Sonja Schmucker

The impact of phosphorus on the immune system and the intestinal microbiota with special focus on the pig.

There is increasing interest in dietary ingredients that are appropriate to support digestive and immune functions, but also maintain a stable microbial ecosystem in the gastrointestinal tract (GIT), particularly in weaned pigs. P is an essential nutrient for both microbes and their host, as it is involved, for example, in bone formation, energy metabolism, cellular signalling and stabilisation of cell membranes. Non-ruminant animals have limited access to phytate, the main storage form of P in plant seeds. The release of P bound to phytate requires phytase activity of plant or microbial origin, resulting in the formation of variable phosphorylated inositol phosphates (InsPs). The present review focuses on interactions between variations in dietary P supply, the immune system of the host, and the intestinal microbial ecosystem. Although results on the interaction between P and the immune system are inconsistent, several studies in different species have shown a positive impact of dietary P and phytase addition on the adaptive immune response. Recent studies with pigs suggest that P supply may influence intestinal microbial composition and activity. Individual InsPs or phosphate may also affect properties of pathogenic micro-organisms, such as metabolism or virulence. In conclusion, P may be considered as part of an integrated approach to support immune functions and maintain a stable microbial ecosystem in the GIT, thereby providing a barrier against potential pathogens. Within this regard, differences in phytate-P content and intrinsic phytase activity of plant feedstuffs, as well as the formation of individual InsPs, have to be taken into account.

Influence of Different Housing Systems on Distribution, Function and Mitogen-Response of Leukocytes in Pregnant Sows

Simple Summary The European Union imposes housing of pregnant sows in social groups since 2013 for animal welfare reasons. Nevertheless, the consequences of different housing conditions for the immune system of pregnant sows remain poorly investigated. We therefore analyzed important aspects of blood cellular immunity and cortisol concentrations of sows either housed in individual crates or in a group during gestation. The results show that individually housed sows had lower T cell numbers, but higher cortisol concentrations. Obviously, common housing conditions can differentially affect key elements of the adaptive immune system and hormonal indicators of stress in pregnant sows. Abstract In pig production, pregnant sows are either housed in individual crates or in groups, the latter being mandatory in the EU since 2013. The consequences of different housing conditions on the immune system are however poorly investigated, although immunological alterations may have severe consequences for the animal’s health, performance, and welfare. This study assessed measures of blood celluar immunity with special emphasis on T cells in pregnant German Landrace sows either housed in individual crates or in a social group. Blood samples were taken at four samplings pre partum to evaluate numbers of lymphocyte subpopulations, mitogen-induced lymphocyte proliferation and cytokine-producing T cells. Plasma cortisol concentrations were evaluated as an indicator of stress. We found lower blood lymphocyte numbers (p < 0.01) in individually housed as opposed to group-housed sows, an effect due to lower numbers of cytotoxic T cells, naive TH cells, and CD8+ γδ-T cells. Individually housed sows showed higher cortisol concentrations (p < 0.01), whereas lymphocyte functionality did not differ between sows of both housing systems. Possible implications and underlying mechanisms for the endocrine and immunological differences are discussed. We favor the hypothesis that differences in the stressfulness of the environment contributed to the effects, with crate-housing being a more stressful environment—at least under conditions of this study.

Diurnal rhythms in peripheral blood immune cell numbers of domestic pigs

ABSTRACT Diurnal rhythms within the immune system are considered important for immune competence. Until now, they were mostly studied in humans and rodents. However, as the domestic pig is regarded as suitable animal model and due to its importance in agriculture, this study aimed to characterize diurnal rhythmicity in porcine circulating leukocyte numbers. Eighteen pigs were studied over periods of up to 50 h. Cosinor analyses revealed diurnal rhythms in cell numbers of most investigated immune cell populations in blood. Whereas T cell, dendritic cell, and eosinophil counts peaked during nighttime, NK cell and neutrophil counts peaked during daytime. Relative amplitudes of cell numbers in blood differed in T helper cell subtypes with distinctive differentiation states. Mixed model analyses revealed that plasma cortisol concentration was negatively associated with cell numbers of most leukocyte types, except for NK cells and neutrophils. The observed rhythms mainly resemble those found in humans and rodents. HighlightsDomestic pigs exhibit diurnal rhythms in peripheral blood immune cell numbers.Immune cell rhythms in pigs mainly resemble those found in humans and rodents.Relative amplitudes and peak times differ among certain porcine immune cell types.Porcine immune cell counts were associated with plasma cortisol concentration.

Data characterizing diurnal rhythms in the number of peripheral CD8α− and CD8α+ γδ T cells in domestic pigs

This data article is related to the original research article “Diurnal rhythms in peripheral blood immune cell numbers of domestic pigs” of Engert et al. [1] and describes diurnal rhythms in the number of CD8α− and CD8α+ γδ T cells in peripheral blood of domestic pigs. Blood samples were taken from 18 animals over periods of up to 50 h and immune cell subtypes were determined by flow cytometry. Diurnal rhythmicity of cell numbers of γδ T cell subtypes was analyzed with cosinor analysis and different properties of rhythmicity (mesor, amplitude, and peak time) were calculated. In addition, associations between cell numbers of the investigated cell types in porcine blood with plasma cortisol concentration, hematocrit, and experimental conditions were identified with linear mixed model analysis.

Characterization of the adaptive immune response following immunization in pregnant sows (Sus scrofa) kept in two different housing systems1

Housing conditions might differentially affect the adaptive immune responses to a neoantigen in pregnant sows with possible consequences for the success of vaccinations. Therefore, this study aimed at characterizing antigen-specific T cell and B cell responses of pregnant sows (German Landrace) either housed in a social group (GP; n = 22) or confined in individual gestation crates (CR; n = 11). All sows were immunized with the neoantigen keyhole limpet hemocyanin (KLH) 7 and 5 wk prepartum. Blood samples were taken 7, 6, 4, and 2 wk prepartum, thus before and after the first as well as second immunization. This study aimed at identifying both the resulting cellular as well as humoral KLH-specific immune response in the pregnant sows. We therefore analyzed total IgG and anti-KLH IgG concentrations and the KLH-specific lymphocyte proliferation as well as the KLH-specific production of the T helper cell type 1 (TH1)-related cytokines tumor necrosis factor (TNF) α and interferon (IFN) γ in main T cell subsets before and after the immunization. Anti-KLH IgG titers significantly increased during the experimental procedure (P < 0.001) reflecting the activation and differentiation of KLH-specific B cells on immunization. However, CR-housed sows showed greater anti-KLH IgG concentrations compared to GP-housed sows (P < 0.05). Keyhole limpet hemocyanin-specific TNFα-producing cytotoxic T cells (CTL) and T helper (TH) cells were detectable in CR-housed sows not before the second immunization (both P < 0.05), whereas those cells were detectable already after the first immunization in GP-housed sows (CTL: P < 0.01 and TH: P < 0.05). Similarly, KLH-specific TNFα/IFNγ-double producing CTL and TH cells were detectable earlier in GP-housed sows than in CR-housed sows (both P < 0.05). Keyhole limpet hemocyanin-induced lymphocyte proliferation and total IgG concentrations were not affected by the housing system. Our results show that housing conditions affect the adaptive immunity to a neoantigen in pregnant sows. Whereas GP housing of pregnant sows induced a rather TH1-mediated cellular response, individual housing in CR resulted in a T helper cell type 2 (TH2)-pronounced humoral response to KLH. The greater anti-KLH IgG concentration and the delayed activation and differentiation of KLH-specific TH1 cells in CR-housed sows support the hypothesis of a shifted TH1:TH2 ratio in individually housed sows of this study. We presume differences in the stressfulness of the housing system to be mainly responsible for the occurring effects.