ABSTRACT The objective with this study was to determine the lysine maintenance requirements (LMR) of male and female broilers as animal models. A total of 252 birds were used for nitrogen balance trials during three periods (I: 6-21, II: 22-37, and III: 38-53 days). Six lysine levels were used (2.76, 5.88, 8.99, 12.1, 15.2, and 18.3 g kg−1) with six replications. A control group also included, totalizing seven treatments for males and females for each assay. The experimental period was 15 days. The response variables included nitrogen intake (NI) and excretion (NEX), and their difference was assumed to be deposited as nitrogen. An exponential regression between NEX and lysine intake (LI) was fitted, and LMR was estimated when LI = 0. The daily values for LMR were 9.29, 33.4, and 40.2 mg BW0.67 kg−1 for males and 9.36, 30.0, and 39.4 mg BW0.67 kg−1 for females. The final value for both sexes were 10.1 (period I), 31.5 (period II), and 39.8 mg BW0.67 kg−1 (period III). Expressed as body protein weight at maturity (BPm), the LMR were 172 and 148 (period I), 216 and 207 (period II), and 189 and 180 mg BPm0.73 kg−1 (period III) for males and females, respectively. The results provided ranges of LMR values recommended in previous studies, validating this procedure. The procedure to estimate the requirements presented here provides new insights into the model of amino acid requirement estimations.

ABSTRACT The objective of this study was to describe the growth of freshwater angelfish (Pterophyllum scalare) using the Gompertz model, determining the relative growth and allometric coefficients of body components in relation to body weight and protein weight. Six hundred animals were grown until 233 days of age. Data on chemical composition (water, lipid, protein, and ash) and weight measurements were obtained each 30 days. The Gompertz growth equation was used to analyze chemical allometry and to estimate growth parameters. The relationship between chemical components and body protein was estimated. Protein and body weight increased proportionally, with ash being the earliest nutrient (209.2 days), while lipid deposition occurred later. Linear regression analysis showed an inverse relationship between lipids and body water. This study provided a useful equation to predict the growth, chemical body composition, and rate of nutrient deposition across the life stages of freshwater angelfish. The rates of nutrient deposition as a function of body weight are important to understand the growth process of freshwater angelfish. Thus, mature weight was estimated in 26.14 g. The allometric relationships of body components and deposition rates indicated that protein and body weight are highly correlated across the life stages of freshwater angelfish. The Gompertz equation is a useful tool to describe the growth and body composition of freshwater angelfish.

RESUMO O intuito desta pesquisa foi analisar o ajuste da função Gompertz fixando, ou não alguns parâmetros para descrever o crescimento corporal e dos principais constituintes químicos corporais de frangas de postura em crescimento. Foram coletados semanalmente os dados de peso corporal e os componentes químicos da carcaça depenada e penas de 1.200 pintainhas de quatro linhagens de postura: Hisex marrom, Hisex branca, Hy Line marrom e Hy Line branca W36, até a 18ª semana de idade. As variáveis foram submetidas a dois ajustes, fixando-se ou não alguns parâmetros da função Gompertz. Foram calculados os parâmetros de um modelo alométrico para os componentes químicos. Lipídeo e proteína foram os componentes da carcaça depenada com maior variação nas últimas semanas. Por outro lado, a composição química da pena apresentou pouca variação. Os parâmetros da função Gompertz assumiram valores de acordo com o ajuste empregado, sobretudo para proteína e gordura da carcaça depenada. O ajuste da função Gompertz, fixando os dois parâmetros, permitiu coerência e significado biológico. Os coeficientes alométricos indicaram que à medida que aumentou o peso proteico, aumentou a proporção de gordura e reduziu a proporção de água e cinzas no corpo. O ajuste do modelo, fixando os parâmetros, possibilita coerência com significado biológico, sem perder a precisão nas estimativas.

ABSTRACT The purpose of this research was analyze the fit of Gompertz function with or without fixing some of the parameters to describe body growth and major bodily chemical constituents of growing pullets. Weekly, data of body weight and chemical components of body free of feathers and feathers were collected from 1,200 chicks of four laying strains (Hisex Brown, Hisex White, Hy Line Brown and Hy Line White W36) until 18 weeks of age. The variables were subjected to two adjustments fixing, or not, some parameters of Gompertz function. The allometric model parameters were calculated for the chemical components. The lipid and protein composition of the body free of feathers were the components with the biggest change in the last weeks. Moreover, the chemical composition of the feather showed small variation. The parameters of the Gompertz function assumed values according to the employed adjustment, especially for protein and fat of the body free of feathers carcass. The adjustment of the Gompertz function by fixing the two parameters allowed coherence and biological significance. The allometric coefficients indicate that as the protein weight increased, the proportion of fat increased and the proportion of water and ashes in the body decreased. The fit of the model allows setting the parameters with consistency and biological significance without losing accuracy in the estimates.

Broilers are traditionally managed with feeding programs that often consist of three or four phases. In this study we investigated whether a multiphase feeding program (14 phases) of broilers based on the optimal mix of two feeds could replace a traditional four phase system while maintaining broiler performance. To evaluate this prposed program we measured variables of performance, carcass yield, and nitrogen excretion. In addition, we determined if the multiphase feeding program (14 phases) would be equally effective regardless of bird gender. A total of 480 day-old Cobb chicks were used, with an average weight of 44.74 ± 0.16 g (females) and 44.71 ± 0.11 g (males). The birds were distributed in a completely randomized 2 × 2 factorial design. Each treatment consisted of six replicates with 20 animals per experimental unit. Results were analyzed separately in two periods (1–21 and 22–42 days) as determined by slaughter date, as well as for the entire growth period (1–42 days). The multiphase program led to improvements in final body weight and average daily weight gain, in addition to an increase in breast yield.

A utilização de procedimento linear-platô para descrever a resposta de um indivíduo a ingestão de um nutriente na população tem sustentação teórica, uma vez que cada indivíduo tem seu máximo potencial de produção determinado geneticamente, e qualquer aumento no consumo de nutriente limitante acima de manutenção resulta numa resposta linear na massa de ovo até atingir o potencial genético e, portanto, atendendo a exigência do indivíduo. No entanto, por causa da distribuição do peso corporal e da massa de ovos na população, a resposta média da população é curvilínea, a qual anula a possibilidade de definir uma "exigência" para o nutriente limitante, e, ao invés disso, leva à possibilidade de definir uma ingestão ótima econômica do nutriente. O Reading Model descreve a resposta da população à ingestão do nutriente limitante, integrando as respostas dos indivíduos que constituem a população. A resposta da população é obtida invertendo um modelo fatorial simples, usando parâmetros para descrever o peso corporal, máximo potencial de produção e as respectivas distribuições (normal) e covariância. Reading Model descreve a resposta da população à ingestão do nutriente limitante, integrando as respostas dos indivíduos que constituem a população. A resposta da população é obtida invertendo um modelo fatorial simples, usando parâmetros para descrever o peso corporal, máximo potencial de produção e as respectivas distribuições (normal) e covariância. A resposta média da população é representada por um modelo linear-platô com uma forma sigmoidal. O Reading Model tem sido amplamente utilizado para estimar a ingestão ótima econômica de aminoácidos para poedeiras comerciais, com diferenças no peso corporal e massa de ovo

The use of a linear-plateau procedure to describe the response of an individual in the population has theoretical support, since the maximum potential performance of each individual is genetically determined, and any increment in intake of the limiting nutrient above maintenance will result in a linear response in output until this genetic potential, and hence requirement, is reached. However, because of the distribution of body weights and maximum potential outputs in the population, the mean response of the population is curvilinear, which negates the possibility of defining a 'requirement' for the limiting nutrient, and instead leads to the possibility of defining an optimum economic intake of the nutrient.. The Reading model describes the response of a flock to a limiting nutrient by integrating the responses of the individuals making up the population. The response of the population is obtained by inverting a simple factorial model using parameters to describe the mean body weight and maximum output of the flock, their distributions (normal) and covariance. The average response of the population is represented by a linear plateau model with a sigmoidal shape. This model has been widely used to predict the optimum economic intake of amino acids for commercial laying flocks varying in body weight and potential egg output

The objective of this study was to measure the response of Dekalb White laying hens to different intakes of digestible methionine + cystine (met+cys) to optimise their performance. Two hundred eighty-eight Dekalb White laying hens, ranging in age from 33 to 48 weeks, were used in the study. The birds were randomly allocated into eight treatment (levels of met+cys and the control treatment) groups with six replicates of six hens per unit. The experimental diets consisted of seven increasing levels of met+cys (1.37, 2.75, 4.14, 5.51, 6.89, 7.92 and 8.95 g kg−1) and were prepared using a dilution technique. A control treatment was used to confirm that the limiting response was due to met+cys intake. Egg production, feed intake, egg weight, egg mass and feed conversion per mass were measured. The data were analysed with repeated measures and regression analyses using Broken Line and Quadratic models, as well as using the combination of both models. The different met+cys intakes influenced the studied variables; all the variables except feed conversion per mass were significantly different between the periods and levels. The digestible met+cys intakes based on the association of the Broken Line and Quadratic models to optimise the birds' response to egg mass are 671 mg/bird d for 33 to 36 weeks, 728 mg/bird d for 37 to 40 weeks, 743 mg/bird d for 41 to 44 weeks, and 770 mg/bird d for 45 to 48 weeks.

Objetivou-se com o presente estudo avaliar a acurácia de cinco modelos matemáticos (Gompertz, Logístico, Linear Hiperbólico, Quadrático e Quadrático Logarítmico) para descrever a curva de crescimento de tilápia nilótica Oreochromis niloticus da linhagem GIFT e, realizar a caracterização da trajetória do crescimento das partes corporais. Para tal, 1.000 alevinos com peso inicial de 2,4 g foram estocados em 20 tanques de alvenaria de 2 m³ numa densidade de 25 peixes m-3, por um período de 180 dias. Os animais foram alimentados diariamente, utilizando níveis de proteína e número de refeições diárias de acordo com cada fase. Quinzenalmente, foram amostrados aleatoriamente 20 peixes, submetidos a um jejum de 48 h e abatidos por choque térmico, para determinação dos pesos do peixe inteiro, peles sem escamas, filés sem pele, coração, fígado, brânquias e trato gastrointestinal. Os modelos Gompertz e Logístico foram os que mais se adequaram ao ajuste da curva de crescimento do peso vivo, do filé e da pele, todavia, o Logístico subestimou os pesos assintóticos. Desta forma, sugere-se o Gompertz para descrever a curva de crescimento de tilápia nilótica da linhagem GIFT. De acordo com os parâmetros estimados pelo modelo Gompertz, a tilápia nilótica atinge a idade de máximo crescimento do filé e pele antes da idade do peso vivo. Dentre os órgãos estudados, o crescimento do trato gastrointestinal e brânquias é mais precoce do que o do coração e fígado.

The objective of this study was to evaluate the accuracy of five mathematical models (Gompertz, Logistic, Linear Hyperbolic, Quadratic and Quadratic Logarithmic) to describe the growth curve of GIFT strain Nile tilapia, Oreochromis niloticus, and to characterize the growth trajectory of body parts. To do this, 1,000 fingerlings, with an initial weight of 2.4 g were placed into 20 brick tanks of 2 m³ each, at a density of 25 fish m-3, for 180 days. The animals were fed daily, using the protein levels and number of meals appropriate to each stage. Every two weeks 20 fish were randomly sampled, submitted to a fasting period of 48 h and then slaughtered by thermal shock, in order to determine the weight of the whole fish, the skin without scales, skinless fillets, heart, liver, gills and gastrointestinal tract. The Gompertz and Logistic models presented the best fit to the growth curve for live weight, fillet and skin, however the Logistic model underestimated the asymptotic weights. Therefore, to describe the growth curve in GIFT strain Nile tilapia, the Gompertz model is suggested. According to the parameters estimated by the Gompertz model, Nile tilapia reach the age for maximum growth of the fillet and skin before that of body weight. Among the organs studied, growth of the gastrointestinal tract and gills takes place earlier than that of the heart and liver.

O objetivo deste estudo foi desenvolver um procedimento baseado na função Gompertz para determinar a eficiência de utilização do aminoácido. O procedimento foi aplicado para determinar a eficiência de utilização da lisina, metionina+cistina e treonina da dieta de frangas de postura em crescimento, e com base nas eficiências foram estimadas as exigências para fase de crescimento das aves. A função Gompertz foi ajustada aos dados de consumo de ração, peso corporal, peso proteico do corpo depenado e peso de penas de quatro linhagens de aves de postura na fase de crescimento. As taxas de consumo e deposição diária de proteína (DP) foram calculadas. A deposição do aminoácido foi obtida multiplicando a DP pela concentração do aminoácido nas penas e corpo depenado. Os resultados obtidos demonstraram que as eficiências de utilização dos aminoácidos diminuíram com a maturidade e, inversamente, houve um aumento proporcional da exigência por kg de ganho de peso. O procedimento baseado na função Gompertz para determinar a eficiência de utilização do aminoácido mostrou ser adequado para avaliar a eficiência de utilização do aminoácido e pode ser uma ferramenta útil para diagnosticar a eficácia do manejo nutricional auxiliando na tomada de decisões sobre o manejo nutricional.

The aim of this study was to develop a procedure based on Gompertz function to determine the efficiency of utilization of amino acid. The procedure was applied to determine the efficiency of utilization of dietary lysine, methionine+cystine and threonine by growing pullets and based on the efficiencies were estimated the requirements for the growth phase of birds. The Gompertz function was fitted to the data of feed intake, body weight, feather-free body protein weight and feather protein weight of four strains of laying hens in the growth phase. The rates of consumption and daily protein deposition (PD) were calculated. The amino acid deposition was obtained by multiplying the PD by the amino acid concentration in feather protein and feather-free body protein. The results showed that the efficiency of utilization of amino acid decreased with maturity and, conversely, there was a proportional increase of the requirement per kg of weight gain. The procedure based on the Gompertz function to determine the efficiency of utilization of amino acid proved to be suitable to evaluate the efficiency of utilization of amino acid and can be a useful tool to diagnose the effectiveness of the nutritional management, aiding in decision-making on the nutritional management.

Broiler strains available in the poultry industry present different requirements for dietary lysine due to their different growth potentials as a result of their genetic makeup. This study aimed to determine the model parameters for maximum nitrogen retention (NRmaxT), the nitrogen maintenance requirement (NMR) and the efficiency of lysine utilization (bc-1) to reevaluate the lysine (Lys) requirements of male and female broilers. Nitrogen balance trials were performed during three periods (I: 6-21 days, II: 22-37 days, and III: 38-53 days). Seven treatments were used for males and females; the treatments consisted of seven diets with protein levels ranging from 61 to 364 g kg-1 dry matter, with Lys being limiting in the dietary nitrogen (4.91 g of Lys in 16 g of N). Nitrogen intake (NI), excretion (NEX), deposition (ND, ND=NI-NEX) and retention (NR, NR=ND+NMR) values were obtained. The NMR was represented by the exponential relationship between NEX and NI. The NRmax T and bc-1 were estimated by the exponential fit between ND and NI. The NRmax T, bc-1, and NMR values were combined in a model to estimate Lys intake by simulating different percentages of the NRmaxT. The Lys intake estimates were 581, 1,538, and 2,171 mg day-1 for males and 512, 1,340, and 1674 mg day-1 for females during periods I, II, and III, respectively. Due to the flexibility of the model, it is possible to calculate the Lys intake for percentages of NR in the range of practical performance data.

Objetivou-se com esta pesquisa descrever o potencial de retenção de nitrogênio por duas técnicas: abate comparativo e balanço de nitrogênio. Também se objetivou comparar os modelos ajustados para cada técnica e estimar as exigências de mantença para frangas de postura. Os ensaios foram realizados no período de 14 a 28, 56 a 70 e 98 a 112 dias de idade, utilizando 168 frangas. Os ensaios tiveram sete tratamentos e oito repetições. Os tratamentos consistiram de níveis de proteína variando de 75 a 435gkg-1 de matéria seca. As variáveis coletadas pelo abate comparativo foram nitrogênio ingerido e depositado e, pela técnica do balanço de nitrogênio, ingestão e excreção de nitrogênio. O intercepto da relação exponencial entre nitrogênio excretado e ingerido foi considerado a exigência de mantença. Os modelos ajustados foram comparados pelo teste da razão de máxima verossimilhança. As técnicas comparadas descreveram de forma diferente a exigência de mantença de nitrogênio. Para o abate comparativo, a exigência de mantença foi estimada em 342, 372 e 543mg/kgPC0,67 e para o balanço de nitrogênio foi de 342, 225 e 284mg/kgPC0,67, para os período de 14 a 28, 56 a 70 e 98 a 112 dias de idade, respectivamente.

The objectives of this study were to describe the potential for nitrogen retention by two techniques: comparative slaughter and nitrogen balance; compare the adjusted models for each technique and estimate the maintenance requirement for pullets. Assays were performed during 14 to 28, 56-70 and 98 to 112 days of age, using 168 pullets. The design was completely randomized with seven treatments and eight replications. Treatments consisted of protein levels ranging from 75 to 435gkg-1 of dry matter. The variables were collected by comparative slaughter and nitrogen ingested and deposited in nitrogen balance technique intake and nitrogen excretion. The intercept of the exponential relationship between ingested and excreted nitrogen was considered a requirement for maintenance. The adjusted models were compared by using the maximum likelihood ratio. The techniques described differently compared the requirement for maintenance of nitrogen. For comparative slaughter requiring maintenance was estimated at 342, 372 and 543mg/kgPC0,67 and for nitrogen balance was 342, 225 and 284mg/kgPC0,67 for the period of 14 to 28, 56-70 and 98 to 112 days of age, respectively.

Objetivou-se descrever o máximo potencial de deposição de nitrogênio e estimar a ingestão de metionina+cistina pela técnica do balanço de nitrogênio e abate comparativo. Foram realizados ensaios no período de 14 a 28, 56 a 70 e 98 a 112 dias de idade, utilizando 168 frangas Dekalb White, distribuídas em sete tratamentos e oito repetições. Os tratamentos consistiram de níveis de proteína na dieta, variando de 75 a 435 g kg-1 de matéria seca, em que a metionina+cistina foi o primeiro aminoácido limitante. As variáveis coletadas pelo abate comparativo foram nitrogênio ingerido e depositado e, nos ensaios de balanço de nitrogênio, coletaram-se ingestão e excreção de nitrogênio. Por meio da relação exponencial entre ingestão e deposição de nitrogênio, determinou-se a máxima deposição de nitrogênio. As técnicas foram comparadas pelo teste da razão de máxima verossimilhança. As técnicas descrevem de forma diferente o máximo potencial de deposição pela ave, mas são similares na estimativa da exigência de metionina+cistina. Com base em 60% do máximo potencial, as ingestões de metionina+cistina digestível foram estimadas em 163, 243 e 343 mg dia-1 para os período de 14 a 28, 56 a 70 e 98 a 112 dias de idade, respectivamente.

This study aimed to describe the maximum potential of nitrogen deposition and to estimate the intake of methionine+cystine by nitrogen balance and comparative slaughter. Assays were performed in the periodsof 14 to 28, 56 to 70 and 98 to 112 days of age, using 168 Dekalb White pullets, distributed in seven treatments and eight replications. Treatments consisted of protein levels in the diets ranging from 75 to 435 g kg-1 dry matter in which methionine+cystine was the first limiting amino acid. The variables collected by comparative slaughter were nitrogen intake and deposition and, in nitrogen balance trials were collected nitrogen intake and excretion. With the exponential relationship between nitrogen intake and deposition was determined the maximum nitrogen deposition. The techniques were compared by the test of maximum likelihood ratio. The techniques described differently the maximum potential for deposition by the bird, but were similar in the estimation of methionine+cystine. Based on 60% of the maximum potential the intakes of digestible methionine+cystine were estimated at 163, 243 and 343mg day-1 for the period of 14 to 28, 56 to70 and 98 to 112 days of age, respectively.

Este estudo teve como objetivo avaliar o uso de microminerais complexados a aminoácidos na alimentação de matrizes de frango de corte sobre o desempenho, variáveis de incubação e desempenho da progênie. O estudo foi dividido em três experimentos: exp.1. desempenho das matrizes, exp.2. incubação e exp.3. desempenho da progênie. No exp. 1, foram utilizadas 260 aves da linhagem CobbAvian 48 (240 matrizes e 20 machos), avaliando-se produção e massa de ovos, conversão alimentar por massa e por dúzia de ovos, peso e gravidade específica. No exp. 2, determinou-se a taxa de eclosão, eclodibilidade e fertilidade. No exp. 3 avaliou-se o desempenho dos pintinhos nascidos das incubações. No exp. 1, não houve interação entre tratamento e período (P>0,05) para produção de ovos, massa de ovos, conversão alimentar por massa e por dúzia de ovos, peso e gravidade específica dos ovos. Contudo, houve efeito (P<0,05) do período para todas as variáveis citadas anteriormente. No exp. 2, a taxa de eclosão, fertilidade e eclodibilidade não apresentaram diferenças significativas (P<0,05). Com relação ao exp. 3 também não houve diferença significativa (P<0,05) no desempenho da progênie. A suplementação com microminerais complexados a aminoácidos não influencia no desempenho das matrizes, variáveis de incubação e desempenho das progênies.

This study aimed to evaluate the use of complexed trace minerals to amino acid in broiler breeder feeding evaluating performance, incubation variables and performance of progeny. The study was divided in three trials: exp. 1. broiler breeders performance, exp. 2. incubation and exp. 3. chickens performance. In the exp. 1 two hundred sixty broilers breeders of lineage Cobb Avian 48 (240 females and 20 males) were used. The variables evaluated were egg production and egg mass, feed conversion for egg mass and per dozen eggs, egg weight and specific gravity. In the exp. 2 it was determined rate of hatching, hatchability and fertility. In the exp. 3, it was evaluated the performance of chicks born from incubations. In the exp. 1, there was no interaction between treatment and period (P>0.05) for egg production, egg mass, feed conversion for egg mass and per dozen eggs, egg weight and specific gravity of eggs. However, there was effect (P<0.05) of the period for all variables mentioned above. In the exp. 2, hatching rate, fertility and hatchability did not show significant difference (P<0.05). Regarding the performance of broilers, in the exp. 3 there was no significant difference (P<0.05). Supplementation with complexed trace minerals to amino acids does not influence the performance of breeders, incubation variables and progeny performance.

O experimento foi conduzido para avaliar a eficiência de enzimas exógenas em dietas sobre o desempenho de frangos de corte. Um total de 1440 pintos de corte machos (Cobb 500®) foram distribuídos em um delineamento inteiramente casualizado em esquema fatorial 2x2 (duas dietas com diferentes densidades nutricionais; com e sem a adição enzimática) com 8 repetições de 45 aves em cada unidade experimental. As dietas com diferentes densidades nutricionais foram: controle positivo (níveis normais) e um controle negativo (com redução de 4,3 e 4,5% de energia metabolizável; 16,7 e 17,7% de cálcio e 35 e 42,7% de fósforo, nas fases inicial e de crescimento, respectivamente). A suplementação enzimática consistiu da combinação das enzimas fitase (100g t-1) e amilase, xilanase e protease (500g t-1). Foi avaliado o desempenho das aves nas fases de 1 a 21 e 1 a 42 dias de idade. Na fase total de criação, as aves alimentadas com a dieta controle negativo com adição enzimática tiveram consumo de ração (5,97%), peso médio (8,47%), ganho de peso (8,64%) e conversão alimentar (2,92%) melhores (P<0,05), comparados às aves alimentadas com dieta controle negativo, sem a suplementação de enzimas. Além disso, as aves alimentadas com a dieta controle negativo com adição enzimática apresentaram consumo de ração, peso vivo médio e ganho de peso similar (P>0,05) ao grupo alimentado com a dieta controle positivo com ou sem enzima. A adição de enzimas exógenas em dieta de frangos de corte com redução de energia metabolizável, cálcio e fósforo, proporciona um consumo de ração, peso vivo médio e ganho de peso similar a uma dieta com níveis nutricionais adequados.

The experiment was conducted to evaluate the effect of enzyme efficiency in diets with and without nutrient reduction on the performance of broilers. Thousand and hundred forty male broiler chicks (Cobb 500®) were distributed in a completely randomized design with 4 treatments in a factorial 2x2 (two diets with different nutrient densities, with and without enzyme) with 8 replications of 45 birds. The diets were: positive control (normal) and a negative control (with a reduction of 4.3% and 4.5% of metabolizable energy, 16.7% and 17.7% of calcium and 35% and 42.7% of phosphorus, in initial and growth phases, respectively). The enzyme supplementation consisted of a combination of phytase enzyme (100g t-1) and amylase, xylanase and protease (500g t-1). It was evaluated the performance of birds in phases 1 to 21 and 1 to 42 days old. In the total period, the birds fed with negative control diet with added enzyme had feed intake (5.97%), body weight (8.47%), body weight gain (8.64%) and feed conversion (2.92%) higher (P<0.05) than compared to birds fed with negative control diet without enzyme supplementation. In addition, birds fed with control diet with added enzyme showed negative feed intake, average live weight and body weight gain similar (P>0.05) to the group fed with positive control diet with or without enzyme. It is concluded that the addition of exogenous enzymes in diets with reduced metabolizable energy, calcium and phosphorus, providing a feed intake, average live weight and weight gain similar to a diet with adequate levels for broiler.

O presente estudo avaliou a digestibilidade aparente da proteína e da energia de ingredientes (farelo de soja, farinha de peixe, farelo de trigo e milho) por juvenis de apaiari (Astronotus ocellatus) usando dois diferentes intervalos de coleta (30 min. e 12h). Os 160 juvenis de apaiari utilizados (22,37 ± 3,06 g de peso corporal) foram divididos em quatro tanques rede plásticos e cilíndricos, cada um colocado em um tanque de alimentação de 1.000 L. O experimento foi inteiramente casualizado em esquema fatorial 2 x 4 (2 intervalos de coleta de fezes e 4 ingredientes foram) com quatro repetições. Os testes estatísticos não detectaram efeito da interação entre o intervalo de coleta e tipo de ingrediente nos coeficientes de digestibilidade. O intervalo de coleta não afetou a digestibilidade da proteína e da energia. As características físicas das fezes dos juvenis de apaiari aparentemente as tornam menos sensíveis à perda de nutrientes por lixiviação, permitindo intervalos de coleta maiores. A digestibilidade da proteína dos ingredientes avaliados foi semelhante, mostrando que a digestibilidade aparente de ingredientes animais e vegetais por juvenis de apaiari é eficiente. Os coeficientes de digestibilidade da energia foram maiores para a farinha de peixe e o farelo de soja comparado a farelo de trigo e milho. Ingredientes ricos em carboidratos (farelo de trigo e milho) apresentaram os piores coeficientes de digestibilidade da energia e, portanto, não são usados eficientemente pelos juvenis de apaiari.

This study evaluated the apparent protein and energy digestibility of common feed ingredients (soybean meal, fish meal, wheat meal and corn) by juvenile oscars using two different sampling intervals (30 min. and 12h). The 160 juvenile oscar fish tested (22.37 ± 3.06 g BW) were divided into four cylindrical plastic net cages, each one placed in a 1000 L feeding tank. The experiment was completely randomized in a 2 x 4 factorial design (2 feces collection intervals and 4 feed ingredients) with four replications. The statistical tests did not detect an interaction effect of sampling interval and type of ingredient on digestibility coefficients. Sampling interval did not affect protein and energy digestibility. The physical characteristics of juvenile oscar feces likely make them less susceptible to nutrient loss by leaching and can therefore be collected at longer intervals. Protein digestibility of the different ingredients was similar, showing that apparent digestibility of both animal and plant ingredients by juvenile oscars was efficient. Energy digestibility coefficients of fish meal and soybean meal were higher than those of wheat meal and corn. Carbohydrate-rich ingredients (wheat meal and corn) had the worst energy digestibility coefficients and are therefore not used efficiently by juvenile oscars.

The objective of this study was to determine the optimal feeding level and feeding frequency for the culture of freshwater angelfish (Pterophyllum scalare). A randomized block design in a factorial scheme (3 × 2) with three feeding levels (30, 60 and 90 g/kg of body weight (BW)/day) and two feeding frequencies (1x and 2x/day) was set up in duplicate, representing 24 experimental units. Data were analyzed using two-way ANOVA and the Tukey test for comparison between means. After 84 days, results indicated that both factors influenced fish performance. No interaction between these factors was, however, observed. Increased feeding level and feeding frequency resulted in increased feed intake. The feed conversion ratio was negatively affected by feeding level, but not affected by feeding frequency. Final weights were higher when fish were fed twice daily, at levels of 60 or 90 g/kg BW/day. Specific growth rate was higher when fish received 60 or 90 g/kg BW/day, regardless of the feeding frequency. Survival was not affected by any treatment, with mean survival rates higher than 90%. It is recommended that juveniles be fed at a level of 60 g/kg BW/day with a minimum of two meals per day, to attain optimal survival, growth and feed efficiency.