Effects Of Artemisia Argyiaqueous Extract On Immunological And Anti-oxidative Function In Broilers Exposedto Lipopolysaccharide And The Underlying Mechanism

The current studyinvestigated the effect of Artemisia argyiaqueous extract(AAE)on broilers exposed to lipopolysaccharide(LPS)and the underlying mechanism.The majorwork and results are as follows.A 2×2 factorial design experimentwas conducted to elucidate the effect of AAE on growth performance,immunological and anti-oxidative function of broilers exposed to LPS and the underlying mechanism.A total of961-day-old Arbor Acres broilers were divided into 2 treatment groupswith two subgroups each,including two AAE treatments(0 or 1000 mg/kg AAE)and two immunological challenge treatments(saline or LPS).On d 14,16,18,and 20,broilers from each subgroup of the two groupswere injected intra-abdominally with LPS at 500?g/kg of body weight,or an equalvolume of sterile saline,respectively.The birds were raised for 28 days,including pre-fed period(d 1-14),immunological challenged period(d 15-21),and recovery period(d 22-28).The results showed:(1)Dietary AAE significantly alleviated the compromised body weight(d 21),ADG and ADFI of broilers challenged with LPS.AAE significantly reduced the elevation of serum ACTH and CORT content,and increased the GH concentration.(2)Dietary AAE significantly increased the relative weight(RW)of thymus,inhibited the elevation of RW of spleen stimulated by LPS.AAE significantly compromised the increased serum level of IL-2,IL-6,TNF-a,NO,iNOS and IgG.The serum MDA content was decreased by AAE supplementation,and the elevated serum concentration of CAT and GSH-Px was also observed.(3)AAE inclusioninhibited the inflammatory mediatorsgenerationbylessening the expression of TLR4,MyD88,NF-?B,IL-1?,IL-6,TNF-?,and iNOS;on the contrary,dietary AAE increased gene expression of the antioxidant enzymeCAT,SOD and GSH-Px,and then enhanced the antioxidant capacity of broilers.The first in vitro testaimed to find out the immunological and anti-oxidativeeffect of Artemisia argyi polysaccharide(AAP)on peripheral blood lymphocytes(PBLs)of broilers.Firstly,the trial consisting oftwo immunological challenges(saline or LPS)and five AAP levels(0,25,50,100 and 200)?g/mL)were conducted in a 2x5factor design with 10 treatments(each treatment repeated 6 times).Then,the trialwas conductedin a 2x2x2 factorial design,which consists of 8 treatments(each treatment repeated 6 times),including two immunological stresstreatments(saline or LPS),two AAP contents(0 or AAP,the dose selectedbasing on the previous experiment),and two PDTC(inhibitor of NF-?B)levels(with or without PDTC).The results showed:(1)under routine culture condition,AAP significantly increased the content of IL-1?,IL-6,TNF-?,NO,and the T-AOC inthe supernatant of PBLs,as well as the relevant gene expression in the PBLs,but had no effect on the TLR4/NF-?B signaling pathway.In the case of LPS stimulation,AAP significantly compromised the increased level of IL-1?,IL-6,TNF-?,NO,and iNOS,otherwise,increased the low SODactivity and T-AOCstimulated by LPS,inhibited the increased gene expression of TLR4,MyD88,NF-?B,IL-1?,IL-6,TNF-?,and iNOS in PBLs caused by LPS,and increased the expression of SOD in PBLs.(2)Under normal circumstance,AAP increased TNF-? concentration and the T-AOC.Under LPS-stimulated circumstance,PDTC or AAP could inhibit the over activation of TLR4 and NF-?B to varying degrees,thus down-regulated the excessive expression of downstream inflammatory mediators.When AAP and PDTC were added to the culture medium together,AAP had no impact on the proteins related to TLR4/NF-?B signaling pathway and the related inflammatory mediators,but markedly increased the SOD gene expression in PBLs.All these results suggested that AAP exerted its anti-inflammatory effectthrough the TLR4/NF-?B signaling pathway;in addition,the antioxidation of AAP might contribute to its anti-inflammatory effect.The following trials investigatedthe effects of RAAP on immunolgical and anti-oxidative function of broiler'sPBLs and the underlying mechanism.The design and main work of experimentswerethe same as previous one.The results showed:(1)under routine culture condition,RAAP significantly increased the supernatant content of IL-6 and SOD activity,and T-AOC.Under LPS-stimulated circumstance,RAAP significantly reduced the elevated level ofIL-6,TNF-?,and iNOS,increased the activity of SOD and GSH-Px,as well as the T-AOC,reduced the MDA concentration.The gene expression results showed that RAAP inhibited the increased gene expression of NF-?B,IL-6,TNF-?,and iNOS in PBLsstimulated by LPS,and increased the expression of GSH-Px and SOD in PBLs.(2)RAAP had no significant effect on the immunological function of PBLs cultured in the routine circumstance,but significantly increased its antioxidative activity.After LPS added into PBLs culture medium,PDTC or AAP could inhibit the over activation of NF-?B to varying degrees,thus down-regulated the level of IL-6,TNF-?,NO and iNOS.In addition,RAAP increased the activity of SOD,GSH-Px,and T-AOC.When AAP and PDTC were added to the culture medium together,AAP had no impact on the gene expression related to TLR4/NF-?B signaling pathway and the related inflammatory mediators,but significantly increased the T-AOC in PBLs.The results demonstratedthe strong anti-oxidative effect and free radical scavenging ability of RAAP,and this might contribute to its anti-inflammatory activity,further inhibiting the activation of NF-?B.