Analysis of fumonisin B 1 removal by microorganisms in co-occurrence with aflatoxin B 1 and the nature of the binding process

The objectives of this investigation were to evaluate the ability of Saccharomyces cerevisiae CECT 1891 and Lactobacillus acidophilus 24 to remove fumonisin B1 (FB1) from liquid medium; to determine the nature of the mechanism involved in FB1?microorganism interaction and to analyze whether the presence of aflatoxin B1 (AFB1) interferes with the removal of FB1 and vice versa. The results obtained indicated that: (i) both microorganisms were able to remove FB1 from liquid medium; (ii) the removal was a fast and reversible process; (iii) cell viability was not necessary; (iv) the amount of FB1 removed was both toxin- and microorganism concentration-dependent; (v) the process did not involve chemical modification of FB1 molecules; and (vi) cell wall structural integrity of the microorganisms was required for FB1 removal. Consequently, we propose that the mechanism involved in the removal of FB1 is a physical adsorption (physisorption) of the toxin molecule to cell wall components of the microorganisms. It is highly probable that FB1 and AFB1 co-occur in contaminated foods, since the fungal genera Aspergillus and Fusarium frequently occur simultaneously. Therefore, we analyzed whether the presence of AFB1 interferes with the removal of FB1 by the microorganisms previously evaluated, and vice versa. Studies of co-occurrence of both mycotoxins clearly showed that they did not compete for binding sites on the microorganism cell wall and the presence of one toxin did not modify the efficiency of the organism in the removal of the other mycotoxin. These findings may be useful for optimization of mycotoxin binding and provide an important contribution to research on microorganisms with ability to remove these secondary metabolites.Fil: Pizzolitto, Romina Paola. Universidad Nacional de Río Cuarto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Salvano, Mario Armando. Universidad Nacional de Río Cuarto; ArgentinaFil: Dalcero, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto; Argentin

Negligible effects of tryptophan on the aflatoxin adsorption of sodium bentonite

The main objective of this study was to determine if the competitive adsorption of tryptophan (Trp) and aflatoxin B1 (AFB1) could potentially affect the ability of a sodium bentonite (NaB) to prevent aflatoxicosis in monogastric animals. The adsorption of Trp and AFB1 on this adsorbent is fast and could be operating on the same time-scale making competition feasible. In vitro competitive adsorption experiments under simulated gastrointestinal conditions were performed. A high affinity of the clay for Trp and NaB was observed. The effect of an excess of KCl to mimic the ionic strength of the physiological conditions were also investigated. A six-times decrease in the Trp surface excess at saturation was observed. A similar behaviour was previously found for AFB1 adsorption. Taking into account the amount of Trp adsorbed by the clay and the usual adsorbent supplementation level in diets, a decrease in Trp bioavailability is not expected to occur. Tryptophan adsorption isotherms on NaB were ‘S’-shaped and were adjusted by the Frumkin–Fowler–Guggenheim model. The reversibility of the adsorption processes was investigated in order to check a potential decrease in the ability of NaB to protect birds against chronic aflatoxicoses. Adsorption processes were completely reversible for Trp, while almost irreversible for AFB1. In spite of the high affinity of the NaB for Trp, probably due to the reversible character of Trp adsorption, no changes in the AFB1 adsorption isotherm were observed when an excess of the amino acid was added to the adsorption medium. As a consequence of the preferential and irreversible AFB1 adsorption and the reversible weak binding of Trp to the NaB, no changes in the aflatoxin sorption ability of the clay are expected to occur in the gastrointestinal tract of birds.Fil: Magnoli, Alejandra Paola. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Copia, P.. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; ArgentinaFil: Monge, Maria del Pilar. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Magnoli, Carina Elizabeth. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Dalcero, Ana Maria. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chiacchiera, Stella Maris. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Exposición crónica a hongos productores de aflatoxinas relacionada a daños hepáticos en chinchillas (chinchilla lanigera) destinadas a la producción de piel

Chinchilla pelt is a rare and expensive fur. Therefore, breeding these animals is a profitable activity. Confirmed acute cases of aflatoxin intoxication have been reported in Argentinean farms. The aims of this study were i) to evaluate mycobiota and AFB1 -producing species in chinchilla feeds ii) to investigate their natural AFB1 contamination and iii) to analyze histopathological lesions in chinchilla livers. Feed samples (A: fur chinchillas, B: mother chinchillas, C: lucerne cubes) were collected from a factory and a farm. Livers of sacrificed chinchilla from the farm were macroscopically and microscopically examined. Total fungal counts of feed C exceeded 1x104 CFU g-1. Aspergillus, Fusarium and Penicillium were the prevalent genera, while A. flavus, A. fumigatus, F. verticillioides and F. proliferatum were the prevalent species. 50 % of A. flavus strains from factory samples and 69.7 % from farm samples produced 2.78 to 8. 64 µg g-1 and 0.66 to 58.8 µg g-1 AFB1 , respectively. Aflatoxin B1 was detected only in feeds from the farm, finding the highest incidence in feed C. Toxin levels varied between 1.90 and 97.34 µg kg-1 AFB1 . Mean levels in feed A and C exceeded 20 µg kg-1. Macroscopic examination of livers revealed normal appearance, size and color. However, histopathological examination indicated 63.3 % showed slight to moderate lipid degeneration with diffuse cytoplasm vacuolation, 9 % intense lipid cytoplasm vacuolation and 27.3 % hydropic degeneration and nuclear vacuolation in hepatocytes. A periodic monitoring of aflatoxins in feeds and their ingredients can prevent acute outbreaks and economic losses caused by chronic exposure.La piel de chinchilla es una de las más exóticas y apreciadas en el mercado internacional. La cría de estos animales es una actividad muy rentable. En Argentina, se han detectado casos de aflatoxicosis aguda en criaderos. Los objetivos de este trabajo fueron: i) estudiar la micobiota y los hongos productores de aflatoxina B1 (AFB1 ) presentes en alimento para chinchillas. ii) analizar la contaminación natural con AFB1 de estos alimentos iii) buscar lesiones histopatológicas en hígados de chinchillas de los criaderos. Se recolectaron muestras de diferentes alimentos (A: chinchilla piel, B: chinchilla madre, C: cubos de alfalfa) en una fábrica y un criadero localizados en la ciudad de Rio Cuarto, en la región central de Argentina. Los hígados de las chinchillas sacrificadas en el criadero fueron analizados macroscópica y microscópicamente. Los recuentos fúngicos totales fueron mayores a 1x104 UFC g-1. Aspergillus, Fusarium y Penicillium fueron los géneros prevalentes, mientras que A. flavus, A. fumigatus, F. verticillioides y F. proliferatum fueron las especies aisladas con mayor frecuencia. 50 % de las cepas de A. flavus aisladas de la fábrica y 69.7 % de las aisladas del criadero produjeron 2.78 a 8.64 µg g-1 y 0.66 a 58.8 µg g-1 de AFB1 , respectivamente. Se detectó AFB1 sólo en las muestras del criadero, con mayor incidencia en el alimento C. Los niveles de toxina variaron entre 1.90 y 97.34 µg kg-1. Los niveles promedios en A y C fueron superiores a 20 µg kg-1. El análisis macroscópico de los hígados reveló apariencia, tamaño y color normal. El análisis microscópico indicó que 63.3 % de los hígados presentaron degeneración lipídica leve a moderada con vacuolización difusa del citoplasma, 9 % presentaron vacuolización lipídica intensa y 27.3 % degeneración hidrópica y vacuolización nuclear en los hepatocitos. El monitoreo periódico de La calidad de los alimentos e ingredientes usados en la alimentación de chinchillas puede evitar intoxicaciones agudas y pérdidas económicas causadas por la exposición crónica a aflatoxinas.Fil: Landa, Maria Florencia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gonzalez Pereyra, Maria Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pena, Gabriela Alejandra. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bagnis, Guillermo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Cavaglieri, Lilia Reneé. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rosa, Carlos Alberto da Rocha. Conselho Nacional de Pesquisas Científicas; BrasilFil: Dalcero, Ana Maria. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Resíduos de aflatoxina B1 em fígado de codornas japonesas (Coturnix japonica) expostas a alimentos contaminados e à corticosterona exógena

The combined effect of aflatoxin B1 (AFB1 ) exposition and stress induced by corticosterone (CORT) upon the residual aflatoxin levels in livers of Japanese quail was examined. A total of 144 Japanese quail (Coturnix japonica) were divided into 6 treatments with 6 replicates per treatment, each containing 2 males and 2 females. The different treatments resulted from the combination of the presence or absence of CORT in drinking water (5 mg/L) with the presence or absence of AFB1 supplementation (100 or 500 ng/g). Dietary treatments were offered from 5 to 11 weeks of age. The different diets were: Treatment (T) 1: basal diet (B) AFB1 (15 ng/g); T2: B plus AFB1 (100 ng/g); T3: B plus AFB1 (500 ng/g); T4: B plus CORT (5 mg/L); T5: B plus AFB1 (100 ng/g) and CORT (5 mg/L); and T6: B plus AFB1 (500 ng/g) and CORT (5 mg/L). The residual levels of AFB1 were remarkably higher in livers of birds fed with AFB1 in comparison with those belonging to the group that received a combination of AFB1 and CORT (P< 0.05). A plausible explanation about the facts that could be responsible for observed reduction in the toxin carryover in liver was suggested. These results are very striking and may constitute the start point for a series of studies that aim to elucidate the precise influence of hypothalamic-pituitary-adrenal axis (HPA) response to stress in birds exposed to AFB.Estudou-se o efeito combinado da exposição à aflatoxina B1 (AFB1 ) e o estresse induzido por corticosterona (CORT) sobre os níveis de residuais de AFB1 em fígados de codornas japonesas. Um total de 144 codornas japonesas (Coturnix japonica) foram divididas em 6 tratamentos com 6 repetições por tratamento, cada uma contendo 2 machos e 2 fêmeas. As dietas dos tratamentos foram oferecidas da 5ª até a 11ª semana de idade. Os diferentes tratamentos resultaram da combinação da presença ou ausência de CORT na água de beber (5 mg / L), com a presença ou ausência de suplementação AFB1 (100 ou 500 ng /g) As dietas diferentes foram: Tratamento (T) 1: dieta basal (B) AFB1 (15 ng/g); T2: B mais AFB1 (100 ng / g); T3: B mais AFB1 (500 ng / g); T4: B mais CORT (5 mg / L); T5: B mais AFB1 (100 ng / g) e CORT (5 mg / L), e T6: B mais AFB1 (500 ng / g) e CORT (5 mg / L). Os níveis residuais de AFB1 foram significativamente mais elevados em fígados de aves alimentadas com AFB1 em comparação com os que pertencem ao grupo que recebeu uma combinação de AFB1 e CORT (P< 0,05). Sugere-se uma possível explicação para a redução dos níveis da toxina observada naqueles animais submetidos a dieta com CORT. Estes resultados constituem-se de um ponto de início para uma série de estudos que visam a elucidar a influência da resposta do eixo hipotalâmico-hipofisário-adrenais (HPA) ao stress em aves expostas a AFB.Fil: Magnoli, Alejandra Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Chiacchiera, Stella Maris. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rosa, Carlos Alberto da Rocha. Universidade Federal Rural de Rio de Janeiro; BrasilFil: Dalcero, Ana Maria. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marin, Raul Hector. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Antifungal activity of two Lactobacillus strains with potential probiotic properties

Aflatoxin (highly toxic and carcinogenic secondary metabolites produced by fingi) contamination is a serious problem worldwide. Modern agriculture and animal production systems need to use high-quality and mycotoxin-free feedstuffs. The use of microorganisms to preserve food has gained importance in recent years due to the demand for reduced use of chemical preservatives by consumers. Lactic acid bacteria are known to produce various antimicrobial compounds that are considered to be important in the biopreservation of food and feed. Lactobacillus rhamnosus L60 and Lactobacillus fermentum L23 are producers of secondary metabolites, such as organic acids, bacteriocins and, in the case of L60, hydrogen peroxide. The antifungal activity of lactobacilli strains was determined by coculture with Aspergillus section Flavi strains by two qualitative and one quantitative methods. Both L23 and L60 completely inhibited the fungal growth of all aflatoxicogenic strains assayed. Aflatoxin B 1 production was reduced 95.7-99.8% with L60 and 27.5-100% with L23. Statistical analysis of the data revealed the influence of L60 and L23 on growth parameters and aflatoxin B 1 production. These results are important given that these aflatoxicogenic fungi are natural contaminants of feed used for animal production, and could be effectively controlled by Lactobacillus L60 and L23 strains with probiotic properties.Fil: Gerbaldo, Gisela Alejandra. Universidad Nacional de Río Cuarto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Barberis, Carla Lorena. Universidad Nacional de Río Cuarto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Pascual, Liliana. Universidad Nacional de Río Cuarto; ArgentinaFil: Dalcero, Ana Maria. Universidad Nacional de Río Cuarto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Barberis, Lucila. Universidad Nacional de Río Cuarto; Argentin

Fungi and mycotoxins from pre and post storage brewer’s grain intended for bovine intensive-rearing

The aim of the study was to determine the mycobiota and natural levels of mycotoxins such as aflatoxin B1 (AFB1), ochratoxin A (OTA), fumonisin B1 (FB1) and deoxinivalenol (DON) present in brewers grains pre and post stored intended for bovine intensive-rearing. Post stored (80%) samples had counts higher than 1 x 104 colony-forming units (CFU/g). Cladosporium spp., and Aspergillus spp. were isolated at high frequencies. Aspergillus flavus was the prevalent isolated species. Pre stored (70%) and post stored (100%) samples showed AFB1 levels over the recommended limits (20 µg/Kg) and OTA levels were below the recommended limits (50 µg/Kg). While pre and post stored samples did not show FB1 and DON natural contamination levels. The presence of mycotoxins in this substrate indicates the existence of contamination. Regular monitoring of feeds is required in order to prevent chronic and acute toxic syndromes related to this kind of contamination.Fil: Keller, Luiz Antonio Moura. Universidade Federal Rural do Rio de Janeiro; Brasil. Conselho Nacional de Desenvolvimento Científico e Tecnológico; BrasilFil: Pereyra, Carina Maricel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cavaglieri, Lilia Reneé. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Dalcero, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Rosa, C. A. R. Conselho Nacional de Desenvolvimento Científico e Tecnológico; Brasil. Universidade Federal Rural do Rio de Janeiro; Brasi

Inhibitory effect of sodium metabisulphite and chlorine on growth of Aspergillus spp. and Penicillium spp. strains isolated from marine shrimp

The sodium metabisulphite (SMB) is used in shrimp farming to prevent melanosis and the 5.0 ppm chlorine (CL) concentration used in the shrimp processing is effi cient as a bactericide, but there is no evidence of the effectiveness of these chemical compounds as fungicides. Therefore, the aim of this study was to evaluate the in vitro effect of sodium metabisulphite (SMB) and chlorine (CL) on the growth of Aspergillus and Penicillium species isolated from marine shrimp in different stages of processing. The samples were collected from a frozen shrimp processing industry, located in Piauí State, Brazil. The total fungi and occurrence of Aspergillus and Penicillium species were evaluated. For in vitro sensibility test using the diffusion disk in agar method, fi ve concentrations of SMB (0%, 1%, 3%, 5% and 10%) and six of CL (0, 1, 2, 3, 4 and 5 μg mL-1) were used. The fungal counts in the different processing stages ranged from 1.74 to 3.38 CFU g-1. Twenty-nine Aspergillus strains were isolated, prevailing A. versicolor (59.3%) and twenty-two of Penicillium, prevailing P. citrinum (74%). One strain of A. fl avus was AFB1 producer. All the isolated strains of P. citrinum produced citrinin. All tested species were in vitro sensitive to 3% of SMB, except the A. fl avus. The 10% concentration of SMB inhibited the in vitro growth of all strains. The CL concentrations tested did not inhibit the studied species growth and SMB concentrations above 3.0% inhibited in vitro the growth of the tested strains. Key words: Aspergillus fl avus, Litopenaeus vannamei, Penicillium citrinum, shrimp culture, conservation. RESUMO O metabissulfi to de sódio (SMB) é usado na carcinicultura para evitar a melanose e a concentração de 5,0ppm de cloro (CL), utilizada no benefi ciamento do camarão, é efi ciente como bactericida, porém não há comprovação da efi cácia destes compostos químicos como fungicida. Desse modo, o objetivo deste estudo foi avaliar o efeito in vitro do metabissulfi to de sódio (SMB) e cloro (CL) sobre o crescimento de espécies de Aspergillus e Penicillium isolados de camarão marinho em diferentes estágios de processamento. As amostras foram coletadas de uma indústria de processamento de camarão congelado, localizada no Estado do Piauí, Brasil. Fungos totais e ocorrência das espécies de Aspergillus e Penicillium foram avaliados. Para o teste in vitro de sensibilidade pelo método disco-difusão em ágar, foram utilizadas cinco concentrações de SMB (0%, 1%, 3%, 5% e 10%) e seis de CL (0, 1, 2, 3, 4 e 5μg mL-1). As contagens fúngicas nos diferentes estágios de processamento variaram de 1,74 a 3,38UFC g-1. Foram isoladas 29 cepas de Aspergillus, prevalecendo o A. versicolor (59,3%) e 22 de Penicillium, prevalecendo o P. citrinum (74%). Uma cepa de A. fl avus era produtora de AFB1. Todas as cepas de P. citrinum isoladas produziram citrinina. Todas as espécies testadas foram sensíveis in vitro a 3% do SMB, com exceção do A. fl avus. A concentração de 10% do SMB inibiu in vitro o crescimento de todas as cepas. As concentrações de CL testadas não inibiram o crescimento das espécies isoladas e concentrações de SMB acima de 3,0% inibiram in vitro o crescimento das linhagens testadas. Palavras-chave: Aspergillus fl avus, Litopenaeus vannamei,Fil: Santos, Ygor Flavio de Moraes. Universidade Federal do Piauí. Centro de Ciências Agrárias; Brasil;Fil: Veloso, Átila Peeter Batista. Universidade Federal do Piauí. Centro de Ciências Agrárias; Brasil;Fil: Calvet, Rodrigo Maciel. Universidade Federal do Piauí. Centro de Ciências Agrárias; Brasil;Fil: Pereira, Maria Marlucia Gomes. Universidade Federal do Piauí. Centro de Ciências Agrárias; Brasil;Fil: Pereyra, Carina Maricel. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales; ArgentinaFil: Dalcero, Ana Maria. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Microbiologia E Inmunologia; ArgentinaFil: Torres, Adriana Mabel. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Microbiologia E Inmunologia. Cat.de Micología; ArgentinaFil: Muratori, Maria Christina Sanches. Universidade Federal do Piauí. Centro de Ciências Agrárias; Brasil

Adsorção in vitro de ocratoxina A por paredes celulares de levedura comercial

The aim of the present study was to evaluate the ochratoxin A (OTA) adsorption capacity by two kinds of commercial yeast cell walls (YCW1 and YCW2) used as dietary supplements. An in vitro test was designed to mimic the temperature (37ºC), pH (2) and passage time (30 min) through the stomach of a monogastric animal. The test was performed using different concentrations of YWC (100 and 200 µg/mL) and OTA (10; 80; 160 and 1000 ng/mL) and extracts were quantified by HPLC. For each OTA concentration, two independent trials varying the concentration of each YCW were performed. The two YCW assayed containing different percentages of polysaccharides, were able to adsorb similar amounts of OTA. Furthermore, the relationship mannans/β-glucans does not influence the rate of adsorption of OTA. In general, it was observed that the adsorption capacity increased with decreasing OTA concentration. Results from this work related to adsorption capacity of OTA with YCW allow predicting that other factor than 3D-structure and β-glucans and mannans could be involved. Future studies could be conducted to test the in vivo binding ability to alleviate the toxic effects of OTA under field conditions. Both YCW are a promising mycotoxin adsorbent to be used in animal feed to prevent mycotoxicoses.O objetivo do presente estudo foi avaliar a capacidade de adsorção de ocratoxina A (OTA) por duas paredes celulares de leveduras comerciais (PCL1 e PCL2) usadas como aditivos alimentares. Os ensaios in vitro foram desenvolvidos de modo a simular as condições de temperatura (37°C), pH (2) e o tempo de passagem (30 min.) do alimento pelo estômago de um animal monogástrico. Os ensaios foram executados usando diferentes concentrações das PCL (100 e 200 µg/mL) e OTA (10; 80; 160; e 1000 ng/mL) e os extratos foram quantificados por CLAE. Para cada concentração de OTA, dois ensaios independentes foram realizados variando-se a concentração de cada PCL. As duas PCL analisadas que continham diferentes percentuais de polissacarídeos foram capazes de adsorver similares quantidades de OTA. Além disso, a relação mananos/b-glucanos não influenciou na taxa de adsorção de OTA. Em geral, foi observado que a capacidade de adsorção aumentava com o decréscimo das concentrações de OTA. Os resultados deste trabalho sobre capacidade de adsorção de OTA por PCL permitem supor que algum outro fator possa estar envolvido além da estrutura 3D e dos b-glucanos e mananos. Estudos futuros podem ser desenvolvidos para testar in vivo esta capacidade adsortiva e então reduzir os efeitos tóxicos da OTA em desafios naturais a campo. Ambas as PCL são promissores adsorventes desta micotoxina podendo ser usadas na alimentação animal para prevenir esta micotoxicose.Fil: Pereyra, Carina Maricel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cavaglieri, Lilia Reneé. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Keller, Kelly Moura. Universidade Federal Rural do Rio de Janeiro; BrasilFil: Chiacchera, Stella Maris. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Rosa, Carlos Alberto da Rocha. Universidade Federal Rural do Rio de Janeiro; BrasilFil: Dalcero, Ana Maria. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

In vitro biological control for lactic acid bacteria isolated from brewer ́s grains

Los residuos de cervecería son suplementos de bajo costo y de fácil disponibilidad, sin embargo, el alto contenido de humedad los hace susceptibles a la degradación fúngica y al desarrollo de microorganismos patógenos. Las bacterias ácido lácticas (BAL) se encuentran formando parte de la microbiota de los granos de cebada, de manera tal, que podrían contribuir en la calidad y seguridad tanto de la malta como de los productos derivados. El objetivo de este estudio fue determinar la presencia BAL, especies fúngicas de Aspergillus sección Flavi, Listeria monocytogenes e incidencia de AFB1 en residuos de cervecería, y evaluar in vitro el efecto antifúngico y antiaflatoxicogénico de las BAL. El análisis de los residuos de cervecería mostró que, en general, los recuentos de BAL fueron elevados durante todos los períodos analizados, sin embargo, el recuento de A. sección Flavi, L. monocytogenes e incidencia natural de AFB1 fue variable. El hallazgo de L. monocytogenes es el primero informado en Argentina en este tipo de sustrato. Lactobacillus coryniformis subsp. coryniformis L47 y Lactobacillus cellobiosus L56 fueron las cepas más efectivas en inhibir el crecimiento y la producción de AFB1 de todas las cepas de A. sección Flavi ensayadas in vitro. Futuros estudios con estas cepas de BAL podrían realizarse para demostrar su efectividad in situ en estos sustratos alternativos destinados a la producción animal, como así también evaluar in vitro sus propiedades antilisteria.Fil: Gerbaldo, Gisela Alejandra. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Microbiologia E Inmunologia. Area de Bacteriologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Asurmendi, Paula. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Microbiologia E Inmunologia. Area de Bacteriologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ruiz, Francisco Oscar. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Microbiologia E Inmunologia. Area de Bacteriologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pascual, Liliana. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Microbiologia E Inmunologia. Area de Bacteriologia; ArgentinaFil: Dalcero, Ana Maria. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Barberis, Isabel Lucila. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Microbiologia E Inmunologia. Area de Bacteriologia; Argentin