Cytokine responses in birds challenged with the human food-borne pathogen Campylobacter jejuni implies a Th17 response.

Development of process orientated understanding of cytokine interactions within the gastrointestinal tract during an immune response to pathogens requires experimentation and statistical modelling. The immune response against pathogen challenge depends on the specific threat to the host. Here, we show that broiler chickens mount a breed-dependent immune response to Campylobacter jejuni infection in the caeca by analysing experimental data using frequentist and Bayesian structural equation models (SEM). SEM provides a framework by which cytokine interdependencies, based on prior knowledge, can be tested. In both breeds important cytokines including pro-inflammatory interleukin (IL)-1ß, , IL-4, IL-17A, interferon (IFN)-γ and anti-inflammatory IL-10 and transforming growth factor (TGF)-ß4 were expressed post-challenge. The SEM revealed a putative regulatory pathway illustrating a T helper (Th)17 response and regulation of IL-10, which is breed-dependent. The prominence of the Th17 pathway indicates the cytokine response aims to limit the invasion or colonization of an extracellular bacterial pathogen but the time-dependent nature of the response differs between breeds.

The acceptability of meadow plants to the slug Deroceras reticulatum and implications for grassland restoration.

BACKGROUND AND AIMS: Despite the selective pressure slugs may exert on seedling recruitment there is a lack of information in this context within grassland restoration studies. Selective grazing is influenced by interspecific differences in acceptability. As part of a larger study of how slug-seedling interactions may influence upland hay meadow restoration, an assessment of relative acceptability is made for seedlings of meadow plants to the slug, Deroceras reticulatum. METHODS: Slug feeding damage to seedling monocultures of 23 meadow species and Brassica napus was assessed in microcosms over 14 d. The severity and rate of damage incurred by each plant species was analysed with a generalized additive mixed model. Plant species were then ranked for their relative acceptability. KEY RESULTS: Interspecific variation in relative acceptability suggested seedlings of meadow species form a hierarchy of acceptability to D. reticulatum. The four most acceptable species were Achillea millefolium and the grasses Holcus lanatus, Poa trivialis and Festuca rubra. Trifolium pratense was acceptable to D. reticulatum and was the second highest ranking forb species. The most unacceptable species were mainly forbs associated with the target grassland, and included Geranium sylvaticum, Rumex acetosa, Leontodon hispidus and the grass Anthoxanthum odoratum. A strong positive correlation was found for mean cumulative feeding damage and cumulative seedling mortality at day 14. CONCLUSIONS: Highly unacceptable species to D. reticulatum are unlikely to be selectively grazed by slugs during the seedling recruitment phase, and were predominantly target restoration species. Seedlings of highly acceptable species may be less likely to survive slug herbivory and contribute to seedling recruitment at restoration sites. Selective slug herbivory, influenced by acceptability, may influence community-level processes if seedling recruitment and establishment of key functional species, such as T. pratense is reduced.