ABSTRACT. The study aimed to evaluate performance and growth curves of broilers fed different nutritional relations. A total of 1,440 Cobb-500 male day-old chicks were assigned to eight treatments in a 2 x 2 x 2 factorial arrangement with six replicates of 30 birds each. The main factors were nutritional density (control and high), lysine source (HCl and sulfate), and calcium pidolate (presence and absence). Analyses were made for body weight gain (BWG), and feed conversion rate (FCR) at 21, and 42 days of age. The growth curves were adjusted by weighing a bird per plot every three days. Data for BWG were tested by ANOVA to evaluate the effects of treatments and their interactions at 5% significance, and the Gompertz model was adjusted by NLS. Birds fed a high nutritional density had higher BWG and lower FCR. Calcium pidolate and different sources of lysine did not influence the FCR of broilers, however a triple interaction was evidenced for BWG at 1 to 42 days of age. The day with maximum gain adjusted by Gompertz of all treatments was at the 32nd day of age and the maximum weight (A) was around 5.85 kg.

Resumo O objetivo deste trabalho foi avaliar parâmetros de desempenho, rendimento de carcaça e cortes, qualidade de carne, atividade plasmática de glutationa peroxidase (GSH-Px) e deposição tecidual de selênio em frangos de corte alimentados com Se de fontes orgânica (Se-levedura) e inorgânica (selenito de sódio). Um total de 1.200 pintos Cobb 500, machos com um dia de idade, foram distribuídos inteiramente ao acaso em quatro tratamentos, com dez repetições. Os tratamentos consistiram de dois níveis de Se-levedura (3.000 e 2.000 ppm), de selenito de sódio (45,7%), e da combinação entre selenito de sódio e 3.000 ppm de Se-levedura. Todas as dietas, à base de milho e farelo de soja, foram suplementadas com 0,3 ppm de Se. Entre os tratamentos, não houve diferenças quanto a desempenho, rendimento de carcaça e de cortes, e qualidade de carne. Dietas apenas com Se-levedura proporcionaram carnes com menores valores de substâncias reativas ao ácido tiobarbitúrico. Observaram-se maior atividade de GSH-Px com 3.000 ppm Se-levedura e maior deposição muscular de Se com Se-levedura. As fontes de Se não afetam os parâmetros de desempenho e o rendimento de carcaça; no entanto, a fonte orgânica 3.000 ppm de Se-levedura resulta em maior deposição do mineral no músculo e maior estabilidade oxidativa da carne.

Abstract The objective of this work was to evaluate performance parameters, carcass and cut yields, meat quality, plasma glutathione peroxidase (GSH-Px) activity, and selenium tissue deposition for broilers fed with Se from organic (Se-yeast) and inorganic (sodium selenite) sources. A total of 1,200 Cobb 500 chicks, males with one day of age, were randomly distributed into four treatments with ten replicates. The treatments consisted of two Se-yeast levels (3,000 and 2,000 ppm), sodium selenite (45.7%), and the combination between sodium selenite and 3,000 ppm Se-yeast. All diets, based on corn and soybean meal, were supplemented with 0.3 ppm Se. Among treatments, there were no differences for performance, carcass and cut yields, and meat quality. Diets containing only Se-yeast provided meat with lower values of thiobarbituric acid reactive substances. A higher GSH-Px activity was observed with 3,000 ppm Se-yeast and a greater deposition of Se in the muscle tissue with Se-yeast. The sources of Se do not affect performance parameters and carcass yield; however, the organic source 3,000 ppm Se-yeast results in a greater deposition of the mineral in the muscle and in a greater oxidative stability in the meat.

ABSTRACT A trial was carried out to evaluate the effects of different levels of microalgae Schizochytrium sp. on performance, yolk lipid profile, and egg quality of Japanese quail. A flock of 210 quail was distributed in a completely randomized design, with five treatments (0, 10, 20, 30, and 40 g of Schizochytrium sp./kg of feed) and six replications with seven birds per cage. Performance and egg quality were not affected, except for a quadratic effect on yolk color, which reached the maximum value with the inclusion of 40 g of Schizochytrium sp./kg. There was linear reduction in the content of saturated fatty acids and a linear increase of polyunsaturated:saturated and polyunsaturated:monounsaturated ratios and n-6. The content of n-3 showed a minimum value with the inclusion of 6.5 g of Schizochytrium sp./kg, and the n-6:n-3 ratio was maximized with the addition of 10.5 g of microalgae/kg. As for the sensory attributes color, aroma, and overall impression, there was linear increase with the addition of increasing levels of microalgae. The inclusion of up to 40 g of microalgae Schizochytrium sp./kg in the diet of Japanese quail did not present changes in the performance nor in the egg quality but accentuated the yolk color, promoted the fortification of n-3 in the eggs, and still provided excellent sensorial acceptance. The egg fortification can add value to the product, increasing the producer remuneration and improving the nutritional quality of the diet for humans.

ABSTRACT. The objective of this study was to investigate the effects of alpha-amylase supplementation on performance and carcass and cuts yield in broilers during finishing phase (21 to 42 days). A completely randomized experimental design with six treatments and eight replications was used: Positive Control (PC): no enzyme; Negative control (NC): without enzyme formulated with 6.34% less energy (- 6.34% ME); NC1: with 250 g ton-1 of alpha-amylase; NC2: with 500 g ton-1 of alpha-amylase; NC3: with 750 g ton-1 of alpha-amylase; NC4: with 1000 g ton-1 of alpha-amylase. Significant differences in weight gain, feed intake and feed conversion were reported with the inclusion of alpha-amylase. The NC treatment with inclusion of amylase provided improvement values of weight gain, feed conversion and feed intake, but do not was similarly in comparison to those obtained in broilers fed a diet that completely met the requirements during this phase. There was no dietary influence on carcass parameters. The use of alpha-amylase was effective in improving performance in broilers fed a diet of 200 kcal kg-1 of reduced metabolizable energy.

ABSTRACT The objective of this study was to ascertain the influence of different dietary fiber sources and the usage of xylanase on diet of commercial layers and their influence on productive performance, egg quality, and digestive organ biometry. A total of 864 Lohmann® White hens was fed diets with three different fiber sources (wheat bran, soybean hull, or coffee husk) with or without xylanase inclusion (concentration of 160,000 BXU/g) in a 3×2 factorial arrangement, with six replicates of 24 birds each, from 25 to 44 weeks of age. There were no interactions between dietary fiber and xylanase inclusion. The enzyme supplementation did not influence any parameters evaluated. There were dietary fiber effects on body weight gain, viability, egg weight, eggshell quality, yolk pigmentation, and liver and gizzard relative weights. Wheat bran, soybean hull, and coffee husk can be used in laying hen diets without detrimental effect on productive performance. The enzyme used had no effect on the performance and eggshell quality of laying hens.

RESUMO: Um experimento foi conduzido para estudar os efeitos de duas fontes e diferentes níveis de selênio (Se) sobre o desempenho, concentração de Se e atividade da glutationa peroxidase no plasma e fígado de leitões após o desmame. Um total de 126 leitões desmamados machos e fêmeas (Large White × Landrace), com peso corporal médio de 7,2±0,67kg foram distribuídos em sete tratamentos em delineamento em blocos casualizados, com duas fontes de Se (orgânico e inorgânico), com níveis de inclusão: dois níveis para a fonte inorgânica (0,30 e 0,60ppm), quatro para a fonte orgânica (0,15, 0,30, 0,45 e 0,60ppm) e uma dieta de controle sem suplemento de Se contendo 0,095ppm em seis repetições de três animais por baia. O período experimental foi de 35 dias após o desmame. A fonte orgânica continha 0,2067% (Se- Levedura) e a inorgânica (Selenito de sódio) 45,86% de Se analisado. Os leitões que receberam Se suplementar tiveram menor consumo de alimento em comparação com os que não foram suplementados. Além disso, a conversão alimentar foi melhor com a suplementação dietética de selênio e a fonte orgânica foi melhor do que a fonte inorgânica ao nível de 0,30ppm. A concentração plasmática de Se foi maior (35,53%) nos animais que receberam suplementação dietética deste mineral, independentemente das fontes estudadas. Não houve efeito de fontes no Se plasmático e hepático, com os valores mais baixos observados para a não suplementação e Se orgânico no nível de dieta de 0,15ppm. Houve uma redução linear da atividade GSH-Px plasmática com níveis de suplementação aumentados de Se orgânico e a atividade hepática GSH-Px aumentou linearmente com o aumento da suplementação, independente da fonte estudada.

ABSTRACT: An experiment was conducted to study the effects of two sources and dietary levels of selenium (Se) on performance, Se concentration and glutathione peroxidase activity in plasma and liver of piglets post weaning. A total of 126 weaned pigs male and female Large White × Landrace, at average body weight of 7.2±0.67kg were allotted to seven treatments in a randomized block design, with two Se sources (organic and inorganic), inclusion levels, two levels for the inorganic source (0.30 and 0.60ppm) and four for the organic source (0.15, 0.30, 0.45 and 0.60ppm) and one control diet without Se supplementation containing 0.095ppm, and six replicates of three animals per pen. The experimental period was 35 days post-weaning. The organic source contained 0.2067% (Se-yeast), and the inorganic 45.86% (sodium selenite) analyzed. Piglets that received supplemental Se had lower feed intake compared to those not supplemented. Furthermore, feed conversion was better with dietary supplementation of Se, and the organic source was better than the inorganic source at level of 0.30ppm. Plasma concentration of Se was higher (35.53%) in animals receiving dietary supplementation of this mineral, regardless of the sources studied. There was no effect of sources on plasma and hepatic Se, with the lowest values observed for the non-supplementation and organic Se at dietary level of 0.15ppm. There was a linear reduction of plasma GSH-Px activity with increased supplementation levels of organic Se, and the hepatic GSH-Px activity increased linearly with the increased supplementation, regardless of the source studied.

O experimento foi conduzido com o objetivo de avaliar o efeito da suplementação da enzima protease sobre o desempenho produtivo e a qualidade de casca de poedeiras semipesadas. Utilizaram-se 240 poedeiras da linhagem comercial Isa Brown com 44 semanas de idade. Foi adotado um delineamento inteiramente casualizado em esquema de parcela subdividida no tempo (5 períodos de 21 dias cada) com quatro tratamentos e seis repetições (10 aves por repetição). Foram avaliados: produção de ovos, consumo de ração, conversão alimentar, peso médio dos ovos, perda de ovos, gravidade específica, porcentagem e espessura de casca. Após a coleta, os dados foram submetidos à análise pelo pacote estatístico SISVAR com as médias comparadas pelo teste de SNK a 5% de probabilidade. Para as variáveis de qualidade externa dos ovos, não houve diferença significativa (p > 0,05) dos tratamentos. Conclui-se que a suplementação de 500 g ton-1 da protease (100 U g-1), em dietas com redução dos níveis nutricionais, proporciona produção de ovos e conversão alimentar semelhantes aos obtido em poedeiras semipesadas, recebendo ração com níveis nutricionais indicados pelo manual da linhagem, porém não mostra efeito sobre a qualidade de casca dos ovos.

The experiment was conducted with the objective of evaluating the effect of protease enzyme supplementation on performance parameters and quality shell of laying hens. We used 240 Isa Brown commercial laying hens with 44 weeks of age. A completely randomized split-plot design (5 periods of 21 days) with four treatments and six replications (10 hens per replication) was used. The experimental diets were formulated according to the requirements of the breed. The following parameters were evaluated: egg production, feed intake, feed conversion, average egg weight, egg loss, specific gravity, percentage and shell thickness. After collection, the data were analyzed with SISVAR Statistical Package, and the means compared by SNK test at 5% probability. It was concluded that supplementation of diets low in nutrients with 500 g ton-1 of protease (100 U g-1), provides egg production and feed conversion rates similar to those obtained in laying hens fed diet with the nutritional level recommended for the breed. However, protease supplementation did not show effect on egg shell quality.

O objetivo deste trabalho foi avaliar o uso de valores de equivalência da fitase como base para redução de fósforo disponível (P-disp) em dietas para frangos. Foram avaliados dez planos nutricionais com seis repetições de 15 aves cada uma. Avaliaram-se: desempenho, teor de cinzas na tíbia e custo da ração. De 1 a 7 e de 36 a 42 dias de idade, as aves receberam dieta basal; de 8 a 21 dias, dieta sem fitase contendo 3,9 g kg-1 de P-disp e quatro dietas com fitase contendo de 1,1 a 2,5 g kg-1 de P-disp; e de 22 a 35 dias, dieta sem fitase contendo 3,4 g kg-1 de P-disp mais dieta com fitase contendo 1,6 g kg-1 de P-disp. O melhor plano nutricional foi composto pelas dietas: 4,7 g kg-1 de P-disp sem fitase (1 a 7 dias); 2,0 g kg-1 de P-disp suplementada com fitase (8 a 21 dias); 3,4 g kg-1 de P-disp em ração sem fitase (22 a 35 dias); e 3,0 g kg-1 de P-disp em ração sem fitase (36 a 42 dias). A redução do P-disp ocorre no período de 8 a 21 dias de idade e corresponde a 2,0 g kg-1 de ração suplementada com fitase.

The objective of this work was to evaluate the use of equivalency values of phytase as a basis for reduction of available phosphorus (aP) in broiler diets. Ten nutritional programs were evaluated with six replicates of 15 birds each. The following were evaluated: performance, tibia ash content, and feed costs. From 1 to 7 and 36 to 42 days of age, the birds received basal diet; from 8 to 21 days, diet without phytase containing 3.9 g kg-1 aP and four diets with phytase containing from 1.1 to 2.5 g kg-1 aP; and from 22 to 35 days, diet without phytase containing 3.4 g kg-1 aP plus diet with phytase containing 1.6 g kg-1 aP. The best nutritional plan was formed by the diets: 4.7 g kg-1 aP without phytase (1 to 7 days); 2.0 g kg-1 aP supplemented with phytase (8 to 21 days); 3.4 g kg-1 aP in feed without phytase (22 to 35 days); and 3.0 g kg-1 aP in feed without phytase (36 to 42 days). The reduction of aP occurs in the period from 8 to 21 days of age and corresponds to 2.0 g kg-1 of feed supplemented with phytase.

A redução do teor de fósforo disponível (Pdisp) na dieta de frangos deve ser acompanhada de adequada suplementação da fitase. Um experimento foi conduzido com frangos de corte, no período de 15 a 28 dias de idade, para determinar o nível de fitase necessário quando a ração farelada é formulada com 0,213% de Pdisp para permitir resultados de desempenho, teor de cinzas na tíbia e aproveitamento do cálcio (Ca) semelhantes ao determinado para aves alimentadas com uma dieta formulada para atender suas exigências nutricionais. Desse modo, 120 frangos foram distribuídos em esquema fatorial (4+1) x2, correspondendo a quatro rações deficientes em Pdisp (0,213%) suplementadas com fitase (0; 750; 1.500 ou 2.250FTU kg-1) mais uma ração controle positivo sem fitase (0,426% de Pdisp), fornecidas a frangos machos e fêmeas. Os machos apresentaram melhor desempenho e maior retenção de Ptotal. A redução do teor de Pdisp da dieta sem o uso de fitase piorou o desempenho, o teor de cinzas ósseas e a retenção do Ca, todavia, esses parâmetros foram gradativamente melhorados com o aumento do nível de fitase na ração. Independente do sexo, ao utilizar 2.250FTU kg-1, é possível reduzir o teor de Pdisp para 0,213% sem prejudicar o desempenho, teor de cinzas na tíbia e a retenção do Ca, além de reduzir a excreção do Ptotal em 56,75% e melhorar seu aproveitamento em 38,58%.

The reduction of the available phosphorus (avP) content in the broiler diet must be followed by the supplementation of adequate phytase. One experiment was conducted with broilers from 15 to 28 days of age to determine the level of necessary phytase when the mashed diet is formulated with 0.213% of avP to enable the results of performance, tibia ash content, and calcium (Ca) utilization similar to those determined for birds fed with diet formulated to meet their nutritional requirements. Thus, 120 broilers were distributed in (4+1) x2 factorial arrangement corresponding to four deficient diets in avP (0.213%) supplemented with phytase (0; 750; 1,500 or 2,250FTU kg-1) plus one positive control diet without phytase (0.426% of avP), supplied to male and female broilers. Males showed better performance and higher totalP retention. Decrease in the avP content of the diet without phytase use worsened the performance, tibia ash content, and Ca retention; however, these parameters were improved gradually with the increase of the phytase level in the diet. Regardless of sex, using 2,250FTU kg-1, it is possible to reduce the avP to 0.213% without impairing performance, tibia ash content, and Ca retention; in addition to reducing the totalP excretion in 56.75% and improving its utilization in 38.58%.

The experiment was carried out to evaluate the influence of nutritional correction on the partial diet replacement or pure-food methodology to determine the energy values (apparent metabolizable energy - AME and nitrogen-correct apparent metabolizable energy - AMEn) and coefficient of metabolizability of nutrients of maize. The method of total excreta collection was used, with 120 female Cobb 500® broilers weighing 1,339±3 g and at 28 days of age distributed in a completely randomized design with five replicates and four birds per experimental unit. The treatments were pure maize with three levels of nutritional correction (0, 50 and 100%) and a maize-replaced basal diet (400 g/kg) with two levels of correction (0 and 100%). The corrections were made in order to meet the nutritional requirements of calcium, available phosphorus and sodium yonder trace minerals, vitamins, choline, lysine, methionine + cystine, threonine and tryptophan. The AME and AMEn of maize and coefficient of metabolizability of dry matter were higher when correction at 100% was made, regardless of the methodology used (pure feed or replaced basal diet). The correction at 50% of nutrients increased the coefficient of metabolizability of crude protein in pure maize when compared with 0 or 100% of correction. The values determined with pure maize were lower than those determined with the method of partial replacement. The absence of nutritional correction underestimates the energy values and metabolizability of nutrients from maize.

A total of thirty-six Landrace × Large White sows were inseminated with semen of Large White boars and studied in late pregnancy (30 days pre-partum) and lactation phases to determine the effects of trace mineral supplementation in organic (bioplex) and inorganic forms at two levels of supplementation (1 and 2 kg/t) on the reproductive performance of the females and on piglet performance and physiologic characteristics until weaning at 21 days of age. The trace mineral supplements contained 0.0075% selenium, 2.50% zinc, 1.00% manganese, 4.00% iron, 0.25% copper and 0.01% chromium. The experimental design was completely randomized in a 2 × 2 factorial scheme with nine replicates each. The piglets were weighed at birth and at weaning (21 days) and were given a dose of 100 mg of dextran iron on the third day of life. For performance, the mean measure of the litter, including both males and females, was considered. Blood and liver were collected from the piglets at birth (two per farrowing, one male and one female), and milk was collected 10 days thereafter. Increased weight at birth and at 21 days and increased iron content in the blood and liver were found for piglets when the sows were given the organic form of trace minerals. Increased iron content in the milk was observed for higher supplementation with organic minerals only. The blood iron levels indicated a significant increase in levels with the use of the organic minerals. These results indicate important benefits in using trace minerals in organic forms for the performance of both sows and piglets.

Dois experimentos distintos foram realizados simultaneamente com fitases de Aspergillus oryzae e A. niger para a determinação da atividade enzimática em resposta ao período de armazenamento (por até 180 dias em temperatura ambiente - TA). No primeiro experimento, as enzimas foram armazenadas como adquiridas (forma pura) e a atividade foi determinada periodicamente durante 180 dias de armazenamento em TA. No segundo experimento, as fitases foram incorporadas a um suplemento contendo vitaminas, minerais e aminoácidos. Então este suplemento foi armazenado em TA por até 180 dias, de modo que, a cada 30 dias de armazenamento, uma alíquota de cada repetição foi coletada para a determinação da atividade enzimática. Conclui-se que a atividade da fitase é afetada pela duração do armazenamento. Para assegurar 80% da atividade inicial, as fitases de A. oryzae e A. niger podem ser armazenadas nas formas pura por até 53 e 135 dias em TA, respectivamente. Entretanto, se as fitases de A. oryzae e A. niger são incorporadas a um suplemento contendo vitaminas, minerais e aminoácidos, o período de armazenamento em TA não deve exceder 67 e 77 dias, respectivamente.

Two distinct experiments were conducted simultaneously with phytases of Aspergillus oryzae and A. niger for determining enzyme activity in response to storage period (up to 180 days at room temperature - RT). In the first experiment, enzymes were stored as they were acquired (pure form) and the activity was measured periodically during 180 days of storage at RT. In the second experiment, the phytases were incorporated to a supplement containing vitamins, minerals, and amino acids; and then this supplement was stored at RT up to 180 days, so that every 30 days of storage was collected one aliquot from each replicate for determining enzymatic activity. In conclusion, the phytase activity is affected by storage duration. To ensure 80% of the initial activity, the phytases of A. oryzae and A. niger can be stored in the pure forms for up to 53 and 135 days at RT, respectively. However, if the phytases of A. oryzae and A. niger are incorporated to a supplement containing vitamins, minerals, and amino acids then the storage period at RT should not exceed 67 and 77 days, respectively.

Em experimentos de desempenho e metabolismo, avaliaram-se os efeitos do fornecimento de rações com níveis reduzidos de proteína bruta, cálcio e fósforo disponível sobre o desempenho, as características de carcaça, o conteúdo de cinzas na tíbia, o balanço e a retenção de nitrogênio e fósforo de frangos de corte nos períodos de 8 a 21 e 8 a 35 dias de idade. Em cada uma destas fases no ensaio de desempenho, foram utilizadas 30 e 25 aves por unidade experimental e, no ensaio de metabolismo, cinco e três aves, respectivamente, em delineamento inteiramente casualizado, com seis repetições. Os tratamentos constituíram-se de rações com 21% proteína bruta sem fitase (controle), formuladas com níveis nutricionais recomendados nas tabelas brasileiras, e rações com 21, 20, 19 e 18% de proteína bruta com fitase (8 a 21 dias) e, no período de 8 a 35 dias, ração com 20% proteína bruta sem fitase (controle), e rações com 20, 19, 18 e 17% de proteína bruta, com fitase. Nas rações com fitase (80 g de fitase - Ronozyme NP(M) por tonelada de ração), o nível de fósforo disponível reduziu em 0,15 e o de cálcio em 0,30 ponto percentual em relação ao da ração controle. Não houve efeito da redução da composição em nutrientes das rações sobre o consumo, o ganho de peso e a conversão alimentar em ambas as fases nem diferença nas características de carcaça aos 35 dias. Todavia, verificou-se maior teor de gordura abdominal quando as aves consumiram ração com o menor nível proteico. A excreção de nitrogênio e fósforo foi menor quando as aves receberam ração com níveis reduzidos desses nutrientes. A porcentagem de cinzas na tíbia, nas fases avaliadas, não diferiu entre os tratamentos. É possível reduzir em até três pontos percentuais o nível proteico das rações, em 0,15 o de fósforo disponível e em 0,30 ponto percentual o de cálcio quando as rações são suplementadas com fitase e aminoácidos.

In performance and metabolism trials, diets with reduced levels of crude protein, calcium and available phosphorus on the performance, carcass characteristics, tibia ashes, balance and retention of nitrogen and phosphorus of broiler chickens in phase from 8 to 21 and 8 to 35 days were evaluated. In each phase, 30 and 25 birds per experimental unit were used in the performance assay and five and three in the metabolism assay, respectively, in a completely randomized experimental design, with six replications. Treatments consisted of diet with 21% crude protein without phytase (control), formulated with nutritional levels recommended on the Brazilian tables, and diets with 21, 20, 19 and 18% crude protein with phytase (8 to 21 days) and from 8 to 35 days, the control diet had 20% crude protein without phytase (control), and others diets with 20, 19, 18, 17% crude protein, with phytase. In the diets with phytase (80 g of Ronozyme NP(M) phytase per ton of diet), the level of available phosphorus was reduced in 0.15 and the calcium in 0.30 percentage points in relation to the control diet. No effect was observed with the reduction of nutrients on feed intake, weight gain, or feed conversion in either phase or for the study of carcass characteristics to the 35 days. However, higher abdominal fat percentage was observed when the broilers were fed diet with lower protein level. The excretion of nitrogen and phosphorus decreased when birds received diets with reduced levels of these nutrients. Ash percentage in the tibia was not influenced by treatments. It is possible to reduce protein level, available phosphorus, and calcium of the diets in up to 3, 0.15 and 0.30 percentage points when the diets are supplemented with phytase and amino acids, respectively.

Dois experimentos independentes, um na fase pré-inicial (1 a 7 dias) e outro na fase inicial (8 a 21 dias de idade), foram realizados com frangos de corte para avaliar níveis de cálcio e fósforo disponível (Pdisp) em rações suplementadas com 500 unidades de atividade de fitase/kg de ração. Cada experimento constou de um ensaio de desempenho e outro de metabolismo e foi conduzido em esquema fatorial (3 × 4) + 1, sendo três níveis de Pdisp (0,42; 0,37; 0,32% na fase pré-inicial e 0,39; 0,34; 0,29% na fase inicial), quatro níveis de cálcio (0,94; 0,84; 0,74; 0,64% na fase pré-inicial e 0,88; 0,78; 0,68; 0,58% na fase inicial) mais uma ração controle. O controle correspondeu à única ração sem fitase e continha 0,47% de Pdisp e 0,94% de cálcio (fase pré-inicial) ou 0,44% de Pdisp e 0,88% de cálcio (fase inicial). Nos ensaios de desempenho, aos 7 e aos 21 dias de idade, foram avaliados o consumo de ração, o ganho de peso, a conversão alimentar e o teor de cinzas na tíbia. Nos ensaios de metabolismo, determinaram-se a energia metabolizável aparente corrigida pelo balanço de nitrogênio (EMAn) das rações e os coeficientes de digestibilidade da matéria seca (CMMS). Na fase pré-inicial, os níveis de cálcio influenciaram o consumo de ração, a EMAn e o CMMS e, na fase inicial, afetaram o conteúdo de cinzas ósseas, a EMAn e o CMMS. Os níveis de Pdisp influenciaram o teor de cinzas na tíbia, a EMAn e o CMMS na fase pré-inicial e as cinzas ósseas e o CMMS na fase inicial. Adicionando 500 unidades de atividade de fitase/kg de ração, é possível reduzir, respectivamente, os níveis de cálcio e Pdisp para 0,64% e 0,37% na fase pré-inicial e 0,58% e 0,29% na fase inicial, pois essa redução não tem efeito negativo sobre o desempenho e a mineralização óssea dos frangos de corte nessas fases.

Two independent experiments, one in pre-starter phase (1 to 7 days) and the other in the starter phase (8 to 21 days of age), were carried out with broilers to evaluate levels of calcium and available phosphorus (aP) in diets supplemented with 500 units of phytase activity/kg of diet. Each experiment consisted of a performance and a metabolic assay, and was conducted in a factorial schedule (3 × 4) + 1, with three aP levels (0.42, 0.37, 0.32% in the pre-starter phase and 0.39, 0.34, 0.29% in the starter phase), four calcium levels (0.94, 0.84, 0.74, 0.64% in the pre-starter phase and 0.88; 0.78, 0.68, 0.58% in the starter phase) plus a control diet. The control corresponded to the only diet without phytase and contained 0.47% of aP and 0.94% of calcium (pre-starter phase) or 0.44% of aP and 0.88% of calcium (starter phase). In the performance assays, at 7 and 21 days of age the feed intake, weight gain, feed conversion and the ash content in the tibia were evaluated. In the metabolic assays the apparent metabolizable energy corrected for nitrogen balance (AMEn) of the feed, and dry matter digestibility coefficients (DMDC) were determined. Calcium levels influenced the feed intake, AMEn and DMDC in the pre-starter phase, and in the starter phase they influenced bone ash, AMEn and DMDC. The aP levels influenced the content of tibia ash, AMEn and DMDC in the pre-starter phase, and bone ash and DMDC in the starter phase. By adding 500 units of phytase activity/kg of diet, it is possible to reduce, respectively, the calcium and aP levels to 0.64% and 0.37% in the pre-starter phase, and to 0.58% and 0.29% in the starter phase, since this reduction does not cause a negative effect on performance or bone mineralization of broilers in the evaluated periods.

Objetivou-se, com este trabalho, avaliar o efeito de rações com reduzidos teores de proteína bruta (PB) e fósforo disponível (Pd), suplementadas com fitase e aminoácidos, para frangos de corte na fase de crescimento (14 a 21 dias) e terminação (35 a 42 dias de idade) sobre o balanço de nitrogênio, potássio e fósforo. Foram utilizados 90 pintos Cobb, distribuídos em um delineamento inteiramente casualizado com três tratamentos e seis repetições, com cinco e três aves por unidade experimental nas fases inicial e de crescimento, respectivamente. As rações foram formuladas para conterem níveis reduzidos de PB e Pd (19 e 17% de PB na fase de crescimento, com 0,34% de Pd e 18 e 16% de PB na fase de terminação, com 0,30% de Pd) e suplementadas com aminoácidos e 500 FTU de fitase/kg de ração Essas rações foram, então, que foram comparadas a uma ração controle (21% de PB e 0,46% de Pd para fase de crescimento e 19% de PB e 0,40% de Pd para fase de terminação). A redução da PB em quatro unidades percentuais reduziu a excreção, e aumentou a retenção de nitrogênio, mostrando que a fitase não interferiu no balanço de nitrogênio ao serem incluídos aminoácidos cristalinos nas rações. A excreção de potássio diminuiu em dietas com PB reduzida, mas esta redução em excesso diminuiu a retenção deste elemento, exceto na fase de retirada. Conclui-se que rações contendo níveis reduzidos de PB, cálcio e fósforo, suplementadas com fitase e aminoácidos, são eficientes em diminuir o poder poluente das excretas de frangos de corte.

The objective of this study was to evaluate the effect of reduced-crude protein (CP) and available phosphorus (aP) diets, added with phytase and amino acids for broilers in the growing (14 to 21 days old) and retirement (35 to 42 days) phases on nitrogen, potassium and phosphorus balance. Ninety Cobb broilers were distributed in a completely randomized design with three treatments and six replications with five and three birds per experimental unit in the growing and retirement phases, respectively. Diets were elaborated to contain reduced CP and aP levels (19 and 17% CP in the growing phase, with 0.34% aP; and 18 and 16% CP in the retirement phase, with 0.30% aP), supplemented with crystalline amino acids and 500 FTU of phytase/kg diet. These were compared to a control diet (21% CP and 0.46% aP for growing phase and 19% CP and 0.40% aP for retirement phase). The reduction of CP in four percentual units reduced the N excretion and increased the retention of this element, showing that the phytase had no influence on N balance when used the crystalline amino acids in the diets. The phytase reduced the P excretion and increased the retention ones. The potassium excretion decreased in reduced-CP diets, but this excessive reduction decreased the retention of this element, except in the retirement phase. It was concluded that the reduced-CP and aP diets, supplemented with phytase and amino acids, are efficient in reducing the pollutant power of the broilers excrements in the growing and retirement phases of production.