Effect Of Aflatoxin (AFB1) On Transcriptomics Of Immune Organs In Lohmann Brown Hens

Aflatoxin B1(AFB1)poses a significant risk to the growth and development of poultry,and AFB1 remaining in meat products can also endanger human health.This study fed 165-day-old Lohmann Brown hens by feeding 0 mg/kg(control),0.3 mg/kg(low toxicity),0.6 mg/kg(medium toxicity)and 1.2 mg/kg(high toxicity)AFB1.After35 days of chicken,the toxic effects were evaluated at different concentration levels.Analysis of egg quality in different concentrations showed that AFB1 increased the proportion of egg yolk,protein decreased,egg diameter(cm)shortened,egg shape index decreased,eggshell strength and middle eggshell thickness became lower(P<0.05).Through observation of liver pathology and apoptosis,the liver showed fat deposition,nuclear destruction,increased interstitial space,and liver cell apoptosis.(1)Highly concentration toxic AFB1 has an effect on the expression levels of protein-coding genes and miRNAs in the liver,spleen and bursa of fabricius of the layer.Compared with the control group,1.2 mg/kg of AFB1 differentially expressed 1927protein-coding genes and 45 miRNAs in the liver,and 1927 protein-coding genes and45 miRNAs were differentially expressed in the 1.2 mg/kg AFB1 group.These differentially expressed protein-coding genes and differentially expressed miRNAs were co-enriched in fat metabolism and apoptosis.Finally,9 hepatic apoptotic autophagy genes and fat metabolism genes were screened(ENPP2,PPARG,LYPLA1,NFATC2,ULK2,RHEB,SGK1,BCL6,AP3S1),and these genes have a targeting relationship with 13 differentially expressed miRNAs(gga-miR-140-5p,gga-miR-301a-3p,gga-miR-301b-3p,gga-miR-138-5p,gga-miR-107-5p,gga-miR-142-3p,ggamiR-142-5p,gga-miR-1454-3p,gga-miR-365-3p,gga-miR-190a-3p,gga-miR-32-3p).(2)Highly concentration toxic AFB1 affects the differential expression of 6333protein-coding genes and 42 miRNAs in the spleen.These differentially expressed miRNA target genes and protein-encoding genes are functionally enriched in the m TOR signaling pathway,Fox O signaling pathway,Erb B signaling pathway,endocytosis,and herpes simplex infection.These signaling pathways are mainly involved in inflammation and cancer.Among them,the interaction of four inflammatory genes PIK3R1,TAB2,PDGFRA and BMPR2 leads to partial spleen immune function loss.NKD1 and PIK3R1 down-regulate presumably AFB1-induced spleen canceration.(3)Bursa of fabricius in high toxicity AFB1 conditions,there are 296 protein-coding gene expression levels,which are functionally enriched in innate immune responses,inflammatory responses,and some signaling pathways such as cytokine-cytokine receptor interactions,p53 signaling pathway,intestinal immune network generated by Ig A,etc.,in which IL4I1 is significantly up-regulated,may result in decreased bursa of fabriciusl B cell output in hens leading to immune dysfunction of bursa of fabricius of Fabricius.In addition,the expression levels of 19 miRNAs changed,and it was finally speculated that the bursa of fabricius may enhance the autoimmunity of glu-miR-19b-5p to reduce the toxicity of AFB1 by autoimmunity.(4)The highly toxic AFB1 also has an effect on the expression level of liver long non-coding RNA(lncRNA)in Lohmann Brown hens.We identified a total of 867 differentially expressed lncRNAs,of which 369 homeopathic differentially expressed protein-coding genes were found in the 100 kb range near 295 differentially expressed lncRNAs,and Pearson correlation coefficients(PCCs)of 295 lncRNAs and 369 mRNAs were calculated.216 pairs of lncRNAs-mRNAs were found.Finally,a total of8 lncRNAs were screened for possible interaction with ADH6,PPARG,ACSL4,PPARD,FADS2,GABARAPL1(ATG8),BCL6,CSNK1 E and fatty liver and apoptosis.(5)Based on liver lncRNA-miRNA-mRNA regulatory network analysis,it was found that highly toxic AFB1 would dysregulate PPARG and BCL6 expression.In one aspect,the gene is cis-regulated by TU10057 and TU45776,and is also a target gene of ggamiR-301a-3p,gga-miR-301b-3p and gga-miR-190a-3p.Therefore,this interaction regulation may help explain the mechanism by which AFB1 triggers fat deposition and apoptosis in the liver.In summary,the effect of AFB1 on the transcriptome of immune organs is mainly concentrated on immunity and inflammation.The toxic effects on the spleen are also reflected in the involvement of some genes in the signaling pathways that occur in cancer.On the other hand,we found mRNA and lncRNA regulatory networks in the transcriptome that explain liver fat deposition and hepatocyte apoptosis.In conclusion,our results enrich the information on the regulation of genomic expression after AFB1 triggers the body poisoning,and provide research ideas for improving poultry health in the future.