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.

Salmonella Enteritidis causes infections in humans and animals which are often associated with extensive gut colonization and bacterial shedding in faeces. The natural presence of flagella in Salmonella enterica has been shown to be enough to induce proinflammatory responses in the gut, resulting in recruitment of polymorphonuclear cells, gut inflammation and, consequently, reducing the severity of systemic infection in chickens. On the other hand, the absence of flagellin in some Salmonella strains favours systemic infection as a result of the poor intestinal inflammatory responses elicited. The hypothesis that higher production of flagellin by certain Salmonella enterica strains could lead to an even more immunogenic and less pathogenic strain for chickens was here investigated. In the present study, a Salmonella Enteritidis mutant strain harbouring deletions in clpP and fliD genes (SE ΔclpPfliD), which lead to overexpression of flagellin, was generated, and its immunogenicity and pathogenicity were comparatively assessed to the wild type in chickens. Our results showed that SE ΔclpPfliD elicited more intense immune responses in the gut during early stages of infection than the wild type did, and that this correlated with earlier intestinal and systemic clearance of the bacterium.

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.

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.

The incidence of foodborne diseases caused by the genus Salmonella spp. in industrialized countries is often high in epidemiological surveys. Obtaining a rapid diagnostic test for identification of bacteria is crucial in order to rapidly implement control measures to contain bacterial spread, to reduce losses in animal production and to avoid risks from food-borne infections to human health. The aim of this study was to standardize duplex real-time PCR using SYBr Green I for differential and quantitative diagnosis of S. Typhimurium and S. Enteritidis. According to the experiment, the melting temperature of 85°C was observed for a 206bp amplified product when S. Enteritidis DNA was added to the reaction. S. Typhimurium DNA showed that the melting temperature of 79°C when observed for a 62bp amplified product. The standard curve showed the high sensitivity of the proposed test, since it was possible to obtain eight quantification points, starting at 10 8 CFU/mL and ending at 10 1 CFU/mL. As a result of the present study, a real-time PCR duplex reaction with high sensitivity, specificity and based on the fluorescence of SYBr Green I was standardized. In addition, this methodology aligns low cost to the faster diagnostic result, in relation to other molecular tests, making it attractive for application in routine laboratory analyzes.