Poultry meat is the major source of human campylobacteriosis, the most frequently reported zoonosis in the EU. The prevalence of Campylobacter colonization in European broiler flocks is 71%. Despite considerable efforts, there is still no effective strategy available to prevent or reduce Campylobacter colonization in broilers. This study tested a wide variety of feed additives to reduce Campylobacter shedding in primary poultry production. Twelve additives containing organic or fatty acids, monoglycerides, plant extracts, prebiotics, or probiotics were tested. For each additive, broilers contaminated with Campylobacter jejuni were fed with an additive free diet (control group) or with a supplemented diet (treated group) and Campylobacter loads compared at three sampling times. No treatment was able to prevent broiler colonization by Campylobacter, and there was a high degree of variation in contamination among the birds. At 14 d of age, eight treatments significantly decreased the colonization level compared to the control group by a maximum of 2 log10 CFU/g. At 35 d of age, three of these treatments still had a significant effect with a maximum reduction of 1.88 log10 CFU/g for a probiotic. At 42 d of age, only one short-chain fatty acid was still significantly efficient with a mean reduction over 2 log10 CFU/g. In addition, a probiotic and a prebiotic-like compound significantly decreased the contamination by a maximum of 3 log10 CFU/g, only at the 42-d sampling period. This study gives promising results regarding the use of feed additives to reduce Campylobacter infection in flocks. Nevertheless, a global approach, combining intervention measures at the different steps of the broiler meat production chain could have a greater impact on the reduction of public health risk.

No abstract

Infectious bursal disease virus (IBDV) is a Birnaviridae family member of economic importance for poultry. This virus infects and destroys developing B lymphocytes in the cloacal bursa, resulting in a potentially fatal or immunosuppressive disease in chickens. Naturally occurring viruses and many vaccine strains are not able to grow in in vitro systems without prior adaptation, which often affects viral properties such as virulence. Primary bursal cells, which are the main target cells of lymphotropic IBDV in vivo, may represent an attractive system for the study of IBDV. Unfortunately, bursal cells isolated from bursal follicles undergo apoptosis within hours following their isolation. Here, we demonstrate that ex vivo stimulation of bursal cells with phorbol 12-myristate 13-acetate maintains their viability long enough to allow IBDV replication to high titres. A wide range of field-derived or vaccine serotype 1 IBDV strains could be titrated in these phorbol 12-myristate 13-acetate -stimulated bursal cells and furthermore were permissive for replication of non-cell-culture-adapted viruses. These cells also supported multistep replication experiments and flow cytometry analysis of infection. Ex vivo-stimulated bursal cells therefore offer a promising tool in the study of IBDV.

Campylobacteriosis is reported to be the leading zoonosis in Europe, and poultry is the main reservoir of Campylobacter. Despite all the efforts made, there is still no efficient vaccine to fight this bacterium directly in poultry. Recent studies have reported interactions between the chicken immune system and gut microbiota in response to Campylobacter colonisation. The present study was designed to analyse in more depth the immune responses and caecal microbiota following vaccination with a DNA prime/protein boost flagellin-based vaccine that induces some protection in specific-pathogen-free White Leghorn chickens, as shown previously. These data may help to improve future vaccination protocols against Campylobacter in poultry. Here a vaccinated and a placebo group were challenged by C. jejuni at the age of 19 days. A partial reduction in Campylobacter loads was observed in the vaccinated group. This was accompanied by the production of specific systemic and mucosal antibodies. Transient relatively higher levels of Interleukin-10 and antimicrobial peptide avian β-defensin 10 gene expressions were observed in the vaccinated and placebo groups respectively. The analysis of caecal microbiota revealed the vaccination’s impact on its structure and composition. Specifically, levels of operational taxonomic units classified as Ruminococcaceae and Bacillaceae increased on day 40.

No abstract

No abstract

Research was carried out to determine the effectiveness of 4 hatching eggs disinfection processes (i.e., disinfecting products and administration method) using a multi-pronged approach assessing the reduction of microbial eggshell contamination, the effects on worker exposure, hatching results and broiler performance, and, finally, suitability for use in commercial hatcheries. The 4 disinfection processes were: sodium dichlorocyanurate (DC) by thermonebulization, hydrogen peroxide 6% by nebulization (HP6), electrolyzed oxidizing water (EOW) by fogging, and hydrogen peroxide 30% vapor (HP30). In order to meet commercial hatchery conditions, the tested products were applied in an experimental hatchery by aerial disinfection in a dedicated room, not sprayed directly onto the eggs. Compared to the untreated control group, eggshell microbial load was significantly decreased by over 1 log10 cfu per egg in groups DC and HP30. These results were confirmed during a second experiment. In addition, these 2 products comply with legal requirements on worker exposure. Fertility and hatching results were significantly higher in group HP30 than in group DC, with no impact on chick quality and subsequent broiler performance. Under these study conditions, the disinfection process (i.e., administration of the product, contact with the eggs and aeration) lasted 65 min in group DC vs. 135 min in group HP30. When considering commercial hatchery conditions, this difference in application time confers a clear advantage on the DC process. Moreover, the investment required for HP30 is much higher than for DC. Overall, HP30 presented a clear advantage for hatching results whereas DC is a relatively more practical and less expensive disinfection process. To our knowledge, this is the first report on the use of hydrogen peroxide vapor as an egg disinfection process. Further research is needed to confirm the results of this study under commercial hatchery conditions.

No abstract