Feed deprivation affects crop environment and modulates Salmonella enteritidis colonization and invasion of leghorn hens.
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Leghorn hens over 50 weeks of age were assigned to two treatment groups designated as either unmolted controls or molted. A forced molt was induced by a 9-day feed withdrawal, and each hen was challenged orally with 10(5) Salmonella enteritidis organisms on day 4 of feed withdrawal. On days 4 and 9 of molt, the numbers of lactobacilli and the concentrations of lactate, acetate, propionate, and butyrate, and total volatile fatty acids in the crops decreased while crop pH increased significantly (P < 0.05) in the molted hens compared to the controls. S. enteritidis crop and cecal colonization, in addition to spleen and liver invasion, increased significantly (P < 0.05) in the molted hens compared to the controls. The invasive phenotype of Salmonella spp. is complex and requires several virulence genes which are regulated by the transcriptional activator HilA. Samples of the crop contents from the molted and unmolted birds were pooled separately, centrifuged, and filter sterilized. The sterile crop contents were then used to measure the expression of hilA. By using a lacZY transcriptional fusion to the hilA gene in S. enteritidis, we found that hilA expression was 1.6- to 2.1-fold higher in the crop contents from molted birds than in those from control birds in vitro. The results of the study suggest that the changes in the microenvironment of the crop caused by feed deprivation are important regulators of S. enteritidis survival and influence the susceptibility of molted hens to S. enteritidis infections. Furthermore, our in vitro results on the expression of hilA suggest that the change in crop environment during feed withdrawal has the potential to significantly affect virulence by increasing the expression of genes necessary for intestinal invasion. (+info)
Molecular identification of Candida parapsilosis from crop mucosa in a cockatiel.
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A 2-month-old cockatiel was evaluated for diarrhea, dyspnea, and death. Histologic examination of lesions in the crop mucosa revealed hyperkeratosis and the presence of blastoconidia and hyphae. Positive immunohistochemical staining of the organisms was achieved with an antibody directed against Candida spp. Polymerase chain reaction amplification of DNA from crop lesion material with internal transcribed spacer 2 (ITS2) primers yielded fragments of approximately 300 bp, which demonstrated 95% DNA homology with the corresponding sequence from a strain of Candida parapsilosis deposited in the GenBank data base. The Candida species in the lesion of the crop mucosa was therefore identified by DNA sequence analysis as C. parapsilosis. (+info)
Pathology of spontaneous hemorrhagic enteritis of turkeys.
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Thirteen turkeys naturally affected with hemorrhagic enteritis were studied pathologically. The main gross lesions were splenomegaly and hemorrhagic contents in the gut. The main histological lesions were intranuclear inclusion bodies in largemononuclear cells in many visceral organs and in reticular cells around the sheathed arteries of the spleens and varying degrees of lymphocytic hyperplasia in most tissues. The inclusions were frequently present in areas of the lymphocytic hyperplasia. The large mononuclear cells with the inclusions frequently showed a degenerative change. (+info)
In vitro adhesion specificity of indigenous Lactobacilli within the avian intestinal tract.
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In vitro adherence of Lactobacillus strains to cell and tissue types along the chicken alimentary tract and to ileal mucus were determined. Fresh isolates from chickens adhered to the epithelium of crop and, in a strain-dependent manner, to follicle-associated epithelium and the apical surfaces of mature enterocytes of intestinal villi. No adherence to the apical surfaces of undifferentiated enterocytes, the mucus-producing goblet cells, or the ileal mucus was detected. (+info)
Lactobacillus ingluviei sp. nov., isolated from the intestinal tract of pigeons.
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Lactic acid bacteria were isolated from the crop and intestines of pigeons. One group of strains, showing similar genomic patterns after screening with tRNA intergenic spacer PCR, could not be identified to the species level. Sequencing of the 16S rRNA gene of one representative strain revealed about 96% similarity to sequences from Lactobacillus fermentum and Lactobacillus mucosae. Determination of the DNA base composition, DNA-DNA hybridization experiments, SDS-PAGE of whole-cell proteins and biochemical testing confirmed that the seven strains studied constitute a single novel Lactobacillus species, for which the name Lactobacillus ingluviei sp. nov. is proposed. The type strain is strain KR3T (=LMG 20380T =CCUG 45722T). (+info)
Detection and identification of Lactobacillus species in crops of broilers of different ages by using PCR-denaturing gradient gel electrophoresis and amplified ribosomal DNA restriction analysis.
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The microflora of the crop was investigated throughout the broiler production period (0 to 42 days) using PCR combined with denaturing gradient gel electrophoresis (PCR-DGGE) and selective bacteriological culture of lactobacilli followed by amplified ribosomal DNA restriction analysis (ARDRA). The birds were raised under conditions similar to those used in commercial broiler production. Lactobacilli predominated and attained populations of 10(8) to 10(9) CFU per gram of crop contents. Many of the lactobacilli present in the crop (61.9% of isolates) belonged to species of the Lactobacillus acidophilus group and could not be differentiated by PCR-DGGE. A rapid and simple ARDRA method was developed to distinguish between the members of the L. acidophilus group. HaeIII-ARDRA was used for preliminary identification of isolates in the L. acidophilus group and to identify Lactobacillus reuteri and Lactobacillus salivarius. MseI-ARDRA generated unique patterns for all species of the L. acidophilus group, identifying Lactobacillus crispatus, Lactobacillus johnsonii, and Lactobacillus gallinarum among crop isolates. The results of our study provide comprehensive knowledge of the Lactobacillus microflora in the crops of birds of different ages using nucleic acid-based methods of detection and identification based on current taxonomic criteria. (+info)
Detection, characterization, and in vitro and in vivo expression of genes encoding S-proteins in Lactobacillus gallinarum strains isolated from chicken crops.
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Thirty-eight isolates of Lactobacillus gallinarum cultured from the crops of broiler chickens were screened for the presence of genes encoding S-layer proteins. All of the isolates had two S-protein genes, which were designated Lactobacillus gallinarum S-protein (lgs) genes. One gene in each isolate was either lgsA or lgsB. The Lactobacillus isolates were further characterized by pulsed-field gel electrophoresis of DNA digests, which grouped the isolates into 17 genotypes (strains). The second gene in each of eight representative strains was sequenced and shown to differ among strains (lgsC, lgsD, lgsE, lgsF, lgsG, lgsH, and lgsI). The genome of each strain thus encoded a common S-protein (encoded by either lgsA or lgsB) and a strain-specific S-protein. The extraction of cell surface proteins from cultures of the eight strains showed that each strain produced a single S-protein that was always encoded by the strain-specific lgs gene. Two of the strains were used to inoculate chickens maintained in a protected environment which were Lactobacillus-free prior to inoculation. DNAs and RNAs extracted from the digesta of the chickens were used for PCR and reverse transcription-PCR, respectively, to demonstrate the presence and transcription of lgs genes in vivo. In both cases, only the strain-specific gene was transcribed. Both of the strains adhered to the crop epithelium, consistent with published data predicting that S-proteins of lactobacilli are adhesins. The results of this study provide a basis for the investigation of gene duplication and sequence variation as mechanisms by which bacterial strains of the same species can share the same habitat. (+info)
Medium-chain triacylglycerols enhance release of cholecystokinin in chicks.
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Whether medium-chain triacylglycerols (MCT) affect the plasma concentration of cholecystokinin (CCK) and crop-emptying rate in chicks was investigated after 0, 30, 60, 90, 120 or 180 min of diet intubation. Triacylglycerol sources used were corn oil [containing long-chain triacylglycerols (LCT)], glyceryl tricaprate and glyceryl tricaprylate at a level of 200 g/kg diet. Plasma CCK concentration was significantly enhanced in chicks given the two MCT treatments, but not in those given the LCT treatment, after 30 min feeding relative to the initial level. At all time points, chicks fed the diet containing LCT had significantly lower plasma CCK concentrations than those fed MCT, and chicks fed glyceryl tricaprate had higher concentrations than those fed glyceryl tricaprylate. Dietary MCT sources significantly delayed diet passage from the crop compared with dietary LCT. These results indicate that MCT are more potent stimulators of CCK secretion in chicks than LCT. (+info)