| In the production practice of modern animal husbandry,due to the stimulation of endogenous and/or exogenous stressors,a large amount of free radicals are produced or the production of antioxidant substances is reduced,which leads to the breakdown of the oxidation-antioxidation balance in the body.The body will be in a state of oxidative stress.Oxidative stress is associated with many pathological processes,including damage to biomolecules apoptosis and tissue damage.This experiment took yellow-feather broilers as the test object,and discussed the effects of adding a certain amount of oxidized soybean oil in the diet on the tissue morphology of immune organs,antioxidant function and HMGB1/TLR4 signal pathway in yellow-feather broilers and the regulation of puerarin and its mechanism.A total of 360 one-day-old(34.3 ± 0.6 g)female yellow-feathered broilers were randomyly divided into 4 treatments with 6 replicates per treatment and 15 birds per replicate.Control group(C): fed with fresh soybean oil diet;puerarin group(P): fed with fresh soybean oil supplemented with 750 mg/kg puerarin diet;oxidized soybean oil group(OS): fed with oxidized soybean oil diet;oxidized soybean oil + puerarin group(OS+P):fed with oxidized soybean oil supplemented with 750 mg/kg puerarin diet.The supplementation level of soybean oil was 2% at the age of 1 to 28 days and 3% at the age of 29 to 56 days.One chicken was randomly selected and slaughtered for per replicate at28 and 56 days old.Blood was collected along the wing veins for activity of serum enzymes;liver and thymus tissues were harvested and fixed with 10% formalin solution for morphology morphology.The tissues of liver,thymus,spleen and bursa of fabricius were taken to determine relative biochemical indicators and the relative expression of levels of m RNA and protein of Keap1/Nrf2 and HMGB1/TLR4 signaling pathway as well as their downstream signaling molecules.The results are as follows:1.Compared with the control group,the activities of GOT at 28 days of age and LDH at 56 days of age in the oxidized soybean oil group were not significant,but the activities of GPT,GOT,CK and LDH at other days of age were extremely significant increased(P<0.01).Compared with the oxidized soybean oil group,the relative weight of immune organs in the oxidized soybean oil + puerarin group increased;The activities of GPT,GOT,CK and LDH in serum at 28 days of age were significantly decreased except for GOT activity in serum at 28 days of age(P<0.01).2.Compared with the control group,oxidized soybean oil induced fibrosis and inflammatory cell infiltration in liver tissue,degeneration of thymus tissue cortex,depletion of lymphocytes,and increased number of thymic corpuscles.Compared with the oxidized soybean oil group,the oxidized soybean oil + puerarin group had less inflammatory cell infiltration in liver tissue,increased thymus cortex,and decreased number of thymic corpuscles.3.Compared with the control group,the content of MDA in liver,thymus,bursa of fabricius and spleen at 28 days of age in oxidized soybean oil group was increased(P<0.05 or P<0.01);The level of T-AOC in spleen at 28 days of age,thymus and bursa of fabricius at 56 days of age,and the activity of SOD in thymus and spleen,bursa of fabricius at 28 days of age and liver at 56 days of age were decreased(P<0.05 or P<0.01).The activity of GSH-Px in liver,spleen,bursa of Fabricius and thymus at 56 days of age was significantly increased(P<0.01).Compared with the oxidized soybean oil group,the MDA content in thymus and 56-day-old spleen in the oxidized soybean oil + puerarin group was significantly reduced(P<0.01).The level of T-AOC in spleen,liver at 56 days of age and thymus at 28 days of age,and the activity of SOD in spleen was increased(P<0.05 or P<0.01).The activity of GSH-Px in bursa of fabricius,spleen and liver at 28 days of age was decreased(P<0.05 or P<0.01).4.Compared with the control group,the relative m RNA expression levels of HO-1,NQO1 and 28-day-old Nrf2,SOD in liver,28-day-old SOD,HO-1 and 56-day-old HO-1,Nrf2,Keap1 in the thymus,28-day-old Nrf2,NQO1 and 56-day-old HO-1 in the spleen,Nrf2,NQO1 and 28-day-old SOD in the bursa of fabricius of the oxidized soybean oil group were reduced(P<0.05 or P<0.01).Compared with the oxidized soybean oil group,the relative m RNA expression of Keap1,56-day-old HO-1 and NQO1 in the liver,Keap1,HO-1 and 28-day-old NQO1 and 56-day-old Nrf2 and SOD in the thymus,28-day-old Keap1 and 56-day-old HO-1,SOD and 28-day-old Nrf2,Keap1,HO-1 and NQO1 in the bursa of fabricius of the oxidized soybean oil group + puerarin group were increased(P<0.05 or P<0.01).5.Compared with the control group,the relative expression of TGF-β,IL-1β,IFN-γm RNA and 28-day-old IL-1β,IFN-γ protein and 56-day-old TNF-α,HMGB1,TLR4 m RNA and TGF-β,TLR4,p-p38/p38 protein in the liver,TGF-β,HMGB1 and 56-day-old IFN-γ m RNA and HMGB1,p-ERK1/2/ERK1/2,p-p38/p38 and p65 proteins in thymus,TGF-β m RNA,28-day-old IL-1β,IFN-γ and TLR4 m RNA and TLR4,p-ERK1/2/ERK1/2and p-JNK/JNK protein in the spleen,TGF-β m RNA and 28-day-old IL-1β and 56-day-old IFN-γ m RNA and HMGB1,p-JNK/JNK protein in the bursa of fabric of the oxidized soybean oil group were increased(P<0.05 or P<0.01).Compared with the oxidized soybean oil group,TNF-α,TLR4 m RNA and 56-day-old TGF-β,IL-1β,HMGB1 m RNA and IL-1β,TLR4,p-p38/p38 protein in the liver,TNF-α,HMGB1 m RNA and 28-day-old IFN-γ m RNA and 56-day-old TGF-β,IFN-γ m RNA and p-JNK/JNK,p-ERK1/2/ERK1/2proteis in the thynus,56-day-old TLR4,p65 and p-ERK1/2/ERK1/2 protein,TNF-α and TGF-β m RNA in the spleen,28-day-old HMGB1 and TNF-α m RNA,p-ERK1/2/ERK1/2protein in the Bursa of Fabric of the oxidized soybean oil + puerarin group were(P<0.05 or P<0.01).In summary,oxidized soybean oil increased inflammatory cytokines and tissue damage in the immune organs of yellow-feather broilers.Further studies showed that puerarin regulated the repair of immune organ damage,enhanced the antioxidant capacity of the system,and regulated the immune function through the HMGB1/TLR4 signaling pathway. |
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