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Introduction Modern layer strains have high genetic potential for egg production, and may produce eggs for more than one laying cycle by inducing molting. Good egg production is obtained when adequate nutrition is provided, one of the most important nutrients is protein, particularly limited nutritional essential amino acid. Additionally, in layer flocks feed represents more than 70% of the cost of production. In this context, protein is one of the most costly nutrients and therefore there is a benefit in reducing any excess protein in the feed by making use of synthetic amino acids wherever feasible to reduce both the excess waste of nitrogen and the production cost. Synthetic amino acids such as methionine, lysine and threonine are commonly used in the poultry industry because those are limiting in diets based on cereal and soybean meal and are now readily available at a competitive cost. The essential amino acid, threonine, is the third limiting amino acid. Most of the previous research has been done on determining the amino acids requirements of laying hens in the first production cycle, and information on laying hens requirements in the second production cycle is very limited. As a result, the nutrient requirements of second-cycle hens are assumed to be similar to those observed in hens during the first laying cycle in the strain booklet guide and or NRC, 1994. The objective of this study was to determine the digestible Threonine (dig Thr) requirement of laying hen during the second production cycle fed wheat-soy diet as measured by laying performance.Materials and methods The birds that used for this experiment were selected from a flock that were molted at the 80wk of age on a non-fasting feeding program according to the molting recommendation by Hy-line W36 laying hens guide and had 103wk age. Hens were selected according to body weight and egg production. The pre-experimental period was two weeks for acclimatization. Basal diet were formulated according to the guidelines in the Hy-Line W-36 Commercial Management Guide (2016) according to the average pre-experimental period data; egg production less than of 80% and feed intake 98 g/b/d. Three hundred and eighty four layers were distributed to the 6 increasing levels of dig Thr 0.44, 0.46, 0.48, 0.50, 0.52 and 0.54%, with Thr-to-Lys ratio of 60, 63, 66, 69, 72 and 75%, respectively in a completely randomized design, with 8 replicates and 8 birds per experimental unit. The experiment lasted from 105 to 116 weeks of ages. All hens were weighed at the beginning and at the end of the experimental period. Birds were given artificial light (16L: 8D). Feed and water were provided ad libitum. Egg production (number and weight) and mortality were recorded daily, whereas feed consumption was measured every 4wks as feed disappearance. The daily intakes of Thr were calculated by multiplying the concentration of each in the experimental diet by feed conception. Digestible threonine requirement for optimal laying performance response parameters such as egg production (EP), egg mass (EM) and feed conversion ratio (FCR) to the daily dig Thr consumption by using NLIN procedure, through linear and quadratic broken-lines and quadratic polynomial regression fit models.Results and discussion The increasing dig Thr levels showed linear effect on egg weight, and quadratic effect on egg production (EP), egg mass (EM), and feed conversion ratio (FCR). The EP and EM increased and FCR improved linearly as dietary dig Thr levels increasing up to 0.48% (Thr-to-Lys ratio of 66%), and then EP and EM decreased and FCR deteriorate. The dig Thr requirements for the optimization of laying performance was depends on what parameter is taken into consideration for optimization and it is possible to compare models by their R2 and MAE. In this study, the model that provided the best fit was the quadratic polynomial regression model for EP, EM and FCR. The predicted dig Thr requirements with quadratic polynomial regression model for optimal EP, EM and FCR were 502, 505 and 517 mg/b/d, respectively. The dig Thr requirement to produce 1 g of EM was 9.57 mg. The optimum values estimated for FCR was slightly higher compared to those estimated for EP and EM.Conclusion The outcomes of the present study showed that, in the wheat-soy based diet formulated for second cycle of laying hen the threonine is a limited amino acid. The dig Thr requirements vary according on what parameter is taken into consideration for optimization. The dig Thr requirement for optimized FCR is higher than EP and EM. In the wheat-soy based diet formulated for second cycle of laying hen the level of digestible Thr 0.48% (Thr-to-Lys ratio of 66%) were recommended.

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This study analysed the effects of digestible lysine on the performance parameters, morphometry and quality of the breast muscle (Pectoralis major) of Cobb 500 broiler chickens aged 21 and 42 days. Two completely randomized experiments were performed, with five treatments and eight replications of 30 birds per treatment. The diets were adjusted according to the nutritional requirements for each phase of poultry development, with digestible lysine levels during the initial phase (birds aged 1 to 21 days) at 1.12, 1.19, 1.25, 1.31, and 1.37% and during the final phase (22 to 42 days) at 0.97, 1.02, 1.08, 1.13, and 1.19%. During the initial phase, lysine supplementation had a significant effect (P<0.05) on weight gain and red content in breast meat, with 1.24% and 1.29% digestible lysine resulting in maximum weight gain and red content, respectively. No significant difference (P>0.05) was observed in breast muscle morphometry, carcass yield, performance, or meat quality in birds aged 22-42 days for the different levels of lysine, suggesting that the lowest level of lysine tested did not have a negative impact on production characteristics even though it was below the recommended levels for this species. In conclusion, 1.24% digestible lysine is recommended for maximum weight gain at the initial phase of broiler chicken development (1-21 days) and 0.97% is sufficient to meet the nutritional requirements of birds at the final phase (22-42 days) without compromising production performance. [ABSTRACT FROM AUTHOR]

ABSTRACT: The objective was to estimate the most appropriate digestible methionine + cysteine:lysine ratios for growing meat-type quails (Coturnix coturnix) from 1 to 21 days of age. Quails were fed with a basal ration deficient in digestible methionine + cysteine, with five levels of DL-methionine, in substitution of glutamic acid and starch, resulting in digestible methionine + cysteine:lysine ratios of 0.61, 0.66, 0.71, 0.76 and 0.81. Feed and methionine + cysteine intake, body weight gain, feed conversion and uniformity were assessed. From 1 to 7 days, an increasing linear effect was observed for feed and methionine + cysteine intake, body weight gain, and uniformity, and a linear decrease for feed conversion. From 8 to 14 days, the 0.70 methionine + cysteine: lysine ratio was the best for feed intake and body weight gain, and for uniformity, the 0.75 methionine + cysteine:lysine ratio was the most appropriate. For methionine + cysteine intake and feed conversion, an increasing and decreasing linear adjustment was observed, respectively. From 15 to 21 days, an increasing linear effect was observed for feed and methionine + cysteine intake and body weight gain; a decreasing linear effect was observed for feed conversion. The 0.81 ratio was the most efficient for feed conversion during all evaluated experimental periods. In conclusion, the 0.81 dietary methionine + cysteine:lysine ratio is the most appropriate for meat-type quails during the first 21 days of age.

Current experiment established different criteria to evaluate the requirements of digestible isoleucine for 22- and 42-day-old broilers by different regression models (quadratic, exponential and Linear Response Plateau) and, in the case of statistical significance, the comparison of means by Duncan’s test at 5% probability. A total of 1,920 Cobb 500 male broilers were used in an entirely randomized experimental design, with 6 treatments (6 digestible isoleucine levels: 0.6118; 0.6655; 0.7192; 0.7729; 0.8265 and 0.8802%) and 8 replications, with 40 broilers each. Data on performance and carcass characteristics were evaluated. Level 0.7192% of digestible isoleucine was considered standard. The digestible isoleucine level recommended for 22- and 42-day-old broilers is 0.7729%, corresponding to a digestible isoleucine:lysine ratio of 72%.

The objective of this study was to evaluate the effect of digestible lysine levels in diets with or without supplementation of industrial amino acids on performance, carcass characteristics and nitrogen excretion in broilers of 22 to 42 days of age. Birds were distributed in a completely randomized experimental design in a 4 × 2 factorial arrangement, with four digestible lysine levels (9.0, 10.0, 11.0 and 12.0 g/kg) and two methods to obtain the lysine levels (variation in the proportion of corn and soybean meal, without supplementation; or supplementation of industrial amino acids), eight replicates and 20 birds per replicate. There was an interaction effect on the performance characteristics and on the weights and yields of prime cuts. In both diets, feed conversion improved linearly as the lysine levels were increased. Feed intake; weight gain; carcass, thigh and drumstick weights; and boneless breast yield increased and abdominal fat reduced linearly as the lysine levels were increased in the unsupplemented diet. The lysine levels of the supplemented diets linearly reduced the yield of drumstick and quadratically reduced the yields of bone-in and boneless breast up to the estimated levels of 10.4 and 10.7 g/kg, respectively. Diets without supplementation increased the excretion and retention of nitrogen. The levels of 9.0 and 12.0 g/kg digestible lysine obtained with supplementation of industrial amino acids and without it, respectively, provide the best performance and yield of prime cuts in the birds. Diets in which the digestible lysine levels are obtained without supplementation provide better performance responses and carcass characteristics compared with supplemented diets.

A total of 1.500 male Cobb 500 broilers were used to determine the optimal digestible lysine level for 18 to 40-day-old broilers. The experimental period started when broilers were 18 days old and had an initial average weight of 737 ± 20 g. A completely randomized experimental design was applied, with five lysine levels, totaling five treatments with 10 replicates of 30 birds each. The experimental diets contained equal energy and protein levels, and 0.86, 0.95, 1.04, 1.13, and 1.22% digestible lysine. The following parameters were evaluated: average body weight at 40 days of age, daily weight gain, daily feed intake, feed conversion ratio, carcass yield and parts yield, and abdominal fat percentage. There was a quadratic effect (p

Current experiment established different criteria to evaluate the requirements of digestible valine for broilers from 22 and 42 days of age, by different regression models (quadratic, exponential and Linear Response Plateau) and, in the case of statistical significance, the comparison of means byDuncantest at 5% probability. A total of 1,920 Cobb 500 male broilers were used and distributed in an entirely randomized experimental design, with 6 treatments (6 digestible valine levels: 0.7192, 0.7729, 0.8265, 0.8802, 0.9339 and 0.9876%) and 8 replications, with 40 broilers each. Data on performance and carcass characteristics were evaluated. The level of 0.8265% digestible valine was considered standard. The inclusion of 0.816, 0.848 and 0.903% of digestible valine levels, corresponding to digestible valine:lysine ratios of approximately 76.00%, 79.00% and 84.12%, provided best feed intake, weight gain and feed conversion ratio, respectively for broiler from 22 to 42 days of age.

This study was conducted to evaluate the effects of digestible lysine levels in diets with and without supplementation of industrial amino acids on performance and fat deposition in the carcass of broilers in the starter phase. One thousand four hundred and forty chickens with initial weight of 168.1±5.0 g were distributed in a completely randomized experimental design, in a 5 × 2 factorial arrangement, composed of five digestible lysine levels (10.0, 11.0, 12.0, 13.0 and 14.0 g/kg) and two types of diet (diet with different proportions of corn and soybean meal and diet supplemented with industrial amino acids to obtain the digestible lysine levels), with eight replications and 18 birds per replication. There was interaction effect only on weight gain and fat deposition in the birds. The lysine levels reduced feed intake linearly in both diets, but caused a linear increase in lysine intake. The lysine levels quadratically affected weight gain and feed conversion, which improved up to the estimated levels of 13.0 and 12.8 g/kg lysine, respectively, when the corn:soybean meal ratio of the diet changed. In the diets supplemented with amino acids, the lysine levels increased weight gain and improved feed conversion linearly. Regardless of the type of diet, protein deposition increased linearly, whereas fat deposition reduced also linearly, as the lysine levels in the diets were increased. The levels of 13.0 and 14.0 g/kg digestible lysine provide, respectively, the best performance in birds fed a diet in which the proportion of corn and soybean meal varies and a diet supplemented with industrial amino acids, in the period from 8 to 21 days of age.

The objective of this experiment was to establish different criteria to evaluate the requirements of digestible tryptophan for broilers from 22 to 42 d of age, using different regression models (quadratic, exponential and Linear Response Plateau) and in case of statistical significance the comparison of means by Duncan test at 5% probability was also adopted. A total of 1,920 Cobb 500 male broilers were distributed in a completely randomized experimental design, with 6 treatments (6 digestible tryptophan levels: 0.1395, 0.1610, 0.1825, 0.2040, 0.2255 and 0.2470%) and 8 replications containing 40 broilers each. Performance and carcass characteristics were evaluated. The level of 0.2255% of digestible tryptophan numerically improves feed conversion, and the 0.1919% estimated by the quadratic equation significantly improves carcass yield.

The objective of the present study was to evaluate nutritional plans for boars. Four hundred animals of 67 to 135 days of age and initial weight of 27.75±1.61 kg were distributed in a randomized block design with seven nutritional plans for boars (9.0-8.0; 9.0-9.0; 10.0-9.0; 10.0-10.0; 11.0-10.0; 11.0-11.0 and 12.0-11.0 g/kg of digestible lysine from 67 to 107 days and from 108 to 135 days, respectively) with four repetitions and a control plan for barrows (11.0-10.0 g/kg of digestible lysine) with eight repetitions and ten animals each. Uncastrated male swine presented better feed conversion; however they showed a lower marbling degree in relation to barrows, regardless of the nutritional plan. The nutritional plan that corresponds to the sequence of 11.0-10.0 g/kg of digestible lysine from the 67 to the 107 days and from the 108 to the 135 days, respectively, meets the nutritional needs of boars.

The need for suitable diets in chickens, considering the ideal protein concept associated with phytase, is important in order to improve the productivity of birds. The aim of this study was to assess the need for the correction of amino acid levels in the diets of broilers, by using different combinations of crude protein (CP) supplemented with phytase. For performance, eight days old Cobb 875 broiler chicks, with initial body weights of 155 ± 1.4g were used. The birds were distributed in a completely randomised design with seven treatments (nutritional plans) and five replicates of 25 birds. For the metabolism trial, 300 birds were selected which were also distributed using the same design, but with five, four and three birds per experimental stage: 8-21 days, 22-35 days and 36- 42 days. The nutritional plans consisted of different combinations of CP in diets with reduced calcium and phosphorus, supplemented with phytase and amino acids. The reduction of amino acids in diets with reduced levels of CP resulted in an increased intake, feed conversion and abdominal fat level, and decreased the yield of thigh + drumstick. The inclusion of phytase reduced the excretion of calcium and phosphorus, but increased nitrogen excretion when the CP was not reduced. As a result, this study concluded that the reduction of amino acids to 3.5%, supplemented with phytase and prepared according to a nutritional plan does not improve the performance and carcass characteristics of broilers, although it may reduce the emission of polluting elements by excreta.A necessidade de dietas adequadas para frangos, considerando o conceito de proteína ideal associada à fitase, é importante para melhorar a produtividade das aves. Objetivou-se avaliar a necessidade de correção dos níveis de aminoácidos em rações para frangos de corte, formuladas em diferentes combinações de proteína bruta (PB) e suplementadas com fitase. Para o desempenho, foram utilizados 875 pintos de corte Cobb, com oito dias de idade e peso inicial de 155±1,4g. As aves foram distribuídas em delineamento inteiramente casualizado, com sete tratamentos (planos nutricionais) e cinco repetições de 25 aves cada. Para o ensaio de metabolismo, foram selecionadas 300 aves que foram também distribuídas no mesmo delineamento, porém com cinco, quatro e três aves por parcela experimental nas fases de 8 a 21, 22 a 35 e 36 a 42 dias. Os planos nutricionais consistiram em diferentes combinações de PB em rações com cálcio e fósforo reduzidos, suplementadas com fitase e aminoácidos. A redução de aminoácidos em dietas com teores reduzidos de PB aumentou o consumo, a conversão alimentar e a gordura abdominal e diminuiu o rendimento de coxa + sobrecoxa. A inclusão de fitase reduziu a excreção de cálcio e de fósforo, porém aumentou a de nitrogênio quando a PB não foi reduzida. Conclui-se que a redução de aminoácidos em 3,5% em rações para frangos de corte suplementadas com fitase e elaboradas segundo um plano nutricional não melhora o desempenho e as características de carcaça das aves, embora possa reduzir a emissão de elementos poluentes pelas excretas.

With the objective to evaluate levels of available phosphorus (aP) in diets with or without ractopamine, 112 gilts with high genetic potential for meat deposition with initial weigh of 94.0±2.28 kg were allotted in a completely randomized block design, in a 4 × 2 factorial arrangement (0.109, 0.209, 0.309, and 0.409% aP and 0 or 5 ppm of ractopamine), with eight treatments, seven replicates, and two gilts per experimental unit. There were no interactions between aP levels and ractopamine. The levels of available phosphorus influenced both daily weight gain and daily phosphorus intake, which increased linearly. Feed conversion improved in a quadratic way up to the estimated level of 0.330% aP maximum response. Daily weight gain increased and feed conversion improved by adding ractopamine to the diets. Serum alkaline phosphatase activity decreased linearly by increasing the levels of available phosphorus. Bone strength, ash, calcium, and phosphorus contents in the bones also increased quadratically with maximum responses at 0.320, 0.270, 0.277, and 0.295% aP, respectively. The available phosphorus level of 0.330%, corresponding to a daily intake of 8.67 g of aP is suitable for 94 to 125 kg gilts selected for meat deposition fed diets with or without ractopamine.

One performance experiment and another metabolism experiment were conducted simultaneously with broilers from 22 to 35 days of age, evaluating five diets in six replicates. The control diet, without phytase, contained 19% of crude protein (CP); 0.412% of available phosphorus (aP) and 0.824% of calcium (Ca). The other diets were supplemented with phytase and were formulated with 0.262% of aP and 0.524% of Ca, with the CP level ranging from 19 to 16%. In the performance assay, 750 birds were used, in which were evaluated the performance, the tibia ash content and yields of carcass, cuts, and abdominal fat at 35 days of age. The metabolism assay was conducted with 90 birds, evaluating the apparent metabolizable energy corrected by the nitrogen balance; the metabolizability coefficient of dry matter (MCDM) of the diets, and also the balance and retention of nitrogen (N) and phosphorus (P). Diets did not affect performance, tibia ash content and yields of carcass, breast and thigh + drumstick. However, birds fed diet containing 16% of CP showed greater abdominal fat. Diets containing 19% of CP had the smaller energetic value and MCDM. The retention of N and P was higher in birds fed diets formulated with reduced CP content and phytase. Therefore, when the broiler feed is supplemented with phytase and amino acids it is possible to reduce the CP, aP and Ca for up to 16; 0.262 and 0.524%, respectively.Um experimento de desempenho e outro de metabolismo foram conduzidos simultaneamente com frangos de corte de 22 a 35 dias de idade, avaliando-se cinco dietas em seis repetições. A dieta controle, sem fitase, continha 19% de proteína bruta (PB); 0,412% de fósforo disponível (Pdisp) e 0,824% de cálcio (Ca). As demais dietas foram suplementadas com fitase e formuladas com 0,262% de Pdisp e 0,524% de Ca, tendo o teor de PB variado em 19 até 16%. No ensaio de desempenho, 750 aves foram utilizadas, avaliando-se o desempenho, o teor de cinzas na tíbia e rendimentos de carcaça, cortes e gordura abdominal, aos 35 dias de idade. O ensaio de metabolismo foi realizado com 90 aves, determinando-se a energia metabolizável aparente, corrigida pelo balanço de nitrogênio e o coeficiente de metabolizabilidade da matéria seca (CMMS) das rações, e também o balanço e retenção de nitrogênio (N) e fósforo (P). As dietas não influenciaram o desempenho, teor de cinzas na tíbia e os rendimentos de carcaça, peito e coxa + sobrecoxa. Entretanto, as aves alimentadas com a ração contendo 16% de PB apresentaram maior teor de gordura abdominal. As rações com 19% de PB apresentaram menor valor energético e CMMS. A retenção de N e P foi maior nas aves que receberam as rações com reduzidos teores de PB e fitase. Portanto, quando a ração de frangos de corte é suplementada com fitase e aminoácidos é possível reduzir a PB, Pdip e Ca em até 16; 0,262 e 0,524%, respectivamente.

Um experimento foi realizado com o objetivo de estabelecer critérios de avaliação das exigências de treonina digestível para frangos de corte de 22 a 42 dias de idade utilizando-se diferentes modelos de regressão (quadrático, exponencial e de retas segmentadas ou Linear Response Plateau). Foram utilizados 1.920 frangos de corte machos com 22 dias de idade, distribuídos em delineamento inteiramente ao acaso, com seis tratamentos (seis níveis de treonina digestível: 0,5904; 0,6441; 0,6977; 0,7514; 0,8051 e 0,8588%) e oito repetições de 40 aves. Utilizou-se como padrão o nível de 0,6977% de treonina digestível. Foram avaliados dados de desempenho e características de carcaça. Com base nos dados, o nível de 0,7642% de treonina digestível, correspondente às relação treonina:lisina digestível de 71,19%, promoveu o melhor resultado de conversão alimentar de acordo com o modelo Linear Response Plateau.The objective of this experiment was to establish different criteria for evaluation of the requirements of digestible threonine for broilers from 22 to 42 d of age, using different regression models (quadratic, exponential, and Linear Response Plateau). A total of 1,920 22-day-old male Cobb broilers were distributed in randomized experimental design, with six treatments (six threonine levels: 0.5904, 0.6441, 0.6977, 0.7514, 0.8051, and 0.8588%) and 8 replications containing 40 broilers each one. The level of 0.6977% digestible threonine was used as standard. Data on performance and carcass characteristics were evaluated. Based on the data, the threonine level of 0.7642%, corresponding to the threonine:digestible lysine ratio of 71.19% had the best result for feed conversion, according to the Linear Response Plateau model.

The objective of this study was to evaluate the effects of increasing dietary digestible tryptophan levels on performance and carcass traits of growing pigs. Fifty crossbred castrated male pigs, with average initial and final body weight of 29.0 ± 1.20 kg and 60.4 ± 1.95 kg were allotted in a completely randomized block design, with five treatments (0.125, 0.133, 0.141, 0.149, and 0.157% of digestible tryptophan, corresponding to digestible tryptophan:lysine relations of 15.0, 16.0, 17.0, 18.0, and 19.0%, respectively) and five replicates, with two pigs per experimental unit, which was represented by the pen. Experimental diets and water were supplied ad libitum throughout the experimental period. Averages of minimum and maximum temperatures inside the facility were of 24.3 ± 0.87 ºC and 28.0 ± 1.82 ºC, respectively. Feed intake and body weight gain increased linearly with increasing dietary tryptophan levels. However, there was no effect of digestible tryptophan on feed conversion or protein deposition of pigs. The highest tryptophan level evaluated (0,157%), corresponding to a digestible tryptophan:lysine relation of 19.0%, provided the greatest weight gain of 30 to 60 kg castrated male pigs.

In order to evaluate the effects of increasing dietary tryptophan levels on performance and carcass characteristics of growing pigs, a total of 60 crossbred castrated male pigs, with average initial and final body weights of 15.50 ± 1.15 and 30.60 ± 1.35 kg were used. Pigs were allotted in a completely randomized block design, with five dietary treatments (0.149, 0.158, 0.168, 0.177, and 0.187% digestible tryptophan, corresponding to digestible tryptophan:lysine relations of 16.0, 17.0, 18.0, 19.0, and 20.0%), six replicates, and two animals per experimental unit, which was represented by the pen. Experimental diets and water were supplied ad libitum throughout the experimental period. The average maximum and minimum temperatures inside the rooms were of 21.5 ± 1.12°C and 26.4 ± 1.91°C, respectively. There was no effect of digestible tryptophan on daily feed intake or protein deposition of pigs. Body weight gain increased quadratically with increasing digestible tryptophan in the diets up to 0.175% maximum response. Increasing digestible tryptophan in the diets linearly improved feed conversion of pigs. The greatest weight gain of 15 to 30 kg castrated male pigs is obtained at 0.175% digestible tryptophan, corresponding to a digestible tryptophan:lysine relation of 18.82% and an estimated daily intake of 2.32 grams of digestible tryptophan.

O experimento foi realizado para avaliar o efeito da redução do nível de proteína bruta (PB) da ração formulada de acordo com o conceito de proteína ideal e suplementada com aminoácidos industriais, sobre o desempenho e rendimento de cortes de frangos de corte machos de 22 a 42 dias de idade mantidos em ambiente termoneutro. Foram utilizados 280 frangos de corte machos "Cobb" com peso inicial de 856 ± 6,48 g, distribuídos em delineamento experimental inteiramente casualizado, com cinco tratamentos (21,6; 20,6; 19,6; 18,6 e 17,6% de PB), oito repetições de sete aves por unidade experimental. A temperatura no interior da sala foi mantida em 21,6 ± 0,7ºC, a umidade relativa em 74 ± 4,0% e a temperatura de globo negro em 22,5 ± 0,7ºC. O índice de temperatura de globo e umidade (ITGU) calculado para o período foi de 70 ± 0,9. Não houve efeito da redução dos níveis de PB sobre o ganho de peso e o consumo de ração, entretanto, a conversão alimentar foi influenciada pela redução dos níveis de PB sendo que as aves alimentadas com a ração que continha 22,0% de PB apresentaram o melhor resultado. A redução dos níveis de PB não influenciou o peso absoluto de carcaça e os pesos absoluto e relativo de peito, coxa e sobrecoxa. A redução do nível de PB da ração, de 21,6 para 17,6%, e formulada de acordo com o conceito de proteína ideal piora a conversão alimentar dos frangos de corte mantidos em ambiente termoneutro, não influenciando as demais variáveis estudadas.The objective of this experiment was to evaluate the effects of dietary crude protein (CP) level reduction of ration formulated according to ideal protein concept and with supplementation of industrial amino acids on the performance and yield of noble cuts of broilers from 22 to 42 days of age kept under thermoneutral conditions. It was used 280 "Cobb" male broilers with initial weight of 856 ± 6.48 g, distributed in a completely randomized experimental design, with five treatments (21.6; 20.6; 19.6; 18.6 and 17.6% CP) and eight replications with seven birds per experimental unit. Temperatures inside the rooms were maintained at 21.6 ± 0.7°C, relative humidity at 74.4.0% and black globe temperature of 22.5 ± 0.7°C. Black globe temperature and humidity index (BGHTI) calculated for a period of 70 ± 0.9. There was no effect of the reduction of the levels of CP on weight gain and on feed intake but feed conversion was influenced by the reduction of the CP levels, and the birds fed diet with 22.0% of CP presented a better result. The reduction of the levels of CP did not influence absolute carcass weight and absolute and relative weights of breast, thigh and drumstick. Reduction of the level of dietary CP from 21.6 to 17.6% and formulated according to ideal protein concept worsens feed conversion of broilers kept in thermoneutral environment, not influencing the other studied variables.

The objective of this work was to evaluate the relationships of methionine plus cystine with lysine for Japanese quails in the laying phase. Thus, it was used 480 birds at initial age of 65 days, distributed in randomized block design with 6 treatments, 10 replicates and 8 birds per experimental unit. The treatments consisted of basal diet deficient in methionine plus cystine (0.65%), with 19.6% of crude protein and 2800 kcal of metabolizable energy/kg of ration, supplemented with six levels of DL-methionine 98% (0.116; 0.167; 0.218; 0.269; 0.320 and 0.371%), corresponding to methionine plus cystine with lysine ratio of 0.65, 0.70, 0.75, 0.80, 0.85 and 0.90, and the digestible lysine set at a suboptimal level of 1.00. The parameters studied were: feed intake, egg production per hen day, egg production per housed hen, commercial egg production, egg weight, egg mass, feed conversion per egg mass, feed conversion per dozen eggs, viability of birds, weight of the egg components (yolk, albumen and shell), percentage of components of eggs, diameter and height of the eggs and specific gravity. It was observed an increasing linear effect for feed intake, egg diameter, shell weight and percentage of yolk. For eggshell percentage, it was observed a decreasing linear effect. For the weight of the eggs, the best adjustment was obtained by using the Linear Response Plateau model. A quadratic effect was observed for egg mass, feed conversion per egg mass, egg production per hen day, egg production per housed hen, yolk weight, albumen weight and height of the eggs. The relationship of methionine plus cystine with lysine of 0.84 which corresponds to the consumption of 221.0 mg/bird/day of methionine + cystine provides better performance and satisfactory quality of Japanese quail eggs.Com o objetivo de avaliar o efeito de relações entre metionina mais cistina com lisina para codornas japonesas na fase de postura, 480 aves com idade inicial de 65 dias foram distribuídas em delineamento em blocos casualisados com 6 tratamentos, 10 repetições e 8 aves por unidade experimental. Os tratamentos consistiram de ração basal deficiente em metionina mais cistina (0,65%), com 19,6% de proteína bruta e 2800 kcal de energia metabolizável/kg de ração, suplementada com seis níveis de DL-metionina 98% (0,116; 0,167; 0,218; 0,269; 0,320 e 0,371%), correspondendo à relação metionina mais cistina com lisina de 0,65; 0,70; 0,75; 0,80; 0,85 e 0,90, sendo a lisina digestível fixada no nível sub ótimo de 1,00. Os parâmetros estudados foram: consumo de ração, produção de ovos por ave dia, produção de ovos por ave alojada, produção de ovos comercializáveis, peso do ovo, massa de ovos, conversão alimentar por massa de ovos, conversão alimentar por dúzia de ovos, viabilidade das aves, peso dos componentes dos ovos (gema, albúmen e casca), porcentagem dos componentes dos ovos, diâmetro e altura dos ovos e gravidade específica. Observou-se efeito linear crescente para consumo de ração, diâmetro dos ovos, peso da casca e porcentagem de gema. Para porcentagem de casca foi observado efeito linear decrescente. Para o peso dos ovos o melhor ajuste foi obtido com a utilização do modelo Linear Response Plateau. Foi verificado efeito quadrático para a massa de ovos, conversão alimentar por massa de ovos, produção de ovos por ave dia, produção de ovos por ave alojada, peso da gema, peso do albúmen e altura dos ovos. A relação metionina mais cistina com lisina de 0,84 que corresponde ao consumo de 221,0 mg/ave/dia de metionina + cistina proporciona melhor desempenho e satisfatória qualidade de ovo de codornas japonesas.

Este estudo foi realizado com o objetivo de determinar a exigência de lisina digestível para suínos machos não castrados de alto potencial genético em fase de crescimento. Foram utilizados 320 machos não castrados e 80 castrados, com peso inicial de 27,75±1,61kg, distribuídos em delineamento experimental em blocos ao acaso composto por cinco tratamentos (0,90; 1,00; 1,10 e 1,20% de lisina digestível para não castrados e 1,10% de lisina digestível para castrados), oito repetições, com 10 animais cada. O aumento da concentração de lisina na dieta aumentou de forma linear (P0,05) o consumo de ração diário dos machos não castrados. Suínos castrados apresentaram maior (PThis study was conducted to determine the digestible lysine requirement for non castrated pigs of high genetic potential in growth phase. It was used 320 not castrated and 80 castrated males, with initial weight of 27.75±1.61kg, distributed in a randomized block design consisting of five treatments (0.90, 1.00, 1.10 and 1.20% digestible lysine for not castrated and 1.10% digestible lysine for castrated males), eight replicates with ten animals each. The increase of lysine concentration in the diet increased linearly (P0.05) daily feed intake of not castrated males. Castrated males had higher (P

The optimal dietary supply of amino acids to tilapia has been studied for many years. Nevertheless, a general agreement on the amino acid requirement for tilapias has not been established. In order to optimize efficiency and reduce surplus nitrogen, values of digestibility of each amino acid of feed must be considered. Due to variations in the amino acid requirement due to new tilapia strains introduction, continuous research on amino acid requirements is necessary to elaborate economical and environmental sustainability diets, also improving fish growth, efficiency and fillet yield. The concept of ideal protein in tilapia diets was introduced more than ten years ago, and new researches have shown the importance of protein and amino acids on fish performance and health, when tilapias are submitted to constant challenging from internal and external factors.O suprimento adequado de aminoácidos dietéticos para tilápias tem sido estudado por muitos anos. No entanto, ainda não foi estabelecida uma concordância geral sobre a exigência de aminoácidos para tilápias. A fim de otimizar a eficiência e reduzir o excesso de nitrogênio, as dietas devem ser elaboradas considerando-se os valores de digestibilidade de cada aminoácido dos alimentos. Devido às variações nas exigências de aminoácidos pela introdução novas linhagens de tilápias, a investigação contínua sobre exigências de aminoácidos é necessária para a elaboração de dietas ambiental e economicamente sustentáveis que melhorem também o crescimento dos peixes, a eficiência alimentar e o rendimento de filé. O conceito de proteína ideal em dietas de tilápias foi introduzido há mais de dez anos, e novas pesquisas têm mostrado a importância da proteína e aminoácidos no desempenho e na saúde dos peixes submetidos a desafios frente a fatores internos e externos.

Este estudo foi realizado para avaliar os efeitos da redução do nível de proteína bruta (PB) da ração com suplementação de aminoácidos sintéticos sobre o desempenho e o rendimento de carcaça de frangos de corte de 22 a 42 dias de idade mantidos sob estresse por calor. Utilizaram-se 280 frangos de corte machos da linhagem Cobb 500 com peso inicial de 856 ± 7,41 g, distribuídos em delineamentointeiramente casualizado, com cinco níveis de PB (21,6; 20,6; 19,6; 18,6 ou 17,6%), oito repetições e sete aves por unidade experimental. A temperatura no interior da sala foi mantida em 32,2 ± 0,6ºC, com umidade relativa de 66 ± 3,2% e temperatura de globo negro de 33,0 ± 0,7ºC. O índice de temperatura de globo e umidade (ITGU) calculado no período foi de 83 ± 0,9. Não houve efeito dos níveis de PB da ração sobre o ganho de peso, o consumo de ração e a conversão alimentar das aves. A redução dos níveis de PB da ração influenciou os pesos absolutos da carcaça e do peito, que foram maiores no nível de 19,6% de PB em relação ao de 21,6%. Entretanto, não houve efeito da redução dos níveis de PB sobre os pesos absolutos de coxa e de sobrecoxa nem sobre os rendimentos de peito, coxa e sobrecoxa. O nível de proteína bruta da ração, formulada utilizando-se o conceito de proteína ideal, pode ser reduzido de 21,6 até 17,6%, pois essa redução não prejudica as características de desempenho, nem o peso absoluto e o rendimento de cortes nobres de frangos de corte submetidos a estresse por calor.This study was performed to evaluate the effects of reduction of dietary crude protein level with supplementation of industrial amino acids on the performance and carcass yield of broilers between 22 to 42 days of age, under heat stress. It was used 280 Cobb broilers with initial weight of 856 ± 7.41 g, distributed in a complete randomized experimental design, with five crude protein levels (21.6; 20.6; 19.6; 18.6 and 17.6%), eight repetitions and seven broilers per experimental unit. The temperature inside the rooms was kept at 32.2 ± 0.6ºC, the relative humidity at 66 ± 3.2% and black globe temperature at 33.0 ± 0.7°C. The black globe-humidity index calculated for the period was 83 ± 0.9. There was no effect of crude protein levels on weight gain, feed intake and feed conversion of the birds. The reduction of dietary crude protein levels influenced the absolute weight of carcass and breast, and the level of 19.6% proportioned higher carcass and breast weights of the broilers compared to the level of 21.6% of crude protein. However, there was no effect of the reduction of levels of crude protein on absolute values of thigh and drumstick and also on breast, thigh and drumstick yields. The dietary crude protein level, formulated by using the ideal protein concept, can be reduced from 21.6 to 17.6% not negatively affecting the performance, absolute weight and noble cut yield of broilers under heat stress.

Foram realizados dois experimentos com o objetivo de estudar, no primeiro, o efeito de diferentes relações treonina:lisina digestíveis (TL) sobre a utilização do nitrogênio (N) em suínos na fase inicial, dos 15 aos 30kg de peso, e, no segundo, o efeito dessas relações sobre o desempenho dos animais. No primeiro experimento, foi avaliado o balanço de nitrogênio, utilizando-se 20 suínos machos castrados, híbridos comerciais de média a alta deposição de tecido magro, com peso inicial de 23,0±4,1kg. Os suínos foram distribuídos em um delineamento experimental inteiramente ao acaso. As rações continham baixo nível de proteína (17,3%), e as relações TL foram: 0,574; 0,624; 0,673; 0,722 e 0,772. A proteína bruta total excretada (PBTE), a proteína bruta retida (PBR) e a utilização líquida da proteína (ULP) apresentaram efeito quadrático, e os melhores valores nas relações foram 0,648; 0,648 e 0,649, respectivamente. A melhor relação TL foi 0,649 (média da PBR e ULP). No segundo experimento, foi avaliado o efeito dessa relação sobre o desempenho dos suínos na fase inicial. Foram utilizados 60 animais (30 machos castrados e 30 fêmeas) com peso inicial de 15,5±1,5kg, de características semelhantes ao primeiro experimento, distribuídos em um delineamento experimental inteiramente ao acaso, em esquema fatorial 5x2 (cinco relações TL e dois sexos, com dois animais por baia). Foram utilizadas seis baias por tratamento, com três de machos e três de fêmeas cada. Não houve efeito da relação TL sobre o consumo diário de ração e o ganho diário de peso, e houve efeito quadrático, com ponto de mínimo, sobre a conversão alimentar com a relação TL de 0,691. Os resultados indicam que a relação TL de 0,649 maximiza a retenção de nitrogênio e a relação TL de 0,691 permite melhor conversão alimentar para leitões dos 15 aos 30kg de peso.Two experiments were carried out to evaluate the effect of digestible threonine:lysine ratio (TL) on nitrogen (N) use and on growth performance of starting pigs (15-30kg). Experiment I evaluated nitrogen balance using twenty high-lean commercial crossbred barrows, with initial weight of 23.0±4.1kg. Pigs were allotted in a randomized design. Diets were formulated with low crude protein levels (17.3 %) and TL ratios were: 0.574; 0.624; 0.673; 0.722; and 0.772. Excreted crude protein (CPEX), crude protein retention (CPR), and net protein utilization (NPU) showed quadratic effect and the best TL ratio values were achieved at 0.648, 0.648, and 0.649, respectively. The best TL ratio was 0.649 (CPR and NPU means). Experiment II was carried out to examine the same TL ratio effects on the performance of pigs. Sixty pigs (30 barrows and 30 gilts), averaging 15.5±1.5kg, used in experiment II, were allotted in a randomized design, following a factorial scheme (5x2), being five TL ratios (same as in experiment I) and two genders. Six pens per treatment (three barrows and three gilts) were used. There was no effect of TL ratio on daily feed intake and on average weight gain. However, the feed:gain ratio showed a quadratic effect and the best TL ratio was achieved at 0.691. The results pointed out that the 0.649 TL ratio maximized nitrogen retention and the 0.694 TL ratio allowed a better feed conversion for starting pigs averaging 15 to 30kg of b.w.

Dois experimentos foram conduzidos para estudar o efeito de cinco relações treonina:lisina digestíveis (TL) sobre o balanço de nitrogênio em suínos em crescimento e de cinco níveis de energia líquida (EL) sobre o desempenho de suínos em crescimento-terminação. No primeiro experimento, foram utilizados 15 suínos machos castrados com peso inicial de 37,0 ± 2,6 kg, híbridos comerciais de média a alta deposição de tecido magro, distribuídos em delineamento inteiramente casualizado, com cinco tratamentos (relações treonina:lisina digestíveis de 0,574; 0,624; 0,673; 0,722 e 0,772 em rações formuladas com baixo nível de proteína, 14,7%) e três repetições. A TL influenciou de forma quadrática a proteína bruta absorvida (PBA) e o nitrogênio da uréia plasmática (NUP), os quais apresentaram melhores resultados com a TL de 0,658 (média do PBA e NUP). No segundo experimento, foram estudados cinco níveis de EL em rações com a relação TL de 0,658. Utilizaram-se 40 suínos (20 machos castrados e 20 fêmeas) com 30,2 ± 1,3 kg, de características semelhantes às dos utilizados no experimento para balanço de nitrogênio, distribuídos em delineamento inteiramente casualizado, em esquema fatorial 5 × 2, composto de cinco níveis de energia líquida (2.410; 2.450; 2.490; 2.530 ou 2.570 kcal/kg) e dois sexos, com um animal por baia. Na fase de terminação e no período total, o aumento nos níveis de EL ocasionou redução do consumo diário de ração (CDR), melhora da conversão alimentar (CA) e acréscimo na deposição de gordura. A relação TL de 0,658 melhora a retenção de nitrogênio e níveis crescentes de energia líquida diminuem o CDR e melhoram a CA, mas podem aumentar a deposição de gordura em suínos.Two experiments were carried out to evaluate the effect of five digestible threonine:lysine ratios (TL) on the nitrogen balance of growing pigs and five levels of net energy (NE) on growing-finishing pigs performance. In the first experiment, 15 high-lean commercial crossbred barrows, with initial weight of 37.0 ± 2.6 kg, were allotted to a completely randomized design, with five diets (digestible threonine:lysine ratio of 0.574, 0.624, 0.673, 0.722, and 0.772, in low protein diets, 14.7%) and three replications. Absorbed crude protein (ACP) and plasma urea nitrogen (PUN) showed a quadratic effect and the best threonine:digestible lysine ratio was 0.658 (mean of ACP and PUN). In the second experiment, five EL dietary levels were evaluated with digestible threonine:lysine ratio of 0.658. Forty pigs (20 barrows and 20 gilts) with 30.2 ± 1.3 kg were allotted to a completely randomized design, as a 5 × 2 factorial arrangement, composed of five levels of NE (2.410, 2.450, 2.490, 2.530, or 2.570 Mcal/kg) and two sexes, with one animal per cage. In the finishing phase and total period, increasing NE levels reduced feed intake (FI), improved feed:gain ratio (FGR) and increased fat deposition. Digestible threonine:lysine ratio of 0.658 improves nitrogen retention and the increasing net energy levels decrease FI and improve FGR, but may increase fat deposition in pigs.

Objetivou-se estimar as exigências nutricionais de lisina digestível de frangos de corte machos de 1 a 42 dias de idade. Utilizaram-se 1.950 pintos de corte Cobb (750 para a fase pré-inicial, 600 para a fase inicial e 600 para a fase de crescimento) com pesos iniciais de 45,1 ± 0,6; 160,5 ± 2,4 e 746,3 ± 10,7 g, respectivamente. As aves foram distribuídas em delineamento inteiramente casualizado, com seis tratamentos, cinco repetições de 25 pintos por unidade experimental na fase pré-inicial e 20 nas fases inicial e de crescimento. Como tratamentos, uma ração basal deficiente em lisina foi suplementada com L-lisina.HCL de modo a conter seis níveis de lisina digestível: 1,10; 1,16; 1,22; 1,28; 1,34 e 1,40% na fase pré-inicial; 0,92; 0,98; 1,04; 1,10; 1,16 e 1,22% na fase inicial e 0,815; 0,875; 0,935; 0,995; 1,055 e 1,115% na fase de crescimento, respectivamente. As variáveis avaliadas foram: consumo de ração (CR), ganho de peso (GP), conversão alimentar (CA), peso e rendimento de carcaça e de cortes nobres, peso absoluto e relativo das vísceras comestíveis e gordura abdominal. Nas três fases, verificaram-se efeito linear dos níveis de lisina digestível sobre o consumo de ração e efeito quadrático sobre o ganho de peso e a conversão alimentar. Não houve efeito significativo dos níveis de lisina sobre os pesos absolutos de carcaça, coração e gordura abdominal, os rendimentos de carcaça, peito, coxa e sobrecoxa e os pesos relativos de coração, fígado, moela e gordura abdominal. No entanto, verificou-se efeito quadrático sobre os pesos absolutos de peito, coxa, sobrecoxa e fígado. Recomenda-se para frangos de corte machos 1,286; 1,057 e 1,009% de lisina digestível para as fases pré-inicial, inicial e crescimento, respectivamente.This study was carried out with the objective of estimating the nutritional requirements of digestible lysine for broiler from 1 to 42 days old. A total of 1,950 male Cobb chicks were used (750, 600 and 600 in pre-initial, initial and growing phase, respectively) with initial weight of 45.1 ± 0.6, 160.5 ± 2.4 g and 746.3 ± 10.7 g, respectively. The birds were distributed in a completely randomized design, using six treatments and five repetitions, with 25, 20, and 20 chicks per experimental unit in the pre-initial, initial and growing phases, respectively. The treatments consisted of a lysine-deficient basal diet that was supplement with L-lysine.HCl in order to contain six digestible lysine levels (1.10, 1.16, 1.22, 1.28, 1.34 and 1.40%; 0.92, 0.98, 1.04, 1.10, 1.16 and 1.22% and 0.815, 0.875, 0.935, 0.995, 1.055 and 1.115%, for the pre-initial, initial and growing phases, respectively). The characteristics evaluated were: feed intake, weight gain and feed conversion, weight and carcass yield and prime cuts, relative and absolute weight of edible viscera and abdominal fat. In all phases, there was a linear effect of digestible lysine levels on feed intake and quadratic effect on weight gain feed conversion. There was no effect of the digestible lysine levels on the absolute weights of carcass, heart, and abdominal fat, carcass yields, breast, thigh and drumsticks, and on the relative weights of the heart, liver, gizzard and abdominal fat. However, there was a quadratic effect on the absolute weights of the breast, drumstick, thigh and liver. Digestible lysine levels recommended for male broilers are 1.286; 1,057 and 0,998% in the pre-initial, initial and growing phases, respectively.

Foi realizado um estudo para avaliar níveis de proteína bruta (PB) e suplementação de aminoácidos em rações para leitoas mantidas em ambiente de alta temperatura (temperatura do ar de 30ºC, umidade relativa de 66,1% e ITGU calculado de 79,7) na fase de crescimento. Foram utilizadas 50 leitoas mestiças (Landrace ´ Large White) com peso inicial médio de 30,2 kg, em delineamento experimental inteiramente ao acaso, com cinco tratamentos e cinco repetições de dois animais por unidade experimental. Os tratamentos consistiram de cinco níveis de PB (19, 18, 17, 16 e 15%) na ração e da suplementação com lisina, metionina, triptofano, treonina e valina para manutenção da mesma qualidade protéica da ração. As rações experimentais foram fornecidas à vontade até o final do experimento, quando os animais atingiram o peso médio de 60,1 kg. Não se observou efeito do nível de proteína bruta da ração sobre o desempenho dos animais (consumo de ração, ganho de peso e conversão alimentar). A deposição de proteína na carcaça também não foi influenciada pela redução do nível de PB da ração, pois os animais alimentados com a ração com 18% de PB apresentaram os maiores valores. Os níveis de PB na ração não influenciaram os pesos absoluto e relativo dos órgãos dos animais. O nível de PB da ração pode ser reduzido em até 4% (de 19 para 15% de PB), pois essa redução não altera o desempenho de leitoas mantidas em ambiente de alta temperatura na fase dos 30 aos 60 kg, desde que as rações sejam devidamente suplementadas com todos os aminoácidos essenciais.An experiment was conduced to evaluate crude protein (CP) levels and amino acid supplementation for gilts from 30 to 60 kg maintained in a high environmental temperature (air temperature of 30ºC; relative humidity of 66.1% and BGHI of 79.7). Fifty crossbreed gilts (Landrace X Large White) with an average initial weight of 30.2 kg were allotted to a randomized experimental design with five treatments and five replications and two animals per experimental unity. The treatment consisted of five levels o CP (19, 18, 17, 16, and 15%) in the ration and of the supplementation with lysine, methionine, tryptophan, threonine and valine to maintain the same protein quality of the ration. The experimental diets were given ad libitum until the end of the experiment when the animals reached the average weight of 60.1 kg. No effect of dietary level of crude protein was observed on pig performance (feed intake, weight gain and feed:gain ratio). Neither carcass protein deposition was influenced by reduction of dietary of dietary level of CP. Animals fed 18% CP showed the best carcass protein deposition. The protein levels did not influence the absolute and relative weights of the pig organs. Dietary CP level can be reduced by 4% (from 19 to 15% of CP) without any effect on performance of gilts from 30 to 60 kg maintained in a high environmental temperature since that the rations be adequately supplemented with all essential limiting amino acids.

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This trial was conducted to evaluate the utilization of low-protein diets formulated based on the ideal protein concept for broiler chickens from 7 to 21 days of age reared at different environmental temperatures. Nine hundred male Cobb-500® chickens were used. At day seven chicks were distributed according to a completely randomized design in a 3 x 3 factorial with four replications of 25 birds each. It was used three crude protein levels in the diet (21.5; 20.0 and 18.5%) and three environmental temperatures (low, thermoneutral and high). The performance, carcass characteristics (yield and chemical composition), and nitrogen ingestion and excretion were assessed. There was no significant interaction among the factors for the evaluated variables. Environmental temperatures affected differently chicken performance. High environmental temperature resulted in lower weight gain and higher wing fat percentage, whereas cold temperature resulted in higher feed conversion. On the other hand, low-protein diets decreased weight gain, breast yield, nitrogen excretion and influenced breast and wings chemical composition. Birds reared at high environmental temperature showed lower nitrogen intake and excretion. The results showed that the decrease in protein levels from 7 to 21 days of age contributed to lower nitrogen excretion in broiler chickens, but impaired performance and carcass characteristics independent of rearing temperature.

Este estudo foi realizado para se avaliar a redução dos níveis de proteína em dietas para tilápia-do-nilo (5 a 125 g), adotando-se o conceito de proteína ideal. Cento e sessenta peixes (4,40 ± 0,9 g) foram distribuídos em um delineamento inteiramente casualizado, com quatro tratamentos [25,5; 27; 28,5 e 30% (controle) de proteína digestível], três repetições e dez animais por unidade experimental. Os aminoácidos sintéticos foram suplementados para se manter as proporções de aminoácidos de acordo com o conceito de proteína ideal. Os aminoácidos lisina, metionina e treonina foram suplementados para se obter os níveis de aminoácidos da dieta controle. As dietas foram fornecidas à vontade, durante 83 dias. Não foram observados efeitos dos níveis de proteína sobre o ganho de peso, a conversão alimentar, o índice hepatossomático, o peso da gordura visceral, a taxa de sobrevivência, os níveis de proteína na carcaça e o diâmetro da fibra intermediária. O aumento nos níveis de proteína resultou em redução linear na taxa de eficiência protéica e de retenção do nitrogênio e aumento linear na excreção de nitrogênio. Foi observado efeito quadrático sobre o rendimento de carcaça e o teor de extrato etéreo na carcaça; os melhores valores foram obtidos com 28,40 e 27,31% de proteína na dieta, respectivamente. Concluiu-se que é possível a redução do nível de proteína de 30 para 27,5% em dietas para juvenis de tilápia do Nilo, sem efeitos negativos sobre o crescimento, rendimento de carcaça e a composição química dos filés. No entanto, a redução do nível de proteína de 30 para 25,5% acarreta redução no diâmetro das fibras musculares vermelha e branca.This trial was carried out to evaluate the effects of ideal protein concept on reduction of dietary protein content for Nile tilapia (5 to 125 g). A hundred and sixty juvenile fishes (4.40 ± 0.9 g) were assigned to a randomized experimental design with four treatments [25.5, 27, 28.5 and 30% (control) of digestible protein], three replicates and ten fish by experimental unit. Crystalline amino acids were added to maintain amino acid levels according to the ideal protein concept. The amino acids (lysine, methionine and threonine) were supplemented at levels to simulate amino acid levels of the reference diet. Diets were fed ad libitum during 83 days. No significant effects of protein levels on weight gain, feed:gain ratio, hepatossomatic, visceral fat, survival rate, carcass protein and intermediate fiber diameter were observed. The protein efficiency rate and nitrogen retention decreased linearly and excreted nitrogen increased linearly as the dietary digestible protein levels increased. Quadratic effect for carcass yield and carcass ether extract content was observed, with the best values at 28.40 and 27.31% dietary protein, respectively. It was concluded that is possible to reduce the dietary protein from 30 to 27.5% for juvenile Nile tilapia, with no change on growth, carcass yield and fillet chemical composition. However, the reduction of white and red fibers diameter was observed when dietary protein decreased from 30 to 27.5%.

Foi conduzido um experimento para determinar o nível de proteína bruta (PB) das rações com suplementação de aminoácidos para leitoas mestiças (Landrace x Large White) mantidas em ambiente de conforto térmico. Os animais (peso médio inicial de 30,1 kg) foram distribuídos em delineamento experimental inteiramente ao acaso, com cinco tratamentos (19, 18, 17, 16 e 15% de PB com suplementação de lisina metionina, triptofano, treonina e valina, para se manter a mesma qualidade proteica), cinco repetições e dois animais por unidade experimental. As rações experimentais foram fornecidas à vontade até o final do experimento, quando os animais atingiram peso médio de 60,3 kg. O nível de PB da ração influenciou o ganho de peso diário e a conversão alimentar, mas não influiu no consumo de ração diário. A deposição de proteína não variou entre os níveis de 19 e 16% de PB da ração, enquanto os animais que consumiram a ração com menor nível de PB (15%) apresentaram o menor valor. Os tratamentos não influenciaram os pesos absoluto e relativo dos órgãos avaliados. Concluiu-se que o nível de PB da ração para leitoas dos 30 aos 60 kg mantidas em ambiente de conforto térmico pode ser reduzido de 19 para 15%, sem prejudicar o desempenho, desde que as rações sejam devidamente suplementada com os aminoácidos essenciais limitantes.An experiment was conduced to determine the crude protein (CP) level in diets with amino acids supplementation for gilts maintained in a thermal comfort environment. Fifty crossbreed crossbred gilts (Landrace x Large White) with initial average weight of 30.1 kg were allotted to a completely randomized experimental design, with five treatments (19, 18, 17, 16 and 15% of CP with supplementation of lysine, methionine, tryptophan, threonine and valine to maintain the same protein quality) five replicates and two animals per experimental unit. The experimental rations were fed ad libitum until the end of the experiment, when the animals reached the average weight of 60.3 kg. The CP level of the ration influenced the daily weight gain and the feed:gain ratio however the treatments did not influence the daily feed intake. The protein deposition (PD) did not change from 19 to 16% of CP of the diet. However the animals that fed diet with smaller level showed the lowest value of PD. The treatments did not influence the absolute and relative weights of all evaluated organs. It was concluded that the crude protein level, for gilts from 30 to 60 kg, maintained in thermal comfort environment can be reduced from 19 to 15% with no negative effect on performance since rations are supplemented with limiting essential amino acids

O trabalho foi conduzido no Setor de Avicultura do Departamento de Zootecnia da Universidade Federal de Santa Maria com o objetivo de verificar as respostas de desempenho de frangos de corte, criados com sexos separados, alimentados pelo conceito tradicional (Proteína Bruta - PB) em comparação a dietas formuladas pelo critério de Proteína Ideal (PI), num período de 1 a 42 dias de idade. A análise econômica comparativa entre os dois métodos de alimentação também foi realizada. Foram utilizados 960 pintos de corte de um dia de idade (480 machos, 480 fêmeas) da linhagem ROSS. As dietas experimentais baseadas no conceito de PB foram formuladas segundo as recomendações do NRC (1994) e as dietas formuladas pelo conceito de PI foram adaptadas de HAN & BAKER (1994). O delineamento experimental foi o inteiramente casualizado, constituindo 4 tratamentos com 12 repetições de 20 aves cada. Foram estudados os parâmetros: consumo alimentar, ganho de peso e peso corporal, ganho médio diário, conversão alimentar e índice de eficiência nutricional. Os resultados obtidos indicaram que os parâmetros estudados foram mais influenciados na fase inicial. As dietas formuladas pelo conceito de PI, baseada no conteúdo de aminoácidos digestíveis (AAD), influenciaram positivamente os parâmetros estudados, proporcionando significativos melhores ganhos de peso e eficiência alimentar, tanto para os machos quanto para as fêmeas nas fases inicial e total, sendo similares nas demais fases. As aves alimentadas com AAD apresentaram uma maior lucratividade nas fases inicial e crescimento. Esses dados permitem concluir que dietas à base de milho e farelo de soja, formuladas para atender às exigências de AAD, proporcionam melhores desempenhos biológico e econômico, em relação àquelas formuladas à base de PB, do primeiro até os 35 dias de idade. A fase final mostrou o contrário, sendo o conceito de PB mais econômico do que a Pl.The study was carried out at the Poultry Section of the Departament of Animal Science at Federal University of Santa Maria, in order to evaluate the performance of broilers grown sexed and fed with diets formulated by the traditional concept (Crude Protein - CP), which is based on total amimo acids (TAA) and fed with the approach of Ideal Protein (IP), which is based on digestible amino acids (DAA), in the period from 1 to 42 days of age. A comparative economic analysis among the two feeding methods was also accomplished. There were 960 chicks (Ross) at the age of 1 day, being 480 males and 480 females. The diet based on the concept of CP was formulated according to the recommendation of NRC (1994) and the diet formulated by the concept of IP was adapted from Han and Baker (1994). The completely randomized experimental design consisted of 4 treatments with 12 replications of 20 chicks each. The feed intake, phase gain, body weight, daily gain, feed conversion and the nutritional efficieny index were evaluated. The results indicated that the parameters studied were more efficient in the initial phase. The diet formulated by the Ideal Protein concept, based on the content of DAA, influenced all parameters studied positively, providing significantly better gain weight and feed efficiency in both male and female chicks in the initial and final phases, being similar in the growing phase. The chicks fed with DAA showed greater profits in the initial phase and during the growth phase. These data allowed the conclusion that diets containing corn and soybean meal as base for the formulated feed provides better biological and economic performance of the broilers when compared to those formulated with crude Protein, from day the first up to 35 days of age. The final phase (35-42) showed the contrary, being the CP concept more economical than IP.

The objective of this research was to determine the nutritional requirement of digestible lysine for white laying hens in old age. Two hundred eighty-eight Hy Line W-36 laying hens at 60 weeks of age were distributed in a completely randomized design, with six levels of digestible lysine (6.0; 6.6; 7.2; 7.8; 8.4 and 9.0g kg-1) and eight replications with six birds per experimental unit. There was linear effect of lysine levels on lysine intake and efficiency of utilization of lysine. For the production and egg mass, the levels of digestible lysine in the diet from which the plateaus occurred were of 6.57g kg-1 and 7.10g kg-1, respectively. There was quadratic effect of lysine levels on yolk weight, with the estimated level of 7.6g kg-1 of digestible lysine. The digestible lysine requirement of white laying hens from 60 to 76 weeks of age is 7.10g kg-1 in diet, corresponding to daily intake of 690mg bird-1 of digestible lysine. [ABSTRACT FROM AUTHOR]

Copyright of Acta Scientiarum: Animal Sciences is the property of Universidade Estadual de Maringa and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of this study was to determine the requirement for digestible Thr for optimum performance of white egg layers in the period from 60 to 76 wk of age. DeKalb White Leghorn layers with an average weight of 1,345 kg were distributed 5 increasing levels of digestible Thr (0.523, 0.546, 0.569, 0.592, and 0.615%) in a completely randomized design, with 6 replicates and 6 birds per experimental unit for a total of 180 birds. The dietary treatments contained 0.759% of digestible Lys, which was obtained using the prediction equation of the Brazilian Tables for Poultry and Swine, and each treatment consisted of a digestible Thr-to-Lys ratio of 69, 72, 75, 78, or 81%. The digestible Thr levels had a linear effect on feed intake and a quadratic effect on egg production, egg mass, and feed conversion per mass and per dozen eggs. In conclusion, a digestible Thr-to-Lys ratio of 75.14% is recommended for White Leghorn of 60 to 76 wk of age, corresponding to the level of 0.570% in the diet and a daily intake of digestible Thr of 622 mg/bird. [ABSTRACT FROM AUTHOR]

The effects of the nutritional reduction of diets supplemented with phytase and amino acids provided to broilers from 36 to 42 days of age were evaluated. Five diets were evaluated in six replicates, totaling 750 and 90 birds in the assays of performance and metabolism, respectively. Control diet, without phytase, contained 18% of crude protein (CP), 0.386% of available phosphorus (aP) and 0.764% of calcium (Ca). The remaining diets (0.236% of aP and 0.464% of Ca) were supplemented with phytase and amino acids, with the CP reduced from 18 to 15%. The performance, yield and nutrient retention by the birds, besides of the energetic value (AMEn) and metabolizability of the diets were evaluated. There was no difference in the performance, yields of carcass and cuts, and in the AMEn. 16 and 15% of CP in the diet increased their metabolizability. The protein reduction improved N retention, but increased abdominal fat. Phytase increased the use of P. With the phytase and amino acids supplementation, the levels of CP, aP and Ca can be reduced to 15, 0.236 and 0.464%, respectively, without compromising on performance, yields of carcass and cuts and AMEn, besides improve the diet metabolizability and utilization of nitrogen and phosphorus. [ABSTRACT FROM AUTHOR]

Copyright of Acta Scientiarum: Animal Sciences is the property of Universidade Estadual de Maringa and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: This study was conducted to evaluate the effect of different levels of soybean oil (SO) and crude protein (CP) on performance and physiological and hormonal parameters of pigs in high-temperature environment. Eighty-four growing pigs with initial weight of 36.9±3.0kg were assigned to treatments in 2×3 factorial arrangement of dietary treatments plus 1 [two levels of CP, 18% and 15.5%, and three levels of SO, 1.5%, 3.0%, and 4.5% with all pigs kept at room temperature of 32°C, and an additional treatment (control) with 18% CP and 1.5% SO with pigs kept at 22°C], in a randomized block design with the block being the initial weight. In animals maintained in the high-temperature environment, there was no interaction between CP and SO levels in any of the variables evaluated. The addition of SO improved (P<0.05) the average daily gain (ADG) and feed:gain (F:G), but did not affect the average daily feed intake (ADFI). The reduction of CP resulted (P<0.05) in lower ADFI. Compared to animals kept at the comfort temperature, a high-temperature environment decreased the F:G (P<0.01) of animals fed diets with 18% CP and 1.5% SO. However, increasing the SO level resulted in similar values of F:G. For animals kept in a high-temperature environment, CP can be reduced in diets supplemented with amino acids only in diets with high SO levels. The high-temperature affected (P<0.01) body temperature and respiratory rate, but was not sufficient to change the levels of T3 and T4. It is concluded that SO levels should be increased in diets for animals kept in high-temperature environment, and the CP levels can be reduced only under these conditions, since supplemented with amino acids. [Copyright &y& Elsevier]

This study was undertaken in a closed system with Nile tilapia (Oreochromis niloticus) to examine the effects of total replacement of fish meal (FM) by soybean meal. Nile tilapia fingerlings with an average weight of 5.34±0.08 g were hand-fed one of the five isoenergetic (≈13.5 MJ digestible energy kg−1) and isoproteic (≈31% of digestible protein) experimental diets to satiation, six times a day during 85 days in eight replicate fibreglass tanks (six fish per tank). The control diet containing FM was substituted by soybean meal, with and without essential amino acids (lysine, methionine and threonine) or dicalcium phosphate supplementation. The supplemental amino acids were added at levels to simulate the reference amino acid profile of Nile tilapia carcass protein, based on the ideal protein concept. The results showed that soybean meal diet supplemented only with dicalcium phosphate was inferior to the control diet with FM and soybean meal diets supplemented with dicalcium phosphate and essential amino acids. Multiple essential amino acids and dicalcium phosphate incorporation in soybean meal diets was associated with performance, whole-body composition and carcass yield equal to that of the fish fed with the control diet containing FM. These data suggest that a diet with all plant protein source, supplemented with essential amino acids, based on tissue amino acid profile, can totally replace FM in a diet for Nile tilapia, without adverse effects on the growth performance, carcass yield and composition. [ABSTRACT FROM AUTHOR]