b Salmonella enterica serovars Typhimurium (S. Typhimurium) and Enteritidis (S. Enteritidis) are foodborne pathogens, and outbreaks are often associated with poultry products. Chickens are typically asymptomatic when colonized by these serovars; however, the factors contributing to this observation are uncharacterized. Whereas symptomatic mammals have a body temperature between 37°C and 39°C, chickens have a body temperature of 41°C to 42°C. Here, in vivo experiments using chicks demonstrated that numbers of viable S. Typhimurium or S. Enteritidis bacteria within the liver and spleen organ sites were >4 orders of magnitude lower than those within the ceca. When similar doses of S. Typhimurium or S. Enteritidis were given to C3H/HeN mice, the ratio of the intestinal concentration to the liver/spleen concentration was 1:1. In the avian host, this suggested poor survival within these tissues or a reduced capacity to traverse the host epithelial layer and reach liver/spleen sites or both. Salmonella pathogenicity island 1 (SPI-1) promotes localization to liver/spleen tissues through invasion of the epithelial cell layer. Following in vitro growth at 42°C, SPI-1 genes sipC, invF, and hilA and the SPI-1 rtsA activator were downregulated compared to expression at 37°C. Overexpression of the hilA activators fur, fliZ, and hilD was capable of inducing hilA-lacZ at 37°C but not at 42°C despite the presence of similar levels of protein at the two temperatures. In contrast, overexpression of either hilC or rtsA was capable of inducing hilA and sipC at 42°C. These data indicate that physiological parameters of the poultry host, such as body temperature, have a role in modulating expression of virulence. Salmonella enterica serovars Typhimurium (S. Typhimurium) and Enteritidis (S. Enteritidis) are major causes of foodborne diseases worldwide. In the United States, S. Typhimurium and S. Enteritidis accounted for the majority of confirmed cases of Salmonella outbreaks between 1970 and 2011 (1). These two are nontyphoid Salmonella (NTS) serovars that are capable of causing disease signs in a variety of animals, which contrasts with typhoid fever serovars that exclusively infect humans. Numerous food products have been associated with Salmonella outbreaks and illnesses in humans; however, poultry products are frequently implicated in outbreaks associated with NTS (www.cdc.gov /Salmonella/outbreaks.html). In 2010, a major poultry-related outbreak occurred that involved S. Enteritidis infections across 11 states and resulted in the recall of 380 million eggs (2).S. Typhimurium invades the host epithelial cell layer and migrates to liver and spleen tissue sites through the action of a type 3 secretion system (T3SS), encoded by Salmonella pathogenicity island 1 (SPI-1). SPI-1 is a DNA segment that is approximately 40 kb in size and encodes the structural components of the secretion system, secreted and chaperone proteins, and transcription factors that activate expression of the SPI-1 genes (3-5). Three regulators that are carried wi...

The purpose of this study was to verify the ability of a probiotic in the feed to maintain the stability of the gut microbiota in chickens after antibiotic therapy and its association with growth performance. One thousand six hundred twenty 1‐day‐old Cobb male were housed in floor pens (36 pens, 45 birds/pen) and were fed corn‐/soya bean meal‐based diets supplemented with or without probiotic (Bacillus subtilis) during the entire rearing phase. From 21 to 24 days of age (three consecutive days), the chickens were submitted to antibiotic therapy via drinking water (bacitracin and neomycin) in order to mimic a field treatment and induce dysbiosis. Growth performance was monitored until 42 days of age. At 2, 4 and 6 days after antibiotic therapy, three chickens from each pen were euthanized and the contents of the small intestine and caeca were collected and pooled. The trial was conducted with four treatments and nine replicates in a 2 × 2 factorial arrangement for performance characteristics (with and without probiotic × with and without antibiotic therapy); for the intestinal microbiota, it was in a 2 × 2 × 3 factorial arrangement (with and without probiotic × with and without antibiotic therapy × 2, 4 and 6 days after the antibiotic therapy) with three replicates per treatment. Terminal restriction length polymorphism (T‐RFLP) analysis showed that the structure of gut bacterial community was shaped by the intestinal segment and by the time after the antibiotic therapy. The number of 16S rDNAs copies in caecum contents decreased with time after the therapeutic treatment. The antibiotic therapy and dietary probiotic supplementation decreased richness and diversity indexes in the caecal contents. The improved performance observed in birds supplemented with probiotic may be related to changes promoted by the feed additive in the structure of the intestinal bacterial communities and phylogenetic groups. Antibiotic therapy modified the bacterial structure, but did not cause loss of broiler performance.

The objective of this study was to evaluate the effects of dietary autolyzed yeast (AY; Saccharomyces cerevisiae) supplementation on growth performance, immune system, and intestinal bacterial count in broiler chickens. A total of 1,260 1-day-old male Ross AP95 chicks were placed in a completely randomized design (4 treatments, 7 replicates each, and 45 birds/replicate). The treatments were: basal diet-negative control (NC); basal diet supplemented with 55 ppm of zinc bacitracin-positive control (PC); NC + 0.2% of AY; NC + 0.4% of AY. The diets were formulated based on corn-soybean meal with 5% inclusion of wheat bran and 5% of poultry by-product meal. At 7 days of age, all birds were eye drop-vaccinated with live vaccine against coccidiosis. At 8 and 21 days of age, one chicken per pen was then euthanized by cervical dislocation to collect ileal and cecal contents for enumeration of Enterococcus sp., Escherichia coli and Lactobacillus sp. Yet, ileal samples were collected to analyze the gene expression of Claudin-1, IL-1β, IL-4, TLR-4, and MUC-2 through real time PCR. On d 21, it was observed that the inclusion of 0.2% of AY improved FCR (P < 0.05) when compared to the NC treatment. In the overall experimental period, the inclusion of zinc bacitracin and 0.4% of AY improved FCR (P < 0.05) compared to the NC group. On d 8, supplementation of 0.2% of AY increased Enterococcus and both concentrations of AY reduced Lactobacillus in the ileal digesta compared to birds supplemented with zinc bacitracin. On d 21, 0.2% of AY reduced E. coli in the cecal digesta. On d 8, AY supplementation downregulated the expression of TLR-4 vs. the PC group (P = 0.04). On d 21, supplementation of AY upregulated the expression of IL-1β (P < 0.05) vs. the NC group. Supplementation of AY improved the growth performance of broiler chickens vaccinated against coccidiosis, partially explained by the modulation of the intestinal microbiota and immune-system.

No abstract

This research evaluated a feed additive (benzoic acid, eugenol, thymol, and piperine), associated or not with colistin, in weaned piglets feeding. The parameters evaluated were growth performance, apparent total tract digestibility (ATTD) of nutrients, diarrhea incidence, intestinal morphology, relative weights of digestive organs, microbial diversity, and the percentages of operational taxonomic units of microorganisms in the cecum content of pigs. One-hundred and eight crossbred piglets (5.3 ± 0.5 kg) were used in a three-phase feeding program (21 to 35, 36 to 50, 51 to 65 d of age) and fed a control diet with no inclusion of growth promoter feed additive, a diet with 40 ppm of colistin, a diet with 0.3% of alternative additive, and a diet with 0.3% of alternative additive and 40 ppm of colistin. The diets were based on corn, soybean meal, dairy products, and spray-dried blood plasma and formulated to provide 3.40, 3.38, and 3.20 Mcal of ME/kg and 14.5, 13.3, and 10.9 g/kg of digestible lysine, in phases 1, 2, and 3, respectively. The piglets were housed three per pen, with nine replicates per diet, in a complete randomized block design based on initial BW. The data were submitted to ANOVA and means were separated by Tukey test (5%), using SAS. Pigs fed diets with the alternative feed additive had greater (P &lt; 0.05) ADG (114.3 vs. 91.8 g) and ADFI (190.1 vs. 163.3 g) in phase 1 than pigs fed diets without the product. The alternative additive improved (P &lt; 0.05) ATTD of crude protein (CP) in phase 1 (71.0% vs. 68.6%), gross energy in phases 1 (77.4% vs. 75.2%) and 3 (79.0% vs. 77.1%), and dry matter in phase 3 (79.1% vs. 77.1%). The antibiotic inclusion in the diets increased (P &lt; 0.05) ATTD of CP in phase 1 (71.5% vs. 68.2%). The alternative feed additive tended (P = 0.06) to increase (46%) normal feces frequency, decreased (P &lt; 0.05) goblet cells count (104.3 vs. 118.1) in the jejunum, and decreased (P &lt; 0.05) small intestine (4.60% vs. 4.93%) and colon (1.41% vs. 1.65%) relative weights, compared with pigs not fed with the alternative additive. There was a tendency (P = 0.09) for a lower concentration of Escherichia–Shigella (1.46% vs. 3.5%) and lower (P &lt; 0.05) percentage of Campylobacter (0.52% vs. 10.21%) in the cecum content of piglets fed diets containing essential oils and benzoic acid compared with pigs fed diets without the alternative feed additive. The alternative feed additive was effective in improving growth performance, diets digestibility, and gut health in piglets soon after weaning.

Sorghum grain can be used to replace corn in broiler diets. However, the effects related to an abrupt change between these grains are not yet clear. The aim of this study was to evaluate the performance and intestinal health of broilers fed diets containing corn and/or sorghum during different periods of rearing. To accomplish this aim, 2100 male chicks were fed the following experimental diets: C100% (corn-based diet); S100% (sorghum-based diet); C:S50% (diet based on corn and sorghum 1:1); PC-S (corn-based diet in the pre-starter phase and sorghum-based diet in subsequent phases); and PS-C (sorghum-based diet in the pre-starter phase and corn-based diet in subsequent phases). The study was conducted with two simultaneous trials in a randomized block design as follows: a performance trial up to 40 days occurred in floor pens (n = 8), and the metabolism trial occurred in cages (n = 10). Performance, jejunal morphometry, number of goblet cells, apparent metabolizable energy (AME), apparent metabolizable energy corrected for nitrogen (AMEn) and the coefficient of apparent metabolizability of dry matter (CMDM) of the diets, and the intestinal microbiota of small intestine and caeca at 10 and 21 days of age (16S gene sequencing) were evaluated. The different experimental diets did not affect performance, jejunal epithelium, AME, AMEn or CMDM. However, the experimental diets altered the percentages of the genera Clostridium, Weissella, Bacillus and Alkaliphilus in the small intestine. In addition, the genera Lactobacillus and Desulfotomaculum in the caeca were altered. The age also affected the microbiota of the intestinal segments. In conclusion, feeding sorghum in place of corn as well as the grain change after the pre-starter phase does not alter broiler performance. However, sorghum alters the intestinal microbiota, resulting in a lower percentage of Clostridium and a higher percentage of Lactobacillus in the small intestine and caeca, respectively.

Alternative feedstuffs, broilers, metabolizable energy, glycerol. ABSTRACTThe objective of the present study was to evaluate the quality of different glycerine sources produced in Brazil and to analyze their metabolizable energy levels and digestibility for broilers. Firstly, the composition of 10 samples of glycerine from different sources was analyzed. Secondly, glycerine from four different sources presenting contrasting compositions were selected to determine their metabolizable energy levels and digestibility in metabolism assays using 200 broilers between 21 and 29 days of age, applying the method of total excreta collection. The values of apparent metabolizable energy corrected for nitrogen balance of the four glycerine sources were 3145, 5026, 2828, and 2892 kcal/kg.

No abstract