444 resultados para Residual feed intake
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Developing nutritional strategies that can reduce production costs for the fish industry without affecting productive performance is paramount to make the activity sustainable. We investigated if short-term cycles of feed deprivation and refeeding elicit compensatory growth in matrinxa (Brycon amazonicus) juveniles, using three feeding protocols for 60 days (Phase 1): two levels of deprivation (feed deprivation for two days and refeeding for three - D2R3, or four days - D2R4) and a control level (daily feeding). Following, all fish groups were fed daily at satiation for 15 days (Phase 2). At Phase 1, matrinxa achieved full compensatory growth in both deprivation levels by increasing feed intake and feed efficiency. Overall, deprived fish consumed 40% (D2R3) and 36% (D2R4) less feed than fish fed daily. In Phase 2, growth was similar for all fish. Feed intake increased in both deprived fish, but feed efficiency did not differ among groups and was lower than in Phase 1, indicating a reduced efficiency in feed utilization when food was freely available. We propose that intermittent cycles of feeding represent an effective means to reduce production costs. (C) 2014 Elsevier B.V. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This study aimed to determine the optimal intake of lysine and threonine for broiler breeder hens. Two experiments were conducted to evaluate the responses of birds to digestible lysine (Lys) and threonine (Thr). Eight treatments were assessed in both experiments, with six replicates of eight birds in the Lys experiment and ten birds in the Thr experiment. The dietary levels of Lys and Thr were obtained by a dilution technique. The experimental period was ten weeks for each amino acid studied, which included six weeks of adaptation and four weeks of data collection. The amino acid intake, egg mass and body weight were adjusted using a Reading model. Based on the model coefficients, the cost of the synthetic amino acids sources and the price of fertile eggs determined the intake of each amino acid to maximize. The minimum intake of Lys and Thr reduced egg production by 40 and 30%, respectively, the weight of the eggs decreased by 12 and 9% with the same intake of Lys and Thr, respectively. The models generated by predicting Lys and Thr intake were as follows: Lys=11 x E+31 x W and Thr=9.5 x E+32 x W, where E=egg mass, g/bird per day, and W=body weight, kg/bird. Based on the models, 3 kg birds with an egg mass production of 50 g/day require 643 mg/bird per day of Lys and 569 mg/bird per day of Thr. The optimum economic intake was calculated at 954 and 834 mg/bird per day for Lys and Thr, respectively, reflecting a dietary concentration of 0.636% Lys and 0.556% Thr for a feed intake of 150 g/bird per day. (C) 2015 Elsevier B.V. All rights reserved.
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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.
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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.
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Most consumers consider the fat of chicken meat undesirable for a healthy diet, due to the high levels of saturated fatty acids and cholesterol. The purpose of this experiment was to investigate the influence of changes in dietary metabolizable energy level, associated with a proportional nutrient density variation, on broiler chickens performance and on the lipid composition of meat. Males and females Cobb 500 broilers were evaluated separately. Performance evaluation followed a completely randomized design with factorial 6x3 arrangement - six energy levels (2,800, 2,900, 3,000, 3,100, 3,200 and 3,300 kcal/kg) and three slaughter ages (42, 49 and 56 days). Response surface methodology was used to establish a mathematical model to explain live weight, feed intake and feed conversion behavior. Total lipids and cholesterol were determined in skinned breast meat and in thigh meat, with and without skin. For lipid composition analysis, a 3x3x2 factorial arrangement in a completely randomized design - three ration’s metabolizable energy levels (2,800, 3,000 and 3,300 kcal/kg), three slaughter ages (42, 49 and 56 days) and two sexes - was used. The reduction in the diet metabolizable energy up to close to 3,000 kcal/kg did not affect live weight but, below this value, the live weight decreased. Feed intake was lower when the dietary energy level was higher. Feed conversion was favored in a direct proportion to the increase of the energy level of the diet. The performance of all birds was within the range considered appropriate for the lineage. Breast meat had less total lipids and cholesterol than thigh meat. Thigh with skin had more than the double of total lipids of skinned thigh, but the cholesterol content did not differ with the removal of the skin, suggesting that cholesterol content is not associated with the subcutaneous fat. Intramuscular fat content was lower in the meat from birds fed diets with lower energy level. These results may help to define the most appropriate nutritional management. Despite the decrease in bird’s productive performance, the restriction of energy in broiler chickens feed may be a viable alternative, if the consumers are willing to pay more for meat with less fat.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Avaliou-se o efeito da inclusão de aditivos na ensilagem de cana-de-açúcar (Saccharum officinarum L.) sobre a composição químico-bromatológica das silagens, o comportamento ingestivo, o consumo voluntário e a digestibilidade em bovinos de corte. Utilizaram-se cinco novilhos da raça Nelore providos de cânula ruminal, alocados em delineamento quadrado latino 5 ´ 5 e alimentados com dietas com 65% de volumoso na MS. Foram avaliadas cinco silagens (base úmida): controle - cana-de-açúcar sem aditivos; uréia - cana-de-açúcar + 0,5% uréia; benzoato - cana-de-açúcar + 0,1% de benzoato de sódio; LP - cana-de-açúcar inoculada com Lactobacillus plantarum (1 ´ 10(6) ufc/g MV); LB - cana-de-açúcar inoculada com L. buchneri (3,6 ´ 10(5) ufc/g forragem). A forragem foi armazenada em silos do tipo poço por 90 dias antes do fornecimento aos animais. A composição químico-bromatológica da cana-de-açúcar foi alterada após a ensilagem, em relação à cana-de-açúcar original, com redução no teor de carboidratos solúveis e na digestibilidade in vitro e elevação relativa nos teores de FDN e FDA. Os teores de etanol (0,30% da MS) e ácidos orgânicos (0,99% de ácido lático e 2,31% de acético) foram baixos e semelhantes entre as silagens. Os aditivos aplicados na ensilagem não promoveram alterações no consumo e na digestibilidade aparente da MS (7,2 kg/dia e 63,6%, respectivamente). O comportamento ingestivo dos animais também não foi alterado, com tempos médios de 230,6; 519,6 e 672,8 minutos/dia despendidos com ingestão de ração, ruminação e ócio, respectivamente. Os aditivos acrescidos à cana-de-açúcar promoveram pequenas alterações na maioria das variáveis avaliadas.
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The aim of the present study was to determine feed intake and average weight gain and to evaluate the ruminal morphologic characteristics of Saanen kids slaughtered at 30, 45 and 60 days of age, according to a completely randomized design. Thirty-six non-castrated male Saanen kids were fed ground total ration, pelleted total ration, or extruded total ration. Feed intake and refusals were controlled daily and the animals were weighed at birth and then once a week. Newborn kids received a milk replacer and were weaned at 45 days. Immediately after slaughter, the animals were eviscerated, the entire digestive apparatus was removed from the carcass. The reticulo-rumen was separated, emptied, washed and weighed. Samples were collected from the dorsal sac, pillar area and ventral sac of the rumen, fixed for about 24h in Bouin's solution, dehydrated, embedded in Histosec and cut into 5 mu m sections. Results showed that dry matter intake (DMI) at weaning and post-weaning and weight gain were higher (P < 0.05) in animals that received the pelleted total ration. The weight of the reticulo-rumen accompanied body development and was heavier in these animals. Histologically, after weaning ruminal papillae were more developed in animals that received pelleted total ration. Length of papillae increased with increase of age. The ratio of papillary height to papillary width increased with age in the ventral sac and until weaning (P > 0.05). We conclude that the pelleting process of the total ration favored increased intake, with a 46.7% increase in weight gain and increase in rumen weight and papillae length, suggesting that best results are obtained with this processing. In general, no difference was observed between the results obtained with extruded and ground total ration, although animals fed extruded total ration showed an increase in rumen weight and papillae width. (c) 2004 Elsevier B.V All rights reserved.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Desempenho zootécnico de girinos de rã-touro com diferentes níveis de proteína e energia digestíveis
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A partir dos valores de digestibilidade de alguns ingredientes foram propostas dietas, com diferentes níveis de proteína e energia digestíveis, em esquema fatorial 3 x 3, destinadas a girinos de rã-touro para avaliar o desempenho zootécnico. O experimento, com duração de 60 dias, foi conduzido com 810 girinos, oriundos da mesma desova, distribuídos em 27 caixas de polipropileno, em uma densidade de 1girino/L. O delineamento experimental foi um esquema fatorial com três níveis de proteína digestível (27; 31 e 35%) e três níveis de energia digestível (2.700; 2.800 e 2.900kcal/kg) com três réplicas. Os parâmetros avaliados aos 60 dias foram ganho de peso, consumo da dieta, consumo em proteína da dieta, conversão alimentar, taxa de eficiência proteica e índice de sobrevivência. Os resultados foram submetidos à análise de variância e ao teste de Duncan (95% de precisão). Os resultados encontrados não apresentaram interação entre proteína e energia digestível para nenhum parâmetro avaliado. em relação à proteína digestível, foram verificadas diferenças nos parâmetros consumo em proteína da dieta e taxa de eficiência proteica (TEP), o que demonstra ineficiência das dietas com altos valores proteicos. Deve-se oferecer aos girinos de rã-touro dietas com 27% de proteína digestível, por apresentarem melhor resultado para taxa de eficiência proteica e para consumo em proteína da dieta.
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Incubation temperature (IT) was changed to evaluate if 6-wk-old birds become more tolerant to heat stress. After 13 d of incubation, 470 eggs were submitted to low (36.8degreesC), normal (37.8degreesC) and high (38.8degreesC) temperatures. At day 7 post-hatching, 144 birds were allocated to three rearing temperatures (48 birds/treatment): control/thermoneutral (35-24degreesC), high (33-30degreesC) or low (27-18degreesC) according to the age of the birds. Hsp70 levels in tissues of birds (1 d and 42 d), stress response (42 d) and performance were evaluated. High IT decreased brain (P < 0.01) and liver (P < 0.01) Hsp70 levels, whereas low IT decreased brain (P < 0.01) but increased heart (P < 0.01) Hsp70 levels in 1-d-old chicks. Birds incubated at a low temperature had higher (P < 0.05) feed intake (1-42d). High rearing temperature decreased feed intake (P<0.01) and liveweight (P<0.01). Colonic temperature was lower in birds incubated at a low temperature (P < 0.05) and higher in birds reared in a high temperature (P < 0.05) before heat stress. Birds reared in low temperature had higher increase in colonic temperature after heat stress (P < 0.05). Tissue Hsp70 levels were differently affected by rearing temperature, which affected broiler performance more than IT. Lower IT seemed to increase the sensitivity of birds to heat stress at market age.
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Determinaram-se os níveis nutricionais de cálcio (Ca) para aves, machos e fêmeas, da linhagem ISA Label, nas fases inicial (um a 28 dias), crescimento (28 a 56 dias) e final (56 a 84 dias). Foram realizados três ensaios, um para cada fase, e, em cada ensaio, 480 aves com idade correspondente à fase de criação foram alojadas em 24 unidades experimentais com áreas de abrigo e de pastejo. Foi utilizado delineamento inteiramente ao acaso, em esquema fatorial 4x2 (Ca e sexo), totalizando oito tratamentos com três repetiç ões de 20 aves. Avaliaram-se: ganho de peso (GP); consumo de dieta (CD); conversão alimentar (CA); teores de fósforo (PT), de cálcio (CaT) e de cinzas na tíbia (CT) e resistência à quebra óssea (RQO). Na fase inicial, recomenda-se 1,16% de Ca na dieta, para aves de ambos os sexos, na fase de crescimento, 0,78 e 0,88% de Ca para machos e fêmeas, respectivamente, e, na fase final, 0,69% de Ca na dieta para ambos os sexos.