Salmonella Enteritidis causes fowl paratyphoid in poultry and is frequently associated to outbreaks of food-borne diseases in humans. The role of flagella and flagella-mediated motility into host-pathogen interplay is not fully understood and requires further investigation. In this study, one-day-old chickens were challenged orally with a wild-type strain Salmonella Enteritidis, a non-motile but fully flagellated (SE ΔmotB) or non-flagellated (SE ΔfliC) strain to evaluate their ability to colonise the intestine and spread systemically and also of eliciting gross and histopathological changes. SE ΔmotB and SE ΔfliC were recovered in significantly lower numbers from caecal contents in comparison with Salmonella Enteritidis at early stages of infection (3 and 5 dpi). The SE ΔmotB strain, which synthesises paralysed flagella, showed poorer intestinal colonisation ability than the non-flagellated SE ΔfliC. Histopathological analyses demonstrated that the flagellated strains induced more intense lymphoid reactivity in liver, ileum and caeca. Thus, in the present study the flagellar structure and motility seemed to play a role in the early stages of the intestinal colonisation by Salmonella Enteritidis in the chicken.
Antimicrobial resistance (AMR) is now a major global problem largely resulting from the overuse of antibiotics in humans and livestock. In some AMR bacteria, resistance is encoded by conjugative plasmids expressing sex-pili that can readily spread resistance through bacterial populations. The aim of this study was to use sex pilus-specific (SPS) phage to reduce the carriage of AMR plasmids. Here, we demonstrate that SPS phage can kill AMR Escherichia coli and select for AMR plasmid loss in vitro . For the first time, we also demonstrate that SPS phage can both prevent the spread of AMR Salmonella Enteritidis infection in chickens and shift the bacterial population towards antibiotic sensitivity.
-The present study examined the effect of aflatoxin (AFB 1 ) and fumonisin (FB 1 ) at the levels of 2 mg kg −1 AFB 1 and 100 mg kg −1 FB 1 and the efficiency of use of different levels of adsorbent based on sodium and calcium aluminosilicate on growth performance, hematological parameters, and biochemical parameters of broilers. A total of 1,440 Cobb broilers were distributed into the following treatments: positive control (PC) -no mycotoxin and adsorbent (AD); PC+3AD -no mycotoxin, with 3 g kg −1 adsorbent in feed; negative control (NC) -only mycotoxin; NC+1AD -with mycotoxin and 1 g kg −1 adsorbent in feed; NC+2AD -with mycotoxin and 2 g kg −1 adsorbent in feed; and NC+3AD -with mycotoxin and 3 g kg −1 adsorbent in feed. The amounts of AFB 1 and FB 1 added to NC reduced weight gain (35%) and feed intake (50%) compared with PC; however, inclusion of 2 or 3 g kg −1 adsorbent to NC alleviated such losses. Birds fed NC showed anemia, immunosuppression, and impaired liver function, observed by reduced cholesterol and increased gamma glutamyl-transferase activity compared with PC; values returned to normal levels when 2 or 3 g kg −1 of the adsorbent (as fed) were used. Mycotoxins cause adverse effects on most of the parameters studied, and the use of adsorbent at the levels of 2 and 3 g kg −1 of the adsorbent as fed partially negates the adverse effect of mycotoxicosis.
Piper cubeba is an Asian pepper used in popular medicine for its known antimicrobial, antiparasitic, and anti-inflammatory actions. The study evaluated the effects of dietary inclusion of Piper cubeba ethanolic extract (PE) as a replacement for anantibiotic growth promoter (AGP) on the performance and biochemical serum profile of 1-to 21-d-old broilers (Cobb ®). Two hundred one-d-old broilers were housed in experimental battery cages and distributed in a completely randomized design. The following treatments were applied: negative control (NC)-basal diet; positive control (PC)-basal diet with addition of AGP; and the basal diet with inclusion of 0.17%, 0.34%, and 0.52% of PE (NCE1, NCE2, and NCE3, respectively). Growth performance, biochemical serum profile and internal organ weights were evaluated. Birds fed the AGP presented higher feed intake compared with the other treatments (p<0.05). The PC, NC, and NCE1 treatments presented higher weight gain compared with those fed NCE2 and NCE3 (p<0.05). The NC, NCE1, and NCE2 diets promoted better feed conversion ratio than the PC and NCE3 (p<0.05). Lower triglyceride serum levels were determined in broilers fed the NC and NCE1 diets. Amylase serum levels were lower in NCE1 and NCE2 treatments compared with the NC (p<0.05), whereas those obtained with the PC and NCE3 diets were not different (p>0.05) from the others. Organ relative weights were not influenced by the treatments. The inclusion of 0.17% of PE did not compromise the growth performance, biochemical serum profile or organ relative weights of 21-d-old broilers.
Brazil is considered as a great broiler feet exporter, especially for the Chinese trade. Contact lesions at the tibiotarsal region are responsible for economic losses and there is no model for its classification, thereby this study presents a fast and practical grade system to be used in the poultry industry and proposes these lesion characterizations into three different grades. For this, correlation was made between macroscopic, histological findings and microbiological quantification ( Escherichia coli , Staphylococcus spp., Streptococcus spp. and sulphite-reducing clostridia) from contact lesions in the tibiotarsal region of 112 broiler carcasses, divided in four groups (n=28), accordingly to the lesion’s intensity. There were no significant differences in microbiological quantification among the groups (p>0.05) except for the grade 3 group, as grade 1 and 2 lesions were in the early stages and histopathological changes such as ulceration were not observed. In grade 3 lesion group, it was observed bacterial cocci grume and ulceration at the articular region and significantly higher microbiological count (p<0.05) for E. coli and Staphylococcus spp. In conclusion, the visual standard proposed in this work, correlated and confirmed by the histopathologic, and microbiologic characterization, allows to precise and fast ascertainment of the contact lesion grade in the tibiotarsal regions of broiler carcasses. Moreover, it should be highlighted that grades 1 and 2 alterations are not caused by an inflammatory process caused by pathogenic agents and should not be considered a public health risk.
Currently there are 2659 Salmonella serovars. The host-specific biovars Salmonella Pullorum and Salmonella Gallinarum cause systemic infections in food-producing and wild birds. Fast diagnosis is crucial to control the dissemination in avian environments. The present work describes the development of a multiplex qPCR in real time using a low-cost DNA dye (SYBr Green) to identify and quantify these biovars. Primers were chosen based on genomic regions of difference (RoD) and optimized to control dimers. Primers pSGP detect both host-specific biovars but not other serovars and pSG and pSP differentiate biovars. Three amplicons showed different melting temperatures (Tm), allowing differentiation. The pSGP amplicon (97 bp) showed Tm of 78°C for both biovars. The pSG amplicon (273 bp) showed a Tm of 86.2°C for S. Gallinarum and pSP amplicon (260 bp) dissociated at 84.8°C for S. Pullorum identification. The multiplex qPCR in real time showed high sensitivity and was capable of quantifying 10-10 CFU of these biovars.
Fowl paratyphoid infections are caused by different Salmonella serovars that can affect a wide range of hosts. Due to its complex epidemiology, Salmonella serovar identification is crucial for the development and implementation of monitoring and control programs in poultry farms. Moreover, the characterization of the antimicrobial resistance profiles of Salmonella strains isolated from livestock is relevant to public health because they are a common causative agent of foodborne diseases. The objective of this study was to investigate the presence of Salmonella spp. and to identify the antimicrobial resistance profiles of strains isolated in the midwestern region of São Paulo state, which accounts for the highest production of table eggs in Brazil. For this purpose, 2008 fecal samples were collected on 151 commercial layer farms and submitted to microbiological analyses. Twenty-two serovars were isolated from 80 (52.9%) farms, among which S. Mbandaka and S. Braenderup were the most prevalent. All isolates expressed resistance to at least one of the 23 antimicrobials tested, and the highest resistance rates were determined against streptomycin (93.5%) and sulfonamide (84.6%). Moreover, multidrug resistance was observed in 41% of the isolates and the maximum drug resistance profile was against ten different antimicrobials. Therefore, the identification of Salmonella serovars in poultry production provides epidemiological knowledge to develop prevention and control measures in order to ensure poultry health and to prevent human infection by multiresistant strains.
Salmonella Gallinarum is a host-restrict pathogen that causes fowl typhoid, a severe systemic disease that is one of the major concerns to the poultry industry worldwide. When infecting the bird, SG makes use of evasion mechanisms to survive and to replicate within macrophages. In this context, phoPQ genes encode a two-component regulatory system (PhoPQ) that regulates virulence genes responsible for adaptation of Salmonella spp. to antimicrobial factors such as low pH, antimicrobial peptides and deprivation of bivalent cations. The role of the mentioned genes to SG remains to be investigated. In the present study a phoPQ-depleted SG strain (SG ΔphoPQ) was constructed and its virulence assessed in twenty-day-old laying hens susceptible to fowl typhoid. SG ΔphoPQ did cause neither clinical signs nor mortality in birds orally challenged, being non-pathogenic. Furthermore, this strain was not recovered from livers or spleens. On the other hand, chickens challenged subcutaneously with the mutant strain had discreet to moderate pathological changes and also low bacterial counts in liver and spleen tissues. These findings show that SG ΔphoPQ is attenuated to susceptible chickens and suggest that these genes are important during chicken infection by SG.
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