Cover cropping system and mulching can shape soil microbial status in fruit orchards

The use of cover crop in agricultural fields has been well elucidated, especially regarding nitrogen fixation from legume crops and their function as weed protection. Furthermore, to cover crops can benefit the soil microbial community. This study aimed to evaluate and compare the benefits of mulching and cover cropping systems on soil microbial growth and activity, and their effects on plant mineral nutrition in pomelo (Citrus maxima ) and macadamia ( Macadamia integrifolia ) orchards. The treatments included: 1) control [Glyphosate herbicide (Roundup at 4 l per ha)], 2) manual weed control, 3) mulching with dead leaves from their respective trees (macadamia and pomelo), 4) millet, 5) faba bean, 6) millet + faba bean. All the treatments were applied for 120 days before soil and plant leaves were sampled for analyses. Plant mineral nutrition, soil microbial biomass C (MBC) and soil microbial biomass N (MBN); basal respiration (BRA), arbuscular mycorrhizal fungi (AMF) colonization (COL); number of AMF spores (SPO) in soil; total organic carbon (TOC) and total nitrogen (TN) were evaluated. Plant nutrition was not altered by the treatments; however, the MBC, COL and SPO markedly increased in response to mulching and faba bean + millet treatments. Especially in macadamia soils, these treatments had a great response to soil microbiology. Significant negative correlations were also detected for the COL, SPO, BRA and TOC with the Nutrient Balance Index (NBI). These results indicate that in short-term the cover cropping system is useful to improve the soil microbial growth and AMF formation in soils of pomelo and macadam orchards.

Cover cropping system and mulching can shape soil microbial status in fruit orchards

The use of cover crop in agricultural fields has been well elucidated, especially regarding nitrogen fixation from legume crops and their function as weed protection. Furthermore, to cover crops can benefit the soil microbial community. This study aimed to evaluate and compare the benefits of mulching and cover cropping systems on soil microbial growth and activity, and their effects on plant mineral nutrition in pomelo (Citrus maxima ) and macadamia ( Macadamia integrifolia ) orchards. The treatments included: 1) control [Glyphosate herbicide (Roundup at 4 l per ha)], 2) manual weed control, 3) mulching with dead leaves from their respective trees (macadamia and pomelo), 4) millet, 5) faba bean, 6) millet + faba bean. All the treatments were applied for 120 days before soil and plant leaves were sampled for analyses. Plant mineral nutrition, soil microbial biomass C (MBC) and soil microbial biomass N (MBN); basal respiration (BRA), arbuscular mycorrhizal fungi (AMF) colonization (COL); number of AMF spores (SPO) in soil; total organic carbon (TOC) and total nitrogen (TN) were evaluated. Plant nutrition was not altered by the treatments; however, the MBC, COL and SPO markedly increased in response to mulching and faba bean + millet treatments. Especially in macadamia soils, these treatments had a great response to soil microbiology. Significant negative correlations were also detected for the COL, SPO, BRA and TOC with the Nutrient Balance Index (NBI). These results indicate that in short-term the cover cropping system is useful to improve the soil microbial growth and AMF formation in soils of pomelo and macadam orchards.(AU)

Changes in the stocks of C and N in organic matter fractions in soil cropped with coffee and fertilized with sunn hemp and ammonium sulfate / Alterações dos estoques de C e N nas frações da matéria orgânica de solo cultivado com cafeeiro e adubado com crotalária e sulfato de amônio

Despite the potential to provide N to crops, the rapid incorporation of green manure nutrients into stable fractions of organic matter in the soil (SOM) may reduce the efficiency of green manuring. Thus, the objective of this work was to characterize the changes of C and N stocks in fractions of SOM cultivated with coffee (Coffea arabica L.) and fertilized with sunn hemp (Crotalaria juncea) and ammonium sulfate. To study the changes in organic C (OC) and total N (TN) in soil and fractions of SOM over time, soil samples were collected in the 0–5 and 5–10 cm layers, with the initial sampling done prior to the application of sunn hemp residues and ammonium sulfate. Five samples were collected every 2 months after the application of the legume and ammonium sulfate. The soil samples were submitted to densimetric and granulometric fractionation, obtaining the free light organic matter (F-LOM), particulate organic matter (POM), and organic matter associated with minerals (MAM). OC and TN stocks were then determined in soil and the SOM fractions. The changes in the stocks of OC (ΔStcC) in the soil in relation to time zero were positive in the evaluations carried out in the two layers. The fractions of SOM showed positive ΔStcC at almost all of the evaluated times. The N supplied to the soil in the form of mineral and organic fertilizer promoted an increase of 0.24 Mg ha-¹ of N in the 0–5 cm layer until after 60 days. Of this total, 0.03 Mg ha-¹ was associated with F-LOM, 0.07 Mg ha-¹ with POM, and the remainder was associated with MAM. Nearly 60% of the N that was supplied to the soil was drawn to the stable fractions of the SOM, indicating a rapid stabilization of this nutrient in the most recalcitrant organic compartments. Despite that, the variations in N stocks of MAM became smaller over time, and eventually became negative, in relation to time zero.[...](AU)

Apesar do potencial para fornecer N aos cultivos, a rápida incorporação dos nutrientes do adubo verde em frações estáveis da matéria orgânica do solo (MOS) pode reduzir a eficiência da adubação verde. Portanto, objetivou-se com este trabalho caracterizar as alterações temporais dos estoques de C e N em frações da matéria orgânica de solo cultivado com cafeeiro (Coffea arabica L.) e adubado com crotalária (Crotalaria juncea) e sulfato de amônio. Para estudar o comportamento do C orgânico (CO) e N total (NT) no solo e nas frações da MOS ao longo do tempo, foram coletadas amostras de solo nas camadas de 0–5 e 5–10 cm, sendo a primeira amostragem antes da aplicação dos resíduos de crotalária e sulfato de amônio. Outras cinco amostras foram coletadas a cada dois meses após a aplicação da leguminosa e sulfato de amônio. As amostras de solo foram submetidas ao fracionamento densimétrico e granulométrico, obtendo-se as frações matéria orgânica leve livre (MOLL), matéria orgânica particulada (MOP) e matéria orgânica associada aos minerais (MAM). Foram determinados os estoques de CO e NT no solo e nas frações da MOS. As variações nos estoques de C (ΔEstC) orgânico no solo, em relação ao tempo zero, foram positivas nas avaliações realizadas nas duas camadas. As frações da MOS apresentaram ΔEstC positivas em quase todos os tempos de avaliação. O N aportado ao solo na forma de fertilizante mineral e orgânico promoveu incremento de 0,24 Mg ha-¹ de N na camada de 0–5 cm até os 60 dias. Desse total, 0,03 Mg ha-¹ estavam associados à MOLL, 0,07 Mg ha-¹ à MOP e o restante estava associado à MAM. Quase 60% do N que foi aportado ao solo teve como destino frações estáveis da MOS, indicando rápida estabilização desse nutriente nos compartimentos orgânicos mais recalcitrantes. Apesar disso, com o passar do tempo as variações nos estoques de N da MAM tornaram-se menores, e posteriormente negativas, em relação ao tempo zero, indicando a mineralização do N desse compartimento.[...](AU)

Fermentation characteristics and nutritive values of sorghum silages / Características fermentativas e valor nutritivo de silagens de sorgo

The objective of this study was to select sorghum genotypes for silage production. The study was carried out at Embrapa Maize & Sorghums experimental field. Planting was performed in randomized blocks, with three replicates and the Scott-Knott test at a 5% probability level. The material was ensilaged in laboratory silos opened after 56 days for analysis concerning fermentation and bromatological composition. Only crude protein showed no significant difference (p > 0.05), with an overall mean of 8.88%. The other variables presented significant differences (p < 0.05): pH (3.34 to 3.94); Aw (0.93 to 0.98); N-NH 3/TN (1.61 to 6.56%); green matter yield (12.05 to 34.14 t ha-1); dry matter yield (6.19 to 11.42 t ha-1); dry matter (26.89 to 49.95%); ashes (4.08 to 6.88%); neutral detergent fiber corrected for ash and protein (47.67 to 65.79%); acid detergent fiber (16.62 to 35.89%); hemicellulose:cellulose (1.07 to 2.71%); lignin (2.03 to 6.52%), digestible dry matter yield (3.70 to 7.41 t ha-1) and dry matter digestibility (56.36 to 72.67%). Based on digestible dry matter yield, the genotypes: male 201191 and hybrids 2012F47484, 2012F47515 and 2012F47525 stood out in relation to the others for showing good yielding, adequate nutritional value, with low dry matter and NDF levels coupled with high digestibility values and good fermentation patterns of the silages.(AU)

Objetivou-se selecionar genótipos de sorgo para produção de silagem. O estudo foi conduzidono campo experimental da Embrapa Milho e Sorgo. O plantio foi realizado em blocos casualizados, com três repetições e teste Scott-Knott em nível de 5% de probabilidade. O material foi ensilado em silos laboratoriais, abertos com 56 dias para realização das análises fermentativa e composição bromatológica. Somente a proteína bruta não apresentou diferença significativa (p > 0,05), com média geral de 8,88%. As demais variáveis apresentaram diferenças significativas (p < 0,05):pH (3,34 a 3,94); Aw (0,93 a 0,98); NNH3/ NT (1,61 a 6,56 %); produção de matéria verde (12,05 a 34,14 t ha-¹); produção de matéria seca (6,19 a 11,42 t ha-¹); matéria seca (26,89 a 49,95 %); cinzas (4,08 a 6,88 %); fibra em detergente neutro corrigido para cinzas e proteínas (47,67 a 65,79 %); fibra em detergente ácido (16,62 a 35,89%); hemicelulose:celulose (1,07 a 2,71 %); lignina (2,03 a 6,52 %), produção de matéria seca digestível (3,70 a 7,41 t ha-¹) e digestibilidade da matéria seca (56,36 a 72,67%). Com base na produção de matéria seca digestível, os genótipos: macho 201191, e os híbridos 2012F47484, 2012F47515 e 2012F47525 se sobressaíram em relação aos demais uma vez que apresenta boa produtividade, adequado valor nutricional, com baixos teores de matéria seca e FDN aliado com altos valores de digestibilidade e bom padrão fermentativo das silagens.(AU)

Fermentation characteristics and nutritive values of sorghum silages / Características fermentativas e valor nutritivo de silagens de sorgo

The objective of this study was to select sorghum genotypes for silage production. The study was carried out at Embrapa Maize & Sorghum’s experimental field. Planting was performed in randomized blocks, with three replicates and the Scott-Knott test at a 5% probability level. The material was ensilaged in laboratory silos opened after 56 days for analysis concerning fermentation and bromatological composition. Only crude protein showed no significant difference (p > 0.05), with an overall mean of 8.88%. The other variables presented significant differences (p < 0.05): pH (3.34 to 3.94); Aw (0.93 to 0.98); N-NH 3/TN (1.61 to 6.56%); green matter yield (12.05 to 34.14 t ha-1); dry matter yield (6.19 to 11.42 t ha-1); dry matter (26.89 to 49.95%); ashes (4.08 to 6.88%); neutral detergent fiber corrected for ash and protein (47.67 to 65.79%); acid detergent fiber (16.62 to 35.89%); hemicellulose:cellulose (1.07 to 2.71%); lignin (2.03 to 6.52%), digestible dry matter yield (3.70 to 7.41 t ha-1) and dry matter digestibility (56.36 to 72.67%). Based on digestible dry matter yield, the genotypes: male 201191 and hybrids 2012F47484, 2012F47515 and 2012F47525 stood out in relation to the others for showing good yielding, adequate nutritional value, with low dry matter and NDF levels coupled with high digestibility values and good fermentation patterns of the silages.

Objetivou-se selecionar genótipos de sorgo para produção de silagem. O estudo foi conduzidono campo experimental da Embrapa Milho e Sorgo. O plantio foi realizado em blocos casualizados, com três repetições e teste Scott-Knott em nível de 5% de probabilidade. O material foi ensilado em silos laboratoriais, abertos com 56 dias para realização das análises fermentativa e composição bromatológica. Somente a proteína bruta não apresentou diferença significativa (p > 0,05), com média geral de 8,88%. As demais variáveis apresentaram diferenças significativas (p < 0,05):pH (3,34 a 3,94); Aw (0,93 a 0,98); NNH3/ NT (1,61 a 6,56 %); produção de matéria verde (12,05 a 34,14 t ha-¹); produção de matéria seca (6,19 a 11,42 t ha-¹); matéria seca (26,89 a 49,95 %); cinzas (4,08 a 6,88 %); fibra em detergente neutro corrigido para cinzas e proteínas (47,67 a 65,79 %); fibra em detergente ácido (16,62 a 35,89%); hemicelulose:celulose (1,07 a 2,71 %); lignina (2,03 a 6,52 %), produção de matéria seca digestível (3,70 a 7,41 t ha-¹) e digestibilidade da matéria seca (56,36 a 72,67%). Com base na produção de matéria seca digestível, os genótipos: macho 201191, e os híbridos 2012F47484, 2012F47515 e 2012F47525 se sobressaíram em relação aos demais uma vez que apresenta boa produtividade, adequado valor nutricional, com baixos teores de matéria seca e FDN aliado com altos valores de digestibilidade e bom padrão fermentativo das silagens.

Ph, Ammonia Flux, and Total Nitrogen in Duck Litter with Chemical Blends - A Field Study

This study was designed to evaluate the effects of chemical blend additives to duck litter on pH, ammonia (NH3) fluxes, total nitrogen (TN) under a small pen trial. One hundred twenty 1-day-old duck (pekin) were randomly assigned to 6 pens in a completely randomized design during 6 weeks. Control received no litter treatment whereas top-dressed treatment at rates of 50 g aluminum sulfate + 50 aluminum chloride/kg duck litter were mixed into the upper 1 cm of duck litter. Duck litter pH at 2 weeks through 5 weeks was significantly affected (p 0.05) by chemical blend treatments compared to controls, but not at 6 weeks. During the experimental periods, NH3 fluxes decreased (p 0.05) in chemical blend treatments. However, there were no remarkable difference (p>0.05) between treatments at 0 and 1 week. Reductions of NH3 fluxes at 3, 4, 5 and 6 weeks were 31, 16, 29 and 24%, respectively. Chemical blend treatments as a function of time resulted in increase in TN contents compared with control. There were no significant differences (p>0.05) in TN between treatments at 2 and 3 weeks, except for 4, 5 and 6 weeks. Chemical blend decreases NH3 fluxes and increases TN positively by reducing duck litter pH.(AU)

Ph, Ammonia Flux, and Total Nitrogen in Duck Litter with Chemical Blends - A Field Study

This study was designed to evaluate the effects of chemical blend additives to duck litter on pH, ammonia (NH3) fluxes, total nitrogen (TN) under a small pen trial. One hundred twenty 1-day-old duck (pekin) were randomly assigned to 6 pens in a completely randomized design during 6 weeks. Control received no litter treatment whereas top-dressed treatment at rates of 50 g aluminum sulfate + 50 aluminum chloride/kg duck litter were mixed into the upper 1 cm of duck litter. Duck litter pH at 2 weeks through 5 weeks was significantly affected (p 0.05) by chemical blend treatments compared to controls, but not at 6 weeks. During the experimental periods, NH3 fluxes decreased (p 0.05) in chemical blend treatments. However, there were no remarkable difference (p>0.05) between treatments at 0 and 1 week. Reductions of NH3 fluxes at 3, 4, 5 and 6 weeks were 31, 16, 29 and 24%, respectively. Chemical blend treatments as a function of time resulted in increase in TN contents compared with control. There were no significant differences (p>0.05) in TN between treatments at 2 and 3 weeks, except for 4, 5 and 6 weeks. Chemical blend decreases NH3 fluxes and increases TN positively by reducing duck litter pH.

ÓLEO DE PEQUI (Caryocar brasilience Camb.) NA ALIMENTAÇÃO DE FRANGOS DE CORTE

O pequi (Caryocar brasiliense camb.) é um fruto nativo do cerrado brasileiro e do qual pode-se extrair o óleo de pequi, apresentando coloração alaranjada e alto teor de carotenoides com propriedades antioxidantes. Diante disso, dois ensaios experimentais foram realizados com o objetivo de avaliar os efeitos da adição do óleo de pequi na alimentação de frangos de corte como aditivo antioxidante e alternativo ao uso de antibióticos como melhoradores de desempenho (AGP). No Ensaio I foram utilizados 400 pintainhos (47,5 ± 1.27g) machos, da linhagem Cobb® 500, os quais foram alojados em duas câmaras climáticas. O delineamento foi inteiramente casualizado, em arranjo fatorial 2 x 5, duas salas com temperatura controlada (sala termoneutra - TN; sala de estresse por calor HS 8h/dia) e 5 níveis de óleo de pequi (PO): 0,0; 1,5; 3.0; 4.5 e 6.0 g/kg da deita, com 8 repetições e 5 aves cada. No Ensaio II foram utilizados 1440 pintainhos (43,70 ± 0.70 g), machos Cobb®500 criados de 1 a 42 dias de idade, distribuídos em um delineamento inteiramente casualizado, com 6 tratamentos: controle positivo (com AGP; sem PO), negativo (sem AGP; sem PO) e quatro níveis de inclusão de PO de 1.5; 3.0; 4.5; 6.0 g/kg, e 8 repetições com 30 aves por unidade experimental. Ens. I: Não houve interação dos fatores nos parâmetros sanguíneos. A concentração plasmática de glicose, triglicerídeos e HDL foram maiores nas aves submetidas ao HS aos 21 dias de idade. As aves alimentadas com PO reduziram linearmente AST (aspartato aminotransferase) e ALT (alanina aminotransferase), e os níveis de MDA foram reduzidos linearmente nas aves submetidas ao HS. Além disso, o PO reduziu em 92% a expressão de Hsp70 no fígado em comparação ao tratamento TN sem PO, principalmente no nível de 6,0 g / kg PO. Os níveis de Nrf2 no fígado foram superiores (58,5%) no tratamento 6,0 g / kg de nível de PO, em comparação com o tratamento HS sem PO. Ens. II: A conversão alimentar e o Índice de Produtividade Europeu foram linearmente melhores com níveis crescentes de PO. Os tratamentos não influenciaram o perfil bioquímico sérico, peso de órgão, função hepática, rendimento de cortes e a qualidade de carne, e estes parâmetros foram semelhantes ao tratamento com AGP. Os frangos de corte alimentados com PO, independentemente do nível, reduziram a concentração de MDA no plasma, e reduziu linearmente a peroxidação lipídica da carne de peito avaliada após 90 dias de armazenando sob refrigeração. Em conclusão, os níveis de PO, principalmente o nível 6.0g/kg, aliviaram a peroxidação lipídica no plasma e na carne, o que também está relacionado com a modulação na expressão dos genes Hsp70 e Nrf2 pelo PO, desta forma, o óleo de pequi pode ser utilizado como um promissor aditivo antioxidante e alternativo ao uso de antibióticos em rações para frangos de corte.

Pequi (Caryocar brasiliense camb.) is a native fruit of the Brazilian cerrado and from which pequi oil can be extracted, showing orange color and high content of carotenoids with antioxidant properties. Therefore, two experimental studies were carried out in order to evaluate the effects of adding pequi oil to broiler chicken diet as an antioxidant additive and alternative to the use of antibiotics growth promoter (AGP). Experiment I- A total of 400 one-day-old male broiler chicks (Cobb 500) were randomly assigned in 2×5 factorially arranged treatments: two temperature-controlled rooms (thermoneutral -TN or heat stress - HS for 8 h/day) and five dietary PO levels (0, 1.5, 3.0, 4.5, or 6.0 g/kg diet) for 42 days. Each treatment consisted of eight replicates of five birds. Experiment II- A total of 1,440 one-day-old Cobb500 broilers were randomly distributed into six dietary treatments with eight replicate pens per treatment and 30 birds per pen. The dietary treatments were as follows: 1) basal diet + Avilamycin at 0.05 g/kg diet and no PO (AGP- antimicrobial growth promoter), 2) basal diet without antibiotic and PO (control, CON), 3) CON + 1.5 g/kg PO, 4) CON + 3.0 g/kg PO, 5) CON + 4.5 g/kg PO, and 6) CON + 6.0 g/kg PO. Exp I: There was no interaction of factors on blood parameters. The plasma concentrations of glucose, triglycerides and HDL were higher in birds submitted to HS at 21 days of age. Birds fed with PO linearly reduced AST (aspartate aminotransferase) and ALT (alanine aminotransferase), and MDA levels were linearly reduced in birds subjected to HS. In addition, PO reduced Hsp70 expression in liver by 92% compared to TN treatment without PO, mainly at the level of 6.0 g/kg PO. Liver Nrf2 levels were up-regulated (58.5%) in the 6.0 g/kg PO level treatment compared to the HS treatment without PO. Exp II: feed conversion ratio and the European Performance Index improved linearly with levels of dietary PO. The treatments did not influence the serum biochemical profile, organ weight, liver function, carcass yield and meat quality, and these parameters were similar to the treatment with AGP. Broilers fed with PO, regardless of the level, reduced the concentration of MDA in plasma, and linearly reduced the lipid peroxidation of breast meat evaluated after 90 days of storage under refrigeration. In conclusion, the PO levels, mainly the 6.0g/kg level, alleviated lipid peroxidation in plasma and meat, which is also related to the modulation in the expression of the Hsp70 and Nrf2 genes by PO, thus, the pequi oil can be used as a promising potential feed additive in broiler production.

Swine manure digestate treatment using electrocoagulation

Anaerobic biodigestion is an appropriate alternative for the treatment of swine wastewater due to its biogas generation properties and the possibility of its application as a source of energy for heating or electricity. However, digestate can still contain high levels of turbidity, organic carbon and nutrients and must be correctly managed as a biofertilizer, or treated to avoid any impact on the environment. Considering this, electrocoagulation (EC) shows promise as a technology because of its ease of handling and high efficiency in effluent remediation. This study aimed to evaluate the performance of EC in a batch system in the treatment of swine wastewater digestate. The wastewater used in the treatment was sampled from a 10 m3 biodigestor effluent (digestate) located at Concórdia, Santa Catarina, Brazil. A batch-scale experiment was carried out to evaluate the following two variables: electrode distance (ED) and voltage applied (V). The removal efficiency levels (%) for the best operational condition (2 cm, 5 V) after 30 min were: 97 %, 98 %, 77 % and 10 % for color, turbidity, total organic carbon (TOC) and total nitrogen (TN), respectively. The EC batch system produced efficient results, underlining its promise as an alternative to be applied in the treatment of digestate.

Swine manure digestate treatment using electrocoagulation

Anaerobic biodigestion is an appropriate alternative for the treatment of swine wastewater due to its biogas generation properties and the possibility of its application as a source of energy for heating or electricity. However, digestate can still contain high levels of turbidity, organic carbon and nutrients and must be correctly managed as a biofertilizer, or treated to avoid any impact on the environment. Considering this, electrocoagulation (EC) shows promise as a technology because of its ease of handling and high efficiency in effluent remediation. This study aimed to evaluate the performance of EC in a batch system in the treatment of swine wastewater digestate. The wastewater used in the treatment was sampled from a 10 m3 biodigestor effluent (digestate) located at Concórdia, Santa Catarina, Brazil. A batch-scale experiment was carried out to evaluate the following two variables: electrode distance (ED) and voltage applied (V). The removal efficiency levels (%) for the best operational condition (2 cm, 5 V) after 30 min were: 97 %, 98 %, 77 % and 10 % for color, turbidity, total organic carbon (TOC) and total nitrogen (TN), respectively. The EC batch system produced efficient results, underlining its promise as an alternative to be applied in the treatment of digestate.(AU)

Notes Total E Híbrida Em Frangos (Gallus Gallus Domesticus) Como Modelo Experimental Para Aves Exóticas

O objetivo do presente estudo foi analisar a factibilidade na técnica de NOTES Híbrida (NH) ou NOTES Total (NT) intracloacal, em frangos (Gallus gallus domesticus) para obtenção de amostras de biopsias, mediante: (1) realização de ambos tratamentos cirúrgicos em cadáveres de frango para biopsia hepática e renal e avaliar quanto a qualidade do acesso, complicações e achados durante a execução; (2) comparação da técnica de NH ou NT, em frangas de postura para biopsia hepática quanto a parâmetros de tempo operatório, complicações e dificuldades da técnica e qualidade na amostra do fígado. Na primeira etapa do estudo, quatro cadáveres de frango de corte (n=4), com peso médio de 2,6±0,7 kg. Foram realizadas ambas as abordagens cirúrgicas em todos os animais. As etapas cirúrgicas foram divididas em: (1) acesso cirúrgico, etapa da cloacoscopia até entrada do endoscópio de 1,9 mm com sua camisa de proteção com 3,3mm na cavidade celomática, etapa comum aos dois tratamentos; (2) coleta de biopsias por NH, mediante inserção de pinça de biopsia 1,7mm. através de um cateter 14G para obtenção de fragmentos hepáticos e renais; (3) coleta de biópsia por NT, mediante inserção da pinça de biópsia pelo mesmo acesso transcloacal, em paralelo com o endoscópio, e a obtenção de fragmentos hepáticos e renais; (4) síntese da incisão de acesso cloacal. Os tempos cirúrgicos das etapas intraoperatórias foram de 2,7±1,4 min. para o acesso cirúgico, 9,2±3,4 min. para realização das biópsias pelo tratamento NH, 14,6±5,7 min. para o tratamento NT e 2,2 (±0,5) min. para a cloacorrafia. Além das coletas, foi possível visibilizar órgãos intracelomáticos de interesse clínico. Na segunda etapa, foram utilizadas 12 frangas de postura (224,2±16,9g), distribuídas aleatoriamente em NH (n=6) e NT (n=6), para realização de biopsia hepática. Em todos os animais foi possível realizar a biopsia hepática, sendo que o tempo total para realização dos procedimentos cirúrgicos foi de 33,5±13,7 min. no NT e 32,3±15,8 min no NH (p=0,8940). Nove amostras apresentaram avaliação com mínimo afetado e foram consideradas de excelente qualidade para avaliação histológica. Concluiu-se que as técnicas de NT e NH são factíveis para coleta de biopsia em galináceos, como um modelo experimental para aves exóticas.

The purpose of this study was to assess the feasibility of the intracloacal hybrid-NOTES (HN) or total-NOTES (TN) techniques in chickens (Gallus gallus domesticus) for biopsy sampling, in two experimental stages: (1) to assess the HN and TN techniques in chicken cadavers for liver and kidney biopsy, regarding the quality of access, complications and general findings; (2) to compare the HN or TN technique for liver biopsy in posture pullets regarding operative time, complications, technical difficulties and histological quality of liver samples. In the first stage of the study, four cadavers of broiler chicken, weighting 2.6 (± 0.7) kg. Both HN and TN surgical approaches for biopsy sampling were performed in all cadavers. Surgical steps were classified into: (1) surgical access, which involved cloacoscopy and endoscope entry into the celomatic cavity. This step was common to both treatments; (2) HN liver and renal biopsy sampling, by insertion of a 5-fr. biopsy forceps through a percutaneous 14G catheter sheath; (3) TN liver and renal biopsy sampling, by insertion of the biopsy forceps through the same cloacal access, in parallel to the endoscope; (4) cloacal synthesis. Both surgical approaches were successfully carried out in all cadavers (n = 4). Time for the surgical steps were 2.7 (± 1.4) min for surgical access, 9.2 (± 3.4) minutes for HN biopsy sampling, 14.6 (± 5.7). min for TN biopsy sampling and 2.2 (± 0.5) min for cloacal incision suture. Besides biopsy sampling, most organs of clinical relevance for avian species were successfully viewed. In the second stage of the study, 12 posture pullets (224.2 ± 16.9g.) were randomly assigned into HN (n = 6) or TN (n = 6) group for liver biopsy. In all animals (n = 12) liver biopsies were successfully carried out. Total surgical time was 33.5 (± 13.7) minutes in the TN group and 32.3 (± 15.8) minutes in the HN group (p = 0.8940). Nine samples presented minimal artifacts and were classified as optimal for histological assessment. In conclusion, both NT and NH transcloacal approaches are feasible for intracoelomatic biopsy sampling in chicken, as an experimental model for exotic avian.

Characterization of the hrpZ gene from Pseudomonas syringae pv. maculicolaM2

Pseudomonas syringae pv. maculicola is a natural pathogen of members of the Brassicaceae plant family. Using a transposon-based mutagenesis strategy in Pseudomonas syringaepv. maculicola M2 (PsmM2), we conducted a genetic screen to identify mutants that were capable of growing in M9 medium supplemented with a crude extract from the leaves of Arabidopsis thaliana. A mutant containing a transposon insertion in the hrpZ gene (PsmMut8) was unable to infect adult plants from Arabidopsis thaliana or Brassica oleracea, suggesting a loss of pathogenicity. The promotorless cat reporter present in the gene trap was expressed if PsmMut8 was grown in minimal medium (M9) supplemented with the leaf extract but not if grown in normal rich medium (KB). We conducted phylogenetic analysis using hrpAZB genes, showing the classical 5-clade distribution, and nucleotide diversity analysis, showing the putative position for selective pressure in this operon. Our results indicate that the hrpAZB operon from Pseudomonas syringaepv. maculicola M2 is necessary for its pathogenicity and that its diversity would be under host-mediated diversifying selection.(AU)

Characterization of the hrpZ gene from Pseudomonas syringae pv. maculicolaM2

Pseudomonas syringae pv. maculicola is a natural pathogen of members of the Brassicaceae plant family. Using a transposon-based mutagenesis strategy in Pseudomonas syringaepv. maculicola M2 (PsmM2), we conducted a genetic screen to identify mutants that were capable of growing in M9 medium supplemented with a crude extract from the leaves of Arabidopsis thaliana. A mutant containing a transposon insertion in the hrpZ gene (PsmMut8) was unable to infect adult plants from Arabidopsis thaliana or Brassica oleracea, suggesting a loss of pathogenicity. The promotorless cat reporter present in the gene trap was expressed if PsmMut8 was grown in minimal medium (M9) supplemented with the leaf extract but not if grown in normal rich medium (KB). We conducted phylogenetic analysis using hrpAZB genes, showing the classical 5-clade distribution, and nucleotide diversity analysis, showing the putative position for selective pressure in this operon. Our results indicate that the hrpAZB operon from Pseudomonas syringaepv. maculicola M2 is necessary for its pathogenicity and that its diversity would be under host-mediated diversifying selection.

INDICADORES BIOLÓGICOS DA QUALIDADE DO SOLO EM SISTEMAS AGROFLORESTAIS DE PALMA FORRAGEIRA E LEGUMINOSAS NO AGRESTE DE PERNAMBUCO

A composição botânica influencia a microbiologia do solo. Assim, é necessário estudar como as diferentes composições de consórcio afetam os parâmetros biológicos do solo e predizer os benefícios de sua implantação. Objetivou-se avaliar o efeito da consorciação de leguminosas arbóreas com palma forrageira sobre a biomassa microbiana do solo no Agreste Pernambucano. Os tratamentos testados foram associações de leguminosas e palma forrageira, conforme descritos a seguir: i) Gliricidia sepium (Jacq.) Steud e palma IPA-Sertânia (Nopalea cochenillifera Salm Dyck), ii) Leucaena leucocephala [Lam.] de Wit. e palma IPA-Sertânia e iii) palma IPA-Sertânia. O delineamento experimental utilizado foi blocos ao acaso em esquema de parcelas subdivididas, com quatro repetições. As coletas de solo foram feitas nos meses de outubro/2018, abril/2019 e julho/2019. Coletaram-se amostras nas profundidades de 0-10 cm e 10-20 cm em 0; 1,5; 3,0 e 4,5m de distância das faixas das leguminosas para as parcelas com consórcio. Nas parcelas de monocultivo foram coletadas amostras simples em apenas um ponto paralelo às árvores de leguminosas nas mesmas profundidades descritas anteriormente. Foram realizadas determinações da respiração basal do solo (RBS), carbono da biomassa microbiana (CBM), nitrogênio da biomassa microbiana (NBM), quociente metabólico (qCO2), quociente microbiano (qMIC), relação carbono e nitrogênio microbiano (C:Nmic), carbono orgânico total (COT), nitrogênio total (NT), relação C:N (C:N) e abundância de 13C e 15N (13C e 15N). A RBS, NBM, qCO2 e qMIC foram menores (P<0,05) para amostras coletadas em abril/2019 nas profundidades de 0-10 e 10-20 cm, 8,74 e 11,45 g CO2 g -1 dia-1 ; 21,48 e 31,45 mg kg-1 ; 0,05 e 0,05 g CO2 g -1 CBM dia-1 ; 1,86 e 1,03%, respectivamente. O CBM e a relação C:Nmic foram menores para amostras coletadas em out/2018 na profundidade de 0-10 cm, e COT na profundidade 10-20 cm. O NT foi maior para amostras coletadas em out/2018. O 13C variou com a distância das árvores, indicando a contribuição dos diferentes grupos de plantas presentes. O 15N também variou com a distância das árvores, apontando maior contribuição do N fixado sob a copa das leguminosas. A atividade microbiana foi similar para amostras coletadas em out/2018 e abr/2019 nos diferentes sistemas de cultivo. A biomassa microbiana foi beneficiada quando se adicionou leguminosas arbóreas ao cultivo de palma durante jul/2019.

Botanical composition influence soil microbiology. Thus, it is necessary to study how different intercropping systems affect soil biological parameters to predict potential benefits of their implementation. The objective was to evaluate the intercropping effect of forage cactus with tree legumes on soil microbial biomass in Agreste Pernambucano. The treatments tested were the association of legumes and forage cactus, as described below: i) Gliricidia sepium (Jacq.) Steud and forage cactus IPA-Sertânia (Nopalea cochenillifera Salm Dyck); ii) Leucaena leucocephala [Lam.] de Wit. and forage cactus IPA-Sertânia; and iii) forage cactus IPASertânia. The randomized complete block design was used in a split-plot scheme, with four replications. Soil sampling were made in the months of October/2018 April/2019 and July/2019. Samples were collected at depths of 0-10 cm and 10-20 cm at 0; 1.5; 3.0 and 4.5 m away from legume rows in intercropping plots. In the monoculture plots, samples were collected at just one point parallel to the legume trees at the same depths described above. Determinations of soil basal respiration (BSR), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), metabolic quotient (qCO2), microbial quotient (qMIC), ratio carbon and microbial nitrogen (C:Nmic), total organic carbon (TOC), total nitrogen (TN), ratio carbon and nitrogen (C:N), and natural abundance of soil 13C and 15N (13C and 15N) were performed. The BSR, MBN, qCO2 and qMIC were lower (P<0.05) for samples collected in Apr/2019 in the 0-10 and 10-20 cm layers, 8.74 and 11.45 g CO2 g -1 day-1 ; 21.48 and 31.45 mg kg-1 ; 0.05 and 0.05 g CO2 g -1 MBC day-1 ; 1.86 and 1.03%, respectively. The MBC and C / Nmic ratio were lower for samples collected in Oct/2018 in the 0-10 cm layer, and TOC in the 10-20 cm layer. The TN was higher for samples collected in the Oct/2018. The 13C varied with distance from trees, indicating the contribution of the different groups of plants. The 15N also varied with the distance from the trees, indicating greater contribution of fixed N under the tree legume canopy. Microbial activity was similar for samples collected in the Oct/2018 and Apr/2019 in the different cropping systems. Microbial biomass benefits by adding leguminous tree to forage cactus cultivation during the Jul/2019.

Caracterização do solo de viveiros de cultivo intensivo e extensivo de Litopenaeus vannamei (BOONE, 1931): um estudo de caso no nordeste do Brasil

O objetivo deste trabalho foi avaliar a qualidade do solo dos viveiros de cultivo intensivo e extensivo de Litopenaeus vannamei, através da caracterização física e química em determinadas zonas da superfície e a descrição da correlação entre os nutrientes. Em que, após esvaziados e os camarões despescados, amostras de solo (n = 150) foram coletadas em três viveiros de duas fazendas de cultivo de camarões (intensivo e extensivo). Os viveiros foram divididos em cinco zonas: entrada de água (EA), saída de água (SA), platô (P), vala (V) e comedouros (C), sendo que de cada zona foram coletadas cinco amostras. Realizaram-se análises de textura do solo, pH e a concentração e deposição relativa de nutrientes e cátions trocáveis. Todas as variáveis analisadas foram submetidas ao teste de Kolmogorov-Smirnov e Levene para verificar a normalidade e homocedasticidade, respectivamente. As variáveis dos tratamentos que cumpriram estes requisitos foram comparadas através de ANOVA e teste Tukey. As concentrações dos nutrientes foram correlacionadas através de regressão polinomial nos dois sistemas de cultivo estudados. O solo dos viveiros da fazenda de cultivo intensivo e extensivo foram classificados como franco arenosos e arenosos, respectivamente. Constataram-se baixos valores de carbono orgânico e potássio, e altos valores de fósforo nas duas fazendas. O solo dos viveiros de cultivo em sistema intensivo apresentaram altos valores de deposição relativa para carbono total (CT), carbono orgânico total (COT), nitrogênio total (NT) e fósforo disponível (FD) nas zonas C e SA, indicando que necessitam de maiores frequências de tratamento de sedimentos do que as outras zonas estudadas (EA, P e V). No solo dos viveiros da fazenda de cultivo extensivo foram encontrados altos valores de deposição relativa para CT, COT, NT e FD nas zonas EA, V e C. Isto pode indicar que estas zonas merecem intervenções diferenciadas, com maiores frequências de manejo de sedimentos em relação ao P e SA. Os resultados também sugerem que o fósforo é o nutriente que apresenta maior propensão ao acúmulo no solo devido ao seu potencial adsortivo, ocorrendo em maiores quantidades em zonas de decomposição da matéria orgânica em ambos os sistemas de cultivo estudados.

The objective of this work was to study the soil quality in culture ponds intensive and extensive Litopenaeus vannamei, across physic and chemical characterization in the pond zones and description of correlation between nutrients. After emptied and the shrimps were fishing, soil samples (n = 150) were collected in three ponds of two shrimp farms (intensive and extensive). The ponds divided into 5 zones: water inlet (WI), water outlet (WO), plateau (P), ditch (D) and feeders (F), from which five samples collected from each zone. Analyzes of soil texture, pH, concentration and deposition of nutrients and exchangeable cations were performed. All variables submitted to the Kolmogorov-Smirnov and Levene test to verify normality and homoscedasticity, respectively. The variables that comply requirements were compared by ANOVA and Tukey test, and the nutrient concentrations correlated by polynomial regression in the two studied farms. The pond soil of the intensive and extensive farms classified as sandy loam and sandy, respectively. Organic carbon and potassium deficiency was founded, and phosphorus excess in the soil of both farms. Pond soils of intensive system presented high values of relative composition for Total Carbon (TC), Total Organic Carbon (TOC), Total Nitrogen (TN) and Available Phosphorus (AP) in the F and WO zones, thats suppose higher sediment treatment frequencies than other studied zones (WI, P and D). While, in pond soils on a farm with extensive system, high values of relative composition for TC, TOC, TN and AP founded in the zones of WI, D and F. This may indicate that these zones are more dangerous than the differences, with higher frequencies of sediment management in relation to WO and P. The results also suggested that either phosphorus is a nutrient, which are more likely to accumulate in the pond soil due to its adsorbed potential, occur in greater quantities in areas of decomposition of organic materials, in both systems studied.

Intake, physiological parameters and behavior of Angus and Nellore bulls subjected to heat stress / Consumo, parâmetros fisiológicos e comportamento de tourinhos Angus e Nelore submetidos a estresse por calor

Genetics differences between breeds may determine the tolerance to high temperature, effect dry matter intake and consequently cattle performance. The effect of temperature and humidity index (THI) on diurnal, nocturnal and daily intake, water intake, physiologic parameters and behavior of Nellore (B. indicus) and Angus (B. taurus) bulls were evaluated. Eight Angus and eight Nellore young bulls (337±7.4 kg and 16 months of age) were allocated in two climate-controlled rooms for 32 days. In the period 1, all bulls were housed in thermoneutral conditions (TN, THI = 72.6) for 10 days. In period 2 (10 days), four Angus and four Nellore bulls were subjected to low heat stress (LHS, THI = 76.4) in daytime, and four Angus and four Nellore bulls were subjected to high heat stress (HHS, THI = 81.5) in daytime. The diurnal and daily dry matter intake (DMI) of Nellore were not affected (P>0.05) by heat stress. However, Angus bulls decreased diurnal DMI by 24% and daily DMI decreased (P 0.05) by 15% on HHS. In TN Angus bulls had higher (P 0.05) daily DMI (36.2 g/kg of BW) than Nellore (29.1 g/kg of BW), but in HHS they had similar (P>0.05) daily DMI (31.6 and 30.2 g/kg of BW, respectively). We observed an increase (P 0.05) in respiratory frequency, but water intake was not affected (P>0.05) by heat stress. The heart rate decreased (P 0.05) with heat stress. No differences were found (P>0.05) in feeding behavior. Therefore, THI stress threshold should distinct for Angus and Nellore bulls. The use of feed intake information may improve the prediction of thermic discomfort on specific climate condition.(AU)

Diferenças genéticas entre raças podem determinar a tolerância a temperaturas elevadas, afetar o consumo de alimentos e consequentemente o desempenho de bovinos. Avaliou-se o efeito do índice de temperatura e umidade (ITU) sobre o consumo diurno, noturno e diário de matéria seca (MS), ingestão diária de água, parâmetros fisiológicos e comportamento de tourinhos da raça Nelore (Bos indicus) e da raça Angus (Bos taurus). Foram utilizados oito tourinhos da raça Nelore e da raça oito Angus (337 ± 7,4 kg e 16 meses de idade) alocados em duas salas climatizadas por 32 dias. No primeiro período, todos os tourinhos foram alojados em condições de termoneutralidade (TN, ITU = 72,6) por 10 dias. No segundo período (10 dias) quatro tourinhos da raça Angus e quatro da raça Nelore foram submetidos a baixo estresse por calor (BEC, ITU = 76,4) durante o dia e quatro tourinhos Angus e quatro Nelore foram submetidos a alto estresse por calor (AEC, ITU = 81,5) durante o dia. O consumo diurno e diário de matéria seca (MS) dos animais da raça Nelore não foi afetado (P> 0,05) pelo estresse calórico. No entanto, os tourinhos da raça Angus reduziram o CMS diurno em 24% e a CMS diário reduziu (P 0,05) em 15% sob AEC. No TN, os animais da raça Angus apresentaram maior (P 0,05) CMS diário (36,2 g / kg de PC) que os da raça Nelore (29,1 g / kg do PC), mas em AEC eles tiveram (P> 0,05) CMS semelhantes (31,6 e 30,2 g / kg do PC, respectivamente). Observou-se aumento (P <0,05) na frequência respiratória, mas a ingestão de água não foi afetada (P> 0,05) pelo estresse calórico. A Frequência cardíaca diminuiu (P <0,05) com o estresse calórico. Não foi observado efeito do ITU (P> 0,05) sobre o comportamento alimentar. Portanto,recomenda-se o uso de intervalos distintos de ITU para indicar segurança térmica em tourinhos das raças Angus e Nelore.(AU)

Intake, physiological parameters and behavior of Angus and Nellore bulls subjected to heat stress / Consumo, parâmetros fisiológicos e comportamento de tourinhos Angus e Nelore submetidos a estresse por calor

Genetics differences between breeds may determine the tolerance to high temperature, effect dry matter intake and consequently cattle performance. The effect of temperature and humidity index (THI) on diurnal, nocturnal and daily intake, water intake, physiologic parameters and behavior of Nellore (B. indicus) and Angus (B. taurus) bulls were evaluated. Eight Angus and eight Nellore young bulls (337±7.4 kg and 16 months of age) were allocated in two climate-controlled rooms for 32 days. In the period 1, all bulls were housed in thermoneutral conditions (TN, THI = 72.6) for 10 days. In period 2 (10 days), four Angus and four Nellore bulls were subjected to low heat stress (LHS, THI = 76.4) in daytime, and four Angus and four Nellore bulls were subjected to high heat stress (HHS, THI = 81.5) in daytime. The diurnal and daily dry matter intake (DMI) of Nellore were not affected (P>0.05) by heat stress. However, Angus bulls decreased diurnal DMI by 24% and daily DMI decreased (P 0.05) by 15% on HHS. In TN Angus bulls had higher (P 0.05) daily DMI (36.2 g/kg of BW) than Nellore (29.1 g/kg of BW), but in HHS they had similar (P>0.05) daily DMI (31.6 and 30.2 g/kg of BW, respectively). We observed an increase (P 0.05) in respiratory frequency, but water intake was not affected (P>0.05) by heat stress. The heart rate decreased (P 0.05) with heat stress. No differences were found (P>0.05) in feeding behavior. Therefore, THI stress threshold should distinct for Angus and Nellore bulls. The use of feed intake information may improve the prediction of thermic discomfort on specific climate condition.

Diferenças genéticas entre raças podem determinar a tolerância a temperaturas elevadas, afetar o consumo de alimentos e consequentemente o desempenho de bovinos. Avaliou-se o efeito do índice de temperatura e umidade (ITU) sobre o consumo diurno, noturno e diário de matéria seca (MS), ingestão diária de água, parâmetros fisiológicos e comportamento de tourinhos da raça Nelore (Bos indicus) e da raça Angus (Bos taurus). Foram utilizados oito tourinhos da raça Nelore e da raça oito Angus (337 ± 7,4 kg e 16 meses de idade) alocados em duas salas climatizadas por 32 dias. No primeiro período, todos os tourinhos foram alojados em condições de termoneutralidade (TN, ITU = 72,6) por 10 dias. No segundo período (10 dias) quatro tourinhos da raça Angus e quatro da raça Nelore foram submetidos a baixo estresse por calor (BEC, ITU = 76,4) durante o dia e quatro tourinhos Angus e quatro Nelore foram submetidos a alto estresse por calor (AEC, ITU = 81,5) durante o dia. O consumo diurno e diário de matéria seca (MS) dos animais da raça Nelore não foi afetado (P> 0,05) pelo estresse calórico. No entanto, os tourinhos da raça Angus reduziram o CMS diurno em 24% e a CMS diário reduziu (P 0,05) em 15% sob AEC. No TN, os animais da raça Angus apresentaram maior (P 0,05) CMS diário (36,2 g / kg de PC) que os da raça Nelore (29,1 g / kg do PC), mas em AEC eles tiveram (P> 0,05) CMS semelhantes (31,6 e 30,2 g / kg do PC, respectivamente). Observou-se aumento (P 0,05) pelo estresse calórico. A Frequência cardíaca diminuiu (P 0,05) sobre o comportamento alimentar. Portanto,recomenda-se o uso de intervalos distintos de ITU para indicar segurança térmica em tourinhos das raças Angus e Nelore.

Relative chlorophyll contents in the evaluation of the nutritional status of nitrogen from xaraes palisade grass and determination of critical nitrogen sufficiency index / Teor relativo de clorofila na avaliação do status nutricional de nitrogênio do capimxaraés e determinação do índice de suficiência do nitrogênio crítico

The nutritional status of xaraes palisade grass with SPAD chlorophyll meter and the critical nitrogen sufficiency index (cNSI) in the dry and rainy seasons were assessed. The experiment was conducted in a completely randomized design with four treatments (50, 100, 200 and 400 kg N ha-1), three replicates and two seasons: dry and rainy. All variables had a high nonlinear relationship with their predictors (p 0.001). Total nitrogen (TN) reached a plateau at doses 262.0 and 514.8 kg of N ha-1 and the concentration of TN in the plant was 1.88 and 1.93% respectively during the rainy and dry season. Relative chlorophyll content (RCC) reached a plateau at 46.05 and 53.65 SPAD units in the rainy and dry seasons, respectively. The production of dry matter (DM) showed maximum response to nitrogen fertilization at 209.5 and 229.1 kg N ha-1 during the rainy and dry season respectively. The nitrogen sufficiency index (NSI) reached the plateau at 0.85 and 0.99 in the rainy and dry season respectively. All variables showed high linear correlation (r = 0.71 to 0.99). The xaraés palisade grasss cNSI is 0.85 and the chlorophyll meter may be used as a nutritional N management tool for the grass.(AU)

Objetivou-se avaliar o estado nutricional do capim-xaraés utilizando o clorofilômetro SPAD e estabelecer o índice de suficiência crítico (ISNc) nas épocas das águas e seca. O experimento foi conduzido em um delineamento inteiramente casualizado com quatro tratamentos (50, 100, 200 e 400 kg N ha-1), três repetições, duas épocas: águas e seca. Todas as variáveis apresentaram alta relação não linear com seus preditores (p 0,001). O nitrogênio total (NT) alcançou o platô na dose de 262,0 e 514,8 kg de N ha-1 e a concentração de NT na planta foi 1,88 e 1,93% no período das águas e seco, respectivamente. O teor relativo de clorofila (TRC) atingiu o platô a 46,05 e 53,65 unidades SPAD no período das águas e seca, respectivamente. A produção de matéria seca (MS) apresentou máxima resposta a adubação nitrogenada na dose de 209,5 e 229,1 kg N ha-1 na época das águas e seca, respectivamente. O índice de suficiência de nitrogênio (ISN) atingiu o platô em 0,85 e 0,99 na época das águas e secas respectivamente. Todas as variáveis apresentaram alta correlação linear (r= 0,71 a 0,99). O ISNc do capim-xaraés é 0,85 e o clorofilômetro pode ser utilizado como ferramenta de manejo nutricional de N para essa gramínea.(AU)

Relative chlorophyll contents in the evaluation of the nutritional status of nitrogen from xaraes palisade grass and determination of critical nitrogen sufficiency index / Teor relativo de clorofila na avaliação do status nutricional de nitrogênio do capimxaraés e determinação do índice de suficiência do nitrogênio crítico

The nutritional status of xaraes palisade grass with SPAD chlorophyll meter and the critical nitrogen sufficiency index (cNSI) in the dry and rainy seasons were assessed. The experiment was conducted in a completely randomized design with four treatments (50, 100, 200 and 400 kg N ha-1), three replicates and two seasons: dry and rainy. All variables had a high nonlinear relationship with their predictors (p 0.001). Total nitrogen (TN) reached a plateau at doses 262.0 and 514.8 kg of N ha-1 and the concentration of TN in the plant was 1.88 and 1.93% respectively during the rainy and dry season. Relative chlorophyll content (RCC) reached a plateau at 46.05 and 53.65 SPAD units in the rainy and dry seasons, respectively. The production of dry matter (DM) showed maximum response to nitrogen fertilization at 209.5 and 229.1 kg N ha-1 during the rainy and dry season respectively. The nitrogen sufficiency index (NSI) reached the plateau at 0.85 and 0.99 in the rainy and dry season respectively. All variables showed high linear correlation (r = 0.71 to 0.99). The xaraés palisade grasss cNSI is 0.85 and the chlorophyll meter may be used as a nutritional N management tool for the grass.

Objetivou-se avaliar o estado nutricional do capim-xaraés utilizando o clorofilômetro SPAD e estabelecer o índice de suficiência crítico (ISNc) nas épocas das águas e seca. O experimento foi conduzido em um delineamento inteiramente casualizado com quatro tratamentos (50, 100, 200 e 400 kg N ha-1), três repetições, duas épocas: águas e seca. Todas as variáveis apresentaram alta relação não linear com seus preditores (p 0,001). O nitrogênio total (NT) alcançou o platô na dose de 262,0 e 514,8 kg de N ha-1 e a concentração de NT na planta foi 1,88 e 1,93% no período das águas e seco, respectivamente. O teor relativo de clorofila (TRC) atingiu o platô a 46,05 e 53,65 unidades SPAD no período das águas e seca, respectivamente. A produção de matéria seca (MS) apresentou máxima resposta a adubação nitrogenada na dose de 209,5 e 229,1 kg N ha-1 na época das águas e seca, respectivamente. O índice de suficiência de nitrogênio (ISN) atingiu o platô em 0,85 e 0,99 na época das águas e secas respectivamente. Todas as variáveis apresentaram alta correlação linear (r= 0,71 a 0,99). O ISNc do capim-xaraés é 0,85 e o clorofilômetro pode ser utilizado como ferramenta de manejo nutricional de N para essa gramínea.

Composition, anti-quorum sensing and antimicrobial activity of essential oils from Lippia alba

Many Gram-negative pathogens have the ability to produce N-acylhomoserine lactones (AHLs) as signal molecules for quorum sensing (QS). This cell-cell communication system allows them to coordinate gene expression and regulate virulence. Strategies to inhibit QS are promising for the control of infectious diseases or antibiotic resistant bacterial pathogens. The aim of the present study was to evaluate the anti-quorum sensing (anti-QS) and antibacterial potential of five essential oils isolated from Lippia alba on the Tn-5 mutant of Chromobacterium violaceum CV026, and on the growth of the gram-positive bacteria S. aureus ATCC 25923. The anti-QS activity was detected through the inhibition of the QS-controlled violacein pigment production by the sensor bacteria. Results showed that two essential oils from L. alba, one containing the greatest geranial:neral and the other the highest limonene:carvone concentrations, were the most effective QS inhibitors. Both oils also had small effects on cell growth. Moreover, the geranial/neral chemotype oil also produced the maximum zone of growth inhibition against S. aureus ATCC 25923. These data suggest essential oils from L. alba have promising properties as QS modulators, and present antibacterial activity on S. aureus.