Fatores extrínsecos que afetam a absorção de água em carcaças de frango de corte

O Brasil ocupa uma posição de destaque como produtor e exportador de carne de frango. Um parâmetro importante na qualidade da carne de frango é a quantidade de água absorvida pela carcaça durante o processamento. No Brasil, o resfriamento das carcaças é feito por imersão em água refrigerada e, neste processo, a carcaça é reidratada, recuperando a água perdida durante o transporte e as operações iniciais. Este projeto teve como objetivo avaliar os fatores extrínsecos que podem influenciar a absorção de água pela carne de frango. Para isso, foram utilizados 144 frangos da linhagem Cobb, divididos em 24 grupos de seis aves. Aos 42 dias de idade, uma ave de cada grupo, com peso variando até 10% para mais ou para menos, em relação à média do grupo, foram abatidas em abatedouro experimental. A etapa de resfriamento foi realizada seguindo um delineamento inteiramente casualizado com arranjo fatorial 3x2, onde os fatores foram: três temperaturas na primeira seção do sistema de refrigeração (4, 10 e 16 º C) e dois graus de dureza da água (água dura e água mole), com seis tratamentos e quatro repetições. A legislação brasileira estabelece que a temperatura da água na primeira seção do resfriador não deve ser superior a 16ºC. Todas as carcaças permaneceram na primeira seção do resfriador durante 30 minutos e, em seguida, foram transferidas para outro tanque com água a 4ºC, permanecendo até atingir 7ºC. As carcaças foram pesadas antes e após o resfriamento por imersão, para avaliação da percentagem de água absorvida. A absorção de água foi influenciada pela temperatura inicial da água no pré-resfriador e pela dureza da água. Quando imersas inicialmente em água a 4ºC, as carcaças absorveram, em média, 2,70%, uma absorção significativamente menor do que a média de 3,83% observada nas carcaças que foram inicialmente imersas em água a 16ºC (p<0,05). As carcaças imersas em água a 10ºC apresentaram média de absorção de água de 3,66%, não diferindo das médias observadas nos outros tratamentos (p>0,05). Em água dura, a média de absorção de água foi de 2,46% e, em água mole, de 4,33% (p<0,05). Em todos os tratamentos, a absorção de água não excedeu o limite estabelecido pela legislação brasileira, que é de, no máximo, 8%. Esta informação é importante para controlar a absorção de água pelas carcaças em processamento de carne de frango, impedindo que os consumidores sejam prejudicados.

Recuperação de biomassa bacteriana produzida no tratamento de efluente industrial

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The strategic application of elecytolyte balance to minimize heat stress in broilers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Strategic use of dietary electrolyte balance and ratio for broiler chickens

The literature reports dealing with the dietary electrolyte ratio (K+Cl)/ Na are rare, although the concept has been proposed by Mongin in 1981. Thus, its application appears to be limited as a nutritional strategy in feed formulation, which usually meets only the minimum nutritional recommendations in Na, K and Cl. The objective of this study was to evaluate the performance of broilers submitted to different dietary electrolyte balances (DEB) Na+K-Cl and dietary electrolyte ratio (DER) from 1 to 21 d of age. A total of 1575 male 1-d old broiler chicks were randomly assigned to 5 treatments with 9 replicates of 35 chicks each. The treatments consisted of diets with 5 relation of electrolytes, arising from combinations DEB/DER 150/3, 250/2, 250/3, 250/4 and 350/3, with use of NaCl, NaHCO3, KCl, K2SO4 and CaCl2. All diets were corn-soybean meal based and formulated to meet or exceed the NRC (1994) requirements. Chicks had ad libitum access to feed and water in floor pens with wood shavings as litter. Body weight, feed intake and feed conversion ratio were measured at 21 d of age. It was found that only the feed conversion was significantly affected (P = 0.0142) by the combinations of relation of electrolytes (DEB and DER). The supplementation levels in DEB and DER were made to fit the data into a surface analysis to allow increasing levels of DEB (150–350 mEq/kg) and narrow and broad ratio of DER (2–4). For the canonical analysis of response surface was obtained the stationary point for body weight (DEB = 255.77 mEq/kg, and DER = 2.73:1) the value was 942.02 g; for feed intake (DEB = 251.69 mEq / kg and DER = 3.51:1), the value was 1200.02 g; and for feed conversion (DEB = 254.62 mEq/kg and DER = 3.06:1) the value was 1.35. The results of this experiment indicated that the best performance was obtained with combinations of relation of electrolytes for DEB between 251 and 255 mEq/kg and DER between 2.73:1 and 3.5:1.

Strategic feed formulation for relation of electrolytes to promote performance and prevent heat stress in broilers

An experiment was conducted to evaluate the impact in relation of dietary electrolytes, based on changes in the balance Na+K-Cl (DEB) and the ratio (K+Cl)/Na (DER) on the performance and survival of broilers subjected to acute heat stress. A total of 1575 male broiler chicks from 1 to 46 d of age were allocated in a 5x3 factorial arrangement in a completely randomized design, totaling of 15 treatments with 3 replicates of 35 birds each. The treatments consisted of 5 diets with electrolyte balances, arising from combinations DEB/DER (150/3, 250/2, 250/3, 250/4 and 350/3), associated with different times of application or not of the acute heat stress on birds at 25 and 36 d old. All diets were cornsoybean meal based and formulated to meet or exceed NRC requirements. Chicks had ad libitum access to feed and water in floor pens with wood shavings as litter. It was possible to verify that a DEB of 250 mEq/kg and a DER very close to the 3:1 providing a more nutritionally adequate diet. There was, however, the impossibility of obtaining a more suitable electrolyte ratio for a very low DEB (150 mEq/kg) or very high (350 mEq/kg) and also, to a very narrow DER (2:1) or very wide (4:1), due to an unfavorable performance and survival rate of birds in these conditions electrolytes adjustments of K, Na and Cl. There was clear indication, with significant difference (P < 0.05), that the DER has the potential to improve the performance of broilers, since simultaneous adjustment made in DEB, even in conditions of acute stress. The results of performance and survival rate of this study also indicate clearly that DER could not replace the DEB, and vice versa, in practical diets for broilers. Therefore, it can be affirmed that the strategic formulation of the correct electrolyte balance for DEB and DER enhances the performance and is able to prevent the effect of heat stress in broiler chickens, leading to better performance and survival.

The use of nonlinear programming as a tool for maximum profit feed formulation of broilers

The purpose of this study was to compare linear and nonlinear programming models for feed formulation, for maximum profit, considering the real variation in the prices of the corn, soybean meal and broilers during the period from January of 2008 to October of 2009, in the São Paulo State, Brazil. For the nonlinear formulation model, it was considered the following scenarios of prices: a) the minimum broiler price and the maximum prices of the corn and soybean meal during the period, b) the mean prices of the broiler, corn and soybean meal in the period and c) the maximum broiler price and the minimum prices of the corn and soybean meal, in the considered period; while for the linear formulation model, it was considered just the prices of the corn and the soybean. It was used the Practical Program for Feed Formulation 2.0 for the diets establishment. A total of 300 Cobb male chicks were randomly assigned to the 4 dietary treatments with 5 replicate pens of 15 chicks each. The birds were fed with a starter diet until 21 d and a grower diet from 22 to 42 d of age, and they had ad libitum access to feed and water, on floor with wood shavings as litter. The broilers were raised in an environmentally-controlled house. Body weight, body weight gain, feed intake, feed conversion ratio and profitability (related to the prices variation of the broilers and ingredients) were obtained at 42 d of age. It was found that the broilers fed with the diet formulated with the linear model presented the lowest feed intake and feed conversion ratio as compared with the broilers fed with diets from nonlinear formulation models. There were no significant differences in body weight and body weight gain among the treatments. Nevertheless, the profitabilities of the diets from the nonlinear model were significantly higher than that one from the linear formulation model, when the corn and soybean meal prices were near or below their average values for the studied period, for any broiler chicken price.

Stunning method in broiler chickens meat processing

Quality is a variable concept, which involves many factors, depending on the consumer market. In meat production, the concern with environmental aspects, animal welfare and the health and safety of workers is increasing. This work studied the effect of controlled atmosphere stunning of broilers on meat features and biochemical parameters for stress. Cobb broilers were stunned by electrical stunning and by controlled atmosphere with 70% CO2 and 70% CO2 + 30% Argon. After stunning, serum levels of glucose, lactate and corticosterone were compared with those of broilers at rest, immediately before transportation and slaughter and after 12 h of feed withdrawal (control group). At slaughter, blood volume drained during bleeding was not different for the stunning methods tested, ranging from 3.3 to 3.4% birds weight. This finding was important to demonstrate that gas stunning was not responsible for the animals′ death. Final pH in breast (6.1 to 6.2) and thigh (6.3 to 6.5) also did not vary among the different stunning methods (P > 0.05). Lightness (L = 60.55) and redness (a = +8.94) values found for breasts from electrical stunning showed that they were darker and redder (P < 0.05), probably due to changes in blood pressure. Glucose and corticosterone levels were not different between gas stunned birds (302.45 to 315.7 mg/dl and 55.71 to 72.49 ng/ml respectively) and birds at rest (305.95 mg/dl and 50.65 ng/ml) (P > 0.05). These stress indicators were higher (337.65 mg/dl for glucose and 104.13 ng/ml for costicosterone) when electrical stunning was used (P < 0.05). Lactate concentrations were lower (5.4 mmol/l) for birds at rest (P < 0.05) but not different for all stunning methods tested (7.3 to 8.1 mmol/l; P > 0.05). These results show that serum glucose may be used as a stress indicator in birds, with the advantage of being a quick and cheap biochemical test. Gas stunning favored birds′ management during slaughter and so reduced workers′ effort and injury hazard and the amount of feces and dust in the room. To make this method available for a large scale process, adjustments in equipments will be necessary to avoid delays in the processing line.

Accuracy of nonlinear feed formulation for broiler chickens: maximising broiler profit

The modeling technique is simple, useful and practical to calculate optimum nutrient density to maximize profit margins, using nonlinear programming by predictive broiler performance. To demonstrate the influence of the broiler price could interact with nutrient density, the experiment aimed to define the quadratic equations for consumption and weight gain, based on modeling, to be applied to nonlinear programming, according to sex (male and female) in the starter (1 to 21 days), grower (22 to 42 days) and finisher phases (43 to 56 days). The experimental design was a randomized, totaling 6 treatments [energy levels of 2800, 2900, 3000, 3100, 3200 and 3300kcal AME/kg with constant nutrient : AME (Apparent Metabolizable Energy)] with 4 replicates and 10 birds per plot, using the program free download PPFR Excel workbook for feed formulation (http://www.foa.unesp.br/downloads/file_detalhes.asp?CatCod=4&SubCatCod=138&FileCod=1677). Data from this trial confirmed that there was a significant relationship between feed intake and total energy consumption of the diet, in which feed intake was increased or decreased simply to keep the amount of energy, with a constant rate of nutrient : AME. Therefore, the data support that if the essential dietary nutrients are kept in proportion to the energy density of the diet, according to the appropriate requirements (male / female) of broilers, the weight and feed conversion are significantly (P<0.05) favored by increasing the energy density of the diet. Thus, it enables the application of models for maximum profit (nonlinear formulation), to estimate the proportion of weight gain most appropriate according to the price paid by the market.

Bacterial oxycarotenoids added into broiler chickens ration modify breast meat color

Some markets around the world demand for well pigmented poultry products, what justifies the intentional use of synthetic additives in rations during breeding. The inconvenient for that practice most times is the elevated price of these products, beyond the argument of being chemicals, which may not be viable for some production systems. So, the aim of this experiment was to check on the ability of natural red oxycarotenoids produced by R. gelatinosus to modify broilers breast meat color. Bacterial biomass containing oxycarotenoids were added into Cobb broilers finisher diets at 0, 1.0, 2.0 and 3.0 g/kg and fed during 10 days (35-45 d). Five replicates (10 birds each) were performed. At days 35, 37, 39, 41, 43 and 45, 100 birds were slaughtered scalded, defeathered and eviscerated. Data on live and carcass weights were recorded. After cooling, color parameters of meat were determined on breast surface using a HunterLab XE Plus colorimeter calibrated with black and white standard tiles. Regression analysis was used for the investigation of relationships between days of consumption and biomass concentration on color values, live weight and carcass yield. Results showed that redness of breast meat was significantly influenced by the biomass concentration in a linear effect (P=0.0056) and also by the time of consumption, in a quadratic effect (P=0.0232). Days of consumption also affected yellowness and lightness with significant quadratic responses (P=0.0225 and P<0.0001, respectively). Birds live weight increased significantly during the application of the experimental diets (P<0.0001), showing no negative influence of the biomass administration. Also no deleterious effects derived from the application of the product were observed on carcass yield. So we concluded that R. gelatinosus oxycarotenoids present in the bacterial biomass can modify broilers breast meat color, performing as an alternative pigmenting additive in poultry production.

Extrinsic factors affecting water absorption in chilling of broiler chicken carcasses

Brazil occupies an outstanding position as a producer and exporter of chicken meat, and the maintenance and expansion of this position require a constant evolution, especially in variables which determine quality. An important quality parameter of poultry meat is the amount of water absorbed by the carcass during processing. In Brazil, carcasses chilling is done by immersion in chilled water. In this process, the carcass is rehydrated and the water lost during transport and initial operations is replaced. At this stage, some care is needed to prevent the absorption of water upper than the level allowed by Brazilian law. This project aimed to evaluate extrinsic factors that can influence the absorption of water by the chicken meat. For this, 144 Cobb chickens divided into 24 groups of six birds were used. At 42 days of age, one chicken of each group, with weight ranging up to 10% more or less from the average of the group, was slaughtered in an experimental pilot scale abattoir where slaughter procedures were conducted under strictly controlled conditions. The chilling procedure was performed following a completely randomized design with factorial arrangement 3x2, where the factors were: three temperatures in the first section of the chilling system (4, 10 and 16ºC) and two degrees of water hardness (hard and soft water), with six treatments and four replications. Brazilian law provides that the water temperature in the first section of the chiller must not be higher than 16ºC, and the length of the carcasses in this section shall not exceed 30 minutes. All carcasses remained in the first section of the chiller for 30 minutes and then were transferred to another tank with water at 4ºC, remaining there until reaching 7ºC. The carcasses were weighed before and after chilling, to evaluate the percentage of water absorbed. The water absorption was influenced by the initial temperature of the water in the chiller and by the water hardness. When initially immersed in water at 4ºC, carcasses water absorption averaged 2.70%, a significantly lower absorption than the values found for the carcasses that were initially immersed in water at 16ºC, 3.83% (p<0.05). The carcasses immersed in water at 10ºC had mean water absorption of 3.66%, not differing from the means observed in the other two treatments (p>0.05). In hard water, the average water absorption was 2.46% and, in soft water, 4.33% (p<0.05). In all treatments, the water absorption did not exceed the limit established by Brazilian legislation, which is a maximum of 8%. This information is important to control the absorption of water by carcasses in chicken meat processing, preventing consumers from being harmed.

Chicken meat consumer profile in northwestern São Paulo State, Brazil

Brazil is the world’s first chicken meat exporter nowadays. The maintenance of this position requires a constant quality attributes evolution. This work evaluated the chicken meat consumer profile in the northwest region of São Paulo state, the most important Brazilian poultry meat consumer market, in order to provide information to the productive sector. The data were collected using 482 interviews and questionnaires that were answered by e-mail. The questionnaires involved questions related to the consumer identification, habits and preferences and their knowledge about food safety, production system, sustainability and animal welfare. Most of the consumers, 62%, were female, with ages ranging from 20 to 50 years. Beef was preferred by the majority of the answerers and chicken and pork meat were together the second choice. Only 2% of the interviewed consumers mentioned not enjoying poultry meat. The main part of consumers, 67%, prefer to buy breast and leg cuts and only 11% are used to buy the whole poultry carcass. More than 60% of the interviewed have already eaten free range chicken meat, but the majority of them, 89%, are used to consume regular industrialized poultry. About 75% of the consumers believe hormones are used to grow the birds. Over 80% of people observe the expiration date before buying the product, but only 55% check if it has the stamp of the official inspection service. Color and appearance of meat are the most important factors that influence the consumer’s choice. The amount of water that drips on the tray is a rejection factor to 88% of answerers. Most of them, 66%, prefer lighter colored meat. Only 27% of them believe that chicken meat causes an environmental impact and 48% do not know the meaning of animal welfare. More than half of the interviewed do not consider animal welfare aspects before consuming any kind of meat. From these results obtained, it is possible to conclude that any effort to improve the product quality, mainly concerned to animal welfare and sustainability aspects, requires prior educational initiatives.

Dietary electrolytes and thermal conditioning: minimizing heat stress in broilers

In tropical climates the heat is one of the major constraints to production of broilers and is responsible for inducing a high mortality, especially in the finishing phase. Thus, the objective of this study was to compare the thermal conditioning early (TC) and feed formulation using dietary electrolytes (DE). Therefore, the electrolyte balance of K+Na-Cl was set at 350 mEq/kg and electrolyte ratio (K+Cl)/Na) in the 3:1 program PPFR (http://www.fmva.unesp.br/ppfr). A total of 300 Cobb 500 1-dold male broiler chicks was randomly allocated to 24 floor pens with six replicates per treatment in a 2x2 factorial arrangement (with and without TC and with and without DE). Dietary treatments consisted: (T1) a traditional diet without TC; (T2) traditional diet with TC; (T3) with the application of dietary electrolyte and without TC and (T4) application of dietary electrolyte with TC. The thermal conditioning was conducted at 5 d of age (36°C for 24 h), only half of the batch (150 birds). After this period, all birds were transferred to boxes of 1.5 x3m (12 birds / box), with wood shavings reused as litter. Chicks were exposed to acute stress (36°C) for 8 h at the age 36, in all treatments, being electronically monitored the temperature and humidity of the microclimate of the birds. Feed and water were provided ad libitum, even during periods of stress. Were measured performance data (weight gain, feed intake and feed conversion) and mortality rate. The early thermal conditioning (T2) and effect of dietary electrolytes (T3) were effective to minimize the mortality of broilers subjected to acute heat stress with a significant difference (P<0.05), without prejudice on broiler performance. The results also showed that there was a more favorable effect when applied dietary electrolytes and thermal conditioning simultaneously (treatment T4). However, for the treatment none of these strategies has been applied (T1), the mortality rate was 83% over that in which they were applied (T4). It was concluded from this study that both techniques: the thermal conditioning early as the dietary electrolytes are efficacious in minimize the damaging effects caused by heat broiler.

Bio-energy conversion cost: a new index to evaluate the bioeconomic eficiency

This study evaluated a nonlinear programming excel workbook PPFR (http://www.fmva.unesp.br/ppfr) for determining the optimum nutrient density and maximize margins. Two experiments were conducted with 240 one-day-old female chicks and 240 one-day-old male chicks distributed in 48 pens (10 chicks per pen, 4 replicates) in a completely randomized design. The treatments include the average price history (2009s and 2010s) for broiler increased and decreased by 25% or 50% (5 treatments to nonlinear feed formulation) and 1 linear feed formulation. Body gain, feed intake, feed conversion were measured at 21, 42 and 56 d of age. Chicks had ad libitum access to feed and water in floor pens with wood shavings as litter. The bio-economic Energy Conversion [BEC= (Total energy intake*Feed weighted cost per kg)/ (Weight gain*kg live chicken cost)] was more sensitive for measuring the bio-economic performance for broilers, and especially with better magnitude. This allowed a better assessment of profitability, the rate of growth and not just energy consumption, the production of broilers, by incorporating energy consumption, allowing for more sensitivity to the new index (BEC). The BEC was demonstrated that the principle of nonlinear formulation minimizes losses significantly (P<0.05), especially under unfavorable conditions the price of chicken in the market. Thus, when considering that a diet of energy supply shows up as the most expensive item of a formulation, it should compose necessarily the formula proposed for a bio-economic index. Thus, there is need to evaluate more accurately, not only the ingredients of a ration, but the impact of nutrients on the stability of a solution, mainly due to the energy requirement. This strategy promotes better accuracy for decision making under conditions of uncertainty, to find alternative post-formulation. From the above, both weight gain and feed conversion, as traditional performance indicators, cannot finalize or predict a performance evaluation of an economic system creating increasingly intense and competitive. Thus, the energy concentration of the diet becomes more important definition to feed formulator, by directly impact profit activity by interactions with the density of nutrients. This allowed a better evaluation of profitability, the rate of energy performance for broilers, by incorporating the energy consumption formula, allowing more sensitivity to the new index (BEC). These data show that nonlinear feed formulation is a toll to offer new opportunities for poultry production to improved profitability.

Quality of egg yolks after oxycarotenoids supplementation in hens' diets

Oxycarotenoids concentration in layer hens’ feed may be increased whenever the consumer market demands for more pigmented egg yolks. Oxycarotenoids present in Rubrivivax gelatinosus biomass grown in industrial wastewater have already proved their ability on enhancing yolk color. Moreover, there is a current interest on the antioxidant properties that some carotenoids may provide to food and health. So, in this experiment, we investigated the effects of oxycarotenoids supplementation in hens´ diets on yolk composition and stability to rancidity. Hy line hens aging 19 weeks were individually housed in wire cages equipped with feeders and drinkers. After 15 days receiving a corn basal diet nutritionally balanced, they were assigned to four different treatments, with six replicates, that lasted for 28 days: T1 – basal diet (control), T2 – basal diet + 1.5 mg/kg canthaxanthin, T3 – basal diet + 4.5 g/kg freeze dried R. gelatinosus biomass and T4 - basal diet + 4.5 g/kg spray dried R. gelatinosus biomass. Eggs laid on the last 5 days of rearing were collected; the yolks were separated, analyzed for pH and then freeze dried for the further analyses. Proximate composition was determined after drying and the rancidity (TBRAS method) was investigated at 0, 30 and 60 days of storage at room temperature/dark conditions. Yolks that received the oxycarotenoids had the lowest moisture content and the highest protein contents (P < 0.05). Lipids and pH were the same for all treatments (P > 0.05) and ashes only were higher for T2 (P < 0.05). All treatments that received oxycarotenoids had lower TBARS than control group and, among them, oxycarotenoids from spray dried R. gelatinosus biomass were the most effective to prevent rancidity (P < 0.05). So, we concluded that the use of R. gelatinosus biomass in hens feed brings positive effects to the yolk quality, since protein content is increased and conservation is increased due to decreased water content and lipid oxidation.