RESUMO

O objetivo deste estudo foi determinar a exigência de lisina digestível para frangos de corte machos sob as características de desempenho, composição corporal e rendimento de carcaça dos animais, de 22 a 42 dias de idade. As dietas diferiram quanto aos níveis de lisina digestível, mantendo-se a relação dos demais aminoácidos com a lisina. Foram utilizados seis níveis de lisina digestível: 0,88%; 0,96%; 1,05%; 1,13%; 1,22%; e 1,30%. Distribuídos em 36 unidades experimentais de 36 aves cada, 1296 animais da linhagem Cobb - 500® tiveram as seguintes características de desempenho avaliadas: consumo de ração (CR), peso corporal (PC), ganho de peso (GP), conversão alimentar (CA), viabilidade criatória (VC) e índice de eficiência produtiva (IEP). Aos 42 dias de idade, foram selecionadas ao acaso cinco aves para avaliação do rendimento de carcaça, e duas para avaliação da composição corporal. A CA, o IEP e o rendimento de peito foram influenciados, sendo sua exigência de 1,30%, sugerindo que níveis maiores de lisina digestível que as recomendações utilizadas como base neste estudo (1,13%) trouxeram benefícios aos animais sobre essas características.(AU)

The objective of the present study was to evaluate the optimal levels of digestible lysine in the diet of male broilers, evaluating performance characteristics, body composition, and carcass yield of the animals in the final phase (22 to 42 days old). The diets differed in digestible lysine content, maintaining the relation among the other amino acids and lysine in accordance with the ideal protein concept. The six levels of digestible lysine in the diet were: 0.88%; 0.96%; 1.05%; 1.13%; 1.22%, and 1.30%. A total of 1296 animals were employed, distributed in 36 experimental units of 36 birds each. The determined performance characteristics corresponded to feed intake (FI), body weight (BW), weight gain (WG), feed conversion (FC), viability (VB), and productive efficiency index (PEI). At 42 days of age seven birds per experimental unit were selected at random, five for the estimation of yield and total carcass and commercial cut weight, and two for the evaluation of body composition. FC, animal breast yield and PEI weres influenced with requirements of 1.30%. With respect to nationally known recommendations regarding digestible lysine (1.13%), higher levels of the amino acid in the diet have brought benefits regarding the characteristics above.(AU)

Assuntos

RESUMO

O objetivo deste estudo foi determinar a exigência de lisina digestível para frangos de corte machos sob as características de desempenho, composição corporal e rendimento de carcaça dos animais, de 22 a 42 dias de idade. As dietas diferiram quanto aos níveis de lisina digestível, mantendo-se a relação dos demais aminoácidos com a lisina. Foram utilizados seis níveis de lisina digestível: 0,88%; 0,96%; 1,05%; 1,13%; 1,22%; e 1,30%. Distribuídos em 36 unidades experimentais de 36 aves cada, 1296 animais da linhagem Cobb - 500® tiveram as seguintes características de desempenho avaliadas: consumo de ração (CR), peso corporal (PC), ganho de peso (GP), conversão alimentar (CA), viabilidade criatória (VC) e índice de eficiência produtiva (IEP). Aos 42 dias de idade, foram selecionadas ao acaso cinco aves para avaliação do rendimento de carcaça, e duas para avaliação da composição corporal. A CA, o IEP e o rendimento de peito foram influenciados, sendo sua exigência de 1,30%, sugerindo que níveis maiores de lisina digestível que as recomendações utilizadas como base neste estudo (1,13%) trouxeram benefícios aos animais sobre essas características.(AU)

The objective of the present study was to evaluate the optimal levels of digestible lysine in the diet of male broilers, evaluating performance characteristics, body composition, and carcass yield of the animals in the final phase (22 to 42 days old). The diets differed in digestible lysine content, maintaining the relation among the other amino acids and lysine in accordance with the ideal protein concept. The six levels of digestible lysine in the diet were: 0.88%; 0.96%; 1.05%; 1.13%; 1.22%, and 1.30%. A total of 1296 animals were employed, distributed in 36 experimental units of 36 birds each. The determined performance characteristics corresponded to feed intake (FI), body weight (BW), weight gain (WG), feed conversion (FC), viability (VB), and productive efficiency index (PEI). At 42 days of age seven birds per experimental unit were selected at random, five for the estimation of yield and total carcass and commercial cut weight, and two for the evaluation of body composition. FC, animal breast yield and PEI weres influenced with requirements of 1.30%. With respect to nationally known recommendations regarding digestible lysine (1.13%), higher levels of the amino acid in the diet have brought benefits regarding the characteristics above.(AU)

Assuntos

RESUMO

Feed formulation using linear programming consists of determining the mixture of feedstuffs required to meet pre-established animal nutritional requirements at the lowest cost. On the other hand, with the use of non-linear programming, it is possible to define nutritional requirements at the time of formulation, aiming at maximum profit. The objective of the present study was to compare feeds formulated using linear and non-linear programming in terms of live performance and internal and external egg quality of commercial laying hens. A total of 288 Hisex® White laying hens, 1.540 ± 0.128 g body weight, were evaluated from 33 to 45 weeks of age. Hens were distributed in a completely randomized block design, including six treatments with six replicates of eight birds each. Three treatments consisted of feeds formulated using linear programming and based on the nutritional requirements of Rostagno et al. (2011), of the genetic strain manual, or mathematical models to maximize performance. The other three treatments consisted of feeds formulated using non-linear programming considering typical, favorable, or unfavorable market scenarios. Data were submitted to analysis of variance, and in case of significance (p 0.05), means were grouped using the Scott-Knott test (5%).The treatments did not influence (p>0.05) Haugh unit, albumen height, or external egg quality parameters. Treatment effects (p 0.05) on yolk weight, albumen weight, yolk color, yolk percentage, albumen percentage, and performance parameters were described. In general, feeds formulated using linear programming and based on nutritional requirements obtained by mathematical models and the genetic strain manual promoted better performance results because the feeds were nutritionally denser. However, the treatments that maximized live performance did not result in higher profitability, which was obtained with the diet formulated for a favorable market scenario using non-linear programming.

Assuntos

RESUMO

Feed formulation using linear programming consists of determining the mixture of feedstuffs required to meet pre-established animal nutritional requirements at the lowest cost. On the other hand, with the use of non-linear programming, it is possible to define nutritional requirements at the time of formulation, aiming at maximum profit. The objective of the present study was to compare feeds formulated using linear and non-linear programming in terms of live performance and internal and external egg quality of commercial laying hens. A total of 288 Hisex® White laying hens, 1.540 ± 0.128 g body weight, were evaluated from 33 to 45 weeks of age. Hens were distributed in a completely randomized block design, including six treatments with six replicates of eight birds each. Three treatments consisted of feeds formulated using linear programming and based on the nutritional requirements of Rostagno et al. (2011), of the genetic strain manual, or mathematical models to maximize performance. The other three treatments consisted of feeds formulated using non-linear programming considering typical, favorable, or unfavorable market scenarios. Data were submitted to analysis of variance, and in case of significance (p 0.05), means were grouped using the Scott-Knott test (5%).The treatments did not influence (p>0.05) Haugh unit, albumen height, or external egg quality parameters. Treatment effects (p 0.05) on yolk weight, albumen weight, yolk color, yolk percentage, albumen percentage, and performance parameters were described. In general, feeds formulated using linear programming and based on nutritional requirements obtained by mathematical models and the genetic strain manual promoted better performance results because the feeds were nutritionally denser. However, the treatments that maximized live performance did not result in higher profitability, which was obtained with the diet formulated for a favorable market scenario using non-linear programming.(AU)

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RESUMO

The objective of this study was to evaluate the effects of dietary nutrient levels on performance, carcass yield, commercial cuts, digestibility and economical viability of broilers from 1 to 42 days of age. During the experiment, 180 COBB 500™ chicks were housed in metal batteries and subjected to a completely randomized design in a 2x3 factorial arrangement, of two sexes and three diets (male, female and mixed), totaling 6 treatments and 6 repetitions of 5 birds each. Data were subjected to statistical analysis and the means were compared using the Tukey test, at 5% probability. The results indicate the effect of sex on performance and commercial cuts, except for breast and thigh fillets, in which males and females showed similar results when given the mixed diet. The influence of the nutritional levels on performance, digestibility and commercial cuts was observed, in which the female diet showed the highest results for feed intake, body weight and weight gain, in addition to greater retention of protein and crude energy. For drumstick and abdominal fat yield, the highest values were obtained using the mixed diet and the female diet, and the lowest values were obtained using the male diet. Regarding economic viability, the female diet showed the highest return per unit of Real (R$) spent on feed. Therefore, these data prove that the female diet had a positive effect when provided to both sexes, and it may be a promising alternative for its application at the production level.

Assuntos

RESUMO

The objective of this study was to evaluate the effects of dietary nutrient levels on performance, carcass yield, commercial cuts, digestibility and economical viability of broilers from 1 to 42 days of age. During the experiment, 180 COBB 500™ chicks were housed in metal batteries and subjected to a completely randomized design in a 2x3 factorial arrangement, of two sexes and three diets (male, female and mixed), totaling 6 treatments and 6 repetitions of 5 birds each. Data were subjected to statistical analysis and the means were compared using the Tukey test, at 5% probability. The results indicate the effect of sex on performance and commercial cuts, except for breast and thigh fillets, in which males and females showed similar results when given the mixed diet. The influence of the nutritional levels on performance, digestibility and commercial cuts was observed, in which the female diet showed the highest results for feed intake, body weight and weight gain, in addition to greater retention of protein and crude energy. For drumstick and abdominal fat yield, the highest values were obtained using the mixed diet and the female diet, and the lowest values were obtained using the male diet. Regarding economic viability, the female diet showed the highest return per unit of Real (R$) spent on feed. Therefore, these data prove that the female diet had a positive effect when provided to both sexes, and it may be a promising alternative for its application at the production level.(AU)

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RESUMO

The aim of this study was to assess the sorption of Fe(III) by extracellular polymeric substances (EPS) of the Acidiphilium 3.2Sup(5) bacterium, which has promising properties for use in microbial fuel cells (MFC). The EPS of A. 3.2Sup(5) was extracted using EDTA. The sorption isotherms were determined using aliquots of purified EPS. The exosubstances loaded with metal were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction spectroscopy (XRD) and Fourier transform infrared spectroscopy (FTIR). The sorption uptake approaches to 536.1 +/- 26.6 mg Fe(III) (g EPS)(-1) at an initial ferric concentration of 2.0 g l(-1). The sorption of Fe(III) by EPS can be fitted to the Freundlich model. The sorption process produces hydrated iron (III) oxalate [Fe(OH)(C2O4) x 2H2O] by a reversible reaction (log K = 1.06 +/- 0.16), indicating that a shift in the sorption of the cation can be easily achieved. Know the magnitude and form of iron sorption by EPS in MFC can foresee the potential impact on the metabolism of iron-reducing and iron-oxidazing bacteria and, therefore, on the feasibility of the system.

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RESUMO

Extraction of extracellular polymeric substances (EPS) from Acidiphilium 3.2Sup(5) was investigated using five methods: EDTA, NaOH, ion exchange resin, heating and centrifugation. The bacterium studied presents promising application in microbial fuel cells (MFCs). The degree of cellular lysis provoked by each method was determined by UV-visible spectroscopy of cultures before and after EPS extraction. In addition, two electron microscopy techniques (TEM and SEM) were employed to determine the degree of attachment and the growth of the biofilm overtime on two solid supports: carbon fibre cloth and graphite rods. The main constituents of the EPS extracted by all methods were proteins and carbohydrates, as confirmed by FT-IR analysis, showing the major presence of carboxylic, hydroxylic and amino groups. The greater extractions of EPS were obtained using EDTA. This method also produced a less degree of cellular lysis. Furthermore, both the amount and the chemical composition of EPS strongly depended on the extraction method used.

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RESUMO

Phaffia rhodozyma (now Xanthophyllomyces dendrorhous) and Haematococcus pluvialis are known as the major prominent microorganisms able to synthesize astaxanthin natural pigment. Important research efforts have been made to determine optimal conditions for astaxanthin synthesis. When the focus is on astaxanthin production, the maximal reported value of 9.2 mg/g cell is obtained within H. pluvialis grown on BAR medium, under continuous illumination (345 micromol photon m(-2) s(-1)) and without aeration. Whereas fermentation by mutated R1 yeast grown on coconut milk produced 1,850 microg/g yeast. However, when looking at astaxanthin productivity, the picture is slightly different. The figures obtained with P. rhodozyma are rather similar to those of H. pluvialis. Maximal reported values are 170 microg/g yeast per day with a wild yeast strain and 370 microg/g yeast per day with mutated R1 yeast. In the case of H. pluvialis, maximal values ranged from 290 to 428 microg/g cell per day depending on the media (BG-11 or BAR), light intensity (177 micromol photon m(-2) s(-1)), aeration, etc. The main aim of this work was to examine how astaxanthin synthesis, by P. rhodozyma and H. pluvialis, could be compared. The study is based on previous works by the authors where pigment productions have been reported.

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RESUMO

Natural carbon sources, such as those present in cane sugar molasses and grape juice, promote the synthesis of astaxanthin in different Phaffia rhodozyma yeasts. One of these, coconut milk, has a very rich nutrient composition. The aim of this work was to investigate the utility of coconut milk as sole source of energy for astaxanthin pigment production by P. rhodozyma strains. Currently, coconut pulp is widely used in industrial processes in Mexico for the production of shampoos, candies, food, etc. However, coconut milk is a waste product. We show that coconut milk enhances astaxanthin production. The fermentation yielded 850 microg/g yeast with the NRRL-10921 wild-type strain and 1850 microg/g yeast with the mutated R1 strain. Production was better than reported results employing other natural carbon sources.

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