Affiliation:
1. College of Veterinary Medicine, China Agricultural University, Beijing, China
2. Department of Animal Nutrition and Management, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
Abstract
ABSTRACT
The mechanism underlying the dose effect of probiotics on ameliorating diarrhea has not been fully elucidated. Here, low (1 × 10
9
CFU/ml) or high (1 × 10
11
CFU/ml) doses of
Lactobacillus rhamnosus
ATCC 7469 were administered orally to piglets for 1 week before F4 (K88)-positive enterotoxigenic
Escherichia coli
(F4
+
ETEC) challenge. Administration of a low, but not a high, dose of
L. rhamnosus
decreased the percentage of CD3
+
CD4
+
CD8
−
T cells in the peripheral blood. Notably, transiently increased serum concentrations of interleukin-17A (IL-17A) were observed after F4
+
ETEC challenge in pigs pretreated with a high dose of
L. rhamnosus
. Administration of
L. rhamnosus
increased the percentage of the small intestinal lamina propria CD3
+
CD4
+
CD8
−
cells and Peyer's patch CD3
+
CD4
−
CD8
−
and CD3
−
CD4
−
CD8
+
cells. The percentage of ileal intraepithelial CD3
+
CD4
−
CD8
+
cells increased only in the high-dose piglets. Administration of
L. rhamnosus
downregulated expression of ileal IL-17A after F4
+
ETEC challenge but had no effect on expression of gamma interferon (IFN-γ), IL-12, IL-4, and FOXP3 mRNA in the small intestine. Expression of jejunal IL-2, ileal transforming growth factor β1 (TGF-β1), and ileal IL-10 was upregulated in the low-dose piglets after F4
+
ETEC challenge. Our findings suggest that amelioration of infectious diarrhea in piglets by
L. rhamnosus
is associated with the generation of lamina propria CD3
+
CD4
+
CD8
−
T cells, the expansion of Peyer's patch CD3
+
CD4
−
CD8
−
and CD3
−
CD4
−
CD8
+
cells, and the attenuation of F4
+
ETEC-induced increase in CD3
+
CD4
+
CD8
+
T cells in the small intestine. However, consumption of high doses of
L. rhamnosus
may increase levels of serum IL-17A after F4
+
ETEC challenge, thus eliciting a strong proinflammatory response.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
60 articles.
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