RESUMO

High environmental temperature is limiting factor in broiler production. In order to minimize the undesirable consequences of acute or chronic heat stress, the techniques of fixed dietary electrolyte balance and early heat conditioning were evaluated. The objective of this study was to evaluate the possible interactions and effects of dietary electrolyte balance and early heat conditioning on feed intake, body weight, feed conversion ratio, mortality, energy bioeconomic index, fecal moisture, abdominal fat, and breast meat color (L*a*b*) of broilers submitted to chronic or acute heat stress. In total, 1280 chicks, were equally divided in experiment I (chronic heat stress, 6h/day at 32ºC from 35 to 39 d of age) and II (acute heat stress, 36 ºC for 6h at 38 days of age). The data of both experiments were combined and analyzed according to a 2x2x2 factorial arrangement (early heat conditioning (ETC) or not; fixed dietary electrolyte balance (EB) or not; and exposure to acute or chronic heat stress). ETC consisted of exposing 5-d-old birds to 36.0 °C for 24 hours. No interaction among the evaluated factors was detected. Birds exposed to acute heat stress presented significantly higher compared with chronic heat stress. Fixed dietary EB resulted in significantly higher fecal moisture. Lower abdominal fat percentage was obtained in birds exposed to chronic relative to acute heat stress. Higher breast meat L* and b* values were observed in birds exposed to acute heat stress than those submitted to chronic heat stress, indicating worse meat quality.(AU)

Assuntos

RESUMO

High environmental temperature is limiting factor in broiler production. In order to minimize the undesirable consequences of acute or chronic heat stress, the techniques of fixed dietary electrolyte balance and early heat conditioning were evaluated. The objective of this study was to evaluate the possible interactions and effects of dietary electrolyte balance and early heat conditioning on feed intake, body weight, feed conversion ratio, mortality, energy bioeconomic index, fecal moisture, abdominal fat, and breast meat color (L*a*b*) of broilers submitted to chronic or acute heat stress. In total, 1280 chicks, were equally divided in experiment I (chronic heat stress, 6h/day at 32ºC from 35 to 39 d of age) and II (acute heat stress, 36 ºC for 6h at 38 days of age). The data of both experiments were combined and analyzed according to a 2x2x2 factorial arrangement (early heat conditioning (ETC) or not; fixed dietary electrolyte balance (EB) or not; and exposure to acute or chronic heat stress). ETC consisted of exposing 5-d-old birds to 36.0 °C for 24 hours. No interaction among the evaluated factors was detected. Birds exposed to acute heat stress presented significantly higher compared with chronic heat stress. Fixed dietary EB resulted in significantly higher fecal moisture. Lower abdominal fat percentage was obtained in birds exposed to chronic relative to acute heat stress. Higher breast meat L* and b* values were observed in birds exposed to acute heat stress than those submitted to chronic heat stress, indicating worse meat quality.

Assuntos

RESUMO

Nutritionists need to make commercial decisions about the optimal nutrient content broiler feeds. In order to demonstrate that broiler prices may influence dietary nutrient density, this study developed quadratic feed intake and weight gain equations, according to broiler sex and feeding phase, to be applied in a nonlinear feed formulation model. Four hundred and eighty Cobb broilers were allotted to a completely randomized experimental with six treatments, each with four replicates of 10 birds each, from 1 to 56 days old. Treatments consisted of diets containing 2800, 2900, 3000, 3100, 3200, or 3300 kcal metabolizable energy (ME)/kg and constant nutrient to ME ratio. A nonlinear version of the PPFR feed formulation software (http://www.fmva.unesp.br/ppfr) was developed with the objective of optimizing energy density and bird performance. According to the results, when the models are applied in the PPFR nonlinear spreadsheet, the most favorable nutrient density content is defined by mathematical models, as optimized by the Excel Solver tool by means of cost/benefit comparisons and as a function of rearing phase (starter, grower, and finisher) and sex. This contradicts the recommendations of genetic company manuals and published requirement tables, whose goal is to maximize weight gain and do not necessarily guarantee maximum economic efficiency.(AU)

Assuntos

RESUMO

Several physiological and metabolic changes are triggered in broilers submitted to high environmental temperatures, resulting in performance losses. Feed formulation manipulation of the dietary electrolyte balance may be applied to reduce the negative impact of heat stress on broiler performance. This experiment was carried out to evaluate the effect of the manipulations of dietary electrolytes by combining changes in the electrolyte (Na++K+-Cl-) balance (EB) and in the [(K++Cl-)/Na+] ratio (ER) in broiler feeds. In total, 1575 male broilers between 21 and 46 days old were allotted to 15 treatments in a 5x3 factorial arrangement, consisting of five diets with different EB/ER combinations (150/3, 250/2, 250/3, 250/4, and 350/3). Birds were submitted to heat stress at 25 or 35 days old. Live performance, mortality rate, and carcass traits were evaluated. The strategic formulation of diets with different EB and ER improves live performance and minimize the effect of heat stress on broilers. Under thermoneutral conditions, an EB of 250 mEq/kg and an ER of 3 are recommended, whereas under heat stress, and EB of 350 mEq/kg and an ER of 3 should be applied.(AU)

Assuntos

RESUMO

The objective of this study was to compare the effects of two methods (electrical water bath or carbonic gas atmosphere) for stunning or killing broiler chickens prior to bleeding on weight loss due to bleeding and meat traits. A completely randomized design with 2 x 2 factorial arrangement (electrical or gas system x stunning or killing) was applied. The time required for stunning and killing and the birds' behavior were evaluated for the gas exposure method. The birds killed by the electrical method retained more blood than those killed by the exposure to gas and, therefore, presented redder meat. The exposure to 10 to 15% CO2 atmosphere caused discomfort reactions in 100% of birds, and the intensity of reaction presented a wide variation: 35% for weak reaction, 40% for intermediate reaction, and 25% for strong reaction. The time required to stun or kill the birds by CO2 exposure varied from 28 to 97 seconds and from 42 to 158 seconds, respectively. It was concluded that the time required to stun or to kill the birds by CO2 exposure widely varied and caused discomfort reactions; however, meat traits were not influenced by the methods used in this experiment.(AU)

Assuntos

RESUMO

Several physiological and metabolic changes are triggered in broilers submitted to high environmental temperatures, resulting in performance losses. Feed formulation manipulation of the dietary electrolyte balance may be applied to reduce the negative impact of heat stress on broiler performance. This experiment was carried out to evaluate the effect of the manipulations of dietary electrolytes by combining changes in the electrolyte (Na++K+-Cl-) balance (EB) and in the [(K++Cl-)/Na+] ratio (ER) in broiler feeds. In total, 1575 male broilers between 21 and 46 days old were allotted to 15 treatments in a 5x3 factorial arrangement, consisting of five diets with different EB/ER combinations (150/3, 250/2, 250/3, 250/4, and 350/3). Birds were submitted to heat stress at 25 or 35 days old. Live performance, mortality rate, and carcass traits were evaluated. The strategic formulation of diets with different EB and ER improves live performance and minimize the effect of heat stress on broilers. Under thermoneutral conditions, an EB of 250 mEq/kg and an ER of 3 are recommended, whereas under heat stress, and EB of 350 mEq/kg and an ER of 3 should be applied.

Assuntos

RESUMO

Nutritionists need to make commercial decisions about the optimal nutrient content broiler feeds. In order to demonstrate that broiler prices may influence dietary nutrient density, this study developed quadratic feed intake and weight gain equations, according to broiler sex and feeding phase, to be applied in a nonlinear feed formulation model. Four hundred and eighty Cobb broilers were allotted to a completely randomized experimental with six treatments, each with four replicates of 10 birds each, from 1 to 56 days old. Treatments consisted of diets containing 2800, 2900, 3000, 3100, 3200, or 3300 kcal metabolizable energy (ME)/kg and constant nutrient to ME ratio. A nonlinear version of the PPFR feed formulation software (http://www.fmva.unesp.br/ppfr) was developed with the objective of optimizing energy density and bird performance. According to the results, when the models are applied in the PPFR nonlinear spreadsheet, the most favorable nutrient density content is defined by mathematical models, as optimized by the Excel Solver tool by means of cost/benefit comparisons and as a function of rearing phase (starter, grower, and finisher) and sex. This contradicts the recommendations of genetic company manuals and published requirement tables, whose goal is to maximize weight gain and do not necessarily guarantee maximum economic efficiency.

Assuntos

RESUMO

The objective of this study was to compare the effects of two methods (electrical water bath or carbonic gas atmosphere) for stunning or killing broiler chickens prior to bleeding on weight loss due to bleeding and meat traits. A completely randomized design with 2 x 2 factorial arrangement (electrical or gas system x stunning or killing) was applied. The time required for stunning and killing and the birds' behavior were evaluated for the gas exposure method. The birds killed by the electrical method retained more blood than those killed by the exposure to gas and, therefore, presented redder meat. The exposure to 10 to 15% CO2 atmosphere caused discomfort reactions in 100% of birds, and the intensity of reaction presented a wide variation: 35% for weak reaction, 40% for intermediate reaction, and 25% for strong reaction. The time required to stun or kill the birds by CO2 exposure varied from 28 to 97 seconds and from 42 to 158 seconds, respectively. It was concluded that the time required to stun or to kill the birds by CO2 exposure widely varied and caused discomfort reactions; however, meat traits were not influenced by the methods used in this experiment.

Assuntos

RESUMO

A bactéria Rubrivivax gelatinosus tem sido utilizada experimentalmente no tratamento despoluente de efluentes industriais de abatedouros de aves e peixes, originando uma biomassa contendo pigmentos carotenoides, substâncias que possuem a capacidade de conferir cor aos alimentos e proteger contra reações oxidativas. Este trabalho teve por objetivo verificar o efeito da biomassa de R. gelatinosus adicionada à alimentação de frangos de corte sobre o desempenho animal e a cor de carne e pele. Duzentos pintos machos Cobb 500 foram distribuídos aleatoriamente em 20 boxes para receber, do 36º ao 45º dia de criação, quatro tratamentos com diferentes quantidades de biomassa na ração (T1 [controle] - 0g/kg; T2 - 1g/kg; T3 - 2g/kg; T4 - 3g/kg), em cinco repetições. As pesagens de aves e rações para a análise de desempenho foram feitas no início da criação e ao fim de cada período de crescimento. Ao final do experimento (45 dias), 20 aves de cada tratamento foram abatidas para a determinação da cor objetiva (L - luminosidade, C - saturação, h - tom) em pele e carne de peito e coxa. Os resultados obtidos foram submetidos à ANOVA, teste t para a comparação múltipla de médias e análise de regressão com nível de significância de 5%. O ganho de peso e o consumo das aves não diferiram estatisticamente entre si (P>0,05), enquanto o índice de conversão alimentar foi superior para o T1. A luminosidade da carne e da pele aumentou significativamente nos tratamentos que receberam a biomassa. O tom da cor em carne e pele aumentou em direção ao amarelo até a concentração de 2g de biomassa por kg de ração, ao passo que, na concentração de 3g/kg, o aumento foi em direção à tonalidade vermelha. Somente na carne da coxa a saturação da cor sofreu influência da presença da biomassa na dieta. Concluiu-se que, até a proporção de 3g/kg, a biomassa não prejudicou o desempenho e foi eficiente em pigmentar a pele e a carne de frangos de corte...

The phototrophic bacterium Rubrivivax gelatinosus has been used experimentally for the depollution of industrial effluents from broiler and fish slaughterhouses, resulting in a biomass containing oxycarotenoids, substances that impart color and protection against to oxidative reactions. This work aimed to check the effect of R. gelatinosus biomass added into broiler chickens' feed on animal performance and meat/skin color. Two hundred Cobb 500 male chicks were randomly divided into 20 boxes to receive, from the 36th to the 45th day of rearing, 4 treatments with different amounts of biomass in the diets (T1 [control] - 0g/kg; T2 - 1g/kg; T3 - 2g/kg; T4 - 3g/kg), in 5 replicates. Chickens and rations were weighted at the beginning of the rearing time and at the end of each growth phase to assess animal performance. At the end of the experiment (45 days), 20 birds from each repetition were slaughtered for the evaluation of the objective color (L - lightness, C - chroma, h - hue) on skin and meat of breast and thigh. Statistical analyses comprised ANOVA, t test for means comparison and regression analysis, at 5% significance level. Weight gain and feed consumption did not differ statistically (P>0.05), while feed conversion was better for T1. Lightness of meat and skin increased significantly in the treatments with the biomass supplementation. Hue angle of meat and skin increased towards yellow until 2g biomass/kg and towards red at 3g/kg. Chroma was only influenced by the presence of the biomass in thigh meat. It was concluded that the addition of the biomass up to 3g/kg was not harmful to birds' performance and was efficient to cause changes in the color of broiler skin and meat...

Assuntos

RESUMO

A bactéria Rubrivivax gelatinosus tem sido utilizada experimentalmente no tratamento despoluente de efluentes industriais de abatedouros de aves e peixes, originando uma biomassa contendo pigmentos carotenoides, substâncias que possuem a capacidade de conferir cor aos alimentos e proteger contra reações oxidativas. Este trabalho teve por objetivo verificar o efeito da biomassa de R. gelatinosus adicionada à alimentação de frangos de corte sobre o desempenho animal e a cor de carne e pele. Duzentos pintos machos Cobb 500 foram distribuídos aleatoriamente em 20 boxes para receber, do 36º ao 45º dia de criação, quatro tratamentos com diferentes quantidades de biomassa na ração (T1 [controle] - 0g/kg; T2 - 1g/kg; T3 - 2g/kg; T4 - 3g/kg), em cinco repetições. As pesagens de aves e rações para a análise de desempenho foram feitas no início da criação e ao fim de cada período de crescimento. Ao final do experimento (45 dias), 20 aves de cada tratamento foram abatidas para a determinação da cor objetiva (L - luminosidade, C - saturação, h - tom) em pele e carne de peito e coxa. Os resultados obtidos foram submetidos à ANOVA, teste t para a comparação múltipla de médias e análise de regressão com nível de significância de 5%. O ganho de peso e o consumo das aves não diferiram estatisticamente entre si (P>0,05), enquanto o índice de conversão alimentar foi superior para o T1. A luminosidade da carne e da pele aumentou significativamente nos tratamentos que receberam a biomassa. O tom da cor em carne e pele aumentou em direção ao amarelo até a concentração de 2g de biomassa por kg de ração, ao passo que, na concentração de 3g/kg, o aumento foi em direção à tonalidade vermelha. Somente na carne da coxa a saturação da cor sofreu influência da presença da biomassa na dieta. Concluiu-se que, até a proporção de 3g/kg, a biomassa não prejudicou o desempenho e foi eficiente em pigmentar a pele e a carne de frangos de corte.(AU)

The phototrophic bacterium Rubrivivax gelatinosus has been used experimentally for the depollution of industrial effluents from broiler and fish slaughterhouses, resulting in a biomass containing oxycarotenoids, substances that impart color and protection against to oxidative reactions. This work aimed to check the effect of R. gelatinosus biomass added into broiler chickens' feed on animal performance and meat/skin color. Two hundred Cobb 500 male chicks were randomly divided into 20 boxes to receive, from the 36th to the 45th day of rearing, 4 treatments with different amounts of biomass in the diets (T1 [control] - 0g/kg; T2 - 1g/kg; T3 - 2g/kg; T4 - 3g/kg), in 5 replicates. Chickens and rations were weighted at the beginning of the rearing time and at the end of each growth phase to assess animal performance. At the end of the experiment (45 days), 20 birds from each repetition were slaughtered for the evaluation of the objective color (L - lightness, C - chroma, h - hue) on skin and meat of breast and thigh. Statistical analyses comprised ANOVA, t test for means comparison and regression analysis, at 5% significance level. Weight gain and feed consumption did not differ statistically (P>0.05), while feed conversion was better for T1. Lightness of meat and skin increased significantly in the treatments with the biomass supplementation. Hue angle of meat and skin increased towards yellow until 2g biomass/kg and towards red at 3g/kg. Chroma was only influenced by the presence of the biomass in thigh meat. It was concluded that the addition of the biomass up to 3g/kg was not harmful to birds' performance and was efficient to cause changes in the color of broiler skin and meat.(AU)

Assuntos

RESUMO

Many factors have contributed to reductions in wild populations of stingless bees, such as: deforestation, displacement and destruction of nests by honey gatherers, as well as use of insecticides and other agrochemicals. All of these can potentially affect the populational structure of native species. We analyzed genetic variability and populational structure of Melipona scutellaris, based on five microsatellite loci, using heterologous primers of M. bicolor. Samples were taken from 43 meliponaries distributed among 30 sites of four northeastern states of Brazil (Pernambuco, Alagoas, Sergipe, and Bahia). Thirty-one alleles were found to be well distributed among the populations, with sizes ranging from 85 to 146 bp. In general, there was a variable distribution and frequency of alleles among populations, with either exclusive and/or fixed alleles at some sites. The population of Pernambuco was the most polymorphic, followed by Bahia, Alagoas and Sergipe. The heterozygosity was Ho = 0.36 on average, much lower than what has been reported for M. bicolor (Ho = 0.65). Most populations were not under Hardy-Weinberg equilibrium. We found a higher variation within rather than among populations, indicating no genetic structuring in those bees maintained in meliponaries. This apparent homogenization may be due to intense beekeeping activity, including exchange of genetic material among beekeepers. Based on our findings, we recommend more studies of meliponaries and of wild populations in order to help orient management and conservation of these native pollinators.

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RESUMO

Foi avaliado o efeito da utilização de óleo de linhaça na ração, em substituição ao óleo de soja em diferentes proporções, e de vitamina E, até o nível de 400mg/kg de ração, sobre o desempenho e a composição de carcaça de frangos de corte. O desempenho produtivo foi avaliado com base em pesagens das aves e da ração aos 21 e 49 dias de idade. No 49º dia, as aves foram abatidas, e os rendimentos de carcaça e dos principais cortes comerciais e a porcentagem de vísceras e de gordura abdominal foram avaliados. A composição da fração oleosa da ração, de forma geral, não interferiu nos parâmetros de desempenho avaliados (P>0,05). Os machos consumiram mais ração e ganharam mais peso que as fêmeas (P<0,01). As fêmeas apresentaram, em geral, pior conversão alimentar, associada à maior deposição de gordura abdominal. Os machos apresentaram maior porcentagem de coxa com sobrecoxa em relação ao peso da carcaça eviscerada, e as fêmeas apresentaram maior porcentagem de peito. A porcentagem de asas e vísceras não diferiu entre os sexos.

The effect of the utilization of linseed oil at different concentrations in poultry feed instead of soy oil and the effect of vitamin E administration up to 400mg/kg feed on performance and carcass traits of broilers was investigated. Productive parameters were determined by weighting birds and rations at 21 and 49 days of experiment. Broilers were slaughtered on the 49th day of the experiment for the evaluation of yields of carcass and main cuts, percentages of viscera and abdominal fat. The oil composition of rations did not influence the performance of the broilers (P>0.05). Male broilers had higher feed consumption and weight gain (P<0.05). Female broilers showed worse feed conversion and higher deposition of abdominal fat (P<0.05). Male broilers also had higher percentages of legs and forelegs in relation the weight of the eviscerated carcass while females showed higher breast percentage (P<0.05). Percentages of wings and viscera did not differ between genders (P>0.05).

Assuntos

RESUMO

Foi avaliado o efeito da utilização de óleo de linhaça na ração, em substituição ao óleo de soja em diferentes proporções, e de vitamina E, até o nível de 400mg/kg de ração, sobre o desempenho e a composição de carcaça de frangos de corte. O desempenho produtivo foi avaliado com base em pesagens das aves e da ração aos 21 e 49 dias de idade. No 49º dia, as aves foram abatidas, e os rendimentos de carcaça e dos principais cortes comerciais e a porcentagem de vísceras e de gordura abdominal foram avaliados. A composição da fração oleosa da ração, de forma geral, não interferiu nos parâmetros de desempenho avaliados (P>0,05). Os machos consumiram mais ração e ganharam mais peso que as fêmeas (P<0,01). As fêmeas apresentaram, em geral, pior conversão alimentar, associada à maior deposição de gordura abdominal. Os machos apresentaram maior porcentagem de coxa com sobrecoxa em relação ao peso da carcaça eviscerada, e as fêmeas apresentaram maior porcentagem de peito. A porcentagem de asas e vísceras não diferiu entre os sexos.(AU)

The effect of the utilization of linseed oil at different concentrations in poultry feed instead of soy oil and the effect of vitamin E administration up to 400mg/kg feed on performance and carcass traits of broilers was investigated. Productive parameters were determined by weighting birds and rations at 21 and 49 days of experiment. Broilers were slaughtered on the 49th day of the experiment for the evaluation of yields of carcass and main cuts, percentages of viscera and abdominal fat. The oil composition of rations did not influence the performance of the broilers (P>0.05). Male broilers had higher feed consumption and weight gain (P<0.05). Female broilers showed worse feed conversion and higher deposition of abdominal fat (P<0.05). Male broilers also had higher percentages of legs and forelegs in relation the weight of the eviscerated carcass while females showed higher breast percentage (P<0.05). Percentages of wings and viscera did not differ between genders (P>0.05).(AU)

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RESUMO

Charqui meats were prepared in laboratory conditions in order to carry out experiments to observe the possibility of development of enterotoxigenic Staphylococcus aureus and Clostridium botulinum proteolytic type B spores and their toxins. Results demonstrated that the harsh processing conditions, high salt concentration, relative high temperature, a(w) values, inhibited the growth of both bacteria. Under our experimental conditions, S. aureus would survive throughout the sequence of salting steps i.e. brine followed by rock salting and the sunshine drying step. However, at final a(w) value of 0.70-0.75 would create conditions to inhibit its development. The other experiment revealed that C. botulinum spores germination also was impaired because of these low a(w) values. Under these conditions, charqui meats revealed to be safe products in relation to toxins from both enterotoxigenic S. aureus and C. botulinum.

RESUMO

Jerked beef, a derivative of charqui meat, is a cured, salted and dried meat product. The presence of halotolerant bacteria, where Staphylococcus spp. (84.2%) were the predominant species, would act eventually as starter cultures and was followed throughout processing. Jerked beef prepared separately with exogenous S. carnosus and S. xylosus as starter cultures resulted in high proteolysis. Samples prepared with S. xylosus had the highest proteolysis and were preferred by the sensory panel. This research has suggested that jerked beef (and thus charqui meat) prepared under these conditions is a fermented meat product.

RESUMO

A new technique was developed for reconstruction of severely decayed posterior teeth, using photo-cured composite resins with human enamel insert(s) in centric holding contract points, by means of adhesive dentistry. It seems nowadays possible different and better restorative procedures than ever before, limited only by the professional ingenuity.

Assuntos