Studies On The Mechanism Of Gut Lactobacillus Frumenti On Nutrients Metabolism In Early-weaned Piglets

Early-weaning of piglets is often accompanied by severe disorders,especially diarrhea.The gut microbiota and its metabolites play a critical role in the maintenance of the physiologic and metabolic homeostasis of the host.Our previous studies have demonstrated that oral administration of Lactobacillus frumenti improves epithelial barrier functions and confers diarrhea resistance in early-weaned piglets.However,the metabolic response to L.frumenti administration remains unclear.Then,proteomic analysis of the small intestine and metabolomic analysis of the serum and liver were performed to investigate the metabolism of the early-weaned piglets response to L.frumenti administration.A total of 100 6-day-old crossbred piglets(Landrace x Yorkshire)was randomly divided into two groups,in which piglets received PBS(sterile,2 m L)and Lactobacillus frumenti(suspension in PBS,10~8 CFU/m L,2 m L)respectively by oral administration once a day from the age of 6 to 20 days.At 21 days of age,piglets were early-weaned.Then serum and liver samples for metabolomic analyses were collected at the age of 26 days.The main results of this paper are as follows:Experiment 1:Screening differentially expressed proteins associated with nutrient metabolism in small intestine of the early-weaned pigelets response to L.frumenti administration by proteomic analysis.Using bioinformatics analysis uncovers the underlying mechanisms how L.frumenti regulates the nutrients metabolism of the the early-weaned pigelets.1. One hundred and ninety-four differentially expressed proteins from early-weaned pigelets response to L.frumenti administration were identified by proteomic analysis,among which 154 differentially expressed proteins were up-regualted while 50proteins were down-regualted.Based on IPA software or database,the functions of differentially expressed proteins were categorized.2. KEGG pathway analysis revealed that L.frumenti administration activated NRF2 mediated oxidation stress response in small intestine of the early-weaned piglets.In addition,L.frumenti administration increased the glutathione synthesis.These results suggested that L.frumenti alleviate early weaning stress and confer early-weaned piglets to gut health.3.Differentially expressed proteins response to L.frumenti were enriched in 11networks,among which amino acid metabolism was enriched to“Cardiovascular Disease,Organismal Injury and Abnormalities,Amino Acid Metabolism”,in which methionine,glutamine,glutamic acid,cysteine and proline were involved.While lipid metabolism was enriched to“Lipid Metabolism,Small Molecule Biochemistry,Hematological Disease”,in which unsatured fatty acids and triacylglycerol were involved.Experiment 2:From the perspective of metabolomics,L.frumenti administration affected the metabolism of the serum and liver in early-weaned piglets.1.PCA analysis indicated that L.frumenti administration obviously changed the metabolism of the serum and liver.The number of altered metabolites in serum and liver was 100 and 113 respectively.L.frumenti administration also increased the growth performance of the early-weaned piglets.2. KEGG pathway analysis revealed that L.frumenti administration regulated the unsatured fatty acids biosynthesis in both serum and liver.Phenylalanine metabolism,D-arginine and D-ornithine metabolism were changed in serum.And Alanine,aspartate and glutamate metabolism,cysteine and methionine metabolism were changed in the liver.3. In serum,L.frumenti administration enhanced the concentrations of several nucleotides and metabolites,such as IMP,GMP,UMP,and their byproduct,uric acid,suggesting that L.frumenti administration contributed to the synthesis of the nucleotides.4. L.frumenti administration increased the concentrations of intermediates of the fatty acid?-oxidation,such as L-acetylcarnitine,Dicarboxylate adipic acid and suberic acid,indicating tha frumenti administration activated the the fatty acid?-oxidation in order to meet the demand of the early-weaned piglets.In summary,L.frumenti regulates the nutrient metabolism in early-weaned piglets,which is mainly involved in amino acid metabolism and lipid metabolism.L.frumenti mediates energy production via fatty acid?-oxidation in the liver of early-weaned piglets.