ABSTRACT It is estimated that Salmonella causes one million illnesses in the United States annually, with 19,000 hospitalizations and 380 deaths. There are various serotypes of this bacterium, and the serotypes Typhimurium and Enteritidis are commonly isolated from outbreaks and, in most cases, present resistance to the antibiotics utilized in clinical medicine. One of the current theories to explain the emergence of bacterial resistance is the continuous use of antibiotics as growth promoters in animal feeds. Despite the lack of evidences that antibiotic growth promoters cause bacterial resistance, the poultry industry has explored strategies to reduce or to eliminate the use of antibiotic growth promoters in the production chain, including the improvement of biosecurity programs, use of vaccines, genetic selection, and the feeding of other additives, such as organic acid blends (OAB) and competitive exclusion (CE) products. This study aimed at evaluating the effect of the continuous dietary supplementation of an OAB and a CE product on the growth performance, pH of the crop and cecal contents, control of Salmonella Enteritidis (SE) in the cecal content, and acute-phase protein serum levels in starter commercial turkeys. The additives promoting similar results as antibiotics under controlled experimental conditions should be further evaluated on commercial farms to allow their utilization under practical conditions. Supplementing commercial turkey diets with the evaluated OAB and CE product may reduce SE load. Serum OVT and AGP levels can be used as effective and fast indicators of infection, including that by SE.

ABSTRACT The present study evaluated a probiotic and a competitive exclusion product injected in ovo on day 18 of incubation together with Marek's disease vaccine in eggs of 56-week-old broiler breeders. Three experiments were carried out. The first trial evaluated the effect of treatments on hatchability, cecal colonization of Salmonella Heidelberg (SH), and intestinal mucosa immunity (immunoglobulin A levels in the intestinal fluid). The second trial evaluated the viability of the microorganisms in the products inoculated in a solution containing diluent and Marek's disease vaccine. The third trial evaluated the colonization of the cecal microbiota in non-challenged chickens during first four days of life by culturing cecal samples under aerobic and anaerobic conditions. Hatchability was not affected by the treatments. SH cecal counts were reduced in three-day-old broilers inoculated in ovo with the competitive exclusion product. Liver and spleen pool SH counts were not different among treatments. Broilers inoculated in ovo presented higher intestinal IgA titers 24 hours after SH challenge compared with the controls. When birds were not challenged, lower cecal microbial counts in aerobic culture were determined in the control group than in the probiotic group on day 3, and in the competitive exclusion group on day 2 when cultured in anaerobiosis. The products inoculated and diluted in the vaccine solution were viable at all analyzed periods when cultured in anaerobiosis. The results of this study suggest in-ovo inoculation is an effective route for the administration of the evaluated products, which effectively enhanced the broilers' immune response to a SH challenge, as shown by the increase in IgA titers, and the reduction in cecal Salmonella Heidelberg colonization with the in-ovo inoculation with the competitive exclusion product.

Several studies point out that eggs are the main cause of human salmonellosis, particularly when poorly processed or eaten raw. In addition of causing public health problems, the presence of Salmonella hinders international food trade, and therefore, it is a health barrier. There are several predisposing factors for the contamination of internal egg content by Salmonella spp, including eggshell quality, which is related to dietary calcium (Ca) and phosphorus (P) levels. In this study, eggs from Japanese quails fed diets containing two different Ca (2.0 or 3.5%) or P (0.25 or 0.45%) levels were evaluated. Three production phases were used in the experiment: starter, intermediate, and final. The presence of Salmonella Enteriditis in the eggshell and internal content in in the periods of 0, 24, 96, and 168 hours after the experimental contamination of the eggs by immersion in broth containing Salmonella Enteriditis. The bacterium was detected in decreasing numbers in the eggshell of eggs from all treatments and during all storage periods. No significant bacterial numbers were found in the internal egg content in none of the treatments during none of the production phases. Therefore, the evaluated Ca and P levels in the diet of Japanese quails did not result in higher or lower public health risk relative to the presence of Salmonella Enteritidis in the internal egg content.

The live vaccine Cevac S. Gallinarum, made from a rough strain of Salmonella enterica subspecies enterica serotype Gallinarum is used for preventing fowl typhoid, a disease that still causes considerable economic losses in countries with a developing poultry industry. The objective of this paper was to evaluate a possible reversion to virulence of the strain used in a vaccine in commercial brown layers. Only Salmonella-free chicks were utilized. One hundred twenty (120) 12-day-old Dekalb brown layers divided in two trials were used. The first trial had six groups of 15 birds each. Birds of group 1 were vaccinated with 10 doses of Cevac S. Gallinarum subcutaneously and 10 doses orally, in a total of 20 doses of vaccine. Then the birds of groups 2, 3, 4, and 5 received inocula that contained feces and a pool of organs with fragments of liver, heart, spleen, and cecal tonsils obtained from the immediately previous group. The second trial had three groups with 10 birds each. Birds in group 7 received inocula containing a pool of organs from birds of group 5 from trial 1, whilst the birds in group 8 were vaccinated subcutaneously with one dose of vaccine. Both trials included negative control groups (6 and 9). Throughout the experimental period, birds were monitored for reactions to the vaccination on the site of administration, clinical signs, and post-mortem lesions. In each passage, in addition to the birds euthanized to provide the inocula material, two birds from each group were euthanized for assessment of possible lesions, and their organs (liver, heart, spleen and cecal tonsils) were cultured in an attempt to isolate the vaccine strain. Except for one bird from group 1, that had a local reaction on the site of vaccination - a small vesicle with less that 0.5 mm that persisted until the third day post vaccination -, no other bird had any local reaction to the vaccine or any visible clinical alteration. Birds in group 8 did not present any reaction or clinical alteration because of the vaccine. We only managed to re-isolate the vaccine strain in the inocula made from organs of birds in group 1. We confirmed the isolation by means of biochemical tests, serology, and acriflavine agglutination test. All other cultures made from organs or feces, from all the other experimental groups did not show any growth of the vaccine strain or any other Salmonella serovar, suggesting that the vaccinated birds did not shed the SG9R vaccine strain. No bird presented any clinical symptoms or died during the trials, and no gross lesions were observed in the post-mortem examinations. Under the controlled conditions and time-frame of the present experiment, it was possible to conclude that the rough 9R strain of Salmonella Gallinarum present in the vaccine Cevac S. Gallinarum (Ceva Campinas Ltda. - Campinas, SP - Brazil) did not revert to virulence.

The expression of immune response as a leukocytic infiltrate by CD4+ and CD8+ cells in the epithelium and in the intestinal lamina propria of chicks fed Lactobacillus spp or cecal microflora (CM) and experimentally challenged or not with Salmonella enterica serovar Enteritidis (SE) was studied using immunohistochemistry. Three hundred and twenty day-of-hatch broiler chicks were divided into four groups of 80 birds each and orally received L. reuteri, L. salivarius, L. acidophilus, or CM. Each group was subdivided into four subgroups of 20 birds each, classified as follows: a subgroup did not receive any oral treatment (negative control), subgroup treated with L. spp or CM, subgroup treated with L. spp or CM and challenged with SE, and subgroup only challenged with SE (positive control). The results show that the oral treatment with L. reuteri, L. salivarius, L. acidophilus, or CM and challenge or not with SE stimulated bird immune response as determined by the leukocytic infiltrate by CD8+ lymphocytes followed by CD4+ in the epithelium and in the lamina propria of the duodenum, jejunum, and cecum of chicks up to 12 days of age. CD8+ lymphocyte number was significantly higher in the intestine of chicks receiving CM and challenged with SE. The duodenum, followed by the jejunum, were the segments in which the immune response, as shown by T, CD4+ and CD8+ cells, was stimulated with the greatest intensity.

The expansion of global poultry production has increased the need to reduce or control the agents responsible for economic losses, including Salmonella spp. These bacteria are also of public health concern due to their potential to cause food poisoning, and, more recently, due to the antimicrobial resistance presented by these bacteria. Molecular biology is an important tool currently used in the diagnosis and research studies of main poultry diseases. The present studied analyzed 100 samples of Salmonella Enteritidis (SE) isolated from avian material aiming at detecting the class 1 integron gene, Integroninvolved in antimicrobial resistance, by means of polymerase chain reaction (PCR), and comparing it with plate inhibition test. Subsequently, SE samples were evaluated for their capacity to horizontally transfer this gene. There was no direct relationship between the presence of the class 1 integron gene and SE resistance to the 14 antimicrobials tested, as 80% of the studied samples were resistant to up to three antimicrobials, and did not present the aforementioned gene. However, horizontal transfer of this gene was accomplished in vitro (from Escherichia coli to Salmonella Enteritidis), demonstrating that capacity class 1 integron gene can be disseminated among enterobacteria.

This study aimed at the antibody production by intestinal mucosa of broilers chicks were orally inoculated with Lactobacillus spp. at one and/or 21 days of age, and subsequently challenged with Salmonella enterica, subspecies enterica, serotype Enteritidis (S. Enteritidis). A total number of 288 drug-free broiler chicks was divided into 6 groups (groups A, B, C, D, E, and F), according to age at Lactobacillus spp. inoculation and SE challenge. The intestinal mucosa immune response was determined as the production of immunoglobulin A against S. Enteritidis, and evaluated by the Enzyme-Linked Immunosorbent Assay (ELISA) technique in intestinal washing fluid. Groups treated with Lactobacillus spp. presented higher IgA production only when the chicks were challenged with S. Enteritidis at 21 days of age. Nevertheless, the expected stimulus for intestinal mucosa antibody production induced by Lactobacillus spp was observed in only some of the treated groups, demonstrating that the protocol utilized in the present experiment resulted in few beneficial effects for chicks, particularly during the first days of life.