Adsorption and desorption of arsenic and its immobilization in soils

Arsenic (As) is a naturally occurring chemical element considered toxic and carcinogenic by health and environmental protection agencies. Studies of As adsorption/desorption behavior in soils are important to predictions of As’ potential mobility in natural systems. The aim of this study was to assess the adsorption of As(V) in soils from Minas Gerais, Brazil, and determine its immobilization rate in order to identify soils with characteristics more favorable to its deployment as an As geochemical barrier. The adsorption experiment was performed using different As concentrations and the data pertaining to the maximum adsorption capacity of As(V) (MACAs) were determined by Langmuir and Freundlich isoterms. The Oxisols, due to their more oxidic mineralogy, especially more gibbsitic, and clayey texture, showed the highest MACAs, followed by Ultisols, Inceptisols, and Entisols. In terms of the desorption of As the Inceptisols were the soils that showed the most As desorption. Both As desorption and mobility was lower in the more oxidic and clayey soils. In all soils, the total amount of As was desorbed in due course, but the As release ratio tended to decrease with the passage of time. In general, soils with higher MACAs did not necessarily show less As desorption. For use as a geochemical barrier, as important as a high adsorption capacity of As by the soil is a low As desorption rate. The increase in As mobility may increase the risks of contaminating the supplies of water. To be a good As geochemical barrier the soil has to be a clayey Oxisol, with relatively high amounts of Fe and Al oxides, especially gibbsite.

Adsorption and desorption of arsenic and its immobilization in soils

Arsenic (As) is a naturally occurring chemical element considered toxic and carcinogenic by health and environmental protection agencies. Studies of As adsorption/desorption behavior in soils are important to predictions of As potential mobility in natural systems. The aim of this study was to assess the adsorption of As(V) in soils from Minas Gerais, Brazil, and determine its immobilization rate in order to identify soils with characteristics more favorable to its deployment as an As geochemical barrier. The adsorption experiment was performed using different As concentrations and the data pertaining to the maximum adsorption capacity of As(V) (MACAs) were determined by Langmuir and Freundlich isoterms. The Oxisols, due to their more oxidic mineralogy, especially more gibbsitic, and clayey texture, showed the highest MACAs, followed by Ultisols, Inceptisols, and Entisols. In terms of the desorption of As the Inceptisols were the soils that showed the most As desorption. Both As desorption and mobility was lower in the more oxidic and clayey soils. In all soils, the total amount of As was desorbed in due course, but the As release ratio tended to decrease with the passage of time. In general, soils with higher MACAs did not necessarily show less As desorption. For use as a geochemical barrier, as important as a high adsorption capacity of As by the soil is a low As desorption rate. The increase in As mobility may increase the risks of contaminating the supplies of water. To be a good As geochemical barrier the soil has to be a clayey Oxisol, with relatively high amounts of Fe and Al oxides, especially gibbsite.(AU)

Saccharomyces cerevisiae as a probiotic agent and a possible aflatoxin B1 adsorbent in simulated fish intestinal tract conditions / Saccharomyces cerevisiae como agente probiótico e possível adsorvente de aflatoxina B1 em condições simuladas do trato intestinal de peixes

The aim of this study was to evaluate in vitro the probiotic potential and absorption of Saccharomyces cerevisiae for the aflatoxin B1 in simulated fish intestinal tract conditions. Three yeast strains were used, two from brewery: S. cerevisiae RC1 and S. cerevisiae RC3 and one from a fish farming environment: S. cerevisiae A8L2. The selected yeasts were subjected to the following in vitro tests: homologous inhibition, self-aggregation, co-aggregation, antibacterial activity, gastrointestinal conditions tolerance and adsorption of AFB1. All S. cerevisiae strains showed good capability of self-aggregation and co-aggregation with pathogenic bacteria. All yeast strains were able to survive the gastrointestinal conditions. In acidic conditions, the factors (strain vs. time) had interaction (P=0.0317), resulting in significant variation among the strains tested in the time periods analyzed. It was observed that there was also interaction (P=0.0062) in intestinal conditions, with an increased number of cells in the 12-hour period for all strains tested. In the adsorption test, the A8L2 strain was statistically more effective (P<0.005) for both AFB1 concentrations evaluated in this study (10 and 25ng/mL). Thus, it was observed that the strains of S. cerevisiae have potential probiotic and adsorbent of AFB1.(AU)

Objetivou-se, com esta pesquisa, avaliar in vitro o potencial probiótico e adsorvente de Saccharomyces cerevisiae para aflatoxina B1 em condições simuladas do trato intestinal de peixes. Foram utilizadas três cepas de leveduras, sendo duas provenientes de cervejaria: S. cerevisiae RC1 e S. cerevisiae RC3, e uma de ambiente de piscicultura: S. cerevisiae A8L2. As leveduras selecionadas foram submetidas aos seguintes testes in vitro: inibição homóloga, autoagregação, coagregação, atividade antibacteriana, viabilidade às condições gastrointestinais e adsorção de AFB1. Todas as estirpes de S. cerevisiae mostraram boa capacidade de autoagregação e coagregação com bactérias patogênicas. Todas as estirpes de levedura foram capazes de sobreviver às condições gastrointestinais. Em condições ácidas, os fatores (cepa x tempo) tiveram interação (P=0,0317), resultando em variações significativas entre as cepas testadas nos períodos de tempo analisados. Observou-se que também houve interação (P=0,0062) em condições intestinais, havendo um aumento do número de células no período de 12h para todas as cepas avaliadas. No ensaio de adsorção, a estirpe A8L2 foi a mais eficaz estatisticamente (P<0,005), para as duas concentrações de AFB1 avaliadas neste estudo (10 e 25ng. mL-1). Dessa forma, conclui-se que as cepas de Saccharomyces cerevisiae possuem potencial probiótico e adsorvente de AFB1.(AU)

Saccharomyces cerevisiae as a probiotic agent and a possible aflatoxin B1 adsorbent in simulated fish intestinal tract conditions / Saccharomyces cerevisiae como agente probiótico e possível adsorvente de aflatoxina B1 em condições simuladas do trato intestinal de peixes

The aim of this study was to evaluate in vitro the probiotic potential and absorption of Saccharomyces cerevisiae for the aflatoxin B1 in simulated fish intestinal tract conditions. Three yeast strains were used, two from brewery: S. cerevisiae RC1 and S. cerevisiae RC3 and one from a fish farming environment: S. cerevisiae A8L2. The selected yeasts were subjected to the following in vitro tests: homologous inhibition, self-aggregation, co-aggregation, antibacterial activity, gastrointestinal conditions tolerance and adsorption of AFB1. All S. cerevisiae strains showed good capability of self-aggregation and co-aggregation with pathogenic bacteria. All yeast strains were able to survive the gastrointestinal conditions. In acidic conditions, the factors (strain vs. time) had interaction (P=0.0317), resulting in significant variation among the strains tested in the time periods analyzed. It was observed that there was also interaction (P=0.0062) in intestinal conditions, with an increased number of cells in the 12-hour period for all strains tested. In the adsorption test, the A8L2 strain was statistically more effective (P<0.005) for both AFB1 concentrations evaluated in this study (10 and 25ng/mL). Thus, it was observed that the strains of S. cerevisiae have potential probiotic and adsorbent of AFB1.(AU)

Objetivou-se, com esta pesquisa, avaliar in vitro o potencial probiótico e adsorvente de Saccharomyces cerevisiae para aflatoxina B1 em condições simuladas do trato intestinal de peixes. Foram utilizadas três cepas de leveduras, sendo duas provenientes de cervejaria: S. cerevisiae RC1 e S. cerevisiae RC3, e uma de ambiente de piscicultura: S. cerevisiae A8L2. As leveduras selecionadas foram submetidas aos seguintes testes in vitro: inibição homóloga, autoagregação, coagregação, atividade antibacteriana, viabilidade às condições gastrointestinais e adsorção de AFB1. Todas as estirpes de S. cerevisiae mostraram boa capacidade de autoagregação e coagregação com bactérias patogênicas. Todas as estirpes de levedura foram capazes de sobreviver às condições gastrointestinais. Em condições ácidas, os fatores (cepa x tempo) tiveram interação (P=0,0317), resultando em variações significativas entre as cepas testadas nos períodos de tempo analisados. Observou-se que também houve interação (P=0,0062) em condições intestinais, havendo um aumento do número de células no período de 12h para todas as cepas avaliadas. No ensaio de adsorção, a estirpe A8L2 foi a mais eficaz estatisticamente (P<0,005), para as duas concentrações de AFB1 avaliadas neste estudo (10 e 25ng. mL-1). Dessa forma, conclui-se que as cepas de Saccharomyces cerevisiae possuem potencial probiótico e adsorvente de AFB1.(AU)

Carboximetilquitosana como agente ioadsorvente de íons Cd(II) / Carboxymethylchitosan as bioadhesive agent of Cd(II)

Biopolímeros são uma alternativa viável para a adsorção de metais tóxicos devido ao baixo custo de obtenção e elevada eficiência. Modificações estruturais nestes podem ser feitas para aumentar seu potencial como material adsorvente. Este trabalho tem como objetivo a modificação de quitosana via carboximetilação para realizar um estudo de adsorção de íons Cd(II) em diferentes valores de pH. O potencial de adsorção foi feito a partir de estudos cinéticos que demonstrou um baixo tempo de equilíbrio e que a amostra obedece a uma cinética de pseudosegunda ordem, caracterizando uma quimissorção, além de elevada remoção de Cd(II) que aumentou à medida que o pH do meio foi elevado. Com isso conclui-se que a carboximetilquitosana é um ótimo material adsorvente de íons Cd(II).

Biopolymers are a viable alternative for the adsorption of toxic metals due to the low cost of obtaining and high efficiency. Structural modifications in these can be made to increase their potential as adsorbent material. This work aims to modify chitosan via carboxymethylation to perform an adsorption study of Cd (II) ions at different pH values. The potential of adsorption was made from kinetic studies that demonstrated a low equilibrium time and that the sample obeys a second order kinetics, characterizing a chemisorption, in addition to high Cd (II) removal that increased as the pH of the medium was raised. With this it is concluded that carboxymethylchitosan is an excellent adsorbent material of Cd (II) ions.

Carboximetilquitosana como agente ioadsorvente de íons Cd(II) / Carboxymethylchitosan as bioadhesive agent of Cd(II)

Biopolímeros são uma alternativa viável para a adsorção de metais tóxicos devido ao baixo custo de obtenção e elevada eficiência. Modificações estruturais nestes podem ser feitas para aumentar seu potencial como material adsorvente. Este trabalho tem como objetivo a modificação de quitosana via carboximetilação para realizar um estudo de adsorção de íons Cd(II) em diferentes valores de pH. O potencial de adsorção foi feito a partir de estudos cinéticos que demonstrou um baixo tempo de equilíbrio e que a amostra obedece a uma cinética de pseudosegunda ordem, caracterizando uma quimissorção, além de elevada remoção de Cd(II) que aumentou à medida que o pH do meio foi elevado. Com isso conclui-se que a carboximetilquitosana é um ótimo material adsorvente de íons Cd(II).(AU)

Biopolymers are a viable alternative for the adsorption of toxic metals due to the low cost of obtaining and high efficiency. Structural modifications in these can be made to increase their potential as adsorbent material. This work aims to modify chitosan via carboxymethylation to perform an adsorption study of Cd (II) ions at different pH values. The potential of adsorption was made from kinetic studies that demonstrated a low equilibrium time and that the sample obeys a second order kinetics, characterizing a chemisorption, in addition to high Cd (II) removal that increased as the pH of the medium was raised. With this it is concluded that carboxymethylchitosan is an excellent adsorbent material of Cd (II) ions.(AU)

Zeolite inclusion in dog extruded diets: digestibility, fecal characteristics, and palatability / Inclusão de zeólita em dietas extrusadas para cães: digestibilidade, características fecais e palatabilidade

Addition of zeolite to caninedietscan improve fecal characteristics, reducing its moisture and odor. The objective of this study was to evaluate the effects of an increasing dietary inclusion of zeolite on nutrient and energy digestibility, fecal characteristics, and diet palatability for dogsfed diets containing high soybean meal level. Two experiments were performed. The first experiment evaluated the effect of increasing concentrations (0, 10, 20, 30, 40, or 50 g/kg) of zeolite (clinoptilolite) in extruded dog foods on diet digestibility and fecal quality. Six adult dogs were distributed to treatments arranged in a 6 x 6 Latin square design. The second assessed the effect of 20 or 50 g clinoptilolite per kg of diet on food palatability, where in 20 dogs were distributedinto two tests, in a completely randomized experimental design (0 vs.20 g/kg and 0 vs. 50 g/kg zeolite). Despite the small variation, dietary zeolite inclusion reduced diet metabolizable energy content (15.4 to 14.7 MJ/kg, P 0.05) in ammonia nitrogen, sialic acid, fecal pH,or diet palatability.The inclusion of up to 50 g natural clinoptilolite per kg of diet increases fDM content, maintains adequate fecal score and has no negative impact on diet palatability.

O uso de zeólita na alimentação de cães é realizado visando melhorar as características fecais, reduzindo sua umidade e odor. O presente trabalho teve como objetivo avaliar a inclusão crescente de zeólita sobre a digestibilidade dos nutrientes e energia, características fecais e palatabilidade de cães alimentados com dieta contendo altos níveis de farelo de soja. Foram realizados dois experimentos. O primeiro avaliou a inclusão crescente de zeólita (clinoptilolita): 0, 10, 20, 30, 40 e 50 g/kg em dietas extrusadas para cães sobre a digestibilidade e qualidade das fezes. Foram utilizados seis cães adultos, em quadrado latino 6x6. No segundo experimento avaliou-se a inclusão de 20 e 50 g/kg de clinoptilolita na dieta sobre a palatabilidade em cães. Foram utilizados 20 cães em delineamento inteiramente casualizado em dois tratamentos (0 vs.20g/kg e 0 vs. 50 g/kg de zeólita). Embora com pequena variação, a inclusão de zeólita resultou em redução linear da energia metabolizável (15,4 a 14,7 MJ/kg, P 0,05). Não foram encontradas diferenças na palatabilidade das dietas. A inclusão de até 50 g/kg de clinoptilolita natural aumenta o teor de matéria seca fecal, com manutenção de adequado escore fecal, sem afetar negativamente a palatabilidade das dietas.

Zeolite inclusion in dog extruded diets: digestibility, fecal characteristics, and palatability / Inclusão de zeólita em dietas extrusadas para cães: digestibilidade, características fecais e palatabilidade

Addition of zeolite to caninedietscan improve fecal characteristics, reducing its moisture and odor. The objective of this study was to evaluate the effects of an increasing dietary inclusion of zeolite on nutrient and energy digestibility, fecal characteristics, and diet palatability for dogsfed diets containing high soybean meal level. Two experiments were performed. The first experiment evaluated the effect of increasing concentrations (0, 10, 20, 30, 40, or 50 g/kg) of zeolite (clinoptilolite) in extruded dog foods on diet digestibility and fecal quality. Six adult dogs were distributed to treatments arranged in a 6 x 6 Latin square design. The second assessed the effect of 20 or 50 g clinoptilolite per kg of diet on food palatability, where in 20 dogs were distributedinto two tests, in a completely randomized experimental design (0 vs.20 g/kg and 0 vs. 50 g/kg zeolite). Despite the small variation, dietary zeolite inclusion reduced diet metabolizable energy content (15.4 to 14.7 MJ/kg, P < 0.05) and the coefficient of total tract apparent digestibility of dry matter (0.773 to 0.740, P < 0.05). Fecal dry matter (fDM) content increased as zeolite concentrations increased (30.4% to 36.1%, P < 0.05), but fecal score had no effect. Zeolite concentrations caused no changes (P > 0.05) in ammonia nitrogen, sialic acid, fecal pH,or diet palatability.The inclusion of up to 50 g natural clinoptilolite per kg of diet increases fDM content, maintains adequate fecal score and has no negative impact on diet palatability.(AU)

O uso de zeólita na alimentação de cães é realizado visando melhorar as características fecais, reduzindo sua umidade e odor. O presente trabalho teve como objetivo avaliar a inclusão crescente de zeólita sobre a digestibilidade dos nutrientes e energia, características fecais e palatabilidade de cães alimentados com dieta contendo altos níveis de farelo de soja. Foram realizados dois experimentos. O primeiro avaliou a inclusão crescente de zeólita (clinoptilolita): 0, 10, 20, 30, 40 e 50 g/kg em dietas extrusadas para cães sobre a digestibilidade e qualidade das fezes. Foram utilizados seis cães adultos, em quadrado latino 6x6. No segundo experimento avaliou-se a inclusão de 20 e 50 g/kg de clinoptilolita na dieta sobre a palatabilidade em cães. Foram utilizados 20 cães em delineamento inteiramente casualizado em dois tratamentos (0 vs.20g/kg e 0 vs. 50 g/kg de zeólita). Embora com pequena variação, a inclusão de zeólita resultou em redução linear da energia metabolizável (15,4 a 14,7 MJ/kg, P < 0,05) e do coeficiente de digestibilidade aparente da matéria seca (0,773 a 0,740, P < 0,05). A matéria seca fecal aumentou com os níveis crescentes de zeólita (30,4% a 36,1%, P < 0,05) não afetando, entretanto, o escore das fezes. Os níveis de zeólita não causaram diferença quanto ao nitrogênio amoniacal, ácido siálico e pH fecal (P > 0,05). Não foram encontradas diferenças na palatabilidade das dietas. A inclusão de até 50 g/kg de clinoptilolita natural aumenta o teor de matéria seca fecal, com manutenção de adequado escore fecal, sem afetar negativamente a palatabilidade das dietas.(AU)

Zearalenone adsorption capacity of lactic acid bacteria isolated from pigs

ABSTRACT The ability to adsorb zearalenone by five strain of lactic acid bacteria was evaluated: four strains of Lactobacillus spp. isolated from pig rectal swabs and one commercial strain (Lactobacillus rhamnosus). Several factors affecting the adsorption capacity were evaluated in order to improve the adsorption of the mycotoxin by bacteria. The stability of the zearalenone-bacteria complex was analyzed. In every case, bacterial adsorption capacity was higher than 40.0%. The strain showing the highest adsorption (68.2%) was selected for the following steps of this research. The adsorption percentages obtained after processing 6.5 and 7.5 mL MRS broth were 57.40% + 3.53 and 64.46% + 0.76, respectively. The stability of zearalenone-bacteria complex was evaluated by successively rinsing. In the first rinsing step 42.26% + 0.414 was still bound. In the second rinsing step 25.12% + 0.664 was still bound, whereas 15.82% + 0.675 remained in the pellet after the third rinse. Results obtained demonstrated that Lactic Acid Bacteria has capacity to adsorb zearalenone. Finally adsorption was increased using a higher volume of initial broth. These results could be used to design a new lyophilized powder for detoxification, using lactic acid bacteria as potential zearalenone adsorbents.(AU)

Zearalenone adsorption capacity of lactic acid bacteria isolated from pigs

ABSTRACT The ability to adsorb zearalenone by five strain of lactic acid bacteria was evaluated: four strains of Lactobacillus spp. isolated from pig rectal swabs and one commercial strain (Lactobacillus rhamnosus). Several factors affecting the adsorption capacity were evaluated in order to improve the adsorption of the mycotoxin by bacteria. The stability of the zearalenone-bacteria complex was analyzed. In every case, bacterial adsorption capacity was higher than 40.0%. The strain showing the highest adsorption (68.2%) was selected for the following steps of this research. The adsorption percentages obtained after processing 6.5 and 7.5 mL MRS broth were 57.40% + 3.53 and 64.46% + 0.76, respectively. The stability of zearalenone-bacteria complex was evaluated by successively rinsing. In the first rinsing step 42.26% + 0.414 was still bound. In the second rinsing step 25.12% + 0.664 was still bound, whereas 15.82% + 0.675 remained in the pellet after the third rinse. Results obtained demonstrated that Lactic Acid Bacteria has capacity to adsorb zearalenone. Finally adsorption was increased using a higher volume of initial broth. These results could be used to design a new lyophilized powder for detoxification, using lactic acid bacteria as potential zearalenone adsorbents.

Phosphorus adsorption in soils under forest and savanna from Northern Amazon, Brazil / Adsorção de fósforo em solos sob floresta e savana do Norte Amazônico, Brasil

Studies on maximum phosphorus adsorption capacity (MPAC) in soils from Roraima State and attributes that interfere with the magnitude of this characteristic are relevant and motivated this study. In this context, topsoil samples (00.20 m) from four soil classes (OxisolLA and OxisolLV [ITÃ, Caracaraí]; OxisolLA [Serra da Prata, Mucajaí]; OxisolLA and UltisolPA [CCA, Boa Vista]; OxisolFT [Bonfim] and Alfisol SN [Surumu, Pacaraima]) representative of Roraima State were used in this study in order to determine the influence of soil physical, chemical, and mineralogical attributes on MPAC. Air-dried soil samples of 2.5 g and 0.01 mol L?1 CaCl2 (25 mL) solution were stirred for 24 h, being added P in the form of KH2PO4 at concentrations of 060, 080, and 0110 mg L?1. P was analyzed in the supernatant for determining its adsorbed amount (P-rem). Adsorption values were fitted to the Langmuir isotherm in order to assess MPAC. Correlation tests were performed between MPAC and binding energy, pH, organic matter, clay, and CEC. MPAC values ranged from 14.50 to 527.93 mg kg?1 in the soil. The soils FTBonfim and LVITÃ presented a higher MPAC. Considering the representative soil classes in the State, MPAC does not correlate with any of the assessed attributes. In the soil classes Oxisol and Ultisol, MPAC has a negative and significant correlation with binding energy.(AU)

Estudos sobre capacidade máxima de adsorção de fósforo (CMAP) em solos de Roraima e atributos que interferem na magnitude dessa característica são relevantes e motivaram esse trabalho. Nesse contexto, amostras da camada superficial (0-0,20 m) de quatro classes de solos: Latossolo Amarelo - LA e Latossolo Vermelho - LV (ITÃ, Caracaraí); Latossolo Amarelo - LA (Serra da Prata, Mucajaí); Latossolo Amarelo - LA e Argissolo Amarelo - PA (CCA, Boa Vista-RR); Plintossolo Argilúvico FT (Bonfim) e Planossolo Nátrico - SN (Surumu, Pacaraima) representativos do estado de Roraima, foram utilizadas no presente trabalho, com a finalidade de determinar a influência de atributos físicos, químicos e da mineralogia dos solos sobre a CMAP. Amostras de 2,5 g de TFSA (terra fina seca ao ar) foram mantidas em contato com soluções de CaCl2 0,01 mol L-1 (25 mL), mediante agitação por 24 h, as quais foram adicionados fósforo (P), na forma de KH2PO4, nas concentrações de 0-60, 0-80 e 0-110 mg L-1. O P foi analisado no sobrenadante para a determinação da quantidade adsorvida (P-rem). Para avaliar a capacidade máxima de adsorção de fósforo (CMAP), os valores de adsorção foram ajustados à isoterma de Langmuir. Foram realizados testes de correlação entre CMAP e energia de ligação, pH, matéria orgânica, argila e CTC. Os valores da CMAP situaram-se entre 14,50 e 527,93 mg kg-1 de P no solo. Os solos FT (Bonfim) e LV (ITÃ) apresentaram maior CMAP. Considerando as classes desolos representativas do Estado, a CMAP não se correlaciona com nenhum dos atributos avaliados. Nasclasses Latossolo e Argissolo, a CMAP tem correlação negativa e significativa com a energia de ligação.(AU)

Sorption and desorption of indaziflam degradates in several agricultural soils

Processes regulating pesticide fate in the environment are influenced by the physicochemical properties of pesticides and soils. Sorption and desorption are important processes as they regulate the movement of pesticides in soil. Although sorption-desorption is widely studied for herbicides, studies involving their metabolites in soil are scarce. Sorption and desorption of indaziflam metabolites (indaziflam-triazinediamine (FDAT), indaziflam-triazine-indanone (ITI) and indaziflam-carboxilic acid (ICA)) were investigated in six Brazilian (BRA) soils and three United States (USA) soils with different physicochemical properties. The Freundlich equation described sorption of the metabolites for all soils (R2 > 0.98; 1/n ~ 1). Sorption order (Kf) was ITI > ICA > FDAT. Mean values of Kf,oc were 453, 289, and 81 (BRA) and 444, 48, and 48 (USA) for metabolites ITI, ICA, and FDAT respectively. Desorption was hysteretic for all metabolites in all soils. These results suggest that these metabolites fall in the classification range of mobile to moderately mobile in soils.

Sorption and desorption of indaziflam degradates in several agricultural soils

Processes regulating pesticide fate in the environment are influenced by the physicochemical properties of pesticides and soils. Sorption and desorption are important processes as they regulate the movement of pesticides in soil. Although sorption-desorption is widely studied for herbicides, studies involving their metabolites in soil are scarce. Sorption and desorption of indaziflam metabolites (indaziflam-triazinediamine (FDAT), indaziflam-triazine-indanone (ITI) and indaziflam-carboxilic acid (ICA)) were investigated in six Brazilian (BRA) soils and three United States (USA) soils with different physicochemical properties. The Freundlich equation described sorption of the metabolites for all soils (R2 > 0.98; 1/n ~ 1). Sorption order (Kf) was ITI > ICA > FDAT. Mean values of Kf,oc were 453, 289, and 81 (BRA) and 444, 48, and 48 (USA) for metabolites ITI, ICA, and FDAT respectively. Desorption was hysteretic for all metabolites in all soils. These results suggest that these metabolites fall in the classification range of mobile to moderately mobile in soils.(AU)

Physical-chemical characterization of pre-cooked mixed rice flour and barley bagasse / Caracterização físico-química de farinha mista pré-cozida de arroz e bagaço de cevada

The extrusion processing parameters, chemical composition and water content of the flour mixture may affect the structure of rice flour, leading to products with different rheological behavior and hygroscopicity. Therefore, this work aimed to study the rheological properties and water adsorption of mixed flours of broken rice and barley bagasse obtained by extrusion cooking. Samples were prepared from a mixture of grits/bagasse between 82/18 and 73/27 (w/w) with water content between 18.04 and 26.96%, using a single screw extruder. The rheological properties of the extruded flour were determined by a rapid viscosity analyzer to evaluate the cooking profile of the pastes by observing the pasting temperature, maximum viscosity, breakdown and retrogradation. The adsorption process was performed by weighing the samples stored at temperatures of 25, 30, 35 and 45 °C with water activity between 0.112 and 0.973. The isotherms were fitted using the following mathematical models: Halsey, Oswin, Smith, GAB and Peleg. The extruded composite flours were characterized by their lack of initial viscosity. The pasting temperature (40-67 °C), maximum viscosity (690-1146 cP), breakdown viscosity (0-175 cP) and retrogradation (613-1382 cP) were lower than for raw rice flour. The Peleg equation fitted well to the water adsorption data and can be used to represent the sigmoidal type II shape of the water adsorption isotherms for the extruded mixed flours from rice grits and barley bagasse.(AU)

Os parâmetros do processo de extrusão, composição química e teor de água da mistura podem afetar a estrutura da farinha de arroz originando produtos com diferentes comportamentos reológicos e higroscópicos. Por isso, o presente trabalho teve por objetivo estudar as principais propriedades reológicas e de adsorção de água de farinhas mistas de quirera de arroz e bagaço de cevada obtidas por extrusão termoplástica. As amostras foram elaboradas a partir de uma mistura de arroz/bagaço entre 82/18 e 73/27 (m/m) e teor de água entre 18,04 e 26,96%, utilizando-se uma extrusora de parafuso único. As propriedades reológicas das farinhas extrudadas foram determinadas por meio de um determinador rápido de viscosidade avaliando-se o perfil de cozimento das pastas pela observação da temperatura de empastamento, viscosidade máxima, quebra de viscosidade e tendência à retrogradação. O processo de adsorção foi determinado utilizando-se o método gravimétrico estático em temperaturas de 25, 30, 35 e 45 °C e atividades de água entre 0,112 e 0,973. As isotermas foram ajustadas a modelos matemáticos de Halsey, Oswin, Smith, GAB e Peleg. As farinhas mistas extrudadas se caracterizaram por não apresentar viscosidade inicial. A temperatura de empastamento (40-67 °C), viscosidade máxima (690-1146 cP), quebra de viscosidade (0-175 cP) e tendência à retrogradação (613-1382 cP) foram inferiores às da farinha de arroz crua. Os dados de adsorção de água foram bem ajustados pela equação de Peleg, podendo-se utilizar para representar as isotermas de adsorção de água de forma sigmoidal do tipo II das farinhas mistas extrudadas de quirera de arroz e bagaço de cevada.(AU)

Phosphorus fractions in an agricultural chronosequence under tillage regimes in the Cerrado area in Goiás, Brazil / Frações de fósforo em uma cronossequência de agricultura sob plantio direto no cerrado goiano

The increase in the amount and quantity of soil organic matter (SOM), as well as the use of phosphorus-based fertilizers in the superficial soil layer in areas under tillage regimes (TR), may affect phosphorus (P) dynamics in the soil. Therefore, the aims of the present work were as follows: to evaluate the inorganic and organic fractions of P and its lability levels (labile, moderately labile, and moderately resistant) in a Distroferric Red Latosol under tillage regimes (TR) 3, 15, and 20 years after implementation, and to compare them with those of areas of native Cerrado and pastures. We also focus on analyzing the correlations of the P fractions in these areas with other soil attributes, such as total carbon and nitrogen levels, light organic matter (LOM), chemical and physical granulometric fractions of the SOM, maximum phosphate adsorption capacity (MPAC), and the remaining phosphorus (Prem). In each of these areas, samples were collected from the 0.0-0.05 and 0.05-0.10 m soil layers. An entirely randomized experimental design was used. After TR implementation, the constant use of phosphorus-based fertilizers as well as the incremental addition of SOM resulted in an increase in the levels of labile, moderate labile, and moderately resistant organic and inorganic P, with a tendency for total P accumulation to be mostly in the inorganic, moderately labile form. The native Cerrado soil presented high levels of labile and moderately labile inorganic P. Pasture areas presented the lowest levels of labile organic and inorganic P, as well as moderately labile and moderately resistant organic P. By principal component analysis (PCA), it was possible to observe alterations in all soil attributes and P levels of the fractions analyzed.(AU)

O aumento da quantidade e qualidade da matéria orgânica do solo (MOS), bem como a aplicação de fertilizantes fosfatados na camada superficial do solo em áreas de sistema de plantio direto (SPD) podem alterar a dinâmica do P no solo. Desta forma, os objetivos deste trabalho foram avaliar as frações inorgânicas e orgânicas de P e o grau de labilidade destas (lábil, moderamente lábil e moderadamente resistente) de um Latossolo Vermelho Distroférrico sob sistema de plantio direto (SPD) com 3, 15 e 20 anos de implantação, e compará-las a áreas de cerrado nativo e pastagem; bem como, analisar correlações entre os resultados das frações de P destas áreas com outros atributos, tais como, teor de carbono e nitrogênio total, matéria orgânica leve (MOL), frações químicas e físicas granulométricas da MOS, capacidade máxima de adsorção de fosfato (CMAP) e fósforo remanescente (Prem). Em cada uma das áreas foram coletadas amostras nas profundidades de 0,0-0,05 e 0,05-0,10 m. O delineamento utilizado foi inteiramente casualizado. O uso constante de adubação fosfatada, bem como, o incremento da MOS, aumenta com o passar dos anos de adoção do SPD os teores de P orgânico e inorgânico lábil, moderadamente lábil e moderadamente resistente, tendendo a acumular a maior parte do P total do solo na forma inorgânica e moderadamente lábil. O solo sob Cerrado nativo apresenta altos valores de P orgânico lábil e moderadamente lábil. A área de pastagem apresentou menores teores de P orgânico e inorgânico lábil, P orgânico moderadamente lábil e moderadamente resistente em relação às demais áreas avaliadas. Através da análise de componentes principais (ACP), pode-se verificar interações entre todos os atributos do solo e os teores de P das frações analisadas.(AU)

Estimation of herbicide bioconcentration in sugarcane (Saccharum officinarum L. ) / Modelagem de bioconcentração de herbicidas em cana (Saccharum officinarum L. )

Sugarcane is an important crop for sugar and biofuel production in Brazil. Growers depend greatly on herbicides to produce it. This experiment used herbicide physical-chemical and sugarcane plant physiological properties to simulate herbicide uptake and estimate the bioconcentration factor (BCF). The (BCF) was calculated for the steady state chemical equilibrium between the plant herbicide concentration and soil solution. Plant-water partition coefficient (sugarcane bagasse-water partition coefficient), herbicide dilution rate, metabolism and dissipation in the soil-plant system, as well as total plant biomass factors were used. In addition, we added Tebuthiuron at rate of 5.0kg a.i. ha-1 to physically test the model. In conclusion, the model showed the following ranking of herbicide uptake: sulfentrazone > picloram >tebuthiuron > hexazinone > metribuzin > simazine > ametryn > diuron > clomazone > acetochlor. Furthermore, the highest BCF herbicides showed higher Groundwater Ubiquity Score (GUS) index indicating high leaching potential. We did not find tebuthiuron in plants after three months of herbicide application.(AU)

A cana de açúcar é uma cultura importante para produção de açúcar e biocombustíveis no Brasil e exige elevada utilização de herbicidas. Utilizamos modelo matemático para ajudar na compreensão da absorção de herbicida dessa cultura. Propriedades físico-químicas dos herbicidas e propriedades fisiológicas das plantas de cana foram usados para estimar a absorção e também o fator de bioconcentração, bioconcentration factor (BCF), calculado para o equilíbrio químico entre a concentração do herbicida na planta e na solução do solo. O coeficiente de partição planta/água, a taxa de diluição de herbicida, o metabolismo e a dissipação no sistema solo-planta e biomassa total das plantas foram adicionados ao modelo. O herbicida tebuthiuron aplicado ao solo na dose de 5,0kg ha-1 i.a. foi utilizado para testar o modelo. A absorção dos herbicidas mostrada pelo modelo indicou em ordem o seguinte: sulfentrazone> picloram> tebuthiuron> hexazinone> metribuzin> simazina> ametryn> diuron> clomazone> acetochlor. Esses herbicidas com alto índice (BCF) também apresentaram alto índice de potencial de lixiviação para água subterrânea "Groundwater Ubiquity Score" (GUS). Tebuthiuron não foi encontrado nas plantas após três meses de aplicação.(AU)

Biomarcadores sanguíneos de exposição à zearalenona e aplicabilidade na avaliação da eficiência de aditivos antimicotoxinas em suínos e bovinos.

A inclusão de aditivos antimicotoxinas (AAM) na dieta de animais de produção tem sido utilizada para evitar a exposição às micotoxinas. Preconiza-se a medição das micotoxinas e/ou seus metabólitos em fluidos biológicos como marcadores para confirmar a eficácia desses produtos. Este trabalho consiste em dois estudos e objetivou: (a) aprimorar uma metodologia analítica baseada em cromatografia líquida de alta eficiência acoplada à espectrometria de massas (HPLC-MS/MS) para a detecção e quantificação de zearalenona (ZEA) e seus metabólitos, -zearalenol (-ZEL), -zearalenol, -zearalanol, -zearalanol (-ZAL) e zearalanona, em soro sanguíneo; e (b) executar testes em espécies susceptíveis à ZEA para avaliar a exposição à micotoxicose e utilizar biomarcadores sanguíneos para verificar a eficácia de AAM. No primeiro estudo, 24 novilhas de corte foram distribuídas aleatoriamente para receber um destes tratamentos (n=6/tratamento): T1) dieta basal (controle); T2) dieta basal + 5 mg/kg ZEA; T3) dieta basal + 5 mg/kg ZEA + 2,5 kg/t AAM; e T4) dieta basal + 5 mg/kg ZEA + 5 kg/t AAM. A investigação durou 37 dias. Após o fornecimento da dieta, amostras de sangue foram colhidas em diferentes dias, centrifugadas para a obtenção do soro sanguíneo e analisadas por HPLC-MS/MS. Entre os metabólitos analisados, -ZAL foi detectado acima do limite de quantificação nas formas não conjugadas (>0,60 µg/kg) e conjugadas (>1,70 µg/kg). Os demais metabólitos apresentaram concentrações abaixo do limite de detecção. Na avaliação da eficácia do AAM, não houve diferença significativa (P>0,05) entre os tratamentos com e sem aditivo nos níveis de inclusão avaliados. No segundo estudo, 70 leitoas pré-púberes foram distribuídas em sete grupos (n=10), alimentadas com dietas apresentando dois níveis de inclusão de AAM à base de argila (0,25% e 0,50%) e três níveis de inclusão de ZEA (0, 0,75 e 1 mg/kg) por 42 dias. Foram realizadas avaliações de peso inicial e final, ganho médio diário, consumo médio diário, conversão alimentar e vulvometria junto às colheitas de sangue para avaliação de ZEA e metabólitos em soro. As amostras de sangue foram centrifugadas para a separação do soro e analisadas por HPLC-MS/MS. Ao fim do período experimental, os animais foram abatidos e eviscerados para avaliar o peso e o comprimento do trato reprodutivo. O desempenho zootécnico não foi afetado pela adição de ZEA à dieta, não havendo diferença na inclusão de AAM (P>0,05). A ZEA aumentou significativamente (P<0,05) o peso, o comprimento do trato reprodutivo e o volume vulvar (largura, comprimento e área); não houve diferença entre os tratamentos com a adição de AAM à dieta (P>0,05). Quanto aos metabólitos pesquisados, -ZEL foi detectado acima do limite de quantificação nas formas não conjugadas (>0,15 µg/kg) e conjugadas (>1,58 µg/kg). A concentração dos demais metabólitos ficou abaixo do limite de detecção, confirmando os resultados da eficácia do AAM (P<0,05). Os resultados obtidos com este trabalho contribuem para a busca da qualidade de AAMs comercializados, bem como para a utilização de métodos analíticos e biomarcadores; estes podem representar uma alternativa para a confirmação da eficácia desses produtos em novilhas e leitoas.

The inclusion of antimycotoxins additives (AMA) in the diet of production animals has been used to avoid mycotoxins exposure. To confirm the efficacy of such products in vivo, measurement of mycotoxins and/or their metabolites in biological fluids is preconized. This work consists of two studies and aimed to: (a) improve an analytical methodology based on High Performance Liquid Chromatography Coupled to Tandem Mass Spectrometry (HPLC-MS/MS) to detect and quantify zearalenone (ZEA) and its metabolites, -zearalenol (-ZOL), -zearalenol, -zearalanol, -zearalanol (-ZAL) and zearalanone, in blood serum; and (b) to conduct tests in species which are susceptible to ZEA to evaluate exposure to mycotoxicosis and to use serological biomarkers to assess the efficacy of AMA. In the first study, 24 beef heifers were randomly assigned to receive one of these treatments (n=6/treatament): T1) basal diet (control); T2) basal diet + 5 mg/kg ZEA; T3) basal diet + 5 mg/kg ZEA + 2.5 kg/t AMA; and T4) basal diet + 5 mg/kg ZEA + 5.0 kg/t AMA. The trial lasted 37 days. Blood was collected on different days after the diet was given, and the samples were centrifuged to obtain the blood serum and then analysed by HPLC-MS/MS. Among the analyzed metabolliates, -ZAL was detected above the limit of quantification both in the unconjugated (>0.60 g/kg) and conjugated (>1.70 g/kg) forms. The remaining metabolites presented concentrations under the limit of detection. In the efficacy evaluation of the AMA, there was no significant difference (P>0.05) between the treatments with and without AMA at the tested levels of inclusion. In the second study, 70 pre-pubertal gilts were distributed in seven feeding groups (n=10/treatment) receiving diets with two levels of three clay-based AMAs (0.25% and 0.50%) and three levels of ZEA (0, 0.75 and 1 mg/kg) for 42 days. Initial and final body weight (BW), mean daily weight gain, mean daily feed intake, feed conversion and vulva volume were assessed at the time of blood sampling to determine ZEA and its metabolites in the serum. Blood samples were spun to obtain the serum, which was analyzed via HPLC-MS/MS. When the experimental period ceased, the animals were slaughtered and eviscerated in order to evaluate weight and length of the reproductive tract. The zootechnical performance was not affected by the presence of ZEA in the diet, and inclusion of AMA did not determine differences (P>0.05). ZEA caused a significant increase (P<0.05) in BW, length of the reproductive tract and vulva measurement (width, length and area), with no difference (P>0.05) between treatments with the addition of AMA to the diet (P>0.05). With respect to the evaluated metabolites, -ZOL was detected above the limit of quantification in both unconjugated (>0.15 g/kg) and unconjugated (>1.58 g/kg) forms. The concentration of the remaining metabolites was below the limit of detection, thus confirming the results of the efficacy of AMA (P<0.05). The findings in this study contribute to the search of quality of the marketed AMA as well as to the assessment of analytical methods and biomarkers; these substances may represent an alternative to confirm the efficacy of such products in heifers and gilts.

Effects of dietary clinoptilolite and calcium levels on the performance and egg quality of commercial layers

Among the different feed additives studied in poultry production, clinoptilolite, an aluminosilicate capable of adsorbing harmful substances and of improving live performance and egg and meat quality, was evaluated. The objective of the present study was to evaluate the influence of dietary clinoptilolite and calcium levels on the performance and egg quality of layers. In total, 576 layers were distributed according to a completely randomized experimental design in a 3 x 4 factorial arrangement (three calcium levels - 2.5, 3.1, or 3.7% and four clinoptilolite levels - 0.0, 0.15, 0.25, or 0.50%), with 12 treatments of six replicates of eight birds each. The experiment included four 28-d cycles. The experimental diets were based on corn and soybean meal. Results were submitted to analysis of variance and means were compared by the test of Tukey at 5% significance level using SISVAR statistical package. There was a significant interaction between the evaluated factors for egg production and feed conversion ratio per dozen eggs and egg mass. The lowest calcium level resulted in worse performance and eggshell quality. Clinoptilolite levels affected albumen and yolk content. It was concluded that up to 0.50% inclusion of clinoptilolite in layer diets does not benefit layer performance or eggshell quality. Although the inclusion of only 2.5% calcium in layer diets is not recommended, it is possible to add 3.1% because it promoted similar results as the recommended level of 3.7%.

Effects of dietary clinoptilolite and calcium levels on the performance and egg quality of commercial layers

Among the different feed additives studied in poultry production, clinoptilolite, an aluminosilicate capable of adsorbing harmful substances and of improving live performance and egg and meat quality, was evaluated. The objective of the present study was to evaluate the influence of dietary clinoptilolite and calcium levels on the performance and egg quality of layers. In total, 576 layers were distributed according to a completely randomized experimental design in a 3 x 4 factorial arrangement (three calcium levels - 2.5, 3.1, or 3.7% and four clinoptilolite levels - 0.0, 0.15, 0.25, or 0.50%), with 12 treatments of six replicates of eight birds each. The experiment included four 28-d cycles. The experimental diets were based on corn and soybean meal. Results were submitted to analysis of variance and means were compared by the test of Tukey at 5% significance level using SISVAR statistical package. There was a significant interaction between the evaluated factors for egg production and feed conversion ratio per dozen eggs and egg mass. The lowest calcium level resulted in worse performance and eggshell quality. Clinoptilolite levels affected albumen and yolk content. It was concluded that up to 0.50% inclusion of clinoptilolite in layer diets does not benefit layer performance or eggshell quality. Although the inclusion of only 2.5% calcium in layer diets is not recommended, it is possible to add 3.1% because it promoted similar results as the recommended level of 3.7%.(AU)

Effects of dietary clinoptilolite and calcium levels on the performance and egg quality of commercial layers

Among the different feed additives studied in poultry production, clinoptilolite, an aluminosilicate capable of adsorbing harmful substances and of improving live performance and egg and meat quality, was evaluated. The objective of the present study was to evaluate the influence of dietary clinoptilolite and calcium levels on the performance and egg quality of layers. In total, 576 layers were distributed according to a completely randomized experimental design in a 3 x 4 factorial arrangement (three calcium levels - 2.5, 3.1, or 3.7% and four clinoptilolite levels - 0.0, 0.15, 0.25, or 0.50%), with 12 treatments of six replicates of eight birds each. The experiment included four 28-d cycles. The experimental diets were based on corn and soybean meal. Results were submitted to analysis of variance and means were compared by the test of Tukey at 5% significance level using SISVAR statistical package. There was a significant interaction between the evaluated factors for egg production and feed conversion ratio per dozen eggs and egg mass. The lowest calcium level resulted in worse performance and eggshell quality. Clinoptilolite levels affected albumen and yolk content. It was concluded that up to 0.50% inclusion of clinoptilolite in layer diets does not benefit layer performance or eggshell quality. Although the inclusion of only 2.5% calcium in layer diets is not recommended, it is possible to add 3.1% because it promoted similar results as the recommended level of 3.7%.