Encapsulated whey-native yeast Kluyveromyces marxianus as a feed additive for animal production.

Whey is the main byproduct of the cheese industry. While the composition is variable, it retains up to 55% of milk nutrients. The beneficial features of whey indicates a promising source of new potentially probiotic strains for the development of food additives destined for animal production. The aim of this study was to identify Kluyveromyces spp. isolated from whey, to study some probiotic properties and to select the best strain to be encapsulated using derivatised chitosan. Kluyveromyces marxianus strains (VM003, VM004 and VM005) were isolated from whey and identified by phenotypic and molecular techniques. These three yeast strains were able to survive under gastrointestinal conditions. Moreover, they exhibited weak auto-aggregation and co-aggregation with pathogenic bacteria (Salmonella sp., Serratia sp., Escherichia coli and Salmonella typhimurium). In general the K. marxianus strains had a strong antimicrobial activity against pathogenic bacteria. The potential probiotic K. marxianus VM004 strain was selected for derivatised-chitosan encapsulation. Material treated with native chitosan exhibited a strong antimicrobial activity of K. marxianus, showing a total growth inhibition at 10 min exposure. However, derivatised-chitosan encapsulation showed a reduced antimicrobial activity. This is the first study to show some probiotic properties of whey-native K. marxianus, in vitro. An encapsulation strategy was applied using derivatised chitosan.

Avaliação in vitro da adsorção de aflatoxina B1 por produtos comerciais utilizados na alimentação animal / In vitro evaluation of aflatoxin B1 adsorption by commercial products used in animal feed

Objetivou-se avaliar a capacidade de adsorção in vitro de aflatoxina B1 (AFB1) por produtos comerciais utilizados na alimentação animal. Muitas pesquisas estão sendo realizadas para a descontaminação de AFB1 em alimentos. Os produtos comerciais utilizados frequentemente na alimentação de peixes, disponíveis na forma de probióticos, são formados por cepas de bactérias e leveduras utilizadas na maioria dos ensaios de adsorção de micotoxinas. Foram utilizados três produtos comerciais: A, composto por Bacillus subtilis, Bifidobacterium bifidum, Enterococcus faecium e Lactobacillus acidophilus; B, por leveduras secas de Saccharomyces cerevisiae provenientes de cervejaria; e C, por Bacillus subtilis, Bacillus licheniformis e Bacillus pumilus. Cinco suspensões da dose máxima recomendada pelo fabricante de cada produto (0; 25; 50; 75 e 100%) foram testadas contra AFB1 (1000 ng.mL-1) em microtubos para determinação da capacidade de adsorção. Para simular o pH do estômago e do intestino de tilápias do Nilo (Oreochromis niloticus) foram formuladas soluções tampão fosfato salino (PBS), com pH 1,5 e 7,5; respectivamente. Os microtubos foram introduzidos em uma centrífuga com agitação mecânica, a 37ºC por 1 h e depois centrifugados por 10 min a 14.000 rpm; os sobrenadantes foram quantificados por cromatografia líquida de alta eficiência. Os produtos comerciais, nas concentrações máximas, foram capazes de adsorver AFB1 em quantidades de 45,01 a 129,59; 123,90 a 215,59 e 209,98 a 370,73 ng.mL-1, respectivamente. Concluiu-se que todos os produtos comerciais analisados adsorvem AFB1 em condições simuladas de pH gastrointestinal e são candidatos potenciais para adsorção de AFB1 para futuros ensaios in vivo.(AU)

The aim of this study was to evaluate the aflatoxin B1 (AFB1) adsorption capacity, in vitro, by commercial products used in animal feed. Many studies are being conducted for the decontamination of aflatoxins in feed. The commercial products destined to fish feed that are available as probiotics and are formed by strains of bacteria and yeasts used in most mycotoxins adsorption assays. Three commercial products were studied: A, consisting of Bacillus subtilis, Bifidobacterium bifidum, Enterococcus faecium and Lactobacillus acidophilus; B, consisting of dry yeast of Saccharomyces cerevisiae from brewery; and C, consisting of Bacillus subtilis, Bacillus licheniformis and Bacillus pumilus. Five suspensions of the maximum dose recommended by the manufacturer of each product (0; 25; 50; 75 and 100%) were tested against AFB1 (1000 ng.mL-1) in microtubes to determine the adsorption capacity. To simulate the pH of the stomach and intestine of the Nile tilapia (Oreochromis niloticus), phosphate buffered saline solutions (PBS) at pH 1.5 and 7.5, respectively, were formulated. Microtubes were introduced into a centrifuge with mechanical agitation at 37ºC for 1 h and then centrifuged for 10 min at 14.000 rpm; the supernatants were quantified by high-performance liquid chromatography. The commercial products in the maximum concentration were capable of adsorbing AFB1 in amounts from 45.01 to 129.59; from 123.90 to 215.59; and from 209.98 to 370.73 (ng.mL-1), respectively. It was concluded that all commercial products, which are added to animal feed, adsorbed AFB1 under simulated gastrointestinal pH conditions and are potential candidates for AFB1 adsorption for future in vivo studies.(AU)

Avaliação in vitro da adsorção de aflatoxina B1 por produtos comerciais utilizados na alimentação animal / In vitro evaluation of aflatoxin B1 adsorption by commercial products used in animal feed

The aim of this study was to evaluate the aflatoxin B1 (AFB1) adsorption capacity, in vitro, by commercial products used in animal feed. Many studies are being conducted for the decontamination of aflatoxins in feed. The commercial products destined to fish feed that are available as probiotics and are formed by strains of bacteria and yeasts used in most mycotoxins adsorption assays. Three commercial products were studied: A, consisting of Bacillus subtilis, Bifidobacterium bifidum, Enterococcus faecium and Lactobacillus acidophilus; B, consisting of dry yeast of Saccharomyces cerevisiae from brewery; and C, consisting of Bacillus subtilis, Bacillus licheniformis and Bacillus pumilus. Five suspensions of the maximum dose recommended by the manufacturer of each product (0; 25; 50; 75 and 100%) were tested against AFB1 (1000 ng.mL-1) in microtubes to determine the adsorption capacity. To simulate the pH of the stomach and intestine of the Nile tilapia (Oreochromis niloticus), phosphate buffered saline solutions (PBS) at pH 1.5 and 7.5, respectively, were formulated. Microtubes were introduced into a centrifuge with mechanical agitation at 37ºC for 1 h and then centrifuged for 10 min at 14.000 rpm; the supernatants were quantified by high-performance liquid chromatography. The commercial products in the maximum concentration were capable of adsorbing AFB1 in amounts from 45.01 to 129.59; from 123.90 to 215.59; and from 209.98 to 370.73 (ng.mL-1), respectively. It was concluded that all commercial products, which are added to animal feed, adsorbed AFB1 under simulated gastrointestinal pH conditions and are potential candidates for AFB1 adsorption for future in vivo studies.

Objetivou-se avaliar a capacidade de adsorção in vitro de aflatoxina B1 (AFB1) por produtos comerciais utilizados na alimentação animal. Muitas pesquisas estão sendo realizadas para a descontaminação de AFB1 em alimentos. Os produtos comerciais utilizados frequentemente na alimentação de peixes, disponíveis na forma de probióticos, são formados por cepas de bactérias e leveduras utilizadas na maioria dos ensaios de adsorção de micotoxinas. Foram utilizados três produtos comerciais: A, composto por Bacillus subtilis, Bifidobacterium bifidum, Enterococcus faecium e Lactobacillus acidophilus; B, por leveduras secas de Saccharomyces cerevisiae provenientes de cervejaria; e C, por Bacillus subtilis, Bacillus licheniformis e Bacillus pumilus. Cinco suspensões da dose máxima recomendada pelo fabricante de cada produto (0; 25; 50; 75 e 100%) foram testadas contra AFB1 (1000 ng.mL-1) em microtubos para determinação da capacidade de adsorção. Para simular o pH do estômago e do intestino de tilápias do Nilo (Oreochromis niloticus) foram formuladas soluções tampão fosfato salino (PBS), com pH 1,5 e 7,5; respectivamente. Os microtubos foram introduzidos em uma centrífuga com agitação mecânica, a 37ºC por 1 h e depois centrifugados por 10 min a 14.000 rpm; os sobrenadantes foram quantificados por cromatografia líquida de alta eficiência. Os produtos comerciais, nas concentrações máximas, foram capazes de adsorver AFB1 em quantidades de 45,01 a 129,59; 123,90 a 215,59 e 209,98 a 370,73 ng.mL-1, respectivamente. Concluiu-se que todos os produtos comerciais analisados adsorvem AFB1 em condições simuladas de pH gastrointestinal e são candidatos potenciais para adsorção de AFB1 para futuros ensaios in vivo.

Potentiation of the effect of a commercial animal feed additive mixed with different probiotic yeast strains on the adsorption of aflatoxin B1.

This study potentiates the adsorbent effect for aflatoxin B1 (AFB1) of a commercial additive (CA) of animal feed, containing inactive lysate of three Saccharomyces cerevisiae strains, active enzymes, adsorbents and a selenium-amino acid complex, when the additive was mixed separately with three S. cerevisiae strains. Levels of AFB1 of 20 and 50 ng g(-1) were used to determine the binding capacity of different concentrations of CA alone and in the presence of yeast strains, as well as toxin desorption, under gastrointestinal conditions. The viability of yeasts in the presence of CA was evaluated. The results show that the CA did not affect the viability of the yeast strains assayed. CA alone showed a low percentage adsorption. At 20 and at 50 ng g(-1), CA was highly efficient in adsorbing AFB1 when combined with RC016 and RC012 strains respectively. Desorption of AFB1 by CA alone and in combination with the yeasts increased with increasing levels of CA. The results demonstrate the improvement of CA in AFB1 adsorption once it is mixed with live yeasts.

Inhibitory effect of sodium metabisulphite and chlorine on growth of Aspergillus spp. and Penicillium spp. strains isolated from marine shrimp / Efeito inibitório do metabissulfito de sódio e do cloro sobre o crescimento de cepas de Aspergillus spp. e Penicilium spp. isoladas de camarão marinho

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 efficient 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, five 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. flavus 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. flavus. 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.

O metabissulfito de sódio (SMB) é usado na carcinicultura para evitar a melanose e a concentração de 5,0ppm de cloro (CL), utilizada no beneficiamento do camarão, é eficiente como bactericida, porém não há comprovação da eficácia destes compostos químicos como fungicida. Desse modo, o objetivo deste estudo foi avaliar o efeito in vitro do metabissulfito 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. flavus 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. flavus. 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.

Qualidade microbiológica de castanhas de caju (Anacardium occidentale, L) industrializadas e processadas artesanalmente / Study on the microbiological quality of industrialized and handmade cashew nuts (Anacardium occidentale L)

O objetivo deste estudo foi avaliar a qualidade microbiológica de castanhas industrializadas e das castanhas artesanalmente processadas, comercializadas por ambulantes em Teresina (PI). Foram coletadas 40 amostras de castanhas, sendo 21 amostras de castanhas industrializadas de três marcas (“A”, “B” e “C”) e 19 amostras de castanhas processadas artesanalmente (“D”), nas quais foram realizadas a determinação de coliformes a 35 °C e a 45 °C (NMP/g), a pesquisa de Salmonella spp. e a contagem de fungos. As amostras da marca “D” apresentaram maiores valores de coliformes a 35 °C (1,16 × 101 NMP/g); para coliformes a 45 °C, foram detectados valores de 7,0 NMP/g, e de 1,22 × 102 UFC/g para fungos e leveduras. Nas amostras da marca “A”, os valores para coliformes a 35 °C e 45 °C foram de 4,0 NMP/g e, para fungos e leveduras,de 1,0 × 102 UFC/g. Foram isoladas 43 cepas fúngicas. Do gênero Aspergillus, houve maior prevalência da espécie Aspergillus niger agregados (64,7%), e as espécies P. corylophillum (33,3%) e P. citrinum (29,2%) do gênero Penicillium. As amostras de castanhas industrializadas e processadas artesanalmente apresentaram condições higiênico-sanitárias satisfatórias e de acordo com a legislação vigente.

Fungi and mycotoxins in feed intended for sows at different reproductive stages in Argentina.

The aim of this study was to evaluate fungi and contamination levels of aflatoxin B(1), ochratoxin A, fumonisin B(1), and zearalenone in raw materials and finished feed intended for sows at different reproductive stages. Total fungi, Aspergillus, Penicillium, and Fusarium species occurrence, were examined. Aspergillus flavus, A. niger aggregate spp., and F. verticillioides were the prevalent species. Fungal counts exceeded the levels proposed as feed hygienic quality limits (1 x 10(4) colony forming units) at all reproductive stages. Aflatoxin B(1), ochratoxin A, fumonisin B(1), and zearalenone were detected by high-pressure liquid chromatography. Aflatoxin levels in 80% samples of finished sow feeds were over the permitted levels of 0.02 mug g(-1) (mean 228.2 +/- 95 mug Kg(-1)). Fumonisin B(1) was detected in all tested raw materials at levels that varied from 50.3 to 1137.64 mug Kg(-1) and finished feed samples at levels that ranged from 99.8 to 512.4 mug Kg(-1). Aflatoxin B(1), zearalenone, and ochratoxin A were not detected in raw materials. All finished feeds were negative for zearalenone contamination whereas all nonpregnant gilt samples were contaminated with low OTA levels (mean 0.259 +/- 0.123). This fact requires periodic monitoring to prevent the occurrence of mycotoxicosis in animal production, to reduce the economic losses, and to minimize hazards to human health.