, respiratory and heart rates and body surface temperature were higher in 2-day-old calves than in other ages. The body surface temperature of 60-day-old calves was higher in spring and summer than in autumn. Rectal temperature remained in the normal range throughout the study period. Season did not influence the erythrogram and plaquetogram. The values for red blood cells, MCV, MCHC, RDW, platelets, and MPV varied among the calf ages. Season did not influence the values of leukocytes, monocytes, lymphocytes, or N/L ratio; however, band neutrophils and eosinophils varied among seasons. Band neutrophils and monocytes were not altered by age, whereas leukocyte, segmented neutrophils, eosinophils, lymphocytes, and N/L ratio values varied with age among the calves.[...]
Assuntos
Animais , Bovinos , Bem-Estar do Animal , Contagem de Eritrócitos/veterinária , Contagem de Plaquetas/veterinária , Fatores Etários , Temperatura Alta/efeitos adversos , Transtornos de Estresse por Calor/fisiopatologia , Transtornos de Estresse por Calor/veterinária , Testes Hematológicos/veterinária , Zona TropicalResumo
Background: The wellbeing and performance of calves may be impaired if raised in high temperature environments. Physiological and hematological variables serve as a tool to assess the welfare of cattle; therefore, the influence of seasons and age on physiological and hematological variables was evaluated of crossbred dairy calves in a tropical environment.Materials, Methods & Results: Forty-two male and female calves were evaluated from July 2016 to July 2017, when the calves were of 2, 15, 30, and 60 days of age. Respiratory (RR) and heart rates (HR) and rectal (RT) and body surface (BST) temperatures were quantified in the morning. Additionally, in the morning, dry bulb (Tdb) and wet bulb (Twb) temperatures were measured, and then, relative humidity (RH) and a temperature-humidity index (THI) were calculated. Blood was collected to perform hemogram. The day before the calves were evaluated, thermal environment data were collected to verify whether there were cyclic periods of heat stress. The mean air temperature ranged from 19°C to 22.1°C, and the highest THI value of 68 occurred in the summer mornings. In the afternoon, the maximum air temperature ranged from 27.5°C to 29.7°C. In autumn, respiratory and heart rates and body surface temperature were higher in 2-day-old calves than in other ages. The body surface temperature of 60-day-old calves was higher in spring and summer than in autumn. Rectal temperature remained in the normal range throughout the study period. Season did not influence the erythrogram and plaquetogram. The values for red blood cells, MCV, MCHC, RDW, platelets, and MPV varied among the calf ages. Season did not influence the values of leukocytes, monocytes, lymphocytes, or N/L ratio; however, band neutrophils and eosinophils varied among seasons. Band neutrophils and monocytes were not altered by age, whereas leukocyte, segmented neutrophils, eosinophils, lymphocytes, and N/L ratio values varied with age among the calves.[...](AU)
Assuntos
Animais , Bovinos , Bem-Estar do Animal , Temperatura Alta/efeitos adversos , Fatores Etários , Contagem de Eritrócitos/veterinária , Contagem de Plaquetas/veterinária , Transtornos de Estresse por Calor/fisiopatologia , Transtornos de Estresse por Calor/veterinária , Zona Tropical , Testes Hematológicos/veterináriaResumo
The objective of this study was to evaluate the effects of different times of exposure to heat on bone parameters and organ morphometry of Cobb Slow® and Hubbard Flex® broilers exposed to high temperatures for 1, 2 or 3 h daily, from 14 days of age. A total of 1120 one-day-old male chicks (half of each line; average weight of 44 g) were housed into 32 cages with 35 birds each, in a randomized-block experimental design. From the first to the 13th day of age, the birds remained under the thermal conditions recommended for their lines; thereafter, from the 14th day, the shed was separated into four parallel sections of 5.60 × 10.20 × 2.8 m delimited by double-sided plastic curtains along the width of the shed. Cyclic heat stress was generated by average temperatures of 36 ºC from 14-20 days, 35 °C from 21-27 days, 34 °C from 28-34 days and 33 °C from 35-42 days. The total length, width, density and mineral matter of the tibia; the size of the duodenum, jejunum and ileum; and the weights of the bursa of Fabricius and spleen were measured. No interaction effect between thermal environment and line was observed. Heat stress for up to 3 h daily, from the 14th to the 41st day of age, led to a longer but narrower tibia. There was no influence on small intestine morphometry. The Hubbard line presented longer and wider tibiae as well as higher relative and absolute weights of the bursa. In conclusion, heat stress from 2 h daily modifies the structure of the tibia in broilers, which increases in length and reduces in width, but heat exposure has no influence on the small intestine or lymphoid organs. The Hubbard line shows better tibia development than the Cobb line as well as different primary lymphoid responses, represented by a heavier bursa.(AU)
Objetivou-se avaliar os efeitos de diferentes tempos de exposição ao calor sobre os parâmetros ósseos e morfometria de órgãos de frango de corte Cobb Slow® e Hubbard Flex® expostos à temperatura elevada por 1h, 2h e 3h diárias a partir de 14 dias de idade. Foram alojados 1120 pintos de cortes machos de um dia, distribuídos em delineamento de blocos casualizados, sendo metade de cada linhagem (peso médio de 44g) em 32 boxes com 35 aves cada. Do primeiro ao 13º dia de idade as aves permaneceram em condições térmicas de acordo com o recomendado para a linhagem, a partir do 14º dia, o galpão foi separado em quatro seções paralelas de 5,60 x 10,20 x 2,8m delimitadas por cortinas plásticas dupla face ao longo da largura do galpão. O estresse cíclico por calor foi gerado com temperaturas médias de 14-20 dias: 36 ºC; 21-27 dias: 35 ºC; 28-34 dias: 34 ºC e 35-42 dias: 33 ºC. O comprimento total, largura, densidade e matéria mineral do osso tíbia; tamanho do duodeno, jejuno e íleo e o peso da bursa e do baço foram determinados. Não foi observado interação entre ambiente térmico e linhagens. O estresse por calor no período de até 3 horas diárias, do 14º ao 41º dia de idade aumentou o comprimento e reduziu a largura do osso tíbia. Não houve influência na morfometria do intestino delgado. A linhagem Hubbard apresentou maiores comprimento e largura da tíbia, bem como maiores pesos relativo e absoluto da bursa. Concluiu-se que o estresse por calor a partir de 2 horas diárias modifica a estrutura da tíbia de frangos de corte, com aumento de seu comprimento e redução de sua largura, porém não há influência da exposição ao calor sobre o intestino delgado e órgãos linfoides. A linhagem Hubbard apresenta melhor desenvolvimento do osso tíbia em relação à Cobb, bem como respostas linfoides primárias diferentes, representada por maior peso da bursa.(AU)
Assuntos
Galinhas , Resposta ao Choque Térmico , Desenvolvimento Ósseo , Tíbia/anormalidades , Intestino Delgado , Temperatura AltaResumo
The objective of this study was to evaluate the effects of different times of exposure to heat on bone parameters and organ morphometry of Cobb Slow® and Hubbard Flex® broilers exposed to high temperatures for 1, 2 or 3 h daily, from 14 days of age. A total of 1120 one-day-old male chicks (half of each line; average weight of 44 g) were housed into 32 cages with 35 birds each, in a randomized-block experimental design. From the first to the 13th day of age, the birds remained under the thermal conditions recommended for their lines; thereafter, from the 14th day, the shed was separated into four parallel sections of 5.60 × 10.20 × 2.8 m delimited by double-sided plastic curtains along the width of the shed. Cyclic heat stress was generated by average temperatures of 36 ºC from 14-20 days, 35 °C from 21-27 days, 34 °C from 28-34 days and 33 °C from 35-42 days. The total length, width, density and mineral matter of the tibia; the size of the duodenum, jejunum and ileum; and the weights of the bursa of Fabricius and spleen were measured. No interaction effect between thermal environment and line was observed. Heat stress for up to 3 h daily, from the 14th to the 41st day of age, led to a longer but narrower tibia. There was no influence on small intestine morphometry. The Hubbard line presented longer and wider tibiae as well as higher relative and absolute weights of the bursa. In conclusion, heat stress from 2 h daily modifies the structure of the tibia in broilers, which increases in length and reduces in width, but heat exposure has no influence on the small intestine or lymphoid organs. The Hubbard line shows better tibia development than the Cobb line as well as different primary lymphoid responses, represented by a heavier bursa.
Objetivou-se avaliar os efeitos de diferentes tempos de exposição ao calor sobre os parâmetros ósseos e morfometria de órgãos de frango de corte Cobb Slow® e Hubbard Flex® expostos à temperatura elevada por 1h, 2h e 3h diárias a partir de 14 dias de idade. Foram alojados 1120 pintos de cortes machos de um dia, distribuídos em delineamento de blocos casualizados, sendo metade de cada linhagem (peso médio de 44g) em 32 boxes com 35 aves cada. Do primeiro ao 13º dia de idade as aves permaneceram em condições térmicas de acordo com o recomendado para a linhagem, a partir do 14º dia, o galpão foi separado em quatro seções paralelas de 5,60 x 10,20 x 2,8m delimitadas por cortinas plásticas dupla face ao longo da largura do galpão. O estresse cíclico por calor foi gerado com temperaturas médias de 14-20 dias: 36 ºC; 21-27 dias: 35 ºC; 28-34 dias: 34 ºC e 35-42 dias: 33 ºC. O comprimento total, largura, densidade e matéria mineral do osso tíbia; tamanho do duodeno, jejuno e íleo e o peso da bursa e do baço foram determinados. Não foi observado interação entre ambiente térmico e linhagens. O estresse por calor no período de até 3 horas diárias, do 14º ao 41º dia de idade aumentou o comprimento e reduziu a largura do osso tíbia. Não houve influência na morfometria do intestino delgado. A linhagem Hubbard apresentou maiores comprimento e largura da tíbia, bem como maiores pesos relativo e absoluto da bursa. Concluiu-se que o estresse por calor a partir de 2 horas diárias modifica a estrutura da tíbia de frangos de corte, com aumento de seu comprimento e redução de sua largura, porém não há influência da exposição ao calor sobre o intestino delgado e órgãos linfoides. A linhagem Hubbard apresenta melhor desenvolvimento do osso tíbia em relação à Cobb, bem como respostas linfoides primárias diferentes, representada por maior peso da bursa.
Assuntos
Desenvolvimento Ósseo , Galinhas , Intestino Delgado , Resposta ao Choque Térmico , Tíbia/anormalidades , Temperatura AltaResumo
The objective of this study was to evaluate the performance and carcass yield of broilers submitted to heat stress during different rearing stages. A total of 840 one-day-old CobbAvian48TM male broilers were housed in an experimental house equipped with conventional ventilation system and foggers. Birds were distributed according to a completely randomized design into four treatments, with six replicates of 35 birds each. The treatments consisted of: T1 (control) - birds reared under natural temperature and relative humidity conditions from 1 to 42 days of age; T2 - birds submitted to heat stress (HS) from 16 to 21 days of age; T3 - birds submitted to HS from 22 to 42 days of age; and T4 - birds submitted to HS from 16 to 42 days of age. Birds were submitted to heat stress daily for one hour (12:00-13:00h).On day 42, performance data were determined. Six birds per replicate were selected and sacrificed to obtain carcass, parts, and giblet weights and yields. Performance parameters were not influenced by the treatments. Broilers submitted to 1-h cyclic heat between 16 and 42 days of age presented lower deboned breast weight compared with those maintained in natural temperature and relative humidity conditions. It was concluded that the performance of broilers submitted to short cyclic heat periods is not impaired.(AU)
Assuntos
Animais , Masculino , Recém-Nascido , Transtornos de Estresse por Calor/veterinária , Galinhas/fisiologia , Umidade/efeitos adversos , Temperatura Alta/efeitos adversos , Fatores Etários , Peso CorporalResumo
The objective of this study was to evaluate the performance and carcass yield of broilers submitted to heat stress during different rearing stages. A total of 840 one-day-old CobbAvian48TM male broilers were housed in an experimental house equipped with conventional ventilation system and foggers. Birds were distributed according to a completely randomized design into four treatments, with six replicates of 35 birds each. The treatments consisted of: T1 (control) - birds reared under natural temperature and relative humidity conditions from 1 to 42 days of age; T2 - birds submitted to heat stress (HS) from 16 to 21 days of age; T3 - birds submitted to HS from 22 to 42 days of age; and T4 - birds submitted to HS from 16 to 42 days of age. Birds were submitted to heat stress daily for one hour (12:00-13:00h).On day 42, performance data were determined. Six birds per replicate were selected and sacrificed to obtain carcass, parts, and giblet weights and yields. Performance parameters were not influenced by the treatments. Broilers submitted to 1-h cyclic heat between 16 and 42 days of age presented lower deboned breast weight compared with those maintained in natural temperature and relative humidity conditions. It was concluded that the performance of broilers submitted to short cyclic heat periods is not impaired.
Assuntos
Masculino , Animais , Recém-Nascido , Galinhas/fisiologia , Temperatura Alta/efeitos adversos , Transtornos de Estresse por Calor/veterinária , Umidade/efeitos adversos , Fatores Etários , Peso CorporalResumo
Macroscopic and microscopic changes in the epiphyseal region of the tibia were recorded in the 42nd day of life of broilers subjected to one-hour heat stress in different rearing phases. The treatments comprised both broilers reared under room temperature and humidity conditions from the 1st to the 42nd day of life (control) and broilers subjected to heat stress from the 16th to the 21st, from the 22nd to the 42nd, and from the 16th to the 42nd day of life. The adopted design was completely randomized with six replicates; 35 broilers were used in each experimental unit. Fragments from the epiphyseal region were extracted and sectioned lengthwise for macro and microscopic analyses. Data on tibia lesion scores were analyzed by Kruskal Wallis test at 5%. The one-hour cyclic heat stress did not change the morphologic integrity in the epiphyseal region of the tibia in the different treatments. Broilers subjected to one-hour cyclic heat stress did not develop lesions that suggested tibial dyschondroplasia, regardless of the rearing phase.
Foram estudadas alterações macroscópicas e microscópicas na região epifisária da tíbia no 42º dia de frangos de corte submetidos ao estresse cíclico de calor por uma hora em diferentes fases de criação. Os tratamentos compreenderam aves criadas em condições naturais de temperatura e umidade relativa do primeiro ao 42º dia de idade (controle), ou estressadas por calor do 16º ao 21º dia, do 22º ao 42º dia e do 16º ao 42º dia. O delineamento utilizado foi o inteiramente casualizado com seis repetições sendo 35 aves por unidade experimental. Para análises macro e microscópicas da tíbia, fragmentos da região epifisária foram extraídos e seccionados longitudinalmente. Os dados de escores de lesões tibiais foram analisados pelo teste de Kruskall Wallis a 5%. O estresse cíclico por calor por uma hora não alterou a integridade morfológica da região epifisária da tíbia nos diferentes tratamentos. Frangos de corte submetidos por uma hora diária ao estresse de calor não desenvolvem lesões sugestivas de discondroplasia tibial independente da fase de criação.
Assuntos
Animais , Galinhas , Osteocondrodisplasias/veterinária , Transtornos de Estresse por Calor/complicações , Tíbia/crescimento & desenvolvimento , Desenvolvimento ÓsseoResumo
Macroscopic and microscopic changes in the epiphyseal region of the tibia were recorded in the 42nd day of life of broilers subjected to one-hour heat stress in different rearing phases. The treatments comprised both broilers reared under room temperature and humidity conditions from the 1st to the 42nd day of life (control) and broilers subjected to heat stress from the 16th to the 21st, from the 22nd to the 42nd, and from the 16th to the 42nd day of life. The adopted design was completely randomized with six replicates; 35 broilers were used in each experimental unit. Fragments from the epiphyseal region were extracted and sectioned lengthwise for macro and microscopic analyses. Data on tibia lesion scores were analyzed by Kruskal Wallis test at 5%. The one-hour cyclic heat stress did not change the morphologic integrity in the epiphyseal region of the tibia in the different treatments. Broilers subjected to one-hour cyclic heat stress did not develop lesions that suggested tibial dyschondroplasia, regardless of the rearing phase.(AU)
Foram estudadas alterações macroscópicas e microscópicas na região epifisária da tíbia no 42º dia de frangos de corte submetidos ao estresse cíclico de calor por uma hora em diferentes fases de criação. Os tratamentos compreenderam aves criadas em condições naturais de temperatura e umidade relativa do primeiro ao 42º dia de idade (controle), ou estressadas por calor do 16º ao 21º dia, do 22º ao 42º dia e do 16º ao 42º dia. O delineamento utilizado foi o inteiramente casualizado com seis repetições sendo 35 aves por unidade experimental. Para análises macro e microscópicas da tíbia, fragmentos da região epifisária foram extraídos e seccionados longitudinalmente. Os dados de escores de lesões tibiais foram analisados pelo teste de Kruskall Wallis a 5%. O estresse cíclico por calor por uma hora não alterou a integridade morfológica da região epifisária da tíbia nos diferentes tratamentos. Frangos de corte submetidos por uma hora diária ao estresse de calor não desenvolvem lesões sugestivas de discondroplasia tibial independente da fase de criação.(AU)
Assuntos
Animais , Galinhas , Transtornos de Estresse por Calor/complicações , Tíbia/crescimento & desenvolvimento , Osteocondrodisplasias/veterinária , Desenvolvimento ÓsseoResumo
The experiment was conducted to study the effect of pure glycerin supplementation (GLYC) in the drinking water of broilers subjected to heat stress and feed restriction. Water with 0, 1, or 2% glycerin was provided ad libitum to broilers in six hours of feed restriction. The birds were housed in two environments: thermoneutral (TN) - 25 ° C, and cyclic heat stress (HS) - 12h with 250C, 6h with 320C, 3h of 250 to 320C and 3h of 320 to 250C. The experimental design was randomized in a factorial arrangement of 2 x 3 + 2, with three GLYC levels, two environments and one control group with ad libitum feeding each environment. When submitted to HS, broiler receiving 2% glycerin presented higher weight gain (WG), water consumption (WC), feed intake (FI) and energy consumption (EI) than those in the other treatments, contrarily to birds in TN, where increasing GLYC levels decreased those responses. Broilers submitted to feed restriction presented reduced FI, but better feed conversion (FCR), independently of rearing environment or GLYC levels. Broilers under HS submitted to feed restriction and receiving 2% GLYC presented higher WC (p < 0.05) and similar WG as the controls, differently from the restricted-fed broilers under TN receiving 2% GLYC, which WC and WG were lower than the controls. The inclusion of 2% pure glycerin in the drinking water may compensate the negative effects on performance caused by feed restriction in broilers submitted to heat stress.
Assuntos
Animais , Galinhas/crescimento & desenvolvimento , Glicerol/análise , Ingestão de Líquidos , Restrição Calórica/veterinária , Transtornos de Estresse por Calor/veterinária , Aditivos Alimentares/análise , Aumento de Peso , Fenômenos Fisiológicos da Nutrição Animal , Ingestão de Alimentos , Água Potável/análiseResumo
The experiment was conducted to study the effect of pure glycerin supplementation (GLYC) in the drinking water of broilers subjected to heat stress and feed restriction. Water with 0, 1, or 2% glycerin was provided ad libitum to broilers in six hours of feed restriction. The birds were housed in two environments: thermoneutral (TN) - 25 ° C, and cyclic heat stress (HS) - 12h with 250C, 6h with 320C, 3h of 250 to 320C and 3h of 320 to 250C. The experimental design was randomized in a factorial arrangement of 2 x 3 + 2, with three GLYC levels, two environments and one control group with ad libitum feeding each environment. When submitted to HS, broiler receiving 2% glycerin presented higher weight gain (WG), water consumption (WC), feed intake (FI) and energy consumption (EI) than those in the other treatments, contrarily to birds in TN, where increasing GLYC levels decreased those responses. Broilers submitted to feed restriction presented reduced FI, but better feed conversion (FCR), independently of rearing environment or GLYC levels. Broilers under HS submitted to feed restriction and receiving 2% GLYC presented higher WC (p < 0.05) and similar WG as the controls, differently from the restricted-fed broilers under TN receiving 2% GLYC, which WC and WG were lower than the controls. The inclusion of 2% pure glycerin in the drinking water may compensate the negative effects on performance caused by feed restriction in broilers submitted to heat stress.(AU)
Assuntos
Animais , Glicerol/análise , Galinhas/crescimento & desenvolvimento , Restrição Calórica/veterinária , Transtornos de Estresse por Calor/veterinária , Ingestão de Líquidos , Aditivos Alimentares/análise , Fenômenos Fisiológicos da Nutrição Animal , Aumento de Peso , Ingestão de Alimentos , Água Potável/análiseResumo
O estresse térmico proporciona muitos prejuízos na avicultura industrial e com o objetivo de minimizá-los, estratégias nutricionais vêm sendo adotadas, com ênfase, principalmente aos alimentos naturais. O objetivo desse trabalho foi estudar o efeito da suplementação de óleo da semente de maracujá (OSM) na imunidade e respostas imunes, qualidade de carne e sistema antioxidante de frangos de corte. Para isso foram utilizados 450 pintainhos de 1 dia de idade, machos, da linhagem Cobb® 500, alojados em gaiolas de arame galvanizado, em duas câmaras com 45 gaiolas cada. O delineamento foi inteiramente casualizado, em esquema fatorial 2 x 5, sendo duas temperaturas (termoneutra e estresse cíclico pelo calor) e cinco tratamentos (controle sem inclusão de OSM + quatro níveis de inclusão de OSM (0,30; 0,50; 0,70; 0,90%) com nove repetições de cinco aves cada. A ração foi desprovida de antibióticos como melhorador de desempenho, porém acrescida de anticoccidiano em todos os tratamentos. Os dados foram analisados utilizando-se análise de variância com auxílio do SAS 9.3 (SAS Institute, 2008) e, sendo significativas a (P<0,05) no teste de média pelo teste de Tukey. Houve efeito significativo para o peso vivo ao abate e peso de cortes comerciais, para frangos criados em ambiente termoneutro, que apresentaram maiores valores em relação ao estresse por calor, e a gordura abdominal apresentou menor valor para aves desafiadas por calor. O OSM influenciou no maior peso (em gramas) das pernas. Frangos de corte criados em estresse por calor apresentaram menores valores de a* na musculatura do peito do que os frangos criados em ambiente termoneutro. Em relação a análise proteômica eletroforese bidimensional em gel de poliacrilamida (2D-PAGE) do plasma sanguíneo para resultados voltados a qualidade de carne, a proteína Actin alpha skeletal muscle, apresentou diferença significativa nos tratamentos com inclusão de 0,9% de OSM em ambas as temperaturas (estresse por calor e termoneutra) e, Neuropilin-1, no tratamento termoneutro com 0% de inclusão de OSM. Com 21 dias de idade foi observado uma interação significativa para titulação de anticorpos, sendo que frangos criados em ambiente de estresse que receberam o nível de 0,90% de OSM, apresentaram maior valor de titulação vacinal. Aos 28 dias de idade, novamente os animais que receberam 0,90% de inclusão de OSM e, independente do ambiente de criação, apresentaram maiores valores de títulos de anticorpos. Na análise proteômica do plasma sanguíneo (2D-PAGE) foram encontradas diversas proteínas que 11 estão relacionadas com o sistema imunológico dos frangos de corte: Complement factor B-like protease (Fragment); Glyceraldehyde-3-phosphate dehydrogenase; Mannose-binding protein; Zinc finger protein ubi-d4; Ig lambda chain C region; Ig lambda chain V-1 region; Apolipoprotein A-I. A análise proteômica também apresentou resultados referentes a manutenção do epitélio gastrointestinal, com a expressão diferencial de Retinol-binding protein 4 e, Homeodomain-only protein. Houve maior % de redução de DPPH com a maior inclusão do OSM, assim como maior expressão de Alcohol dehydrogenase 1, nos tratamentos com maior inclusão de OSM. Também houve diferença significativa para o efeito temperatura sobre a atividade da enzima catalase que se apresentou maior em ambiente termoneutro. Assim como, Nuclear receptor coactivator 7 que foi diferencialmente expresso no tratamento 0% de frangos de corte criados em ambiente termoneutro. Hemoglobin subunit epsilon teve sua expressão diferenciada no tratamento 0,9% de frangos de corte criados em ambiente de estresse. Além disso, vários spots proteicos relacionados as chaperonas moleculares foram diferencialmente expressas nos tratamentos 0,5% e 0,9% de inclusão de OSM em ambas as temperaturas de criação. Membrane-associated progesterone receptor component 1 foi diferencialmente expresso nos tratamentos de 0,9% de inclusão de OSM em ambos os ambientes de criação.
Heat stress causes many damages in industrial poultry farming and in order to minimize them, nutritional strategies have been adopted, with emphasis, mainly on natural foods. The objective of this work was to study the effect of passion fruit seed oil (OSM) supplementation on immunity and immune responses, meat quality and antioxidant system of broiler chickens. For this, 450 1-day-old male chicks of the Cobb® 500 strain were used, housed in galvanized wire cages, in two chambers with 45 cages each. The design was completely randomized, in a 2 x 5 factorial scheme, with two temperatures (thermoneutral and cyclic heat stress) and five treatments (control without inclusion of OSM + four levels of inclusion of OSM (0.30; 0.50; 0) .70; 0.90%) with nine replicates of five birds each.The ration was devoid of antibiotics as a performance enhancer, but added anticoccidial in all treatments. Data were analyzed using analysis of variance with the aid of SAS 9.3 (SAS Institute, 2008) and, being significant (P<0.05) in the mean test by the Tukey test. which had higher values in relation to heat stress, and abdominal fat had lower value for heat challenged birds. OSM influenced the higher weight (in grams) of the legs. Broilers reared under heat stress had lower value a* in the breast musculature than broilers raised in a thermoneutral environment. Regarding proteomic two-dimensional electrophoresis analysis in polyacrylamide gel (2D-PAGE) of blood plasma for meat quality results, the protein Actin alpha skeletal muscle showed a significant difference in treatments with inclusion of 0.9% OSM in both temperatures (heat stress and thermoneutral) and, Neuropilin-1, in thermoneutral treatment with 0% inclusion of OSM. At 21 days of age, a significant interaction for antibody titration was observed, and broilers reared in a stress environment that received the level of 0.90% of OSM had a higher value of vaccine titration. At 28 days of age, again the animals that received 0.90% inclusion of OSM and, regardless of the rearing environment, had higher antibody titers. In the proteomic analysis of blood plasma (2D-PAGE) several proteins that are related to the immune system of broiler chickens were found: Complement factor B-like protease (Fragment); Glyceraldehyde-3-phosphate dehydrogenase; Mannose-binding protein; Zinc finger protein ubi-d4; Ig lambda chain C region; Ig lambda chain V-1 region; Apolipoprotein A-I. Proteomic analysis also showed results regarding the maintenance of the gastrointestinal epithelium, with the differential expression of Retinol-binding protein 4 and Homeodomain-only protein. There was a greater % reduction of DPPH with the 13 greater inclusion of OSM, as well as greater expression of Alcohol dehydrogenase 1, in treatments with greater inclusion of OSM. There was also a significant difference for the temperature effect on the catalase enzyme activity, which was higher in a thermoneutral environment. As well as, Nuclear receptor coactivator 7 which was differentially expressed in the 0% treatment of broilers reared in thermoneutral environment. Hemoglobin subunit epsilon had its expression differentiated in the treatment of 0.9% of broilers reared in stress environment. Furthermore, several protein spots related to molecular chaperones were differentially expressed in the 0.5% and 0.9% OSM inclusion treatments at both rearing temperatures. Membrane-associated progesterone receptor component 1 was differentially expressed in treatments of 0.9% inclusion of OSM in both rearing environments.
Resumo
Background: The growing concern of the effects of high temperatures in the production of broilers, apart from the consistent increase of the consumption of chicken meat in Brazil and in the world and form the demands of consumers and industries increase the need for comprehensive studies on organoleptic characteristics of this meat, such as color and loss of water drip (drip loss). In this scenario, the objective of this research was to investigate the effects of cyclic heat stress on color and drip loss of chicken breast of broilers at different growth stages.Materials, Methods & Results: A group of 840 1-day-old CobbAvian48® broiler male chicks was housed in a shed, in 24 boxes with 35 birds each according to a completely randomized design. The broilers were reared under thermal comfort for 15 days. On the 16th day the shed was divided in sections with the following thermal environments: Control - Broilers reared under natural temperature and humidity conditions between day 16 and 42 (C 16-42), and broilers submitted to cyclic heat stress between day 16 and 21 (CHS 16-21), day 22 and 42 (CHS 22-42), and between day 16 and 42 (CHS 16-42). Stress was imposed from 12:00 noon to 1:00 pm, with temperature above the maximum recommended for the lineage. On day 42, one broiler of each box weighing close to the mean weight on a box basis was slaughtered and the breast meat removed, totaling 24 breasts. Color was analyzed using the following visual standard: 1 = PSE meat (pale, soft, exudative), 2 = normal meat, and 3 = DFD meat (dark, firm, dry). Chicken breasts were visually compared to the standard. To determine drip loss, a meat fragment was removed, weighed, and placed in a nylon-poly plastic bag, which in turn was placed in polyethylene plastic packaging properly labeled. After, these were hung in a refrigerator for 48 h at controlled temperature of 4-8°C. Drip loss data were analyzed using ANOVA, and the means were compared using the Tukey test at 5%.[...](AU)
Assuntos
Animais , Transtornos de Estresse por Calor/veterinária , Carne/análise , Qualidade dos Alimentos , Galinhas/fisiologiaResumo
Background: The growing concern of the effects of high temperatures in the production of broilers, apart from the consistent increase of the consumption of chicken meat in Brazil and in the world and form the demands of consumers and industries increase the need for comprehensive studies on organoleptic characteristics of this meat, such as color and loss of water drip (drip loss). In this scenario, the objective of this research was to investigate the effects of cyclic heat stress on color and drip loss of chicken breast of broilers at different growth stages.Materials, Methods & Results: A group of 840 1-day-old CobbAvian48® broiler male chicks was housed in a shed, in 24 boxes with 35 birds each according to a completely randomized design. The broilers were reared under thermal comfort for 15 days. On the 16th day the shed was divided in sections with the following thermal environments: Control - Broilers reared under natural temperature and humidity conditions between day 16 and 42 (C 16-42), and broilers submitted to cyclic heat stress between day 16 and 21 (CHS 16-21), day 22 and 42 (CHS 22-42), and between day 16 and 42 (CHS 16-42). Stress was imposed from 12:00 noon to 1:00 pm, with temperature above the maximum recommended for the lineage. On day 42, one broiler of each box weighing close to the mean weight on a box basis was slaughtered and the breast meat removed, totaling 24 breasts. Color was analyzed using the following visual standard: 1 = PSE meat (pale, soft, exudative), 2 = normal meat, and 3 = DFD meat (dark, firm, dry). Chicken breasts were visually compared to the standard. To determine drip loss, a meat fragment was removed, weighed, and placed in a nylon-poly plastic bag, which in turn was placed in polyethylene plastic packaging properly labeled. After, these were hung in a refrigerator for 48 h at controlled temperature of 4-8°C. Drip loss data were analyzed using ANOVA, and the means were compared using the Tukey test at 5%.[...]
Assuntos
Animais , Carne/análise , Qualidade dos Alimentos , Transtornos de Estresse por Calor/veterinária , Galinhas/fisiologiaResumo
A produção avícola no Brasil enfrenta um grande desafio que é o estresse por calor, ele pode afetar negativamente o sistema imunológico reduzindo o desempenho produtivo. O objetivo desse estudo foi avaliar os efeitos da suplementação da arginina e da vitamina C sobre o desempenho e resposta imune de frangos de corte em ambiente de termoneutralidade e estresse cíclico pelo calor. Foram utilizados 384 frangos de corte machos no período de 1 a 35 dias de idade. As aves foram distribuídas em delineamento inteiramente casualizado (DIC) em um esquema fatorial 3x2x2: 3 níveis de inclusão de arginina digestível (100, 130 e 160% da exigência da arginina), dois níveis de inclusão de vitamina C (0 e 200 ppm) e 2 temperaturas (termoneutralidade e estresse cíclico por calor) totalizando 12 tratamentos com 8 repetições de 4 aves cada. Foram avaliados índices zootécnicos, hemograma completo, perfil bioquímico sorológico, peso relativo dos órgãos imunes, histomorfometria Bursa de Fabricíus e expressão relativa dos genes HSP 70 e GPx utilizando-se o gene actina como controle interno. O estresse cíclico por calor teve impactos negativos nos frangos de corte, reduzindo o consumo de ração e, por consequência, o ganho de peso aos 21 e 35 dias. Aos 21 e 35 dias de idade a suplementação de 200 ppm de vitamina C na dieta dos frangos de corte melhorou o consumo de ração e o ganho de peso dos frangos, entretanto, não influenciou o peso dos órgãos imunes e as concentrações séricas de glicose, colesterol e creatina quinase. Aos 35 dias de idade, a suplementação da arginina não influenciou o desempenhos dos frangos, o peso dos órgãos, a concentração de glicose e de creatina quinase, mas influenciou a concentração sérica de colesterol. A vitamina C e a Arginina aumentaram a percentagem da área do córtex da Bursa. E a inclusão de arginina e vitamina C aumentou a expressão genica HSP 70 e do GPx. Conclui-se os frangos de corte quando recebem vitamina C sofrem uma resposta ao estresse menos severa após exposição a altas temperaturas e a suplementação de Arginina e vitamina C aumentou a expressão genica do HSP 70 dando maior resistência as aves durante períodos de calor e a expressão de GPx que indicando um aumento na atividade antioxidante de frangos de corte.
Brazilian poultry production faces a major challenge that is heat stress, it affects negatively the immune system, reducing productive performance. The aim of this study was to evaluate supplementation of arginine and vitamin C effects on performance and immune response of broilers in thermoneutrality and cyclic heat stress environments. A total of 384 male broilers from 1 to 35 days of age were allotted in a 3x2x2 completely randomized factorial scheme: 3 digestible arginine levels (100, 130 and 160% of the requirement), two vitamin C levels (0 and 200 ppm) and 2 temperatures (thermoneutrality and cyclic heat stress), totaling 12 treatments with 8 repetitions of 4 birds each. Zootechnical indexes, complete blood count, serological biochemical profile, relative weight of immune organs, Bursa of Fabricius histomorphometry and relative expression of HSP 70 and GPx genes, using the actin gene as an internal control, were evaluated. Cyclic heat stress had negative impacts on broilers, reducing feed intake and, consequently, weight gain at 21 and 35 days. At 21 and 35 days of age, supplementation of 200 ppm of vitamin C improved feed intake and weight gain, however, did not influence immune organs weight and serum glucose concentrations, cholesterol and creatine kinase. At 35 days of age, arginine supplementation did not influence the performance of the chickens, the organs weight, concentration of glucose and creatine kinase, but it did influence the serum concentration of cholesterol. Vitamin C and Arginine increased the Bursa cortex percentage. The inclusion of arginine and vitamin C increased HSP 70 and GPx gene expression. In conclusion, broilers when receiving vitamin C undergo a less severe stress response after exposure to high temperatures, and supplementation of arginine and vitamin C increased the genetic expression of HSP 70 promoting greater resistance during periods of heat. The expression of GPx indicates an increase in antioxidant activity of broilers.
Resumo
O presente estudo teve como objetivos desenvolver equações de predição para a variação no desempenho em frangos de corte submetidos ao estresse por calor, analisar a influência do tipo de estresse à que as aves são submetidas, e demonstrar o grau de correlação entre o balanço eletrolítico da dieta e o calor, utilizando a ferramenta de meta-análise. Foram construídas duas bases de dados independentes contendo informações de desempenho e estresse por calor em frangos de corte; a primeira referente à fase inicial de criação (1 a 21 dias) e a segunda para a fase de crescimento e terminação (após 21 dias). Para compor a base de dados da fase inicial foram utilizados 14 artigos e 7.667 animais, de estudos realizados entre os anos de 2001 e 2018. Enquanto para a base de dados após 21 dias de idade foram tabulados 74 artigos, com um total de 25.145 frangos de corte, de estudos entre 1983 e 2018. Os principais critérios para a seleção dos artigos foram: (1) experimentos usando no mínimo duas temperaturas (termoneutra e alta temperatura); (2) conter respostas de desempenho (consumo, ganho de peso e conversão alimentar); (3) alimento e água fornecidos ad libitum durante o período experimental; (4) conter características do animal (sexo, linhagem, fase de criação, idade inicial e final). Em ambas as bases de dados foram classificados dois tipos de estresse: cíclico e constante. Os modelos de predição foram validados utilizando duas bases de dados independentes das primeiras, com informações de dissertações e teses publicadas a partir de julho de 2018. Para a validação na fase inicial (1 a 21 dias) e final foram utilizadas 171 e 169 observações, respectivamente. As equações de predição foram apresentadas em porcentagem e gramas e geradas para ganho de peso de 1 a 21 dias e para consumo de ração e ganho de peso após 21 dias. O estresse por calor não influenciou o consumo de alimentos na fase inicial (1 a 21 dias), bem como a conversão alimentar em nenhuma fase de criação, não sendo possível a construção de equações de predição para estas variáveis nas respectivas fases. O estresse por calor constante mostrou-se mais deletério ao desempenho do que o cíclico em frangos após 21 dias, mas na fase inicial os tipos de estresse não se diferenciaram significativamente. A relação entre o balanço eletrolítico da dieta e o desempenho em aves em estresse pelo calor foi estudada para aves a partir dos 21 dias de idade, tendo sido observada uma baixa correlação entre estas variáveis. Conclui-se que o estresse por calor afeta de forma mais aguda os frangos de corte após 21 dias, embora a conversão alimentar não seja afetada o consumo de ração é a variável mais importante no estresse por calor e que a relação entre o balanço eletrolítico da dieta e as altas temperaturas é muito pequena ou inexistente.
The present study aimed to develop prediction equations for the performance variation of broilers submitted to heat stress, analyze the influence of the type of stress that the broilers are submitted and demonstrate the degree of correlation between the electrolytic balance of the diet and the heat stress, using the meta-analysis tool. Two independent databases containing information of performance and heat stress in broilers were developed; the first one refers to the initial phase (1 to 21 days) and the second one refers to the growing and finishing phase (over 21 days). In order to compose the database of the initial phase 14 articles and 7667 animals from studies performed between the years of 2001 and 2008 were used. For the database over 21 days of age it was used 74 articles between 1983 and 2018 with a total of 25145 broilers. The main criteria for the articles selection were (1) experiments using two temperatures (thermo neutral and high temperature); (2) the presence of performance responses (intake, weight gain and feed conversion); (3) food and water ad libitum during the experimental period; (4) information about the animals characteristics (sex, bloodlines, growing phase, initial and final age). Both databases were classified in two types of stress: cyclic and constant stress. The prediction models were validated using two independent databases not related to the first ones, with information of dissertations and thesis published since July, 2018. For the validation of the initial (1 to 21 days) and final phase, 171 and 169 observations were used, respectively. The prediction equations were presented in percentage and grams and it were generated for weight gain from 1 to 21 days and for ration intake and weight gain over 21 days. The heat stress did not influenced the feed intake in the initial phase (1 to 21 days), as well as the feed conversion in any of the growing phases, not being possible the construction of prediction equations for these variables in the respective phases. The constant heat stress showed to be more negative than the cyclic heat stress to the performance of broilers after 21 days of age, but in the initial phase these types of stress did not differ significantly. The relation between the electrolytic balance of the diet and the performance in broilers under heat stress was analyzed considering broilers over 21 days of age, being observed a weak correlation between these variables. It was concluded that the heat stress affects more the broilers over 21 days, although the feed conversion is not affected. The ration intake is the most important variable during the heat stress and the relation between the electrolytic balance of the diet and the high temperatures is too low or inexistent.
Resumo
O experimento foi conduzido com o objetivo de avaliar o efeito da suplementação de cromo-orgânico, sobre o desempenho, biometria dos órgãos digestivos e linfoides, histomoformetria da bolsa cloacal e rendimento de carcaça e cortes nobres de frangos de corte de 1 a 41 dias de idade, naturalmente submetidos a estresse por calor cíclico. Foram utilizados 400 pintos de corte da linhagem Cobb, em um delineamento experimental inteiramente casualizado, com cinco tratamentos: 0; 350; 700; 1050 e 1400 ppb de cromo na ração. Os valores do índice de temperatura de globo e umidade foram respectivamente, 83,39 e 80, para fase de crescimento e terminação. A suplementação do cromo orgânico influenciou (P 0,01) de forma quadrática a conversão alimentar dos animais segundo a equação Y=1,67-0,00016x+0,00000012x² (r² 0,976), na fase de 1 a 21 dias de idade. Os níveis de suplementação do cromo orgânico proporcionaram melhor índice de eficiência produtiva e maior percentual de parênquima cortical nas aves aos 21 dias. Na fase de 1 a 41 dias de idade, verificou-se que o peso de penas foi influenciado positivamente com os níveis de cromo orgânico e que não houve efeito para o desempenho dos frangos. Conclui-se que a suplementação da ração com cromo orgânico melhora desempenho e a resposta imune de frangos de corte frente a condições de estresse por calor.(AU)
This study was conducted to evaluate the effect of adding organic chromium dietary supplementation on performance, digestiveand lymphoid organs biometry and histomorphometry of the clocal bursa and on carcass and prime cuts performance of broilersfrom 1 to 41 days old, naturally stressed by heat cyclic. We used 400 chicks Cobb, the experimental design adopted was acompletely randomized, with five treatments: 0; 350; 700; 1050 and 1400 ppb chromium in diet. The supplementation withorganic chromium influenced (p<0,01) quadratic form on alimentary conversion the animals according to the equation Y = 1.67to 0.00016 x 0.00000012 x ² (r ² 0.976) in the period 1 to 21. The levels of supplementation of organic chromium improvementproductive efficiency and percentage of cortical parenchyma of broilers to 21 days. In phase to 1 from 41 days old, it was observedimprovement the feathers weight with levels of organic chromium, and there wasnt influence on performance of broilers. Thechromium in the organic form improves the performance of broiler chickens and immune response by broiler chickens in cyclic heat stress.(AU)
Assuntos
Animais , Galinhas , Cromo/administração & dosagem , Compostos de Cromo/administração & dosagem , Ração Animal , Cloaca , Resposta ao Choque Térmico , Suplementos Nutricionais , Sistema LinfáticoResumo
O experimento foi conduzido com o objetivo de avaliar o efeito da suplementação de cromo-orgânico, sobre o desempenho, biometria dos órgãos digestivos e linfoides, histomoformetria da bolsa cloacal e rendimento de carcaça e cortes nobres de frangos de corte de 1 a 41 dias de idade, naturalmente submetidos a estresse por calor cíclico. Foram utilizados 400 pintos de corte da linhagem Cobb, em um delineamento experimental inteiramente casualizado, com cinco tratamentos: 0; 350; 700; 1050 e 1400 ppb de cromo na ração. Os valores do índice de temperatura de globo e umidade foram respectivamente, 83,39 e 80, para fase de crescimento e terminação. A suplementação do cromo orgânico influenciou (P 0,01) de forma quadrática a conversão alimentar dos animais segundo a equação Y=1,67-0,00016x+0,00000012x² (r² 0,976), na fase de 1 a 21 dias de idade. Os níveis de suplementação do cromo orgânico proporcionaram melhor índice de eficiência produtiva e maior percentual de parênquima cortical nas aves aos 21 dias. Na fase de 1 a 41 dias de idade, verificou-se que o peso de penas foi influenciado positivamente com os níveis de cromo orgânico e que não houve efeito para o desempenho dos frangos. Conclui-se que a suplementação da ração com cromo orgânico melhora desempenho e a resposta imune de frangos de corte frente a condições de estresse por calor.
This study was conducted to evaluate the effect of adding organic chromium dietary supplementation on performance, digestiveand lymphoid organs biometry and histomorphometry of the clocal bursa and on carcass and prime cuts performance of broilersfrom 1 to 41 days old, naturally stressed by heat cyclic. We used 400 chicks Cobb, the experimental design adopted was acompletely randomized, with five treatments: 0; 350; 700; 1050 and 1400 ppb chromium in diet. The supplementation withorganic chromium influenced (p<0,01) quadratic form on alimentary conversion the animals according to the equation Y = 1.67to 0.00016 x 0.00000012 x ² (r ² 0.976) in the period 1 to 21. The levels of supplementation of organic chromium improvementproductive efficiency and percentage of cortical parenchyma of broilers to 21 days. In phase to 1 from 41 days old, it was observedimprovement the feathers weight with levels of organic chromium, and there wasnt influence on performance of broilers. Thechromium in the organic form improves the performance of broiler chickens and immune response by broiler chickens in cyclic heat stress.