Effects of Guava (Psidium guajava L.) Leaf Extract on the Metabolomics of Serum and Feces in Weaned Piglets Challenged by Escherichia coli.

Dingfa Wang,Hanlin Zhou,Luli Zhou,Guanyu Hou

doi:10.3389/fvets.2021.656179

Abstract

The effects of dietary supplementation with guava leaf extracts (GE) on intestinal barrier function and serum and fecal metabolome in weaned piglets challenged by enterotoxigenic Escherichia coli (ETEC) were investigated. In total, 50 weaned piglets (Duroc × Yorkshire × Landrace) from 25 pens (two piglets per pen) were randomly divided into five groups: BC (blank control), NC (negative control), S50 (supplemented with 50 mg kg−1 diet GE), S100 (100 mg kg−1 diet GE), and S200 (200 mg kg−1 diet GE), respectively. On day 4, all groups (except BC) were orally challenged with enterotoxigenic ETEC at a dose of 1.0 × 109 colony-forming units (CFUs). After treatment for 28 days, intestinal barrier function and parallel serum and fecal metabolomics analysis were carried out. Results suggested that dietary supplementation with GE (50–200 mg kg−1) increased protein expression of intestinal tight junction proteins (ZO-1, occludin, claudin-1) (p < 0.05) and Na+/H+ exchanger 3 (NHE3) (p < 0.05). Moreover, dietary supplementation with GE (50–200 mg kg−1) increased the level of tetrahydrofolic acid (THF) and reversed the higher level of nicotinamide-adenine dinucleotide phosphate (NADP) induced by ETEC in serum compared with the NC group (p < 0.05), and enhanced the antioxidant capacity of piglets. In addition, dietary addition with GE (100 mg kg−1) reversed the lower level of L-pipecolic acid induced by ETEC in feces compared with the NC group (p < 0.05) and decreased the oxidative stress of piglets. Collectively, dietary supplementation with GE exhibited a positive effect on improving intestinal barrier function. It can reprogram energy metabolism through similar or dissimilar metabolic pathways and finally enhance the antioxidant ability of piglets challenged by ETEC.

Highlights

Weaned piglets infected with enterotoxigenic Escherichia coli (ETEC) may cause post-weaning diarrhea, which leads to growth retardation and damage to the innate and adaptive immune systems of piglets
We evaluated the effects of guava leaf extracts (GE) on tight junction-related proteins in weaned piglets, aiming to provide a potential window through which to explore the crosstalk between GE-mediated metabolic changes and its antidiarrheal processes during the progression of weaned piglets challenged by ETEC
The five groups were as follows: [1] blank control group (BC), piglets were fed diet without supplements and ETEC challenge; [2] negative control group (NC), piglets were fed diet without supplements and challenged by ETEC; [3] S50 group (S50), piglets were fed diet supplemented with 50 mg kg−1 GE and challenged by ETEC; [4] S100 group (S100), piglets were fed diet supplemented with 100 mg kg−1 GE and challenged by ETEC; [5] S200 group (S200), piglets were fed diet supplemented with 200 mg kg−1 GE and challenged by ETEC

Summary

Introduction

Weaned piglets infected with enterotoxigenic Escherichia coli (ETEC) may cause post-weaning diarrhea, which leads to growth retardation and damage to the innate and adaptive immune systems of piglets These risk factors increase the morbidity and mortality of piglets and result in large economic losses in the swine industry worldwide [1, 2]. Concerns about antimicrobial resistance, residue accumulation in animal products, and environmental pollution have led to a limited application of antibiotics as growth promoters [4, 5] Due to these factors, searching for alternatives to antibiotic growth promoters, such as pro- and prebiotics, organic acids, enzymes, and plant extracts, have attracted more and more attention [5,6,7]. Among the candidate alternatives to antibiotics, plant extracts appear to be one of the most widely accepted [8, 9]

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Results

Conclusion