Supplemental L-arginine improves feed conversion and modulates lipid metabolism in male and female broilers from 29 to 42 days of age.

The excessive accumulation of abdominal fat in broilers is an economic waste. Supplemental dietary L-arginine has been shown to reduce lipogenesis in broilers, but studies on this subject are still scarce. Two experiments were conducted in a 5×2 factorial design, with five L-arginine concentrations in diets (0, 3, 6, 9 and 12 g/kg) provided to male and female broilers, from 29 to 42 days of age, reared in boxes or cages, with six replicates of 23 broilers per box and six replicates of three broilers per cage, totalling 1560 broilers. Data on performance, carcass and cuts yield, abdominal fat deposition, chemical composition of the breast, lipid profile and liver enzyme activity were evaluated in experiment 1. In experiment 2, the balance and retention of nitrogen, metabolizability coefficients and metabolizable energy of feed were determined and the treatments were evaluated in six replicates of three broilers per cage, totalling 180 broilers. In both experiments, there was no interaction (P > 0.05) between L-arginine concentration in the diet and sex of the broilers for all parameters evaluated. Male broilers showed higher (P < 0.05) weight gain, noble cuts yield, levels of CP and mineral matter in the breast, better feed conversion (P < 0.05) and lower (P < 0.05) malic enzyme activity in the liver and abdominal fat deposition. On the other hand, regardless of sex, the increase in L-arginine concentration in the diet improved (P < 0.05) the feed conversion in addition to reducing (P < 0.05) serum levels of total cholesterol and low-density lipoprotein cholesterol, the malic enzyme activity in the liver and abdominal fat deposition. In conclusion, male broilers had better productive results than females. However, supplementing the diet of male or female broilers from 29 to 42 days of age with L-arginine at a concentration of 6.87 g/kg represents a nutritional strategy to improve feed conversion and reduce circulating triacylglycerol and cholesterol levels, NADPH synthesis by liver malic enzyme and abdominal fat deposition, without negatively affecting the carcass and noble cuts yield, the amount of nitrogen excreted by the broilers and the energy value of the feed.

Validation of Prediction Equations of Energy Values of a Single Ingredient or Their Combinations in Male Broilers.

A set of prediction equations to estimate the nitrogen-corrected apparent metabolizable energy (AMEn) of individual ingredients and diets used in the poultry feed industry was evaluated. The AMEn values of three energy ingredients (maize, sorghum and defatted maize germ meal), four protein ingredients (soybean meal, maize gluten meal 60% crude protein, integral micronized soy and roasted whole soybean) and four diets (three containing four feedstuffs, complex diets, and one containing only corn-soybean meal, basal diet) were determined using a metabolism assay with male broilers from 1 to 7, 8 to 21, 22 to 35, and 36 to 42 days old. These values were compared to the AMEn values presented in the tables of energy composition or estimated by equation predictions based on chemical composition data of feedstuffs. In general, the equation predictions more precisely estimated the AMEn of feedstuffs when compared to the tables of energy composition. The equation AMEn (dry matter [DM] basis) = 4,164.187+51.006 ether extract (% in DM basis)-197.663 ash-35.689 crude fiber (% in DM basis)-20.593 neutral detergent fiber (% in DM basis) (R(2) = 0.75) was the most applicable for the prediction of the energy values of feedstuffs and diets used in the poultry feed industry.

Efficiency of microbial phytase supplementation in diets formulated with different calcium:phosphorus ratios, supplied to broilers from 22 to 33 days old.

An experiment was conducted with broilers from 22 to 33 days of age to evaluate the efficiency of six microbial phytases supplemented in diets (1500 FTU/kg) that were formulated with three different calcium:available phosphorus (Ca:P(avail)) ratios (4.5:1.0, 6.0:1.0 and 7.5:1.0). A positive control diet without phytase was formulated with a Ca:P(avail) ratio of 7.5:3.4 to meet the nutritional requirements of the broilers. The P and ash contents of the tibia, magnesium in the plasma, performance, balance and retention of phytate phosphorus (P(phyt)), intake of total P and nitrogen (N), nitrogen-corrected apparent metabolizable energy and apparent digestibility of dry matter of the diets were not influenced (p > 0.05) by the type of phytase or the dietary Ca:P(avail) ratio. However, there was an interaction (p < 0.05) between the phytase type and the Ca:P(avail) ratio for the retention coefficients of total P, Ca and N. Phytase B resulted in the highest Ca deposition in the tibia (p < 0.01). Phytases D, E and F reduced the Ca concentrations in the tibia (p < 0.01) and plasma (p < 0.05). Phytase D increased the P level in the plasma and decreased the total P excretion (p < 0.01). Phytases E and F increased Ca excretion, while phytase A reduced it (p < 0.01). Regardless of the phytase type, increasing the dietary Ca:P(avail) ratio reduced (p < 0.05) the plasma P concentration and the excretion of total P and N and, conversely, increased (p < 0.05) the plasma concentration, intake and excretion of Ca. For the rearing period evaluated, it is possible to reduce the P(avail) of the diet to 1.0 g/kg when Ca is maintained at 7.5 g/kg, and the diet is supplemented with 1500 FTU of phytase A, C, D or E/kg. This diet allows the maintenance of performance and adequate bone mineralization, and it improves the Ca, total P and P(phyt) utilization in addition to reducing the excretion of N and P into the environment.

Comparison of methodologies to quantify phytate phosphorus in diets containing phytase and excreta from broilers.

The use of a suitable methodology to quantify the phytate phosphorus (Pphy) content in both the feed and the excreta from broilers is required to enable accurate calculation of the catalytic efficiency of the phytase supplemented in the feed. This study was conducted to compare 2 analytical methodologies (colorimetry and also high-performance liquid chromatography with a refractive index detector) in order to calculate the phytase efficiency by utilizing the results from the methodology that was shown to be the most appropriate. One hundred and twenty broilers were distributed in a (4+1)×2 factorial arrangement, corresponding to 4 diets that were equally deficient in P supplemented with increasing levels of phytase (0, 750, 1,500, and 2,250 units of phytase activity - FTU - per kg of feed) plus 1 positive control diet without phytase, supplied to male and female birds. The result indicated that the colorimetric methodology with an extraction ratio of 1:20 (mass of sample in g:volume of the solvent extractor in mL) was shown to be the most adequate. There was no interaction between the phytase level and the sex of the broilers (p>0.05). Males consumed 12% more Pphy than did females (p<0.01), but the sex of the broilers did not affect (p>0.05) the excretion and retention coefficient of Pphy. The increase in the phytase level of the diet reduced (linear, p<0.01) the Pphy excretion. The greatest Pphy retention was estimated at 87.85% when the diet contained 1,950 FTU/kg (p<0.01), indicating that it is possible to reduce the inorganic P in the formulation at an amount equivalent to 87.85% of the Pphy content present in the feed, which, in this research, corresponds to a decrease in 2.86 g of P/kg of the feed.

Content of plasmatic glycerol and activity of hepatic glycerol kinase in broiler chickens fed diets containing different sources and concentrations of glycerine.

The objective of this study was to evaluate the effect of three sources of glycerine (crude glycerine from soya bean oil - CGSO, mixed crude glycerine from frying oil and lard--MCG, and a semipurified glycerine from soya bean oil--SPGSO) in four concentrations in the diet (17.5, 35.0, 52.5 and 70.0 g of each type of glycerine per kg of feed) on the levels of plasmatic glycerol and the activity of the hepatic enzyme glycerol kinase in broilers of 22-35 days old (experiment I) and 33-42 days old (experiment II). The highest (p < 0.05) plasmatic glycerol level was detected in broilers fed diet containing CGSO. Independent of the source, increasing the concentration of glycerine led to a linear increase (p < 0.05) in the plasmatic glycerol concentration. In experiment I, all the diets containing glycerine resulted in increased concentrations of plasmatic glycerol, in relation to the control diet without glycerine. However, in experiment II, only the diet containing 17.5 g of CGSO per kg of feed and the diets formulated with any of the three types of glycerine in the inclusion concentrations of 35, 52.5 and 70 g/kg of feed resulted in higher plasmatic glycerol levels than those observed in the control broilers. The source of glycerine influenced the glycerol kinase activity only in experiment II, where the use of CGSO in the diet increased the enzyme activity. For both experiments, the glycerol kinase activity increased with the inclusion of glycerine in the diet. In conclusion, based on the absence of saturation of the glycerol kinase activity for the three glycerine sources and for both rearing periods evaluated, the broilers can metabolize the glycerol (at the level of the phosphorylation of the glycerol to glycerol-3-phosphate in the liver) present in the glycerine when the diet is supplemented with up to 70 g of glycerine per kg of feed.

Activity of glutamate dehydrogenase and protein content in the breast of broilers fed diets containing different sources and levels of glycerine.

According to scientific literature, glycerol in the diet can spare glucogenic amino acids by inhibiting the activity of enzymes, such as glutamate dehydrogenase, thereby promoting protein deposition in muscle tissues. Therefore, the objective of this study was to evaluate the effect of three sources of glycerine (crude glycerine from soybean oil--CGSO, mixed crude glycerine from frying oil and lard--MCG and a semipurified glycerine from soybean oil--SPGSO) in four concentrations in the diet (17.5, 35.0, 52.5 and 70.0 g of each type of glycerine/kg of feed) on the activity of hepatic glutamate dehydrogenase, performance and protein content in the breast of broilers, during 22-35 days of age (experiment I) and 33-43 days of age (experiment II). In both experiments, an increase in MCG induced a linear decline in glutamate dehydrogenase activity (p < 0.05). In contrast, increasing the concentration of SPGSO in the diet caused a linear increase in enzyme activity (p < 0.05). There was no (p > 0.05) isolated effect of glycerine on the enzyme activity in either evaluated phase; however, during 33-42 days of age, MCG inhibited (p < 0.05) the glutamate dehydrogenase activity by up to 34.43%. During 22-35 days of age, the diet containing SPGSO induced a higher protein content (p < 0.05) in the breast, and regardless of the source utilized, the maximum protein deposition was estimated (p < 0.05) when broilers were fed with 55.08 g glycerine/kg of diet. There was no (p > 0.05) interaction or isolated effects of the sources and levels of glycerine on the protein content in the breast of broilers at 33-42 days of age, and moreover, all diets containing glycerine promoted a similar protein deposition in the breast compared with birds that received the diet without glycerine. The bird age also showed to influence the feed intake and weight gain of broilers fed diet containing glycerine. It is concluded that for both rearing phases, an increase in glycerine in the diet did not necessarily reduce the glutamate dehydrogenase activity, and the protein deposition in the breast of broilers may not be strictly correlated with the activity of this enzyme.

Prediction of the energy values of feedstuffs for broilers using meta-analysis and neural networks.

Several researchers have developed prediction equations to estimate the metabolisable energy (ME) of energetic and protein concentrate feedstuffs used in diets for broilers. The ME is estimated by considering CP, ether extract, ash and fibre contents. However, the results obtained using traditional regression analysis methods have been inconsistent and new techniques can be used to obtain better estimate of the feedstuffs' energy value. The objective of this paper was to implement a multilayer perceptron network to estimate the nitrogen-corrected metabolisable energy (AMEn) values of the energetic and protein concentrate feeds, generally used by the poultry feed industry. The concentrate feeds were from plant origin. The dataset contains 568 experimental results, all from Brazil. This dataset was separated into two parts: one part with 454 data, which was used to train, and the other one with 114 data, which was used to evaluate the accuracy of each implemented network. The accuracy of the models was evaluated on the basis of their values of mean squared error, R 2, mean absolute deviation, mean absolute percentage error and bias. The 7-5-3-1 model presented the highest accuracy of prediction. It was developed an Excel® AMEn calculator by using the best model, which provides a rapid and efficient way to predict the AMEn values of concentrate feedstuffs for broilers.

The energy value of biodiesel glycerine products fed to broilers at different ages.

The objective of this study was to determine the apparent metabolisable energy corrected for nitrogen balance (AMEn) of some products containing glycerine from soybean oil (GOIL), a mixture of frying oil and lard (GMIX) and a semi-purified process (GSP) in broilers of different ages (10, 20, 30 and 40 days post-hatching), using two methodologies. In trial 1, the basal diets were replaced with 100 g/kg of each studied glycerine product and the diets were supplied ad libitum. Three hundred broilers were used in five replicates, with five, four, three and three animals per cage in each age group, respectively. The AMEn was calculated for each experimental unit. In trial 2, dietary treatments included the addition of glycerine at 0, 40, 80 or 120 g/kg for each crude glycerine product, with 900 broilers in six replicates, using the same number of animals per cage as described in trial 1. Depending on the experimental unit, the feeding was restricted in 88%, 92%, 96% and 100% of estimated intake according to the Cobb guide. The AMEn was determined using linear regression between the feed intake and the AMEn of each diet. In both trials, the total excreta collection method was used. Because of the chemical composition, GMIX was not considered crude glycerine. The mean AMEn values of the products were 20.55 MJ/kg, 15.80 MJ/kg and 15.05 MJ/kg for GMIX, GSP and GOIL, respectively. There was a linear decrease (p < 0.01) in the AMEn values with the increasing age of the broilers. Numerically, it was observed that the AMEn values decreased until 28-30 day post-hatching and then remained constant until the finishing phase. It is concluded that products containing glycerine can be used as an energy source for broilers, but that AMEn values can vary according to age. Younger broilers have a higher capacity of energy utilisation from these feedstuffs.

Validation of prediction equations to estimate the energy values of feedstuffs for broilers: performance and carcass yield.

The objective was to evaluate the use of prediction equations based on the chemical composition of feedstuffs to estimate the values of apparent metabolisable energy corrected for nitrogen balance (AMEn) of corn and soybean meal for broilers. For performance and carcass characteristics, 1,200 one-d-old birds (male and female) were allotted to a completely randomised factorial 2×8 (two genders and eight experimental diets) with three replicates of each sex with 25 birds. In the metabolism trial, 240 eight-d-old birds were distributed in the same design, but with a split plot in time (age of evaluation) with five, four and three birds per plot, respectively, in stages 8 to 21, 22 to 35, and 36 to 42 d of age. The treatments consisted of the use of six equations systems to predict the AMEn content of feedstuffs, tables of food composition and AMEn values obtained by in vivo assay, totalling eight treatments. Means were compared by Scott-Knott test at 5% probability and a confidence interval of 95% was used to check the fit of the energy values of the diets to the requirements of the birds. As a result of this study, the use of prediction equations resulted in better adjustment to the broiler requirements, resulting in better performance and carcass characteristics compared to the use of tables, however, the use of energy values of feedstuffs obtained by in vivo assay is still the most effective. The best equations were: AMEn = 4,021.8-227.55 Ash (for corn) combined with AMEn = -822.33+69.54 CP-45.26 ADF+90.81 EE (for soybean meal); AMEn = 36.21 CP+85.44 EE+37.26 NFE (nitrogen-free extract) (for corn) combined with AMEn = 37.5 CP+46.39 EE+14.9 NFE (for soybean); and AMEn = 4,164.187+51.006 EE-197.663 Ash-35.689 CF-20.593 NDF (for corn and soybean meal).

Performance and egg quality of laying hens fed with dietary levels of digestible lysine and threonine / Desempenho e qualidade de ovos de poedeiras alimentadas com dietas contendo níveis de lisina e treonina digestíveis

The present study was developed using 864 Hy-Line W36 laying hens (42 to 58 weeks of age) with a randomized experimental design in a 4x3 factorial arrangement, with five replicates and 12 birds per experimental unit and 4 evaluation periods of 28 days each. The digestible lysine levels studied were 0.675%, 0.743%, 0.811% and 0.879%, and the digestible threonine levels were 0.542%, 0.596% and 0.650%. The performance and egg quality was evaluated. There were no significant effects on the egg production, specific gravity, albumen and yolk percentage and total solids in albumen and yolk for birds submitted to the different dietary digestible lysine and threonine levels. There was significant interaction between these amino acids on the egg shell percentage and Haugh unit in fresh eggs. There was a decreasing linear effect on the feed intake with increase of digestible lysine level. Egg weight, egg mass and feed conversion demonstrated a quadratic effect with the increase of the digestible lysine level with the best results in the diets with 0.754, 0.772 and 0.795% of digestible lysine, respectively.

O presente trabalho foi desenvolvido utilizando 864 poedeiras Hy-Line W36 (42 a 58 semanas de idade) em um delineamento inteiramente casualizado no esquema fatorial 4x3 com 5 repetições e 12 aves por parcela e 4 períodos de avaliação de 28 dias cada. Os níveis de lisina digestível estudados foram 0,675%; 0,743%; 0,811% e 0,879%, e os de treonina digestível de 0,542%, 596% e 0,650%. Foram avaliados o desempenho e a qualidade dos ovos. Não houve efeitos significativos sobre a produção de ovos, gravidade específica, proporção de clara ou albúmen e seus respectivos teores de sólidos totais para poedeiras submetidas aos respectivos níveis de lisina e treonina na ração. Houve interação entre os níveis de treonina e lisina, para porcentagem de casca e unidade Haugh. Houve redução linear no consumo de ração em função do aumento dos níveis de lisina digestível na ração. Houve comportamento quadrático para peso dos ovos, massa dos ovos e conversão alimentar em função dos níveis de lisina digestível, estimando-se níveis ótimos para respectivas características em 0,754; 0,772 e 0,795%, respectivamente.

Redução de proteína e fósforo em dietas com fitase para frangos de corte dos 22 aos 42 dias de idade / Reduction of protein and phosphorus in diets containing phytase for broilers from 22 to 42 days of age

Avaliou-se o efeito da inclusão de fitase em dietas com proteína bruta (PB) e fósforo disponível (Pd) reduzidos sobre o desempenho, rendimento de carcaça e cortes e quantidade de poluentes na cama de frangos dos 22 aos 42 dias de idade. Foram utilizados 1200 pintos aos 21 dias, média de peso inicial de 646±8g, distribuídos em blocos ao acaso em esquema fatorial 3x3+1 (três porcentagens de Pd - 0,2, 0,3 e 0,4 por cento - e três de PB - 14, 16 e 18 por cento - e um tratamento adicional, padrão) em seis repetições de 20 aves cada. A fitase (500FTU/kg) foi adicionada nas dietas com fósforo reduzido (0,2 e 0,3 por cento). Aos 42 dias as aves foram abatidas e amostras das camas foram encaminhadas para análise. Em dietas com reduzido teor de PB, melhor desempenho e rendimento de carcaça e menor quantidade de fósforo, cálcio, potássio e zinco nas camas foram obtidos com 0,3 por cento Pd+fitase. Menor quantidade de nitrogênio e potássio, porém com maior deposição de gordura abdominal e maior excreção de cobre, foram obtido com 14 por cento de PB. Comparadas ao controle, dietas com 14 por cento de PB e 0,3 por cento de Pd reduziram a excreção de fósforo em 34 por cento. Conclui-se que dietas com 14 por cento de PB e 0,3 por cento de Pd, suplementadas com fitase e aminoácidos cristalinos, podem ser utilizadas para frangos de corte dos 22 aos 42 dias.

The effect of the inclusion of phytase in reduced crude protein (CP) and available phosphorus (aP) diets on performance, carcass and cut yields and the amount of pollutant elements in the litter of broilers from 22 to 42 days of age was evaluated. One thousand and two hundred male broilers at 21 days of age, initial weight of 646±8g, were distributed in randomized block design in factorial scheme 3x3+1 (three levels of aP - 0.2, 0.3 and 0.4 percent - and three of CP - 14, 16 and 18 percent - and an additional treatment, standard) in six repetitions of 20 birds each. Phytase (500 FTU/kg) was added in reduced phosphorus (0.2 and 0.3 percent) diets. At 42 days of age, the birds were sacrificed and samples of the litters were sent to the laboratory for analysis. In reduced-CP diets, the best performance and carcass yield and lesser quantity of phosphorus, calcium, potassium and zinc in the litter was obtained with 0.3 percent aP + phytase diets. The minor quantity of nitrogen and potassium in the litter, with higher abdominal fat deposition and excretion of cupper were obtained with 14 percent CP diets. Compared to control, diets with 14 percent CP and 0.3 percent aP reduced the excretion of phosphorus in 34 percent. It was concluded that diets with 14 percent CP and 0.3 percent aP, supplemented with phytase and crystalline amino acids, can be used in broilers from 22 to 42 days old.

Altos níveis de fitase em rações para frangos de corte / High levels of phytase in diets for broilers

Avaliaram-se o desempenho, o coeficiente de digestibilidade da matéria seca (CDMS), da proteína bruta (CDPB), a retenção aparente de cálcio (Ca) e fósforo (P) e a energia metabolizável aparente corrigida para balanço de nitrogênio (EMAn) de dietas suplementadas com altos teores de fitase (FTU) para frangos, até 35 dias de idade. Foram utilizados 1848 pintos, distribuídos em delineamento inteiramente ao acaso, com sete tratamentos e oito repetições de 35 aves. Os tratamentos foram: T1: dieta-controle; T2: dieta com inclusão de 1.500FTU/kg; T3: 3.000FTU/kg; T4: 4.500FTU/kg; T5: 6.000FTU/kg; T6: 8.000FTU/kg e T7: 10.000FTU/kg de ração. No 10º e 28º dias de experimento, quatro e três aves, respectivamente, foram transferidas para gaiolas de metabolismo. A partir da inclusão de 4.500FTU/kg, o desempenho das aves de 1 a 35 dias foi semelhante ao das aves do grupo-controle (P>0,05). Não houve diferença (P>0,05) entre os tratamentos nos CDPB e nos valores de EMAn, porém, na fase inicial, observou-se maior aproveitamento da MS com os altos níveis de fitase (P<0,05). Em relação à retenção de Ca e P, houve efeito positivo da suplementação enzimática, com aumento significativo do uso desses minerais pelas aves. Concluiu-se que é possível suplementar altos teores de fitase valorando adequadamente os nutrientes da dieta.

The digestibility of dry matter (DMD), and of crude protein (CPD), the apparent retention of calcium (Ca) and phosphorus (P) and apparent metabolizable energy corrected by nitrogen balance (AME) of diets supplemented with high levels of phytase (FTU) for broilers, 35 days old were evaluated. A total of 1848 chicks were distributed in a completely randomized experiment with seven treatments and eight repetitions. The treatments were: T1: control diet, T2: inclusion of 1,500FTU/kg; T3: 3,000FTU/kg; T4: 4,500FTU/kg; T5: 6,000FTU/kg; T6:8,000FTU/kg; and T7: 10,000FTU/kg feed. On the 10th and 28th days of the experiment, four and three birds, respectively, were transferred to metabolism cages. An addition of 4,500FTU/kg from 1 to 35 days resulted in a performance similar to the control group (P>0.05). There was no difference (P>0.05) among treatments for DMD and AME, however, during the initial phase there was a higher use of MS with high levels of phytase (P<0.05). Regarding the retention of Ca and P, a positive effect of enzyme supplementation significantly increased the use of these minerals by birds. It is possible that high levels of supplemental phytase adequate valuing the nutrients.

Efeito de fontes e níveis de selênio sobre parâmetros fisiológicos em frangos de corte / Effect of sources and levels of selenium on physiological traits in broilers

Avaliaram-se a retenção aparente, a deposição hepática, tecidual e plasmática, bem como a eficiência da glutationa peroxidase hepática e plasmática em frangos de corte alimentados com diferentes níveis e fontes de selênio. Utilizaram-se 300 pintos machos com 14 dias, submetidos a um esquema fatorial 3x3 + 1 (três níveis de Se - 0,150; 0,300; 0,450ppm, e três fontes comerciais de Se - uma inorgânica e duas orgânicas + um tratamento controle sem suplementação), em DIC. Do primeiro ao 14º dia de idade - período de depleção -, as aves receberam rações basais sem suplementação de selênio. Aos 14 dias, receberam as dietas com selênio, por um período de 14 dias, sendo coletadas as excretas nos últimos quatro dias. A retenção de selênio foi relativamente alta. O uso da fonte orgânica A em níveis crescentes apresentou menor queda na retenção aparente de selênio. As fontes orgânicas participaram mais ativamente nas atividades de tecidos de forma geral, e a fonte inorgânica foi neutralizada no tecido hepático. A eficiência dessa enzima no plasma aumentou linearmente quando se elevaram os níveis dietéticos. Para a fonte inorgânica, não houve mudança nesta eficiência.

We evaluated the apparent retention, the hepatic, tissue and plasmatic deposition as well as the efficiency of the enzyme hepatic and plasmatic Glutathione Peroxidase in broiler chickens fed different sources and levels of selenium. 300 male Cobb- 500 chicks aged 14 days were submitted to a factorial scheme 3x3+1 (three levels - 0.150; 0.300; 0.450ppm, three commercial sources - one inorganic and two organic + one control treatment without a supplementation) in CRD. The first 14 days of age (depletion period) the birds were fed basal diets without a supplementation of selenium. At 14 days the birds were given the diets with selenium for a period for 14 days, and the excreta collected in the last four days. The work suggested that the selenium retentions were relatively high, due to the use of organic source A at growing levels they presented a lower decrease in apparent retention of selenium. The organic sources participated more actively in the activities of tissues in general and the inorganic source is neutralized in the hepatic tissue. The efficiency of this enzyme in plasma was increased linearly, when we increased dietary levels for the inorganic source there was no change in efficiency.

Equações de predição para estimar valores da energia metabolizável de alimentos concentrados energéticos para aves utilizando meta-análise / Prediction equations to estimate metabolizable energy values of energetic concentrate feedstuffs for poultry by the meta-analysis process

Obtiveram-se equações de predição dos valores de energia metabolizável aparente corrigida (EMAn) para alimentos energéticos mais utilizados nas dietas de frangos de corte por meio do princípio da meta-análise. Foi realizada uma revisão bibliográfica de estudos realizados no Brasil para catalogar informações sobre valores de EMAn e composição química dos alimentos (PB; EE; MM; FB, FDN e FDA). Também foram considerados os efeitos de sexo, macho, fêmea e mistos de idade (primeira e segunda semanas, terceira e quarta semanas, quinta e sexta semanas e acima de seis semanas ou indefinido), e da metodologia empregada no metabolismo (coleta total de excretas ou alimentação forçada + coleta total de excretas), formando um esquema fatorial (3x4x2). Adotou-se o procedimento de Stepwise para estudar a associação entre as variáveis, incluindo-as na equação em função de suas importâncias, e o Proc Reg do SAS para ajustar o modelo de regressão linear múltipla. As melhores equações para estimar a EMAn dos alimentos foram EMAn = 4371,18 - 26,48PB + 30,65EE - 126,93MM - 52,26FB - 25,14FDN + 24,40FDA (R²=0,81) e EMAn = 4205,23 + 30,58EE - 130,35MM - 58,29FB - 28,31FDN + 16,71FDA (R²=0,81). As variáveis FDN e FDA foram importantes nas equações ao influenciarem os valores energéticos dos alimentos.

Prediction equations were obtained for the apparent metabolizable energy (EMAn) values of energetic feedstuffs used in broiler chicken diets by meta-analysis. A bibliographical review of the studies carried out in Brazil was performed to collect information concerning energy values and chemical composition (CP, EE, MM, CF, NDF, and ADF) of feedstuffs. The effects of gender (male, female and mixed), age (1st and 2nd week, 3rd and 4th week, 5th and 6th week, and older 6th weeks or indefinite), and the metabolism assay methodology (excrete total collection or forced fed + excrete total collection) were also considered, constituting a factorial scheme (3x4x2). The stepwise procedure was used to study the association among equation variables by their importance, and Proc Reg (SAS) was used to fit the multiple linear regression model. The equations which best estimated the EAMn of the energetic feedstuffs were AME = 4,371.18 - 26.48CP + 30.65EE - 126.93MM - 52.26CF - 25.14NDF + 24.40FDA (R²=0.81) and AME = 4,205.23 + 30.58EE - 130.35MM - 58.29CF - 28.31NDF + 16.71NDA (R²=0.81). NDF and ADF variables were important in the equations, influencing the feedstuffs energetic values.

Níveis de metionina + cistina digestíveis em rações para poedeiras no pico de produção / Digestible methionine plus cystine levels in diets for laying hens at the production peak

Avaliaram-se os efeitos de níveis de aminoácidos sulfurados digestíveis (AASD) sobre o desempenho e a qualidade interna e externa de ovos de 360 poedeiras de 25 a 41 semanas de idade. Foram formuladas seis dietas experimentais: cinco continham 0,578; 0,636; 0,694; 0,752 ou 0,810 por cento de AASD, e em uma o nível de AASD foi o usualmente recomendado, cada tratamento com cinco repetições de 12 aves, em quatro períodos de avaliação de 28 dias cada. Melhores resultados para produção de ovos, conversão alimentar, massa de ovos e ovos viáveis foram obtidos com as aves que consumiram 729; 751; 801 e 730mg AASD/dia, respectivamente. A elevação dos níveis de AASD resultou em aumentos lineares no consumo de ração, no ganho de peso, nas porcentagens de gema e no extrato etéreo na gema. Nos ovos armazenados por sete dias, houve aumento linear da porcentagem de gema e decréscimo linear da porcentagem de casca, unidade Haugh e peso específico com a elevação dos níveis de AASD. Conclui-se que, para melhores produção e qualidade interna e externa de ovos, é necessário o consumo de 752mg de AASD ou de 864mg de aminoácidos sulfurados totais por ave/dia.

An experiment was conduct using 360 laying hens to evaluate the dietary levels of digestible sulfur amino acids (DSAA) on performance and egg quality of hens from 25 to 41 weeks of age. Five experimental diets were formulated containing 0.578, 0.636, 0.694, 0.752, and 0.810 percent of DSAA and one additional diet using the recommend level. Each treatment was replicated five times with 12 birds per replicate during four evaluation periods of 28 days each. The best results for egg production, feed conversion, egg mass yield, and viable eggs were obtained by birds that consumed 729, 751, 801, and 730 DSAA mg/day, respectively. Feed intake, weight gain, percentage of yolk, and lipid yolk linearly increased with increasing levels of DSAA. A linear increase in the percentage of yolk and a linear decrease on the percentage of shell weight, Haugh unit, and specific weight were observed with increasing levels of DSAA for eggs stored during seven days. It is concluded that for the best production and egg quality, a consumption of 752 mg of DSAA or 864 mg of total sulfur amino acid per bird per day is required.

Utilização de ácidos orgânicos e fitase em dietas para leitões na creche / Utilization of organic acids and phytase in diets for weaned piglets

Verificou-se o efeito da inclusão de um complexo de ácidos orgânicos (AO) e diferentes níveis de fitase em dietas de leitões na creche. Foram utilizados 40 leitões desmamados (7,8±0,8kg), distribuídos em delineamento de blocos inteiramente ao acaso, com cinco tratamentos e quatro repetições, durante um período experimental de 28 dias. Os tratamentos foram: T1- ração basal com 500UF/kg (controle); T2- ração basal com 500UF/kg + 0,2 por cento do complexo de AO; T3- ração basal com 450UF/kg + 0,2 por cento do complexo de AO; T4- ração basal com 400UF/kg + 0,2 por cento do complexo de AO; e T5- ração basal com 350UF/kg + 0,2 por cento do complexo de AO. A adição de AO à ração que continha 500UF propiciou maior (P<0,05) ganho de peso médio diário em relação ao tratamento-controle. Com relação aos níveis de fitase em dietas que continham AO não foram observadas diferenças (P>0,05) no ganho de peso. Para o consumo de ração médio diário, observou-se uma regressão quadrática (P<0,05), sendo o nível de 411UF o que propiciou o menor consumo de ração. O nível de 500UF + AO resultou em maior porcentagem de fezes normais em relação ao grupo-controle durante as duas últimas semanas do período experimental. Conclui-se que há efeito positivo da adição do complexo de ácidos orgânicos quando se suplementa fitase nas dietas de leitões na fase de creche dos oito aos 20kg.

The effect of inclusion of organic acids complex (OAC) and different levels of phytase in piglet diets were evaluated. Forty weaned piglets (7.8±0.8kg) were allotted in a completely randomized block design with five treatments and four repetitions, during an experimental period of 28 days. The treatments were: T1-basal diet with 500 phytase unit/kg (control); T2-basal diet with 500PU/kg + 0.2 percent of OAC; T3-basal diet with 450PU/kg + 0.2 percent of OAC; T4-basal diet with 400PU/kg + 0.2 percent of OAC; and T5-basal diet with 350PU/kg + 0.2 percent complex of OA. The addition of OAC at the 500PU diet increased (P<0.05) daily average gain compared to the control treatment. Comparing the phytase levels in diets containing OAC, it was not observed difference (P>0.05) in the weight gain. For the daily average feed intake, it was observed a quadratic effect (P<0.05), and the 411PU level caused lesser feed intake. The level of 500PU + OAC resulted in higher percentage of hard feces compared to the control group during the two last weeks of the experimental period. It was concluded that the effect of the OAC resulted positive when phytase was supplemented to the diets of piglets from eight to 20kg.