Probiotic Treatment Decreases the Number of CD14-Expressing Cells in Porcine Milk Which Correlates with Several Intestinal Immune Parameters in the Piglets.

Lydia Scharek-Tedin,Robert Pieper,Jürgen Zentek,Karsten Tedin,Robert Klopfleisch,Bianca Siepert,Sven Olaf Twardziok,Susanne Kreuzer-Redmer

doi:10.3389/fimmu.2015.00108

Abstract

Modulating the mucosal immune system of neonates by probiotic treatment of their mothers is a promising approach which can only be investigated through the use of animal models. Here, we used sows and their piglets to investigate the impact of a bacterial treatment on the sow’s milk and on the neonate piglet intestinal immune system. In previous experiments, feed supplementation of sows with the probiotic Enterococcus faecium NCIMB 10415 during pregnancy and lactation had been shown to affect intestinal microbiota and cytokine expression of the offspring during the suckling and weaning periods. We therefore investigated the composition of the milk from treated sows in comparison to samples from a control group. In treated sows, the amount of lactose increased, and the somatic cell numbers were reduced. In all milk samples, the percentage of cells expressing membranous CD14 (mCD14) was greater than the fractions of immune cells, indicating expression of mCD14 on mammary epithelial cells. However, in the milk of E. faecium-treated sows, mCD14+ cells were reduced. Furthermore, the number of CD14+ milk cells was positively correlated with the percentages of B cells and activated T cells in the ileal MLN of the piglets. This study provides evidence for the expression of mCD14 by the porcine mammary epithelium, and suggests an immunological effect of mCD14+ milk cells on the piglets’ intestinal immune system. Our study further suggests that mCD14+ mammary epithelial cell populations can be modulated by probiotic feed supplementation of the sow.

Highlights

Probiotic feed supplementation of sows during pregnancy and lactation has been shown to affect the piglets’ intestinal microbiota and the mucosal cytokine levels during the suckling period [1, 2]
The proportion of macrophages in cell suspensions of sow milk has been reported faecium group are pictured with filled squares or blank circles, respectively
In our milk samples of the control group, an average of 41% of somatic cells was found to be positive for membranous CD14 (mCD14)

Summary

Introduction

Probiotic feed supplementation of sows during pregnancy and lactation has been shown to affect the piglets’ intestinal microbiota and the mucosal cytokine levels during the suckling period [1, 2]. An altered composition of the sow milk could be an additional possibility. Antibacterial substances such as lysozyme and lactoferrin, antibodies, cytokines, growth factors, and hormones which are known to be important for the immune defense and the development of the intestinal epithelial cells (IECs) of the offspring [reviewed in Ref. It has been shown that maternal lymphoid cells, delivered through milk, cross the piglets’ intestinal epithelium and are transported to the mesenteric lymph nodes, where they support the piglets’ developing immune system [4]. Immunological experience with dietary antigens by the sow is likely to be important for tolerance induction in the offspring, and the ability to distinguish between commensal and pathogenic bacteria appears to be affected by substances delivered through milk [5]

Methods

Results

Conclusion