Host genotype and amoxicillin administration affect the incidence of diarrhoea and faecal microbiota of weaned piglets during a natural multiresistant ETEC infection.

Enterotoxigenic Escherichia coli (ETEC) is the aetiological agent of postweaning diarrhoea (PWD) in piglets. The SNPs located on the Mucine 4 (MUC4) and Fucosyltransferase 1 (FUT1) genes have been associated with the susceptibility to ETEC F4 and ETEC F18, respectively. The interplay between the MUC4 and FUT1 genotypes to ETEC infection and the use of amoxicillin in modifying the intestinal microbiota during a natural infection by multiresistant ETEC strains have never been investigated. The aim of this study was to evaluate the effects of the MUC4 and FUT1 genotypes and the administration of amoxicillin through different routes on the presence of diarrhoea and the faecal microbiota composition in piglets naturally infected with ETEC. Seventy-one piglets were divided into three groups: two groups differing by amoxicillin administration routes-parenteral (P) or oral (O) and a control group without antibiotics (C). Faecal scores, body weight, presence of ETEC F4 and F18 were investigated 4 days after the arrival in the facility (T0), at the end of the amoxicillin administration (T1) and after the withdrawal period (T2). The faecal bacteria composition was assessed by sequencing the 16S rRNA gene. We described that MUC4 and FUT1 genotypes were associated with the presence of ETEC F4 and ETEC F18. The faecal microbiota was influenced by the MUC4 genotypes at T0. We found the oral administration to be associated with the presence of diarrhoea at T1 and T2. Furthermore, the exposure to amoxicillin resulted in significant alterations of the faecal microbiota. Overall, MUC4 and FUT1 were confirmed as genetic markers for the susceptibility to ETEC infections in pigs. Moreover, our data highlight that group amoxicillin treatment may produce adverse outcomes on pig health in course of multiresistant ETEC infection. Therefore, alternative control measures able to maintain a healthy faecal microbiota in weaners are recommended.

Dietary Saccharomyces cerevisiae boulardii CNCM I-1079 Positively Affects Performance and Intestinal Ecosystem in Broilers during a Campylobacter jejuni Infection.

In poultry production, probiotics have shown promise to limit campylobacteriosis at the farm level, the most commonly reported zoonosis in Europe. The aim of this trial was to evaluate the effects of Saccharomyces supplementation in Campylobacter jejuni challenged chickens on performance and intestinal ecosystem. A total of 156 day old male Ross 308 chicks were assigned to a basal control diet (C) or to a Saccharomyces cerevisiae boulardii CNCM I-1079 supplemented diet (S). All the birds were orally challenged with C. jejuni on day (d) 21. Live weight and growth performance were evaluated on days 1, 21, 28 and 40. The histology of intestinal mucosa was analyzed and the gut microbiota composition was assessed by 16S rRNA. Performance throughout the trial as well as villi length and crypt depth were positively influenced by yeast supplementation. A higher abundance of operational taxonomic units (OTUs) annotated as Lactobacillus reuteri and Faecalibacterium prausnitzii and a lower abundance of Campylobacter in fecal samples from S compared to the C group were reported. Supplementation with Saccharomyces cerevisiae boulardii can effectively modulate the intestinal ecosystem, leading to a higher abundance of beneficial microorganisms and modifying the intestinal mucosa architecture, with a subsequent improvement of the broilers' growth performance.

Evaluation of immune responses in mice and sheep inoculated with a live attenuated Brucella melitensis REV1 vaccine produced in bioreactor.

The Brucella melitensis REV1 vaccine is the most widely employed vaccine for prophylaxis against brucellosis in sheep and goats. The objective of vaccination is disease control in herds or preventing infection in farms. In this study, we produced REV1 vaccine with a protocol, based on the use of liquid medium in a bioreactor, that resulted efficient, safe, relatively fast, and cost-effective. The live attenuated vaccine produced was tested in mice and sheep to investigate its immunogenicity and efficacy. Seventy-two female BALB/c mice were obtained and subdivided in 2 groups, one was stimulated with 1 × 106 colony-forming units (CFUs) of B. melitensis while the other with physiological solution alone and acting as control group. Furthermore, 25 sheep were subdivided into 5 groups: four were inoculated with a B. melitensis dose, ranging from 0.6 × 109 and 3.2 × 109 CFUs and the other was the control group. In addition, a serological diagnosis was performed for sheep by rapid serum agglutination and the complement-fixation test. Immunocompetent cells from both experiment were collected at different times post vaccination and immunostained to evaluate innate and adaptive-immune responses. In mice flow cytometry was used to detect macrophages, T lymphocytes, dendritic cells, memory cells, naïve cells, natural killer cells, major histocompatibility complex type II, B lymphocytes, regulatory T lymphocytes, T helper lymphocytes, cytotoxic T lymphocytes and recently activated CD4+ and CD8+ lymphocytes. In sheep, macrophages, T helper cells, cytotoxic T lymphocytes, regulatory T lymphocytes, dendritic cells, memory cells and naïve lymphocytes, by the same method, were analyzed. The results showed, both in mice and sheep, that the live, attenuated REV1 vaccine stimulated all immunocompetent cells tested, with a balanced innate and adaptive response. In the sheep experiment, the administered vaccine dose was very important because, at the lower doses, immunological tolerance tended to disappear, while, at the highest dose, the immunological tolerance remained active for a long period. In our experimental conditions, the optimal vaccine dose for sheep was 3.2 × 109 CFUs, although a good immune response was found using a dose of 1.6 × 109 CFUs. The vaccine produced in this study could be extensively employed in developing countries to control the brucellosis in sheep and goats.