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1.
Int J Food Microbiol ; 341: 109074, 2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33508583

RESUMO

Campylobacter jejuni (C. jejuni) is one of the most common foodborne pathogens that cause human sickness mostly through the poultry food chain. Cinnamon essential oil (CEO) has excellent antibacterial ability against C. jejuni growth. This study investigated the antibacterial mechanism of CEO against C. jejuni primarily through metabolism, energy metabolism of essential enzymes (AKPase, ß-galactosidase, and ATPase), and respiration metabolism. Results showed that the hexose monophosphate pathway (HMP) was inhibited, and that the enzyme activity of G6DPH substantially decreased upon treatment with CEO. Analysis of the effect of CEO on the expression of toxic genes was performed by the real-time PCR (RT-PCR). The expression levels of the toxic genes cadF, ciaB, fliA, and racR under CEO treatment were determined. Casein/CEO nanospheres were further prepared for the effective inhibition of C. jejuni and characterized by particle-size distribution, zeta-potential distribution, fluorescence, TEM, and GC-MS methods. Finally, the efficiency of CEO and casein/CEO nanospheres in terms of antibacterial activity against C. jejuni was verified. The casein/CEO nanospheres displayed high antibacterial activity on duck samples. The population of the test group decreased from 4.30 logCFU/g to 0.86 logCFU/g and 4.30 logCFU/g to 2.46 logCFU/g at 4 °C and at 25 °C for C. jejuni, respectively. Sensory evaluation and texture analysis were also conducted on various duck samples.


Assuntos
Antibacterianos/farmacologia , Infecções por Campylobacter/veterinária , Campylobacter jejuni/efeitos dos fármacos , Caseínas/farmacologia , Cinnamomum zeylanicum/química , Óleos Voláteis/farmacologia , Animais , Infecções por Campylobacter/tratamento farmacológico , Galinhas/microbiologia , Preparações de Ação Retardada/farmacologia , Patos/microbiologia , Metabolismo Energético/efeitos dos fármacos , Doenças Transmitidas por Alimentos/microbiologia , Doenças Transmitidas por Alimentos/prevenção & controle , Expressão Gênica/efeitos dos fármacos , Glucosefosfato Desidrogenase/antagonistas & inibidores , Humanos , Nanosferas , Via de Pentose Fosfato/efeitos dos fármacos , Aves Domésticas/microbiologia
2.
Int J Food Microbiol ; 339: 109014, 2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33333444

RESUMO

The objective of this study was to develop a method with improved sensitivity for Campylobacter jejuni detection in foods. Nitrogen-doped carbon nanodots (N-CNDs) were synthesized and added to an enrichment medium (Bolton broth) at a concentration of 10 mg/mL. A light-emitting diode (LED) at a wavelength of 425 nm was used to irradiate the N-CNDs-supplemented enrichment medium to induce an exothermic reaction for 1 h. Additionally, a monoclonal antibody specific to C. jejuni NCTC11168 was developed using hybridoma cells to aid detection. The C. jejuni detection capabilities of N-CNDs-supplemented enrichment medium and the conventional Bolton broth enrichment, were compared using duck samples. C. jejuni in the enrichment was detected with the monoclonal antibody based-indirect enzyme-linked immunosorbent assay (ID-ELISA). The N-CNDs-supplemented enrichment medium showed a better C. jejuni detection capability than the conventional Bolton broth enrichment. Additionally, data from ID-ELISA showed excellent detection efficiency and a shortened detection time in the N-CNDs-supplemented enrichment medium after LED irradiation at 425 nm. These results indicate that 1-h LED irradiation at 425 nm to Bolton broth supplemented with the N-CNDs increased the detection efficiency and shortened the detection time with the monoclonal antibody for C. jejuni in food.


Assuntos
Campylobacter jejuni/isolamento & purificação , Ensaio de Imunoadsorção Enzimática , Microbiologia de Alimentos/métodos , Carne/microbiologia , Nanopartículas/química , Animais , Anticorpos Monoclonais/metabolismo , Bactérias/efeitos dos fármacos , Carbono/química , Carbono/farmacologia , Meios de Cultura , Patos/microbiologia , Nitrogênio/química , Nitrogênio/farmacologia
3.
Int J Syst Evol Microbiol ; 70(10): 5287-5295, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32841110

RESUMO

Four unknown strains belonging to the genus Arthrobacter were isolated from plateau wildlife on the Qinghai-Tibet Plateau of PR China. Phylogenetic analysis based on 16S rRNA gene sequences showed that the four isolates were separated into two clusters. Cluster I (strains 785T and 208) had the greatest 16S rRNA gene sequence similarity to Arthrobacter citreus (98.6 and 98.7 %, respectively), Arthrobacter luteolus (98.0 and 98.1%, respectively), Arthrobacter gandavensis (97.9 and 98.0 %, respectively) and Arthrobacter koreensis (97.6 and 97.7 %, respectively). Likewise, cluster II (strains J391T and J915) had the highest sequence similarity to Arthrobacter ruber (98.6 and 98.3 %, respectively) and Arthrobacter agilis (98.1 and 97.9  %, respectively). Average nucleotide identity and the digital DNA-DNA hybridization values illustrated that the two type strains, 785T and J391T, represented two separate novel species that are distinct from all currently recognized species in the genus Arthrobacter. These strains had DNA G+C contents of 66.0-66.1 mol% (cluster I) and 68.0 mol% (cluster II). The chemotaxonomic properties of strains 785T and J391T were in line with those of the genus Arthrobacter: anteiso-C15:0 (79.3 and 40.8 %, respectively) as the major cellular fatty acid, MK-8(H2) (65.8 %) or MK-9(H2) (75.6 %) as the predominant respiratory quinone, a polar lipid profile comprising diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, glycolipids and phospholipid, and A3α or A4α as the cell wall peptidoglycan type. On the basis of our results, two novel species in the genus Arthrobacter are proposed, namely Arthrobacter yangruifuii sp. nov. (type strain, 785T=CGMCC 1.16725T=GDMCC 1.1592T=JCM 33491T) and Arthrobacter zhaoguopingii sp. nov. (type strain, J391T=CGMCC 1.17382T=GDMCC 1.1667T=JCM 33841T).


Assuntos
Arthrobacter/classificação , Fezes/microbiologia , Filogenia , Animais , Arthrobacter/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Patos/microbiologia , Equidae/microbiologia , Ácidos Graxos/química , Lagomorpha/microbiologia , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
4.
J Appl Microbiol ; 129(5): 1185-1192, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32441051

RESUMO

AIMS: Riemerella anatipestifer infections of goslings and ducklings can result in high mortality. Since there are at least 21 serotypes of R. anatipestifer, cross-protection is an important goal for vaccine development. METHODS AND RESULTS: In this study, we evaluated the immunostimulatory effect of different immunization regimens - the traditional inactivated vaccine vs prime-boost regimens using DNA and protein subunit vaccines (DNA+subunit, subunit+subunit, subunit+inactivated and DNA+DNA). Results showed that, when compared to the inactivated vaccine, prime-boost regimens induced higher and up to 16-week longer lasting levels of antibody responses, significantly elevated the percentage of the cytotoxic CD8+ T cell and higher expression levels of IFN-γ, IL-6 and IL-12 mRNAs. Furthermore, as an indication of cross-protection, sera from prime-boost regimens were able to recognize lysates of R. anatipestifer serotypes 1, 2 and 6. CONCLUSIONS: Prime-boost regimens especially DNA-prime and protein-boost, induce strong long-term immune response and may prove protective for breeder ducks requiring long-term protection. SIGNIFICANCE AND IMPACT OF THE STUDY: It is worth mentioning that the subunit+inactivated regimen group also elicited strong immune response. The cost of this regimen may only be half of the other prime-boost regimens, making this subunit + inactivated combination an attractive option.


Assuntos
Vacinas Bacterianas/imunologia , Infecções por Flavobacteriaceae/veterinária , Imunização/métodos , Doenças das Aves Domésticas/prevenção & controle , Riemerella/imunologia , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Vacinas Bacterianas/administração & dosagem , Proteção Cruzada , Patos/microbiologia , Infecções por Flavobacteriaceae/microbiologia , Infecções por Flavobacteriaceae/prevenção & controle , Doenças das Aves Domésticas/microbiologia , Riemerella/genética , Vacinas de DNA/administração & dosagem , Vacinas de DNA/imunologia , Vacinas de Subunidades/administração & dosagem , Vacinas de Subunidades/imunologia
5.
Poult Sci ; 99(5): 2662-2674, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32359603

RESUMO

The gut microbiome is a complex ecosystem that contributes to host nutrition and health. However, our current knowledge of the relationship between ambient temperature and gut microbiota of poultry is still limited. The objective of the present study was to characterize the intestinal microbiota of ducks exposed to high ambient temperature. Sixty 60-day-old Shaoxing ducks were allocated to control and heat-treated groups. The ducks in the control group were kept at 25°C, and the ducks in the heat treatment group were raised at 30-40°C, which simulated the temperature change of day and night in summer. After 15 D, the intestinal contents of the duodenum, jejunum, and ileum were obtained from 6 ducks of each group. Genomic DNA was extracted and amplified based on the V4-V5 hypervariable region of 16S rRNA. The results showed that Firmicutes was the dominant bacterial phylum with the highest abundance in the contents of the small intestine of ducks, and the relative abundance of the phylum Firmicutes in all 3 intestinal segments was increased by high temperature. At the genus level, Lactobacillus was found to be the most dominant bacterial genus across 3 gut segments, and its abundance was increased in ducks under heat treatment. Compared with the corresponding intestine segment of control ducks, a total of 36 genera in the duodenum, 19 genera in the jejunum, and 6 genera in the ileum of heat-treated ducks were found to be significantly different in the abundance (linear discriminant analysis score >3.0, P < 0.05). Functional prediction of gut microbiota revealed that high temperature caused changes in the abundance of metabolism and transcription-related pathways. It is noteworthy that most of the altered pathways are related to metabolism. In conclusion, high temperature induced remarkable taxonomic changes in the gut microbiome of ducks, which might be related to the negative effects of high temperature in ducks. Our present study provided an important theoretical ground for high-temperature intervention.


Assuntos
Patos/microbiologia , Microbioma Gastrointestinal , Temperatura Alta , Animais , Bactérias/isolamento & purificação , Sequenciamento de Nucleotídeos em Larga Escala/veterinária , RNA Bacteriano/análise , RNA Ribossômico 16S/análise , Distribuição Aleatória
6.
Acta Trop ; 207: 105485, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32277927

RESUMO

Carbapenems are traditionally recognized to be the last resort drugs to treat infections due to MDR organisms such as E. coli. As such, the emergence of New Delhi metallo-ß-lactamase-producing E. coli strains have become a challenging threat to the public health. In this regard, we examined the molecular characteristics of carbapenem-resistant E. coli (CRE) isolated from waterfowls in China's tropical island, Hainan. A total of 311 single E. coli strains were obtained from 20 various farms of healthy ducks and geese in 2 districts of Hainan island. The CRE strains were initially identified via phenotypic resistance and modified Hodge test. PCR assay and subsequent nucleotide sequencing were used to detect different types of carbapenemase encoding genes (blaNDM, blaVIM, blaIMP, blaOXA and blaKPC). In addition, MLST and PFGE analyses were also performed. Among the 311 E. coli strains, 8 strains were detected to produce a single type of carbapenemase i.e. NDM-1 (2.6%). A total of 5 sequence types (STs) were observed, of which ST10 was the most prevalent accounting for 37.5% (3/8). Moreover, these 8 isolates yielded 6 different PFGE clusters but showed approximately related PFGE types, suggesting the propagation of similar clone between the farms. This is the first report on the identification of NDM-1-producing E. coli from waterfowls in Hainan island, China. Our results emphasize the need for better efforts to control the further spread of NDM-1-producing E. coli strains in this tropical island.


Assuntos
Patos/microbiologia , Escherichia coli/isolamento & purificação , Gansos/microbiologia , beta-Lactamases/biossíntese , Animais , Escherichia coli/enzimologia , Ilhas
7.
Sheng Wu Gong Cheng Xue Bao ; 36(4): 693-699, 2020 Apr 25.
Artigo em Chinês | MEDLINE | ID: mdl-32347063

RESUMO

To study the interaction between C4b-binding protein (C4BP) and Riemerella anatipestifer (RA), we cloned duck C4BPα, conducted prokaryotic expression and prepared the polyclonal antibody by immunizing mice. Then indirect immunofluorescence assay and dot blotting hybridization assay were used to verify the interaction between C4BP and RA. The full length of duck C4BPα nucleotide sequence was 1 230 bp, with the highest similarity to chicken C4BPα (82.1%). Phylogenetic tree analysis showed that duck C4BPα and chicken C4BPα were on the same phylogenetic tree branch and the genetic evolution relationship between them was the closest. C4BPα was efficiently expressed in Escherichia coli BL21 (DE3). The recombinant proteins existed in intracellular soluble form. The titer of polyclonal antibody was more than 1:10 000 and polyclonal antibodies could specifically recognize the recombinant proteins. The results of indirect immunofluorescence assay and dot blot hybridization assay showed that RA could interact with duck C4BP. The results provide a basis to further reveal the pathogenesis of RA.


Assuntos
Proteína de Ligação ao Complemento C4b , Patos , Regulação da Expressão Gênica , Riemerella , Animais , Clonagem Molecular , Proteína de Ligação ao Complemento C4b/química , Proteína de Ligação ao Complemento C4b/genética , Proteína de Ligação ao Complemento C4b/metabolismo , Patos/classificação , Patos/genética , Patos/microbiologia , Camundongos , Filogenia , Riemerella/metabolismo
8.
Vet Microbiol ; 243: 108641, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32273020

RESUMO

Riemerella anatipestifer is a Gram-negative bacterium, which is an important pathogen infecting ducks and resistant to various antibiotics. The efflux pump is an important resistance mechanism of Gram-negative bacteria, but little research has been done in R. anatipestifer. In this study, the drug resistance mediated by RIA_1614 gene of R. anatipestifer RA-GD strain was studied, because the gene was presumed to be an efflux pump component of ABC. Firstly, the deletion strain RA-GD△RIA_1614 and complemented strain RA-GD△RIA_1614 pCPRA::RIA_1614 were constructed. Then, MICs of various antimicrobial agents to parent and deletion strains and the tolerance of the strains to organic solvents were detected to screen the substrates for RIA_1614 gene. Moreover, the transcription levels of RIA_1614 gene in the parent and the complemented strains exposed to the substrates were detected by quantitative real-time RT-PCR. Furthermore, the efflux abilities of parent, deletion and complemented strains to substrates were determined by antibiotic accumulation test. In addition, in vitro competition ability and virulence of the strains were also detected. The results showed that the deletion strain was more sensitive to aminoglycosides and organic solvents than parental strain RA-GD. When RA-GD and complemented strain were exposed to sub-repression levels of aminoglycosides and organic solvents, the transcription levels of RIA_1614 gene were significantly up-regulated. Sodium o-vanadate inhibitor assay confirmed that RIA_1614 protein contributed to amikacin and streptomycin resistance and organic solvent tolerance. Streptomycin accumulation test showed that the RIA_1614 protein was able to export streptomycin, and the addition of ATPase inhibitor sodium o-vanadate increased the accumulation of streptomycin, indicating that RIA_1614 protein was an ATP-dependent efflux transporter. Growth and competition experiments revealed that RIA_1614 protein had no significant effect on growth of RA-GD, but decreased in vitro competition ability of the strain. Furthermore, pathogenicity tests showed that RIA_1614 protein involved in the virulence of the strain. Based on the results and amino acid sequence analysis, it was determined that RIA_1614 protein was a member of ABC efflux pumps, and the protein was named RanB.


Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Aminoglicosídeos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Proteínas de Membrana Transportadoras/genética , Riemerella/efeitos dos fármacos , Solventes/farmacologia , Transportadores de Cassetes de Ligação de ATP/classificação , Animais , Patos/microbiologia , Deleção de Genes , Genes MDR/genética , Testes de Sensibilidade Microbiana , Compostos Orgânicos/farmacologia , Doenças das Aves Domésticas/microbiologia , Riemerella/genética , Riemerella/patogenicidade , Deleção de Sequência , Solventes/química
9.
Vet Microbiol ; 243: 108642, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32273021

RESUMO

Riemerella anatipestifer (RA) is the significant pathogen of septicemia and duck infectious serositis, diseases which can result in high mortality for ducklings. However, these diseases are difficult to treat because of the bacteria's broad resistance to multiple drugs. The purpose of this study was to produce a specific egg yolk immunoglobulin Y (IgY) targeted to RA, and to evaluate the protective efficacy of this IgY against RA infection. An RA-inactivated vaccine was produced via centrifugation and formalin treatment, using the most predominant serotype 2 wild-type strains in terms of worldwide prevalence. Anti-RA IgY was produced by immunizing Beijing Red No.1 hens with the inactivated vaccine. Enzyme-linked immunosorbent assays showed that the titer levels of anti-RA IgY antibodies increased significantly after exposure. Specific IgY isolated and purified from yolks effectively inhibited the growth of RA in the antibacterial activity assay, which revealed an 80 % reduction of bacteria populations. Animal experiments showed that duckling survival rates were able to reach up to 100 % after the ducklings were treated with 10 mg intramuscular injections of anti-RA IgY from 1 to 12 h after infection. However, the survival rates of ducklings treated with 30 mg of nonspecific IgY at 1 h after infection were 0%. Additionally, ducklings injected once with anti-RA IgY received complete protection in the first week, but the efficacy of this protection almost entirely disappeared after two weeks. The results suggested that specific anti-RA IgY has the potential to improve the degree of protection and responsiveness of ducklings to RA infections and provide them with passive immunity to RA. With further study, this is expected to become a new method for controlling RA infections.


Assuntos
Gema de Ovo/imunologia , Infecções por Flavobacteriaceae/terapia , Infecções por Flavobacteriaceae/veterinária , Imunização Passiva , Imunoglobulinas/uso terapêutico , Riemerella/patogenicidade , Animais , Anticorpos Antibacterianos/imunologia , Vacinas Bacterianas/administração & dosagem , Vacinas Bacterianas/imunologia , Contagem de Colônia Microbiana , Patos/imunologia , Patos/microbiologia , Feminino , Injeções Intramusculares , Doenças das Aves Domésticas/microbiologia , Doenças das Aves Domésticas/terapia , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/imunologia
10.
Poult Sci ; 99(4): 2078-2086, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32241493

RESUMO

This study was conducted to evaluate the effects of grape seed extract (GSE) on growth performance, immunity, antioxidant capacity, relative organ weight, jejunum morphology, ileal microflora, and meat quality in Pekin ducks. A total of 1,500 female 1-day-old Pekin ducklings (52.0 ± 0.2 g) were blocked based on body weight (BW) and randomly allocated into 3 treatments with 10 replicates of 50 birds each. The experiment lasted for 6 wk, and dietary treatments included corn-soybean meal-based diet supplemented with 0, 0.01, and 0.02% GSE. The supplementation of GSE increased (P < 0.05) body weight gain (BWG) and final BW linearly but decreased (P < 0.05) feed-to-gain ratio (F/G) linearly during day (D) 22 to 42 and the entire experiment. The inclusion of GSE increased (P < 0.05) serum superoxide dismutase, glutathione peroxidase, total antioxidative capacity, catalase, complement4, immunoglobin G, interleukin-2, and interferon-γ linearly but decreased (P < 0.05) serum malondialdehyde linearly. The relative weight of carcass, breast meat, and spleen in GSE treatments was increased (P < 0.05) linearly, whereas the relative weight of abdominal fat was decreased linearly (P < 0.05). Birds fed GSE1 and GSE2 diets had lower (P < 0.05) cook loss, 2-thiobarbituric acid reactive substances, and drip loss on day 3 and 5 linearly but higher (P < 0.05) pH24h and water-holding capacity. The addition of GSE decreased (P < 0.05) jejunum crypt depth and ileal Escherichia coli counts linearly but increased (P < 0.05) jejunum villus height: crypt depth ratio and ileal Lactobacilli linearly. Taken together, the inclusion of GSE increased final BW and BWG, decreased F/G during day 22 to 42 and day 1 to 42, partially improved antioxidant activities, immunity, meat quality, and gut health in Pekin ducks.


Assuntos
Antioxidantes/metabolismo , Patos/fisiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Extrato de Sementes de Uva/metabolismo , Imunidade/efeitos dos fármacos , Jejuno/efeitos dos fármacos , Carne/análise , Ração Animal/análise , Animais , Dieta/veterinária , Suplementos Nutricionais/análise , Relação Dose-Resposta a Droga , Patos/crescimento & desenvolvimento , Patos/imunologia , Patos/microbiologia , Feminino , Extrato de Sementes de Uva/administração & dosagem , Íleo/microbiologia , Jejuno/anatomia & histologia , Tamanho do Órgão/efeitos dos fármacos , Distribuição Aleatória
11.
J Food Prot ; 83(4): 605-608, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32221562

RESUMO

ABSTRACT: Little information has been published on the microbiological aspects of U.S. commercial duck processing. The objective of this study was to measure prevalence and/or levels of bacteria in duck samples representing the live bird and partially or fully processed oven-ready duck meat. At 12 monthly sampling times, samples were collected at six sites along the processing line in a commercial duck slaughter plant. Crop and cecum samples were collected at the point of evisceration. Whole carcass rinse samples were collected before and after carcass immersion chilling plus application of an antimicrobial spray. Leg quarters were collected from the cut-up line before and after application of an antimicrobial dip treatment. All samples (five from each site per monthly replication) were directly plated and/or enriched for Salmonella and Campylobacter. For the last 10 replications, carcass and leg quarter rinse samples were also evaluated for enumeration of total aerobic bacteria, Escherichia coli, and coliforms. Most cecum, crop, and prechill carcass rinse samples were positive for Campylobacter (80, 72, and 67%, respectively). Carcass chilling and chlorinated spray significantly lowered Campylobacter prevalence (P < 0.01), and even fewer leg quarters were positive for Campylobacter (P < 0.01). Passage through a chlorinated dip did not further reduce Campylobacter prevalence on leg quarters. Salmonella was infrequently found in any of the samples examined (≤10%). Total aerobic bacteria, coliforms, and E. coli levels were reduced (P < 0.01) on whole carcasses by chilling but were not different after cut-up or leg quarter dip treatment. Overall, current commercial duck processing techniques as applied in the tested plant were effective for reducing the prevalence and levels of Campylobacter on duck meat products.


Assuntos
Campylobacter , Patos , Indústria de Processamento de Alimentos , Animais , Bactérias , Campylobacter/isolamento & purificação , Galinhas , Contagem de Colônia Microbiana , Patos/microbiologia , Escherichia coli/isolamento & purificação , Manipulação de Alimentos , Microbiologia de Alimentos , Carne , Salmonella/isolamento & purificação
12.
Poult Sci ; 99(2): 1096-1106, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32029146

RESUMO

We studied the microbial profiles of the duodenum, jejunum, and ileum during different developmental stages in the duck using high-throughput sequencing of the bacterial 16S rRNA gene. We also investigated the differences in the microbiota in the duodenum, jejunum, and ileum at different developmental times. A correlation analysis was performed between the most abundant bacterial genera and the development of the small intestine. An analysis of alpha diversity indicated different species richness and bacterial diversity in the different small intestinal segments and at different development times. A beta diversity analysis indicated differences in the bacterial community compositions across time. In a weighted UniFrac principal coordinates analysis, the samples clustered into two categories, 2 to 4 wk and 6 to 10 wk, in the duodenum, jejunum, and ileum. Our results show that the small intestine is predominantly populated by the phyla Firmicutes, Bacteroidetes, and Proteobacteria throughout the developmental stages of the duck. The duodenum, jejunum, and ileum shared most of the bacterial phyla and genera present, although they showed significant differences in their relative abundances in the intestinal segments and developmental stages. They shared different bacterial taxa during development times and among different segments when the intergroup differences were analyzed. The genera Bacillus, Corynebacterium 1, Lactococcus, Sphingomonas, and Haliangium correlated moderately positively with the increase in bodyweight and the lengths and weights of the duodenum, jejunum, and ileum, and these genera may be considered important markers when assessing the heath of the intestinal microbiota in ducks. This study provides a foundation upon which to extend our knowledge of the diversity and composition of the duck microbiota and a basis for further studies of the management of the small intestinal microbiota and improvements in the health and production of ducks.


Assuntos
Bactérias/isolamento & purificação , Patos/microbiologia , Microbioma Gastrointestinal , Animais , Bactérias/classificação , Patos/crescimento & desenvolvimento , Duodeno/microbiologia , Íleo/microbiologia , Jejuno/microbiologia , RNA Bacteriano/análise , RNA Ribossômico 16S/análise
13.
J Virol ; 94(10)2020 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-32102887

RESUMO

Ducks usually show little or no clinical signs following highly pathogenic avian influenza virus infection. In order to analyze whether the microbiota could contribute to the control of influenza virus replication in ducks, we used a broad-spectrum oral antibiotic treatment to deplete the microbiota before infection with a highly pathogenic H5N9 avian influenza virus. Antibiotic-treated ducks and nontreated control ducks did not show any clinical signs following H5N9 virus infection. We did not detect any significant difference in virus titers neither in the respiratory tract nor in the brain nor spleen. However, we found that antibiotic-treated H5N9 virus-infected ducks had significantly increased intestinal virus excretion at days 3 and 5 postinfection. This was associated with a significantly decreased antiviral immune response in the intestine of antibiotic-treated ducks. Our findings highlight the importance of an intact microbiota for an efficient control of avian influenza virus replication in ducks.IMPORTANCE Ducks are frequently infected with avian influenza viruses belonging to multiple subtypes. They represent an important reservoir species of avian influenza viruses, which can occasionally be transmitted to other bird species or mammals, including humans. Ducks thus have a central role in the epidemiology of influenza virus infection. Importantly, ducks usually show little or no clinical signs even following infection with a highly pathogenic avian influenza virus. We provide evidence that the microbiota contributes to the control of influenza virus replication in ducks by modulating the antiviral immune response. Ducks are able to control influenza virus replication more efficiently when they have an intact intestinal microbiota. Therefore, maintaining a healthy microbiota by limiting perturbations to its composition should contribute to the prevention of avian influenza virus spread from the duck reservoir.


Assuntos
Influenza Aviária/imunologia , Influenza Aviária/microbiologia , Influenza Aviária/terapia , Influenza Aviária/virologia , Microbiota/fisiologia , Replicação Viral/fisiologia , Animais , Animais Selvagens/virologia , Antibacterianos/uso terapêutico , Antivirais , Patos/microbiologia , Patos/virologia , Células Epiteliais , Humanos , Íleo/patologia , Vírus da Influenza A/imunologia , Intestinos/microbiologia , Pulmão/patologia , Microbiota/efeitos dos fármacos , Poli I-C/uso terapêutico , Sistema Respiratório/virologia , Carga Viral
14.
Vet Microbiol ; 240: 108548, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31902494

RESUMO

Based on its causing ever-increasing heavy economic losses, Riemerella anatipestifer has been viewed as an important bacterial pathogen in the duck industry worldwide. However, the molecular mechanisms regarding its pathogenicity are poorly understood. In our previous study, we have built a random mutagenesis library of Riemerella anatipestifer CH3 using transposon Tn4351. In this study, we screened the library by determining bacterial median lethal dose in ducklings. A mutant strain showed about 376-fold attenuated virulence in comparison with the wild-type strain CH3 was obtained. Subsequently, the Tn4351 inserted gene was identified as M949_RS00050, which encodes a putative protein containing an outer membrane protein beta-barrel domain by genome walking and sequence analyses. Southern blot analysis indicated a single Tn4351 insertion in the CH3 chromosomal DNA. Inactivation of M949_RS00050 gene did not affect bacterial metabolic activity and the silver stained lipopolysaccharide pattern. However, the bacterial sensitivity to normal duck sera killing and bacterial hydrophobicity were dramatically enhanced in the M949_RS00050 gene inactivated mutant strain, compared to its wild-type strain CH3. Moreover, bacterial adherence and invasion abilities, bacterial capsular polysaccharide quantity, biofilm formation capacity and the bacterial virulence of the mutant strain were obviously decreased, compared to the wild-type strain CH3. Thus, our finding demonstrates that the M949_RS00050 gene functions on multiple bacterial biological properties and virulence in Riemerella anatipestifer.


Assuntos
Aderência Bacteriana/genética , Infecções por Flavobacteriaceae/veterinária , Riemerella/genética , Riemerella/patogenicidade , Fatores de Virulência/genética , Animais , Atividade Bactericida do Sangue , Elementos de DNA Transponíveis/genética , Patos/microbiologia , Infecções por Flavobacteriaceae/microbiologia , Deleção de Genes , Biblioteca Gênica , Genes Bacterianos , Mutação , Doenças das Aves Domésticas/microbiologia
15.
Microb Pathog ; 138: 103849, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31704465

RESUMO

Avian colibacillosis is one of the most serious infectious bacterial diseases that endanger the modern poultry industry. Lactobacillus is believed to inhibit intestinal pathogens and maintain a healthy gut microbiota. This study aimed to investigate Lactobacillus supplementation in Cherry Valley ducks to prevent the intestinal flora dysbiosis caused by Duck Escherichia coli 17. One hundred and twenty healthy one day old Cherry Valley ducks were randomized to three study groups (Group I = the control group; Group II = duck Escherichia coli 17 challenge group and Group III = DE17 challenge group supplemented with lactic acid bacteria composite preparation). Cherry Valley ducks in Group II and Group III were gavage challenged with DE17 (1 × 105 CFU/mL) on day 14. Pyrosequencing of the V3/V4 variable regions of the genes encoding for 16S rRNA was used for sequence analysis. The results showed that the normal intestinal microecology was affected by DE17, including a relative increase in proteobacteria. At the same time, the Lactobacillales were increased and harmful bacteria were decreased in different intestinal segments of ducks in Group III, compared to those in Group II. Network analysis showed that dietary lactic acid bacteria addition improved the interaction pattern within the cecal microbiota of ducks and the result showed that in Ruminococcus_2 was independently present in the group III and Lachnospiraceae_NK4A136_group species correlation existed between group I and group III. This study proved that oral supplementation with Lactobacillus casei 1.2435, Lactobacillus rhamnosus 621 and Lactobacillus rhamnosus A4 can mitigate DE17 induced intestinal flora dysbiosis.


Assuntos
Ceco/microbiologia , Patos , Infecções por Escherichia coli/veterinária , Escherichia coli/patogenicidade , Probióticos/farmacologia , Animais , Suplementos Nutricionais , Patos/microbiologia , Disbiose , Infecções por Escherichia coli/dietoterapia , Microbioma Gastrointestinal/genética , Lactobacillus , Lactobacillus rhamnosus , RNA Ribossômico 16S/genética
16.
Br J Nutr ; 123(2): 172-181, 2020 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-31495347

RESUMO

Resistant starch (RS) was recently approved to exert a powerful influence on gut health, but the effect of RS on the caecal barrier function in meat ducks has not been well defined. Thus, the effect of raw potato starch (RPS), a widely adopted RS material, on microbial composition and barrier function of caecum for meat ducks was determined. A total of 360 Cherry Valley male ducks of 1-d-old were randomly divided and fed diets with 0 (control), 12, or 24 % RPS for 35 d. Diets supplemented with RPS significantly elevated villus height and villus height:crypt depth ratio in the caecum. The 16S rRNA sequence analysis indicated that the diet with 12 % RPS had a higher relative abundance of Firmicutes and the butyrate-producing bacteria Faecalibacterium, Subdoligranulum, and Erysipelatoclostridium were enriched in all diets. Lactobacillus and Bifidobacterium were significantly increased in the 24 % RPS diet v. the control diet. When compared with the control diet, the diet with 12 % RPS was also found to notably increase acetate, propionate and butyrate contents and up-regulated barrier-related genes including claudin-1, zonula occludens-1, mucin-2 and proglucagon in the caecum. Furthermore, the addition of 12 % RPS significantly reduced plasma TNF-α, IL-1ß and endotoxin concentrations. These data revealed that diets supplemented with 12 % RPS partially improved caecal barrier function in meat ducks by enhancing intestinal morphology and barrier markers expression, modulating the microbiota composition and attenuating inflammatory markers.


Assuntos
Ração Animal/análise , Ceco/microbiologia , Patos/metabolismo , Patos/microbiologia , Amido/administração & dosagem , Animais , Ceco/metabolismo , Dieta/veterinária , Suplementos Nutricionais , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/metabolismo , Masculino , Carne , Microbiota/efeitos dos fármacos , RNA Ribossômico 16S/metabolismo , Solanum tuberosum
17.
Comp Immunol Microbiol Infect Dis ; 68: 101398, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31775114

RESUMO

To characterize the florfenicol resistance gene and analyze the structure of the resistance gene-related sequence of an Raoultella planticola strain S25 isolated from a duck fecal sample from a farm in South China. Molecular cloning was performed to clone the resistance genes such as mdfA, floR and so on, and the minimum inhibitory concentrations (MICs) were quantified to determine the resistance levels generated by the cloned genes and the related strains. Sequencing and comparative genomics methods were used to analyze the structure of the resistance gene-related sequence. The result showed that the genome of R. planticola S25 consists of a 5.47 Mb chromosome encoding 4962 predicted coding sequence (CDS) and a 68,566 bp plasmid, pS25-68, encoding 84 ORFs. The plasmid sharing the greatest sequence identity with the floR-carrying plasmid pS25-68 is plasmid1 in Klebsiella pneumoniae strain blaNDM-1, which was isolated from a patient in Canada. The mdfA1 gene encoded on the chromosome generated resistance to florfenicol in addition to chloramphenicol. Comparative genomic analysis of the floR-related transposon-like fragment of pS25-68 showed that an approximately 3 kb sequence encoding IS91-virD2-floR-lysR was conserved and presented in the majority of the sequences (84.5 %, 169/200) collected from the database. The results of this work demonstrated that horizontal transfer of the florfenicol resistance gene floR occurred widely between the bacteria of different species and with different origins and that additional florfenicol resistance genes may be present in the bacterial population.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/genética , Tianfenicol/análogos & derivados , Animais , China , Clonagem Molecular , DNA Bacteriano/genética , Patos/microbiologia , Fezes/microbiologia , Transferência Genética Horizontal , Genoma Bacteriano , Genômica , Klebsiella pneumoniae/genética , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Análise de Sequência de DNA , Tianfenicol/farmacologia
18.
BMC Microbiol ; 19(1): 271, 2019 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-31795952

RESUMO

BACKGROUND: Riemerella anatipestifer is one of the most serious infectious disease-causing pathogens in the duck industry. Drug administration is an important method for prevention and treatment of infection in duck production, leading to widespread drug resistance in R. anatipestifer. METHODS: For a total of 162 isolates of R. anatipestifer, the MICs were determined for a quinolone antimicrobial agent, namely, nalidixic acid, and three fluoroquinolones, namely, ciprofloxacin, enrofloxacin and ofloxacin. The gyrA, parC, and parE gene fragments were amplified by PCR to identify the mutation sites in these strains. Site-directed mutants with mutations that were detected at a high frequency in vivo were constructed (hereafter referred to as site-directed in vivo mutants), and the MICs of these four drugs for these strains were determined. RESULTS: In total, 100, 97.8, 99.3 and 97.8% of the 137 R. anatipestifer strains isolated between 2013 and 2018 showed resistance to nalidixic acid, ciprofloxacin, enrofloxacin, and ofloxacin, respectively. The high-frequency mutation sites were detected in a total of 162 R. anatipestifer strains, such as Ser83Ile and Ser83Arg, which are two types of substitution mutations of amino acid 83 in GyrA; Val799Ala and Ile811Val in ParC; and Val357Ile, His358Tyr, and Arg541Lys in ParE. MIC analysis results for the site-directed in vivo mutants showed that the strains with only the Ser83Ile mutation in GyrA exhibited an 8-16-fold increase in MIC values, and all mutants showed resistance to ampicillin and ceftiofur. CONCLUSIONS: The resistance of R. anatipestifer to quinolone agents is a serious problem. Amino acid 83 in GyrA is the major target mutation site for the fluoroquinolone resistance mechanism of R. anatipestifer.


Assuntos
DNA Girase/genética , DNA Topoisomerase IV/genética , Infecções por Flavobacteriaceae/veterinária , Fluoroquinolonas/farmacologia , Riemerella/efeitos dos fármacos , Riemerella/genética , Animais , Antibacterianos/farmacologia , China , Farmacorresistência Bacteriana Múltipla , Patos/microbiologia , Fazendas , Infecções por Flavobacteriaceae/microbiologia , Testes de Sensibilidade Microbiana , Mutação , Doenças das Aves Domésticas/microbiologia , Prevalência , Riemerella/patogenicidade
19.
Microbiome ; 7(1): 151, 2019 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-31779704

RESUMO

BACKGROUND: Ochratoxin A (OTA) is a widespread mycotoxin and induces liver inflammation to human and various species of animals. The intestinal microbiota has critical importance in liver inflammation; however, it remains to know whether intestinal microbiota mediates the liver inflammation induced by OTA. Here, we treated ducklings with oral gavage of OTA (235 µg/kg body weight) for 2 weeks. Then, the microbiota in the cecum and liver were analyzed with 16S rRNA sequencing, and the inflammation in the liver was analyzed. To explore the role of intestinal microbiota in OTA-induced liver inflammation, intestinal microbiota was cleared with antibiotics and fecal microbiota transplantation was conducted. RESULTS: Here, we find that OTA treatment in ducks altered the intestinal microbiota composition and structure [e.g., increasing the relative abundance of lipopolysaccharides (LPS)-producing Bacteroides], and induced the accumulation of LPS and inflammation in the liver. Intriguingly, in antibiotic-treated ducks, OTA failed to induce these alterations in the liver. Notably, with the fecal microbiota transplantation (FMT) program, in which ducks were colonized with intestinal microbiota from control or OTA-treated ducks, we elucidated the involvement of intestinal microbiota, especially Bacteroides, in liver inflammation induced by OTA. CONCLUSIONS: These results highlight the role of gut microbiota in OTA-induced liver inflammation and open a new window for novel preventative or therapeutic intervention for mycotoxicosis.


Assuntos
Ceco/microbiologia , Patos , Microbioma Gastrointestinal/imunologia , Inflamação/imunologia , Inflamação/microbiologia , Fígado/microbiologia , Animais , Ceco/imunologia , Patos/imunologia , Patos/microbiologia , Transplante de Microbiota Fecal/métodos , Inflamação/induzido quimicamente , Fígado/imunologia , Ocratoxinas
20.
Poult Sci ; 98(12): 6542-6551, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31541252

RESUMO

Interspecies transmission of fecal microbiota can serve as an indicator for (indirect) contact between domestic and wild animals to assess risks of pathogen transmission, e.g., avian influenza. Here, we investigated whether oral inoculation of laying hens with feces of wild ducks (mallards, Anas platyrhynchos) resulted in a hen fecal microbiome that was detectably altered on community parameters or relative abundances of individual genera. To distinguish between effects of the duck inoculum and effects of the inoculation procedure, we compared the fecal microbiomes of adult laying hens resulting from 3 treatments: inoculation with wild duck feces (duck), inoculation with chicken feces (auto), and a negative control group with no treatment. We collected cloacal swabs from 7 hens per treatment before (day 0), and 2 and 7 D after inoculation, and performed 16S rRNA amplicon sequencing. No distinguishable effect of inoculation with duck feces on microbiome community (alpha and beta diversity) was found compared to auto or control treatments. At the individual taxonomic level, the relative abundance of the genus Alistipes (phylum Bacteroidetes) was significantly higher in the inoculated treatments (auto and duck) compared to the control 2 D after inoculation. Seven days after inoculation, the relative abundance of Alistipes had increased in the control and no effect was found anymore across treatments. These effects might be explained by the perturbation of the hen's microbiome caused by the inoculation procedure itself, or by intrinsic temporal variation in the hen's microbiome. This experiment shows that a single inoculation of fecal microbiota from duck feces to laying hens did not cause a measurable alteration of the gut microbiome community. Furthermore, the temporary change in relative abundance for Alistipes could not be attributed to the duck feces inoculation. These outcomes suggest that the fecal microbiome of adult laying hens may not be a useful indicator for detection of single oral exposure to wild duck feces.


Assuntos
Galinhas/microbiologia , Patos/microbiologia , Fezes/microbiologia , Microbiota , Vacinação/veterinária , Animais , Animais Selvagens/microbiologia , Feminino , RNA Ribossômico 16S/análise
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