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Seed-based pigeon diets could be expected to result in exposure of pigeons to mycotoxins such as deoxynivalenol (DON). Ingestion of low to moderate contamination levels of DON may impair intestinal health, immune function and/or pathogen fitness, resulting in altered host-pathogen interactions and thus different outcome of infections. Here we demonstrate that DON was one of the most frequently detected mycotoxins in seed-based racing pigeons feed, contaminating 5 out of 10 samples (range 177-1,466 μg/kg). Subsequently, a toxicokinetic analysis revealed a low absolute oral bioavailability (F) of DON in pigeons (30.4%), which is comparable to other avian species. Furthermore, semi-quantitative analysis using high-resolution mass spectrometry revealed that DON-3α-sulphate is the major metabolite of DON in pigeons after intravenous as well as oral administration. Following ingestion of DON contaminated feed, the intestinal epithelial cells are exposed to significant DON concentrations which eventually may affect intestinal translocation and colonization of bacteria. Feeding pigeons a DON contaminated diet resulted in an increased percentage of pigeons shedding Salmonella compared to birds fed control diet, 87 ± 17% versus 74 ± 13%, respectively. However, no impact of DON was observed on the Salmonella induced disease signs, organ lesions, faecal and organ Salmonella counts. The presented risk assessment indicates that pigeons are frequently exposed to mycotoxins such as DON, which can affect the outcome of a Salmonella infection. The increasing number of pigeons shedding Salmonella suggests that DON can promote the spread of the bacterium within pigeon populations., Competing Interests: The authors have the following interests: This work received the financial support from Biomin GmbH, Herzogenburg, Austria. There are no patents, products in development or marketed products to declare. This does not alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials.

Salmonella infections in amphibians are supposedly highly prevalent. Migrating common amphibian species in cultivated areas such as common toads (Bufo bufo) may thus promote spread and zoonotic transfer of Salmonella to humans, both indirectly by crop and livestock contamination and by direct contact. Between February and April 2011, the intestinal content of 1,740 samples of road-killed migrating common toads in five Flemish provinces of Belgium was examined for the presence of Salmonella using bacterial culture and PCR. All the samples were negative. These results suggest that the role of migrating common toads in maintaining the infection cycle of Salmonella in northern European temperate regions is negligible.

Salmonella enterica serotype Enteritidis is the predominant serotype associated with egg-borne salmonellosis in humans. Apparently this serotype possesses particular characteristics that increase its chance to contaminate eggs. To identify these characteristics, two Salmonella serotype Enteritidis strains as well as one strain of each of the serotypes Salmonella Typhimurium, Salmonella Heidelberg, Salmonella Virchow and Salmonella Hadar strain were used to examine different aspects related to egg contamination. After an intravenous infection of laying hens, it was observed that the ability of the serotype Enteritidis strains to colonize the reproductive organs was significantly higher compared with the Salmonella Heidelberg, Salmonella Virchow and Salmonella Hadar strains but not with the Salmonella Typhimurium strain. Inoculating low numbers of the different Salmonella serotypes in egg albumen at 42 degrees C demonstrated that the growth of the strains belonging to the Salmonella serotypes Virchow and Hadar was seriously repressed. The other serotypes, however, survived in albumen for 24 h. Furthermore, using two different specifically designed egg infection models, it was shown that all strains used in this study were able to penetrate into and multiply inside the yolk at 25 degrees C. These findings indicate that the ability to grow in eggs post lay is not specific for the serotype Enteritidis. In conclusion, comparing strains belonging to different Salmonella serotypes has revealed that most probably a preferential colonization of the reproductive organs and an enhanced survival at 42 degrees C allows the serotype Enteritidis to contaminate eggs.

Reptile-associated salmonellosis in humans is an increasing public health issue. This study aimed at characterizing Salmonella isolates from captive lizards and to compare them to human isolates. Salmonella was isolated from 25 of 33 cloacal and 47 of 79 faecal samples from captive lizards (75.8 and 59.5%, respectively). The strains belonged to 44 serotypes of subspecies I (27 serotypes), II (9), IIIb (3) and IV (5). Two strains, one of serotype Enteritidis and one of serotype Amsterdam, were resistant to nitrofurantoin. Invasion assays in Caco-2 cells were performed with 40 saurian isolates of subspecies I, 15 isolates of subspecies II, 4 strains of subspecies IIIb, 6 subspecies IV isolates and 17 human isolates of corresponding serotypes of subspecies I. Saurian isolates belonging to subspecies I invaded the Caco-2 cells to a higher extent than those from the other subspecies. The human isolates invaded the Caco-2 cells to a lesser degree compared to their saurian counterparts. In the same strains, the presence of virulence genes agfA, shdA, spvR, pefA and sopE was determined using PCR. Whereas agfA was detected in all strains, pefA was only detected in one saurian and in the human serotype Enteritidis strains. The spvR gene was detected in the same serotype Enteritidis strains and in 33% of the subspecies IV strains. The shdA gene was present in all the human isolates and in 86% of subspecies I saurian isolates. SopE was found in 17% of the human isolates, in 24% of the saurian subspecies I strains and in all of the subspecies IV strains.

To determine whether cats were a risk for transmission of Salmonella to humans, we evaluated the excretion of Salmonella by pet cats. Rectal-swab specimens were taken from 278 healthy house cats, from 58 cats that died of disease, and from 35 group-housed cats. Group-housed cats were kept in one room with three cat trays and a common water and feed tray. Eighteen (51.4%) of 35 group-housed cats, 5 (8.6%) of 58 diseased cats (5/58), and 1 (0.36%) of 278 healthy house cats excreted Salmonella. Salmonella isolates were of serotypes Typhimurium, Enteritidis, Bovismorbificans and 4:i:-. Acquired antimicrobial resistance was found in serotype Typhimurium (resistance to ampicillin, chloramphenicol, and tetracycline; to ampicillin; and to chloramphenicol) and 4:i:- strains (resistance to ampicillin, chloramphenicol, sulfonamides, trimethoprim, and sulfamethoxazole/trimethoprim). Cats that excrete Salmonella can pose a public health hazard to people who are highly susceptible to Salmonella, such as children, the elderly, and immunocompromised persons.

Peritoneal macrophages were collected from juvenile turtles 72h after intraperitoneal inoculation with a 3% Sephadex suspension. The macrophages were assayed for their chemiluminescent (CL) properties, reflecting their respiratory burst activity, after stimulation with Zymosan A, phorbol 12-myristate 13-acetate (PMA), N-formyl-methionyl-leucyl-phenylalanine (fMLP), and calcium ionophore A23187. Except for fMLP, all triggering agents induced a marked CL response. Luminol was used as the chemiluminescent probe. When comparing CL responses in temperatures ranging from 15 to 35 degrees C, lower assay temperatures induced lower and slower CL responses. Stimulation with viable Salmonella muenchen resulted in a distinct response. Bacteria, inactivated by means of heat or acetone, induced a faster and stronger oxidative burst. Opsonization of either viable or heat-inactivated S. muenchen with non-inactivated anti-S. muenchen serum, prepared in turtles, induced faster and higher CL responses. On the other hand, opsonization of acetone-inactivated S. muenchen caused CL responses to be slower and weaker. S. muenchen, opsonized with heat-inactivated turtle anti S. muenchen serum, induced higher responses than non-opsonized bacteria, but slower and weaker responses than bacteria opsonized with native turtle antiserum. No response was recorded after stimulation with LPS and the supernatant of heat-inactivated bacteria.

Endemic infections with the common avian pathogen Salmonella enterica subspecies enterica serovar Typhimurium (Salmonella Typhimurium) may incur a significant cost on the host population. In this study, we determined the potential of endemic Salmonella infections to reduce the reproductive success of blue (Cyanistes caeruleus) and great (Parus major) tits by correlating eggshell infection with reproductive parameters. The fifth egg of each clutch was collected from nest boxes in 19 deciduous forest fragments. Out of the 101 sampled eggs, 7 Salmonella Typhimurium isolates were recovered. The low bacterial prevalence was reflected by a similarly low serological prevalence in the fledglings. In this study with a relatively small sample size, presence of Salmonella did not affect reproductive parameters (egg volume, clutch size, number of nestlings and number of fledglings), nor the health status of the fledglings. However, in order to clarify the impact on health and reproduction a larger number of samples have to be analyzed. Phage typing showed that the isolates belonged to the definitive phage types (DT) 193 and 99, and multi-locus variable number tandem repeat analysis (MLVA) demonstrated a high similarity among the tit isolates, but distinction to human isolates. These findings suggest the presence of passerine-adapted Salmonella strains in free-ranging tit populations with host pathogen co-existence. [ABSTRACT FROM AUTHOR]

In all European Union member states, Salmonella monitoring in poultry flocks is obligatory. In these monitoring programmes, a limited number of pooled faeces and/or dust samples are collected to determine whether Salmonella is present in the flocks or not. Whether these limited sampling protocols are sufficiently sensitive to detect expected low within-flock prevalences of an intermittently shed pathogen is not yet clear. In this study, a comparison is made between different sampling procedures for the assessment of the between- and within-flock prevalence of Salmonella in laying hens. In total, 19 farms were sampled. Using a comparable sampling methodology as in the official surveillance programmes, Salmonella could not be detected in any of the flocks. After transportation of the hens to the laboratory and subsequent analysis of cloacal swabs and caecal contents, Salmonella Enteritidis was detected in laying hens from five of 19 farms. The observed within-flock prevalence ranged from 1% to 14%. Based on the results of this study, it can be expected that, depending on the sampling procedure, different estimates of the prevalence of Salmonella can be obtained and the proportion of Salmonella infected flocks is underestimated based on the results of the official monitoring programme. [ABSTRACT FROM AUTHOR]

Broiler meat is one of the sources of Salmonella contamination of humans. Concerns about food safety have prompted the poultry industry and governments to introduce control plans to combat Salmonella. This has been strengthened by legislation, as is the case in the EU, where targets have been set forcing member states to decrease Salmonella prevalence in poultry flocks. Strategies to prevent transmission of Salmonella to humans should focus on the whole production chain of broiler meat and on the subsequent storage and handling of meat, thus from farm to fork. In the primary production phase, both hygienic measures and general farm management strategies are important. These management strategies should include in-feed Salmonella control and product administration. A wide range of feed additives is currently available for that purpose. Hygienic measures and logistic slaughter are tools to reduce the Salmonella contamination in the slaughterhouse. At retail and in the consumer's kitchen, care needs to be taken of product storage and handling to avoid contamination and bacterial growth. The numbers of contaminated Salmonella broiler flocks will most likely decrease in the future due to the established action plans, but complete eradication of Salmonella is unrealistic. The main issue is, however, to keep the flock prevalence, the within-flock prevalence and the numbers of bacteria in infected animals at such a low level, that contamination of meat, and thus transmission to humans, becomes a highly unlikely event. This clearly underlines the need for coordinated action of governments and poultry-related industries (including feed industry and slaughterhouses), at all stages of the production chain. [ABSTRACT FROM PUBLISHER]

Salmonella Typhimurium infections in pigs pose an important human health hazard. One promising control measure is the development of live attenuated vaccine strains using defined knockout mutants. Preferably, screening of candidate knockout vaccine strains for attenuation should first be done in models allowing testing of a large number of strains. Thereafter, a limited number of selected strains should be further characterized in an experimental infection model in pigs. The aim of the present study was to develop such models. The invasive and proliferative characteristics of S. Typhimurium were assessed in both a non-polarized and a polarized porcine intestinal epithelial cell line. Neutrophils obtained from porcine blood were used to study the capacity of Salmonella to withstand killing by these phagocytes. The ability to induce an intestinal inflammatory response was investigated in a terminal intestinal loop model. The systemic phase of infection was mimicked by studying the uptake and intracellular survival of S. Typhimurium in porcine pulmonary alveolar macrophages and peripheral blood monocytes. These models should allow screening for attenuated strains. For further characterization, an experimental infection model was established, providing extensive data on the course of an oral infection and the optimal time points for colonization (day 5 postinoculation [ pi]) and persistency (days 21-28 pi) in pigs. In conclusion, screening for virulence of S. Typhimurium strains with subsequent confirmation for a subset of strains in a well-defined experimental infection model would significantly reduce the number of experimental pigs required. [ABSTRACT FROM AUTHOR]

Abstract: Porcine carcasses contaminated with Salmonella typhimurium pose significant public health problems. Prolonged faecal shedding of Salmonella in pigs contributes to the contamination level of carcasses. Although the mechanism of prolonged faecal shedding is not yet clarified, the CS54 Island, and more specifically the shdA gene encoding a fibronectin binding autotransporter protein, was identified as an important locus for intestinal colonization and persistence of Salmonella typhimurium in mice. The aim of this study was to assess the contribution of ShdA in faecal shedding of Salmonella typhimurium in pigs. Pigs were orally inoculated with a Salmonella typhimurium wild type field strain or its isogenic shdA mutant strain. For the first few days after inoculation, the shdA mutant strain was excreted more, the diarrhoea was more pronounced and higher numbers of internal organs were infected. No effect on long-term shedding was found. In a porcine ileal loop model, the wild type strain and shdA mutant strain did not show any differences in the induction of neutrophil influx into the intestinal wall and lumen. In conclusion, we have shown that a Salmonella typhimurium deletion mutant in shdA is more virulent during the first days after inoculation and is not significantly impaired in persistence or prolonged shedding in pigs. [Copyright &y& Elsevier]

Salmonella is a human pathogen that is commonly found in poultry products. It is possible to decrease chicken carcass and egg contaminations by adding organic acids to the feed or drinking water at appropriate times. Medium-chain fatty acids are more antibacterial against Salmonella than short-chain fatty acids. The antibacterial effect of these acids is species specific. Bacteria that are unable to decrease intracellular pH accumulate organic acid anions in accordance with the pH gradient across their cell membranes. The short-chain fatty acid butyrate specifically down-regulates expression of invasion genes in Salmonella spp. at low doses. Also medium-chain fatty acids and propionate decrease the ability of Salmonella spp. to invade epithelial cells, in contrast to acetic acid. Because not all bacteria are affected in a similar fashion by organic acids, it may be possible to use probiotic and prebiotic bacteria to achieve beneficial effects. If diets can be designed to stimulate organic acid production in the caecum, it may be possible to control Salmonella spp. via even easier and more cost-effective measures, compared with addition of acids to feed or drinking water. [ABSTRACT FROM AUTHOR]

Salmonella enterica serovar Enteritidis is the predominant serovar associated with salmonellosis worldwide, which is in part due to its ability to contaminate the internal contents of the hen's egg. It has been shown that S. enterica serovar Enteritidis has an unusual tropism for the avian reproductive tract and an ability to persist in the oviduct and ovary. Factors allowing S. enterica serovar Enteritidis strains to contaminate eggs could be a specific interaction with the oviduct tissue, leading to persisting oviduct colonization. In vivo expression technology, a promoter-trap strategy, was used to identify genes expressed during oviduct colonization and egg contamination with S. enterica serovar Enteritidis. A total of 25 clones with in vivo-induced promoters were isolated from the oviduct tissue and from laid eggs. Among the 25 clones, 7 were isolated from both the oviducts and the eggs. DNA sequencing of the cloned promoters revealed that genes involved in amino acid and nucleic acid metabolism, motility, cell wall integrity, and stress responses were highly expressed in the reproductive tract tissues of laying hens. [ABSTRACT FROM AUTHOR]

Invasion of intestinal epithelial cells by Salmonella enterica is decreased after exposure to butyric acid. To understand the molecular mechanisms of this phenomenon, a comparative transcriptomic analysis of Salmonella enterica serovar Enteritidis and Salmonella enterica serovar Typhimurium grown in medium supplemented with butyrate was performed. We found that butyrate down-regulated the expression of 19 genes common to both serovars by a factor of twofold or more, and 17 of these genes localized to the Salmonella pathogenicity island 1 (SPI1). These included the SPI1 regulatory genes hilD and invF. Of the remaining two genes, ampH has 91% homology to an Escherichia coli penicillin-binding protein and sopE2 encodes a type III-secreted effector protein associated with invasion but located at a separate site on the chromosome from SPI1. [ABSTRACT FROM AUTHOR]

Poultry are very likely to become infected with Salmonella in the early posthatch period, due to environmental contamination. The purpose of this study was to evaluate the effect of infection dose on the risk of persistent infection in laying hens. In this study, young layer chicks were orally infected with a low (10² at 1 d posthatch) or a high dose (109 cfu at 1 wk posthatch) of Salmonella Enteritidis. The pattern and duration of fecal shedding was studied for 18 wk. All chickens shed Salmonella early after infection and shed Salmonella intermittently during the whole study period. There were more positive birds in the high-dose group than in the lowdose group in the first weeks following Salmonella exposure. From 10 wk postinfection onwards, however, birds that were orally infected with the low dose of Salmonella Enteritidis shed more Salmonella than the birds that received the high dose. At 18 wk of age, there was no difference in cecal colonization between the treatment groups. It can be concluded that infection of newly hatched chicks with a low dose of Salmonella Enteritidis can lead to persistent infection until onset of lay, hereby excreting Salmonella bacteria intermittently. [ABSTRACT FROM AUTHOR]

• Vaccination of sows increased the concentration of maternally derived antibodies in 3-day old piglets. • Piglet and fattening pig vaccination resulted in higher sample-to-positive (S/P) ratios at slaughter compared to non-vaccinated pigs. • Piglet and fattening pig vaccination could interfere with serology-based Salmonella monitoring programs at slaughter. Vaccination of pigs against Salmonella Typhimurium (S. Typhimurium) can be effective for the control of Salmonella infections at the farm level and reduce the risk of Salmonella contamination in the food chain. However, vaccination may interfere with herd serological status in serology-based Salmonella monitoring programs. The present study investigated the effects of an attenuated S. Typhimurium vaccine (Salmoporc, IDT Biologika) on Salmonella serology in sows, neonatal piglets and slaughter pigs from three subclinically infected herds. Within each herd, five different vaccination protocols were tested as follows: group 1, vaccination of sows; group 2, vaccination of sows and piglets; group 3, vaccination of sows and fattening pigs; group 4, vaccination of piglets; and group 5 vaccination of fattening pigs. Each group was compared to a non-vaccinated control group (group 6). Sera were analyzed by ELISA (HerdChek Swine Salmonella, IDEXX Laboratories) and sample-to-positive (S/P) ratios were calculated. At day 3 after farrowing, but not before vaccination, S/P ratios in vaccinated sows (mean: 2.21) were significantly higher than S/P ratios in non-vaccinated sows (mean: 0.87, P < 0.001). S/P ratios in 3-day old piglets from vaccinated sows (mean: 2.46) were significantly higher than S/P ratios in similar piglets from non-vaccinated sows (mean: 0.73, P < 0.001). At slaughter, S/P ratios in pigs from groups 2, 3, 4 and 5 were significantly higher than those in the non-vaccinated control group (P < 0.001). Therefore, vaccination of piglets and fattening pigs could have implications for current serology-based Salmonella monitoring programs in slaughter pigs. [ABSTRACT FROM AUTHOR]

An explorative field study was carried out to determine risk factors for Salmonella infections in commercial laying hen flocks. For this purpose, 29 laying hen farms, including farms using conventional and alternative housing systems, were intensively sampled. An on-farm questionnaire was used to collect information on general management practices and specific characteristics of the sampled flock such as flock size, age of the hens, and age of the infrastructure. Salmonella was detected in laying hens from 6 of the 29 sampled farms. Using multivariate logistic regression with the Salmonella status of the flock as an outcome variable, a previous Salmonella contamination on the farm and the age of the production system were identified as risk factors for the presence of Salmonella in laying hens (P < 0.05). The housing system did not have a significant influence on the prevalence of Salmonella in the current study. [ABSTRACT FROM AUTHOR]

Abstract: Salmonella outbreaks in humans are often linked with the consumption of contaminated eggs. Therefore a profound knowledge of the actual prevalence of Salmonella spp. in laying hens and the factors that influence the presence and persistence of Salmonella on a farm is of utmost importance. The housing of laying hens in conventional battery cages will be forbidden in the European Union (EU) from 2012 onwards. There is an urgent need to evaluate whether this move to alternative housing systems will influence the prevalence of Salmonella in laying hens. Therefore, a cross-sectional study was performed in 5 European countries (Belgium, Germany, Greece, Italy and Switzerland) to determine the between and within flock prevalence of hens shedding Salmonella and to investigate whether there is an effect of the housing type on Salmonella prevalence. In total 292 laying hen farms were sampled in the month prior to depopulation. An on-farm questionnaire was used to collect information on general management practices and specific characteristics of the sampled flock. Twenty-nine flocks were found positive for at least 1 Salmonella-serotype. In these flocks the within flock prevalence of shedding hens, determined by individual sampling of 40 hens, varied between 0% and 27.50%. A wide variety of serotypes was isolated with Salmonella Enteritidis as the most common. Housing in conventional battery cages, the absence of dry cleaning in between production rounds and sampling in winter turned out to be risk factors for the shedding of Salmonella Enteritidis or Typhimurium (P <0.05). [Copyright &y& Elsevier]

Abstract: Salmonella Typhimurium infections in pigs are a major source of human foodborne salmonellosis. To reduce the number of infected pigs, acidification of feed or drinking water is a common practice. The aim of the present study was to determine whether some frequently used short- (SCFA) and medium-chain fatty acids (MCFA) are able to alter virulence gene expression and to decrease Salmonella Typhimurium colonization and shedding in pigs using well established and controlled in vitro and in vivo assays. Minimal inhibitory concentrations (MIC) of 4 SCFA (formic acid, acetic acid, propionic acid and butyric acid) and 2 MCFA (caproic and caprylic acid) were determined using 54 porcine Salmonella Typhimurium field strains. MIC values increased at increasing pH-values and were two to eight times lower for MCFA than for SCFA. Expression of virulence gene fimA was significantly lower when bacteria were grown in LB-broth supplemented with sub-MIC concentrations of caproic or caprylic acid (2mM). Expression of hilA and invasion in porcine intestinal epithelial cells was significantly lower when bacteria were grown in LB-broth containing sub-MIC concentrations of butyric acid or propionic acid (10mM) and caproic or caprylic acid (2mM). When given as feed supplement to pigs experimentally infected with Salmonella Typhimurium, coated butyric acid decreased the levels of faecal shedding and intestinal colonization, but had no influence on the colonization of tonsils, spleen and liver. Uncoated fatty acids, however, did not influence fecal shedding, intestinal or tonsillar colonization in pigs. In conclusion, supplementing feed with certain coated fatty acids, such as butyric acid, may help to reduce the Salmonella load in pigs. [Copyright &y& Elsevier]

Short-chain fatty acids have been widely used as feed additives to control Salmonella in poultry. Data on the use of butyric acid in poultry are lacking. In this study, powder form and coated butyric acid were compared in their ability to reduce Salmonella colonization of ceca and internal organs shortly after infection of young chickens with Salmonella enteritidis. In the first trial, 4 groups of 25 specific pathogen free layer chickens were given feed either supplemented with powder form butyric acid, coated butyric acid, a combination of powder form and coated butyric acid (all groups received a total of 0.63 g of butyric acid/kg) or nonsupplemented feed. The specific pathogen free layer chickens were orally infected with 106 cfu of S. enteritidis. Coated butyric acid significantly decreased cecal colonization 3 d post-infection compared with control chickens, and powder form butyric acid had no effect. To study long-term shedding and colonization of Salmonella in broilers given coated butyric acid as feed additive (0.63 g of active product butyric acid/kg), 10 Ross broiler chickens were infected at d 5 with 105 cfu of S. enteritidis and housed together with 40 noninfected broilers. A control group received nonsupplemented feed. The group of broilers receiving coated butyric acid had a significantly lower number of broilers shedding Salmonella bacteria, but cecal colonization at slaughter age was equal for both groups. In conclusion, butyric acid decreases cecal colonization shortly after infection, decreases fecal shedding, and as a consequence, decreases environmental contamination by S. enteritidis-infected broilers. However, complete elimination can probably only be achieved with a combined approach using both hygienic measures and different protection measures, as the broilers still carried S. enteritidis bacteria in the ceca at slaughter age, although at enrichment level. [ABSTRACT FROM AUTHOR]

The most common source of Salmonella infections in humans is food of poultry origin. Salmonella enterica serovar Enteritidis has a particular affinity for the contamination of the egg supply. In this study, the medium-chain fatty acids (MCFA), caproic, caprylic, and capric acid, were evaluated for the control of Salmonella serovar Enteritidis in chickens. All MCFA were growth inhibiting at Iow concentrations in vitro, with caproic acid being the most potent. Contact of Salmonella serovar Enteritidis with Iow concentrations of MCFA decreased invasion in the intestinal epithelial cell line T84. By using transcriptional fusions between the promoter of the regulatory gene of the Salmonella pathogenicity island I, hiLA, and luxCDABE genes, it was shown that all MCFA decreased the expression of hilA, a key regulator related to the invasive capacity of Salmonella. The addition of caproic acid (3 g/kg of feed) to the feed of chicks led to a significant decrease in the level of colonization of ceca and internal organs by Salmonella serovar Enteritidis at 3 days after infection of 5-day-old chicks. These results suggest that MCFA have a synergistic ability to suppress the expression of the genes required for invasion and to reduce the numbers of bacteria in vivo. Thus, MCFA are potentially useful products for reducing the level of colonization of chicks and could ultimately aid in the reduction of the number of contaminated eggs in the food supply. [ABSTRACT FROM AUTHOR]

Examines the efficacy of a new range of products encapsulating short-chain fatty acids in mineral carriers, against early colonization and invasion of Salmonella (S.) enteritidis bacteria in young chickens in the U.S. Increase in colonization of ceca and internal organs through feed supplementation with acetic and formic acid; Extent of the Salmonella colonization on birds receiving propionic acid-coated microbeads as feed supplement and that of the control group; Decrease of S. enteritidis in the ceca but not in liver and spleen for butyric acid-impregnated microbeads in feeds.