Changes in gut microbial populations, intestinal morphology, expression of tight junction proteins, and cytokine production between two pig breeds after challenge with Escherichia coli K88: A comparative study1

Abstract

This study hypothesized that the gut microbial populations, intestinal morphology, and cytokine production are differentially altered in 2 different pig breeds, namely, Chinese native Jinhua pigs and European Landrace pigs, after orally challenge with enterotoxigenic Escherichia coli (ETEC) K88. A total of 12 Jinhua pigs and 12 Landrace pigs were allocated to either the nonchallenged or the challenged groups (6 pigs per group). The challenged pigs were orally administered ETEC K88, and their nonchallenged counterparts were given sterile Luria-Bertani broth. Selected gut microbial populations, intestinal morphology, mRNA expression of tight junction proteins, and the levels of ileal cytokines and secretory immunoglobulin A (sIgA) production were measured in Jinhua and Landrace pigs. The results showed that the challenged Jinhua pigs exhibited a significantly (P < 0.05) lower incidence of diarrhea compared with their Landrace counterparts. The Escherichia coli (E.coli) population and the percentage of E. coli in the total bacteria population were increased in response to ETEC K88 challenge in both Jinhua and Landrace pigs. The challenged Landrace pigs shed more E. coli (P < 0.05) and had higher percentage of E. coli in the total bacteria population in the colon (P < 0.05) compared with their Jinhua counterparts. Both pig breeds tended to exhibit greater villous atrophy and crypt depth reduction in all of the intestinal segments with challenge. The expression of tight junction proteins decreased in response to ETEC K88 challenge in both pig breeds. The levels of the proinflammatory cytokines interferon (IFN)-γ, tumor necrosis factor-α, and IL-6 and the secretion of sIgA were positively altered whereas the levels of the anti-inflammatory cytokine IL-4 and transforming growth factor (TGF)-β were negatively altered by ETEC K88 challenge in both breeds. Jinhua pigs exhibited significantly higher levels of IFN-γ and TGF-β (P < 0.05) in the challenged group. Our findings provide valuable evidence to explain the differences in the intestinal physiology between Jinhua and Landrace pigs; that is, Jinhua pigs appeared to show better growth performance, a lower incidence of diarrhea, and a lower extent of immune activation in response to ETEC K88 challenge and a higher Lactobacillus population, a higher percentage of Lactobacillus in the total bacteria population, a higher ratio of Lactobacillus to E. coli, and higher levels of tight junction proteins with and without challenge.

Lactobacillus reuteri LR1 Improved Expression of Genes of Tight Junction Proteins via the MLCK Pathway in IPEC-1 Cells during Infection with Enterotoxigenic Escherichia coli K88

“…Infection with the enterotoxigenic ETEC K88 usually impaired the integrity of the intestinal epithelial barrier [25, 26]. Although the regulatory mechanism of beneficial probiotics on the intestinal epithelial barrier is still unclear, it is established that some probiotics do improve barrier function, thereby maintaining intestinal homeostasis [27–30].…”

Effects of dietary zinc oxide nanoparticles supplementation on growth performance, zinc status, intestinal morphology, microflora population, and immune response in weaned pigs

“…Images were acquired using a DM3000 microscope (Leica, Wetzlar, Germany). Villous height (V, from the tip of the villi to the villus‐crypt junction) and crypt depth (C, from this junction to the base of the crypt) were measured using Image‐Pro software (MediaCybernetics, Rockville, MD, USA) according to the previously reported methods . The same person executed all the analyses of small intestinal morphology.…”

Cathelicidin-BF suppresses intestinal inflammation by inhibiting the nuclear factor-κB signaling pathway and enhancing the phagocytosis of immune cells via STAT-1 in weanling piglets

“…RNA integrity was inspected on a 1% agarose gel. The cDNA was generated via reverse transcription as described by Gao et al [21]. Real-time PCR was performed using the StepOne Plus TM real-time PCR system (Applied Biosystems, USA).…”

“…Intestinal morphological analysis was performed as described previously [21]. In brief, sections were dehydrated in 10% formalin, embedded in paraffin and stained with hematoxylin and eosin (H&E).…”