Nitrogen fixation and in vitro production of indolacetic acid by endophytic diazotrophic bacteria

O objetivo deste trabalho foi isolar e quantificar bactérias diazotróficas associadas a raízes de arroz, e avaliar a produção de ácido indolacético e o potencial de fixação biológica de nitrogênio dessas bactérias, a fim de selecionar isolados promissores para inoculação em plantas. Bactérias fixadoras de nitrogênio, habitantes do interior das raízes de cultivares de arroz do Rio Grande do Sul, foram isoladas e quantificadas em nove cultivares. Raízes de arroz superficialmente esterilizadas foram maceradas e introduzidas em meios de crescimento, elaborados sem fonte de nitrogênio e em condições semi-sólidas. Entre os 58 isolados nos meios NFb, LGI e LGI-P, foram escolhidos UFSM-BD-02-06, UFSM-BD-08-06, UFSM-BD-14-06, UFSM-BD-20-06, UFSM-BD-26-06, UFSM-BD-31-06, UFSM-BD-36-06, UFSM-BD-42-06, UFSM-BD-48-06, UFSM-BD-54-06. Avaliaram-se a fixação biológica de nitrogênio e a produção de ácido indolacético in vitro, pelos métodos Kjeldahl e colorimétrico, respectivamente. Azospirillum brasilense e A. lipoferum apresentam maiores valores para N total, 41,08 e 46,82 µg mL-1, respectivamente. A. brasilense e UFSM-BD-31-06 são os maiores produtores de ácido indolacético, 41,09 mg mL-1 e 13,47 µg mL-1, respectivamente.The aim of this work was to isolate and to quantify diazotrophic bacteria associated with rice root, and evaluate their acid indolacetic production and their potential for biological nitrogen fixation, with the purpose of selecion promissing isolates for plant inoculation. N-fixing bactéria, settlers of the root interior of rice cultivars used in Rio Grande do Sul, Brazil, were isolated and quantified in nine cultivars. Rice root superficialy sterilized were macerated and introduced in specific culture media. Among 58 isolates obtained in the culture media NFB, LGI and LGI-P, the following were selected: UFSM-BD-02-06, UFSM-BD-08-06, UFSM-BD-14-06, UFSM-BD-20-06, UFSM-BD-26-06, UFSM-BD-31-06, UFSM-BD-36-06, UFSM-BD-42-06, UFSM-BD-48-06, UFSM-BD-54-06. The biological nitrogen fixation was determined by the Kjeldahl method, and indolacetic acid production by colorimetry. Azospirillum brasilense e A. lipoferum present greater values, 41.08 and 46.82 µg N mL-1, respectively, for total N, and for indolacetic acid production, A. brasilense, 41.09 µg mL-1, and UFSM-BD-31-06, 13.47 µg mL-1, are the greatest producers

ESTUDO DA CURVA DE CRESCIMENTO E DE CONSUMO ALIMENTAR DE FILHOTES DE PAPAGAIO-VERDADEIRO (Amazona aestiva) EM CRIADOURO COMERCIAL NO RIO GRANDE DO SUL

A determinação da curva de crescimento do papagaio-verdadeiro (Amazona aestiva) é uma ferramenta auxiliar para avaliação da dieta usada nos criadouros e saber se os filhotes criados estão tendo um desenvolvimento corporal satisfatório em relação à sua faixa etária. Modelos matemáticos não lineares, desenvolvidos empiricamente para relacionar peso e idade, têm-se mostrado adequados para descrever a curva de crescimento em diferentes espécies animais. O objetivo deste trabalho é determinar a curva de crescimento e curva de consumo alimentar de filhotes de papagaio-verdadeiro (A. aestiva) e analisar quais modelos matemáticos são adequados para essa finalidade. O trabalho foi desenvolvido com o banco de dados oriundo de um criadouro comercial localizado no Rio Grande do Sul, Brasil. Os dados utilizados são referentes a 485 filhotes de A. aestiva nascidos durante o período de 2005 a 2010. Para estimar a curva de crescimento e de consumo alimentar dos papagaios-verdadeiros, após a purificação dos dados, foram testados quatro modelos lineares polinomiais e quatorze modelos de regressão não lineares. O melhor critério de escolha foi o modelo de regressão não linear Função Gama Incompleto que pode ser utilizado tanto para definir a curva de crescimento quanto à curva de consumo alimentar em filhotes de papagaios-verdadeiros.   Palavras-chave: Amazona aestiva, curva de crescimento, curva de consumo alimentar, regressão não linear, Função Gama Incompleto

Antimicrobial activity of poultry hatch baskets containing copper inserts

Commercial poultry hatcheries provide ideal conditions for the multiplication and spread of microorganisms. Formaldehyde is widely used as a disinfectant; however, it is harmful to human health and can cause abnormal morphology in chicks. An alternative microbiological control is the use of copper, a metallic antimicrobial agent for contact surfaces. The antimicrobial efficacy of copper surfaces has been established in healthcare environments. However, its use in the poultry chain is still limited. This study aimed to compare the antimicrobial activity of common polypropylene hatch baskets with hatch baskets composed of copper (polypropylene hatch baskets covered by copper hatch baskets; polypropylene hatch baskets with solid copper plates on the bottom; polypropylene hatch baskets covered by copper hatch baskets and with solid copper plates on the bottom). To simulate a hatching environment with high contamination, the eggs and hatching cabinet were not fumigated. Microbiological analysis of the hatching cabinet environmental, surface of hatch basket, and fluff were performed. The results indicated that the absence of bottom holes resulted in a higher volume of organic matter that interfered with the copper's antimicrobial activity. The presence of copper in the hatch baskets did not decrease microbial contamination under the conditions evaluated, confirming that the metal should only be used as a complement to standard hygiene and not as a substitute for surface disinfectants. Further analysis will evaluate the antimicrobial activity of hatch baskets composed only of copper and the ability of nanoparticles to remove the biofilms formed by bacteria isolated from the poultry environment

Development of copper hatch baskets and evaluation of the productive indexes of a commercial hatchery

Background: The dissemination of pathogenic microorganisms in hatcheries leads to a higher number of contaminated eggs, causing reduction in hatchability and increase of discarded chicks. Sanitation programs are crucial for maximum hatchability and chick quality. Efforts have been made to find alternative approaches to the conventional disinfectants, and surfaces with copper, which have antimicrobial properties, could assist in this process. However, the possible adverse effects of copper surfaces on chicks in hatcheries have not yet been evaluated. The present study aimed at developing hatch baskets composed of copper and evaluating the effect of these baskets on the productive indexes of a hatchery. Materials, Methods & Results: For this experiment, 3.15 kg hatch tray prototypes with 99.9% Cu (Cu11000) were developed to fit inside conventional polypropylene hatch baskets (580 × 755 × 83 mm). Six polypropylene hatch baskets (control group) and six polypropylene hatch baskets covered by 99.9% copper (Cu11000) hatch trays (test group) were evaluated during 5 hatchings. Hatched eggs and chicks remained in contact with the hatch basket surfaces for at least 72 h, corresponding to the entire period in which they were located in the hatcher. Cleaning and disinfection programs of the hatchery were not modified. The level of microbial contamination on the hatch baskets was evaluated at 6 different periods: 0 h (initial contamination after disinfection and egg transfer to the trays); 24 h, 30 h, 45 h and 60 h after the first sampling; and at the moment when chicks were removed from the hatching cabinet and transferred to the chick-holding room (> 60 h). Counting of total moulds and yeasts, mesophilic microorganisms, Enterobacteria and Escherichia coli colonies was performed. The number of hatched chicks, non-hatched eggs, and chicks discarded were registered for each hatching. Microbiologic analyses showed no growth on hatch baskets neither of the test group nor on those of the control group, regardless of the period evaluated. No significant difference was found between the two groups in the counts of hatched chicks, non-hatched eggs, and chicks discarded. Discussion: The antimicrobial efficacy of copper surfaces has been established for a variety of bacteria and fungi, including in the healthcare environment. In addition, antimicrobial resistance to copper is extremely rare because of copper’s multisite kill mechanism and other mostly nonspecific damage mechanisms. Several copper applications have been established; however, the potential adverse effects of using copper surfaces in hatcheries on chicks or on hatchery productive indexes had not yet been evaluated. The analyses performed in this study did not show microbiological growth. The results showed that the copper surface did not cause any significant adverse effects on chicks. The hatched chicks were visually healthy, and no significant difference was found between the numbers of chicks discarded in the control and test groups. Since the production parameters were not altered or impaired in the present study, it is possible to conclude that the use of copper surfaces in hatcheries can be an effective tool in the microbiological control of these environments. Nevertheless, copper alloys lend themselves to the creation of self-sanitizing surfaces that should be used as a complement and not as a substitute for standard cleaning and disinfection practices

Development of Copper Hatch Baskets and Evaluation of the Productive Indexes of a Commercial Hatchery

Background: The dissemination of pathogenic microorganisms in hatcheries leads to a higher number of contaminated eggs, causing reduction in hatchability and increase of discarded chicks. Sanitation programs are crucial for maximum hatchability and chick quality. Efforts have been made to find alternative approaches to the conventional disinfectants, and surfaces with copper, which have antimicrobial properties, could assist in this process. However, the possible adverse effects of copper surfaces on chicks in hatcheries have not yet been evaluated. The present study aimed at developing hatch baskets composed of copper and evaluating the effect of these baskets on the productive indexes of a hatchery.Materials, Methods and Results: For this experiment, 3.15 kg hatch tray prototypes with 99.9% Cu (Cu11000) were developed to fit inside conventional polypropylene hatch baskets (580 × 755 × 83 mm). Six polypropylene hatch baskets (control group) and 6 polypropylene hatch baskets covered by 99.9% copper (Cu11000) hatch trays (test group) were evaluated during 5 hatchings. Hatched eggs and chicks remained in contact with the hatch basket surfaces for at least 72 h, corresponding to the entire period in which they were located in the hatcher. Cleaning and disinfection programs of the hatchery were not modified. The level of microbial contamination on the hatch baskets was evaluated at 6 different periods: 0 h (initial contamination after disinfection and egg transfer to the trays); 24 h, 30 h, 45 h and 60 h after the first sampling; and at the moment when chicks were removed from the hatching cabinet and transferred to the chick-holding room (> 60 h). Counting of total moulds and yeasts, mesophilic microorganisms, Enterobacteria and Escherichia coli colonies was performed. The number of hatched chicks, non-hatched eggs, and chicks discarded were registered for each hatching. Microbiologic analyses showed no growth on hatch baskets neither of the test group nor on those of the control group, regardless of the period evaluated. No significant difference was found between the two groups in the counts of hatched chicks, non-hatched eggs, and chicks discarded. Discussion: The antimicrobial efficacy of copper surfaces has been established for a variety of bacteria and fungi, including in the healthcare environment. In addition, antimicrobial resistance to copper is extremely rare because of copper’s multisite kill mechanism and other mostly nonspecific damage mechanisms. Several copper applications have been established; however, the potential adverse effects of using copper surfaces in hatcheries on chicks or on hatchery productive indexes had not yet been evaluated. The analyses performed in this study did not show microbiological growth. The results showed that the copper surface did not cause any significant adverse effects on chicks. The hatched chicks were visually healthy, and no significant difference was found between the numbers of chicks discarded in the control and test groups. Since the production parameters were not altered or impaired in the present study, it is possible to conclude that the use of copper surfaces in hatcheries can be an effective tool in the microbiological control of these environments. Nevertheless, copper alloys lend themselves to the creation of self-sanitizing surfaces that should be used as a complement and not as a substitute for standard cleaning and disinfection practices

Reação em cadeia pela polimerase (PCR) para detecção de Salmonella em carne de frango artificialmente contaminada

The aim of this study was to develop a polymerase chain reaction (PCR) protocol for the detection of Salmonella in artificially contaminated chicken meat. Tests were performed with different dilutions of Salmonella Typhimurium or Salmonella Enteritidis cells (10-7, 10-8 or 10-9 CFU/mL) inoculated in chicken meat samples, in order to establish the limits of detection, incubation times (0, 6, 8 and 24 hours of pre-enrichment in PBW 1%) and three DNA extraction protocols (phenol-chloroform, thermal treatment and thermal treatment and Sephaglass). The assay was able to detect until 10-9 CFU/mL of initial dilution of Salmonella cells inoculated in chicken meat, which allows detection of Salmonella within 48 hours, including 24 hours of pre-enrichment and using the phenol-chloroform DNA extraction protocol. As the results are obtained in a shorter time period than that of microbiological culture, this procedure will be useful in the methodology for detection of Salmonella in chicken.O objetivo deste trabalho foi adequar um protocolo de reação em cadeia pela polimerase (PCR) para detecção de Salmonella em carne de frango artificialmente contaminada. Foram realizados ensaios com amostras de carne de frango inoculadas com diluições de Salmonella Typhimurium ou Salmonella Enteritidis (10-7, 10-8 ou 10-9 UFC/mL), procurando-se determinar o limite de detecção da técnica, intervalos de incubação das amostras (0, 6, 8 ou 24 horas de pré-enriquecimento em água peptonada 1%) e três protocolos de extração de DNA (fenol-clorofórmio, tratamento térmico ou tratamento térmico e Sephaglass). Foi possível amplificar DNA de Salmonella nas amostras de carne de frango inoculadas inicialmente com diluições de até 10-9 UFC/mL, utilizando-se protocolo de extração de DNA por fenol-clorofórmio e após um período de 24 horas de pré-enriquecimento, totalizando 48 horas de análise. Como os resultados são obtidos mais rapidamente que a cultura, este procedimento será útil na metodologia para detecção de Salmonella em carne de frango

Prevalência de anticorpos para Toxoplasma gondii em emas (Rhea americana) em diferentes criatórios do Estado do Rio Grande do Sul

Neste trabalho foram analisados 74 amostras de soro de emas provenientes de dez criatórios diferentes localizados no Estado do Rio Grande do Sul. O exame sorológico realizado foi hemaglutinação indireta, de acordo com as normas preconizadas pelo fabricante do Kit utilizado, para detecção e quantificação de anticorpos contra Toxoplasma gondii. A titulação mínima considerada foi a diluição maior ou igual a 1/8. A análise dos resultados demonstrou que uma pequena quantidade (8,10%) destes animais estava infectada pelo parasita, no entanto 40% das propriedades onde as amostras foram obtidas apresentaram animais reagentes. Esses resultados salientam a importância de um estudo mais aprofundado sobre a susceptibilidade imunológica destas ratitas ao agente da toxoplasmose.In this work we analyzed 74 (seventy-four) samples of rhea serum from ten different breeders located in the state of Rio Grande do Sul. The serologic exam accomplished was indirect hemaglutination test, in agreement with the norms extolled by the manufacturer of the used Kit, for detection and quantification of antibodies against Toxoplasma gondii. The considered minimum titration was the larger dilution or same to the 1/8 (one-eight). The analysis of the results demonstrated that a small amount (8,10%) of these animals were infected with the parasite, however 40% of the properties where the samples were obtained presented reacting animals. Those results point out the importance of a study more deepened on the immunological susceptibility of these ratites to the agent of the toxoplasmosis