RESUMO

Vacuum-packed lamb sausages with or without red propolis extract and a reduced sodium nitrite content were evaluated for oxidative and microbiological stability during storage for 21 days at 2 °C. The following treatments were evaluated: EN150 (control, base formulation (BF) + 500 mg/kg sodium erythorbate and 150 mg/kg sodium nitrite); EN75 (BF + 500 mg/kg sodium erythorbate and 75 mg/kg sodium nitrite); P1N75 (without the addition of erythorbate, BF + 1800 mg/kg propolis extract and 75 mg/kg sodium nitrite); and P2N75 (without the addition of erythorbate, BF + 3600 mg/kg propolis extract and 75 mg/kg sodium nitrite). Analyses were conducted to characterize the samples on day 0 with respect to the proximate composition (moisture, protein, fat, and ash) and sensory acceptance. Stability during refrigerated storage was evaluated on days 0, 7, 14 and 21 for the parameters pH, color profile (L*, a*, and b*), TBARs index (oxidative stability) and microbiological count of aerobic psychrotrophic microorganisms. Texture profile, cooking weight loss (WLC), peroxide index and free fatty acids were evaluated on days 0 and 21. The treatments with propolis and reduced nitrite (EN150 and P1N75) showed a red color intensity (a*) similar to the treatment with erythorbate and the same nitrite content (EN75) at the end of storage, maintaining the characteristic reddish color of the sausages. The extract slowed down lipid oxidation during storage, especially P2N75, which showed the lowest level of TBARS (0.39 mg MDA/kg) and the peroxide index (2.13 mEq g O2) on day 21. The residual nitrite value in EN75 was the lowest (p < 0.05) on day 21, showing that synthetic antioxidants are more efficient than the extract in nitrite reduction reactions. The results for the counts of psychrotrophic microorganisms showed that the extract did not have the expected antimicrobial effect on the growth of this microorganisms, and leveling the results revealed no differences (p < 0.05) between the treatments. Despite the red propolis extract not showing a significant antimicrobial improvement in lamb sausages, it can be considered a healthy option with good prospects for replacing synthetic antioxidants with a natural product.

RESUMO

This study determined thyroid hormone (T3 and T4) serum levels and investigated thyroid gland histology, as well as two broiler strains performance kept at different periods of heat stress. Broilers (560 Cobb Slow™ and 560 Hubbard Flex™) were distributed in control environment (0) reared following the thermal recommendations, and environments 1, 2, and 3 exposed to high temperatures for 1 h, 2 h, and 3 h a day, respectively, from 14 to 42 days old. At 21, 28, 35, and 42 days old, blood samples were collected to determine T3 and T4 serum levels. At 42 days old, thyroid glands were removed for histological analyses. The performance was calculated weekly. T3 levels decreased with age advance, while T4 serum concentration was higher at 42 days old (23.27 nmol L-1) and lower at 28 days old (15.69 nmol L-1). The histological sections revealed that thyroid morphology was well preserved. Live weight was higher in Cobb Slow™ (2.97 kg) than Hubbard Flex™ (2.93 kg) broilers at 42 days old. It is possible to conclude that cyclic heat stress exposure for a 3-h period from 14 to 42 days old did not affect performance, thyroid histology, or T3 and T4 serum levels. Cobb Slow™ broilers had the best live weight values at slaughtering. With increasing age, T3 levels decreased and T4 levels increased for both strains.

Assuntos

RESUMO

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

RESUMO

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

RESUMO

This study aimed to evaluate the influence of age and cyclical heat stress for 1 hour per day on the levels of serum proteins, metabolites, and enzymes in broiler chickens of 21-42 days of age. We used 420 male broiler chickens, Cobb Avian48TM breed, in a completely randomized experimental design, composed of two treatments and six replicates. The treatments consisted of two thermal environments: one in which broiler chickens were raised under natural conditions of temperature and humidity for the first 42 days of age (control) and another in which chickens were subjected to heat stress at 36°C, from days 16 to 42, for 1 hour per day (1200-1300 hours). At 21, 28, 35, and 42 days of age, approximately 5 mL of blood was collected by cardiac puncture in two birds per replicate. In each serum sample, levels of total protein, albumin, globulin, albumin:globulin ratio, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma-glutamyltransferase (GGT) activity and uric acid, creatinine, total cholesterol, triglycerides, high-density lipoproteins (HDL), very low density lipoproteins (VLDL), low-density lipoproteins (LDL), and glucose levels were determined. Concerning the environment and the age, no significant differences in the levels of glucose, uric acid, ALT, triglycerides, and very low density lipoproteins were observed. There was a significant interaction between the environment and the age for cholesterol and LDL values. At 21 days of age, cholesterol and LDL-cholesterol (LDL-C) were higher in birds under stress than in the control treatment birds, which did not occur in other age groups. Aspartate aminotransferase activity was higher in chickens under cyclical heat stress than in chickens subjected to control treatment and displayed a cubic response regarding the environment. The age of the birds influenced the values of total protein, albumin, globulin, albumin:globulin (A:G) ratio, creatinine, GGT, and HDL...(AU)

Objetivou-se avaliar a influência da idade e do estresse cíclico por calor durante uma hora por dia, nas concentrações das proteínas, metabólitos e enzimas séricas em frangos de corte de 21 a 42 dias de idade. Foram utilizados 420 pintos de corte machos, da linhagem Cobb Avian48TM, em um delineamento inteiramente casualizado, composto de dois tratamentos e seis repetições. Os tratamentos foram constituídos de dois ambientes térmicos: um para frangos de corte criados em condições naturais de temperatura e umidade do primeiro ao 42° dia de idade (controle); e outro para estressados por calor à 36 °C do 16° ao 42° dia, durante uma hora do dia (12h00m às 13h00m). No 21º, 28º, 35º e 42º dias de idade, foram coletados em duas aves por repetição aproximadamente 5mL de sangue por punção cardíaca. Foram determinadas em cada amostra de soro as concentrações de proteína total, albumina, globulinas, relação A/G, aspartato aminotransferase, alanina aminotransferase, gama glutamiltransferase, ácido úrico, creatinina, colesterol total, triacilgliceróis, lipoproteínas de alta densidade, lipoproteínas de muito baixa densidade, lipoproteínas de baixa densidade e glicose. Para as concentrações de glicose, ácido úrico, alanina aminotransferase, triacilgliceróis e lipoproteínas de muito baixa densidade, não houve diferenças significativas para ambiente e idade. Observou-se interação significativa entre ambiente e idade para os valores de colesterol e lipoproteínas de baixa densidade. Aos 21 dias de idade o colesterol e as LDL-C foram maiores nas aves em estresse comparados àquelas do tratamento controle, o que não ocorreu nas demais idades. A aspartato aminotransferase nos frangos sob estresse cíclico de calor foi maior em comparação ao tratamento controle e apresentou efeito cúbico para ambiente. A idade das aves influenciou os valores de proteínas totais, albumina, globulina, albumina: globulina, creatinina, gama glutamiltransferase e das lipoproteínas de alta densidade...(AU)

Assuntos

RESUMO

This study aimed to evaluate the influence of age and cyclical heat stress for 1 hour per day on the levels of serum proteins, metabolites, and enzymes in broiler chickens of 21-42 days of age. We used 420 male broiler chickens, Cobb Avian48TM breed, in a completely randomized experimental design, composed of two treatments and six replicates. The treatments consisted of two thermal environments: one in which broiler chickens were raised under natural conditions of temperature and humidity for the first 42 days of age (control) and another in which chickens were subjected to heat stress at 36°C, from days 16 to 42, for 1 hour per day (1200-1300 hours). At 21, 28, 35, and 42 days of age, approximately 5 mL of blood was collected by cardiac puncture in two birds per replicate. In each serum sample, levels of total protein, albumin, globulin, albumin:globulin ratio, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma-glutamyltransferase (GGT) activity and uric acid, creatinine, total cholesterol, triglycerides, high-density lipoproteins (HDL), very low density lipoproteins (VLDL), low-density lipoproteins (LDL), and glucose levels were determined. Concerning the environment and the age, no significant differences in the levels of glucose, uric acid, ALT, triglycerides, and very low density lipoproteins were observed. There was a significant interaction between the environment and the age for cholesterol and LDL values. At 21 days of age, cholesterol and LDL-cholesterol (LDL-C) were higher in birds under stress than in the control treatment birds, which did not occur in other age groups. Aspartate aminotransferase activity was higher in chickens under cyclical heat stress than in chickens subjected to control treatment and displayed a cubic response regarding the environment. The age of the birds influenced the values of total protein, albumin, globulin, albumin:globulin (A:G) ratio, creatinine, GGT, and HDL...

Objetivou-se avaliar a influência da idade e do estresse cíclico por calor durante uma hora por dia, nas concentrações das proteínas, metabólitos e enzimas séricas em frangos de corte de 21 a 42 dias de idade. Foram utilizados 420 pintos de corte machos, da linhagem Cobb Avian48TM, em um delineamento inteiramente casualizado, composto de dois tratamentos e seis repetições. Os tratamentos foram constituídos de dois ambientes térmicos: um para frangos de corte criados em condições naturais de temperatura e umidade do primeiro ao 42° dia de idade (controle); e outro para estressados por calor à 36 °C do 16° ao 42° dia, durante uma hora do dia (12h00m às 13h00m). No 21º, 28º, 35º e 42º dias de idade, foram coletados em duas aves por repetição aproximadamente 5mL de sangue por punção cardíaca. Foram determinadas em cada amostra de soro as concentrações de proteína total, albumina, globulinas, relação A/G, aspartato aminotransferase, alanina aminotransferase, gama glutamiltransferase, ácido úrico, creatinina, colesterol total, triacilgliceróis, lipoproteínas de alta densidade, lipoproteínas de muito baixa densidade, lipoproteínas de baixa densidade e glicose. Para as concentrações de glicose, ácido úrico, alanina aminotransferase, triacilgliceróis e lipoproteínas de muito baixa densidade, não houve diferenças significativas para ambiente e idade. Observou-se interação significativa entre ambiente e idade para os valores de colesterol e lipoproteínas de baixa densidade. Aos 21 dias de idade o colesterol e as LDL-C foram maiores nas aves em estresse comparados àquelas do tratamento controle, o que não ocorreu nas demais idades. A aspartato aminotransferase nos frangos sob estresse cíclico de calor foi maior em comparação ao tratamento controle e apresentou efeito cúbico para ambiente. A idade das aves influenciou os valores de proteínas totais, albumina, globulina, albumina: globulina, creatinina, gama glutamiltransferase e das lipoproteínas de alta densidade...

Assuntos

RESUMO

Grains, brans, and vegetable meals may contain non-starch polysaccharides (NSP), which increases viscosity in the gastrointestinal tract (GIT) and interfere with the digestion and absorption of nutrients. This study aimed to evaluate the performance and determine the metabolizable energy of a sorghum-based broiler diet with and without the supplementation of an enzymatic complex. The experiments were conducted in a completely randomized design with 1200 chickens, using sorghum-based feed with and without the addition of 50 g of enzyme-CCE complex (β-glucanase and β-xylanase), and with two levels of metabolizable energy (ME kg-1): ME; ME + CCE; reduced ME (-50 kcal kg-1); and reduced ME + CCE. The data were subjected to an analysis of variance and the means were compared using a Tukeys test at the 5% significance level. At 42 and 47 days of age, the living weight of the birds fed with the reduced ME was low, while birds fed with reduced ME + CCE had the same weight as those fed with other energy diets (ME and ME + CCE). Feed conversion was poorest at 47 days of age for the birds on reduced ME diet. In the metabolic test (with fattening diets) to determine AME and AMEn, the reduced ME diet had the lowest result, confirming the effect of the addition of enzymes. The addition of CCE to sorghum-based diets provides enough enzymatic activity to increase the metabolizable energy of the diet (50 kcal of AME) and influence the growth performance of broilers at the slaughtering age.(AU)

Grãos, farelos e farinhas de origem vegetal podem conter polissacarídeos não amiláceos (PNAs), que aumentam a viscosidade do trato grastro intestinal (TGI) e interferem na digestão e absorção de nutrientes. Objetivou-se avaliar o desempenho e determinar à energia metabolizável da dieta a base de sorgo, com e sem adição do complexo enzimático (CCE), para frangos de corte. Foram utilizados 1200 frangos de corte, distribuídos em delineamento inteiramente casualisado, alimentados com dois níveis de Energia Metabolizável (EM kg-1), em dietas à base de sorgo com ou sem a adição de 50g de completo enzimático (β-glucanase e β-xylanase): Energia Metabolizável (EM); Energia Metabolizável com Complexo Enzimático (EM + CCE); EM reduzida (-50kcal EM kg-1) e EM reduzida + CCE. Os dados obtidos foram submetidos à análise de variância e as médias dos tratamentos em cada variável estudada foram comparadas entre si pelo Teste de Tukey a nível de 5% de significância. Aos 42 e 47 dias de idade o peso vivo das aves alimentadas com EM reduzida foi menor, enquanto que EM reduzida + CCE apresentou peso igual ao das dietas EM e EM + CCE. A conversão alimentar aos 47 dias de idade na dieta EM reduzida apresentou o pior resultado. No teste metabólico, com as dietas de engorda, os valores de Energia Metabolizável Aparente (EMA) e Energia Metabolizável Aparente corrigida para nitrogênio (EMAn) foram menores na dieta com EM reduzida, comprovando o efeito da adição das enzimas. Concluiu-se que a adição de complexo enzimático (β-glucanase and β-xylanase) melhora o desempenho de frangos de corte e aumenta a energia metabolizável aparente da dieta em 50 kcal.(AU)

Assuntos

RESUMO

Grains, brans, and vegetable meals may contain non-starch polysaccharides (NSP), which increases viscosity in the gastrointestinal tract (GIT) and interfere with the digestion and absorption of nutrients. This study aimed to evaluate the performance and determine the metabolizable energy of a sorghum-based broiler diet with and without the supplementation of an enzymatic complex. The experiments were conducted in a completely randomized design with 1200 chickens, using sorghum-based feed with and without the addition of 50 g of enzyme-CCE complex (β-glucanase and β-xylanase), and with two levels of metabolizable energy (ME kg-1): ME; ME + CCE; reduced ME (-50 kcal kg-1); and reduced ME + CCE. The data were subjected to an analysis of variance and the means were compared using a Tukey’s test at the 5% significance level. At 42 and 47 days of age, the living weight of the birds fed with the reduced ME was low, while birds fed with reduced ME + CCE had the same weight as those fed with other energy diets (ME and ME + CCE). Feed conversion was poorest at 47 days of age for the birds on reduced ME diet. In the metabolic test (with fattening diets) to determine AME and AMEn, the reduced ME diet had the lowest result, confirming the effect of the addition of enzymes. The addition of CCE to sorghum-based diets provides enough enzymatic activity to increase the metabolizable energy of the diet (50 kcal of AME) and influence the growth performance of broilers at the slaughtering age.

Grãos, farelos e farinhas de origem vegetal podem conter polissacarídeos não amiláceos (PNAs), que aumentam a viscosidade do trato grastro intestinal (TGI) e interferem na digestão e absorção de nutrientes. Objetivou-se avaliar o desempenho e determinar à energia metabolizável da dieta a base de sorgo, com e sem adição do complexo enzimático (CCE), para frangos de corte. Foram utilizados 1200 frangos de corte, distribuídos em delineamento inteiramente casualisado, alimentados com dois níveis de Energia Metabolizável (EM kg-1), em dietas à base de sorgo com ou sem a adição de 50g de completo enzimático (β-glucanase e β-xylanase): Energia Metabolizável (EM); Energia Metabolizável com Complexo Enzimático (EM + CCE); EM reduzida (-50kcal EM kg-1) e EM reduzida + CCE. Os dados obtidos foram submetidos à análise de variância e as médias dos tratamentos em cada variável estudada foram comparadas entre si pelo Teste de Tukey a nível de 5% de significância. Aos 42 e 47 dias de idade o peso vivo das aves alimentadas com EM reduzida foi menor, enquanto que EM reduzida + CCE apresentou peso igual ao das dietas EM e EM + CCE. A conversão alimentar aos 47 dias de idade na dieta EM reduzida apresentou o pior resultado. No teste metabólico, com as dietas de engorda, os valores de Energia Metabolizável Aparente (EMA) e Energia Metabolizável Aparente corrigida para nitrogênio (EMAn) foram menores na dieta com EM reduzida, comprovando o efeito da adição das enzimas. Concluiu-se que a adição de complexo enzimático (β-glucanase and β-xylanase) melhora o desempenho de frangos de corte e aumenta a energia metabolizável aparente da dieta em 50 kcal.

Assuntos

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%.[...]

Assuntos

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