日粮添加包被丁酸钠对急性热应激肉鸡抗氧化、免疫功能及肝脏结构的影响

Effects of Dietary Coated Sodium Butyrate on Antioxidant,Immune Function and Liver Structure of Broilers Subjected to Acute Heat Stress

[目的]旨在探讨日粮添加包被丁酸钠(CSB)对急性热应激肉鸡抗氧化、免疫功能及肝脏结构的影响,为阐释急性热应激对肉鸡的损伤机制及营养调控手段提供科学理论依据。[方法]试验选用21 d爱拔益加(AA)肉公鸡450羽,随机分成5组,每组有6重复,每重复15羽。5组分别为常温组(NT组)、热应激组(HS组)和3个热应激同时添加CSB组(HS+CSB组)。NT组肉鸡喂食基础日粮,在(24±2)℃环境中饲养。HS组与3个HS+CSB组在(37±1)℃环境中饲养,HS组喂食基础日粮,3个HS+CSB组分别喂食在基础日粮中补充300,600,900 mg/kg CSB。[结果](1)与NT组比,HS组肉鸡肝脏门管区结构严重变形扭曲、狄氏间隙极度增宽、肝细胞脂肪变性等病理变化。与HS比,日粮添加CSB可减轻急性热应激肉鸡肝脏结构损伤。(2)与NT组比,HS组肉鸡血清过氧化氢酶(CAT)活性极显著降低(P<0.01),总抗氧化能力(T-AOC)显著降低(P<0.05),谷草转氨酶(AST)、谷丙转氨酶(ALT)、乳酸脱氢酶(LDH)和肌酸激酶(CK)活性及丙二醛(MDA)含量极显著上升(P<0.01)。与HS组比,日粮添加900 mg/kg和600 mg/kg CSB显著提高热应激肉鸡血清SOD活性,极显著降低LDH活性(P<0.01),显著降低ALT活性(P<0.05);添加900 mg/kg CSB显著增加血清T-AOC水平(P<0.05),显著降低AST活性(P<0.05)。(3)与NT组比,HS组肉鸡血清促炎症细胞因子白介素-6(IL-6)和白介素-8(IL-8)含量显著增加(P<0.05)。与HS组比,添加CSB极显著降低热应激肉鸡血清IL-6含量(P<0.01);添加900 mg/kg CSB极显著增加转化生长因子-β(TGF-β)含量(P<0.01),显著增加白介素-10(IL-10)含量(P<0.05);添加600 mg/kg CSB显著增加血清IL-10和TGF-β含量(P<0.05);添加300 mg/kg CSB显著增加血清TGF-β含量(P<0.05)。(4)与NT组比,HS组肉鸡肝脏IL-6和IL-8 mRNA表达显著增加(P<0.05),TNF-α mRNA表达极显著增加(P<0.01)。与HS组比,添加900 mg/kg CSB显著降低肝脏IL-6 mRNA表达(P<0.05),显著增加TGF-β和IL-10 mRNA表达(P<0.05);添加600 mg/kg CSB显著增加肝脏IL-10 mRNA表达(P<0.05)。[结论]日粮添加CSB可提高肉鸡抗氧化能力,有效缓解急性热应激所致的炎性反应,减轻肝脏功能结构损伤。本研究以900 mg/kg CSB添加剂量的效果最佳。

[Objective]This study aims to investigate the effects of dietary coated sodium butyrate(CSB)on serum antioxidant capacity and immune function,and liver function structure of broilers subjected to acute heat stress,the damage mechanism and nutritional regulation methods of the broilers were interpreted.[Method]A total of 450,21-day-old Arbor Acres(AA)broilers were stochastically separated into 5 groups,6 replicates per group,15 birds per replicate.The five groups were separated into normal temperature group(NT group),heat-stress group(HS group)and three heat-stress groups supplemented CSB group(HS+CSB group).The broilers of NT group were fed basal diet and reared at(24±2)℃.The broilers of HS group and HS+CSB groups were reared at(37±1)℃,and fed the basal diet supplemented with CSB(supplemental dosages were 0,300,600 and 900 mg/kg,respectively).[Result](1)Compared with NT group,the liver of broilers in HS group showed serious pathological changes:deformation and distortion of portal area structure,extremely widened dirichlet gap,hepatocyte steatosis.Compared with HS group,dietary CSB supplementation could reduce liver structural damage of broilers subjected to acute heat stress.(2)Compared with NT group,serum catalase(CAT)activity of broilers in HS group was extremely significantly decreased(P<0.01),total antioxidant capacity(T-AOC)was significantly decreased(P<0.05).The activities of aspartate aminotransferase(AST),alanine aminotransferase(ALT),lactate dehydrogenase(LDH)and creatine kinase(CK)and the content of malondialdehyde(MDA)in serum were significantly increased(P<0.01).Compared with HS group,dietary 900 mg/kg or 600 mg/kg CSB significantly increased SOD activity,extremely and significantly decreased LDH activity(P<0.01)and significantly decreased ALT activity(P<0.05)in serum of heat-stressed broilers.Dietary 900 mg/kg CSB significantly increased serum T-AOC level(P<0.05)and decreased AST activity(P<0.05).(3)Compared with NT group,serum contents of proinflammatory cytokines interleukin-6(IL-6)and interleukin-8(IL-8)of broilers in HS group were significantly increased(P<0.05).Compared with HS group,serum IL-6 content of heat-stressed broilers in 3 groups supplemented with CSB groups was significantly decreased(P<0.01);broilers supplemented with 900 mg/kg CSB extremely and significantly increased the level of TGF-β(P<0.01),and significantly increased the content of interleukin-10(IL-10)in serum(P<0.05);Broilers supplemented with 600 mg/kg CSB significantly increased the contents of IL-10 and TGF-βin serum(P<0.05);Broilers supplemented with 300 mg/kg CSB significantly increased the contents of TGF-βin serum(P<0.05).(4)Compared with the NT group,the liver of broilers in HS group had inflammatory reaction,which showed that the mRNA mexpression of pro-inflammatory cytokines IL-6 and IL-8 was significantly increased(P<0.05),and the mRNA expression of TNF-αwas extremely significantly increased(P<0.01).Compared with HS group,900 mg/kg CSB significantly decreased the mRNA expression of IL-6(P<0.05),and increased the mRNA expression of IL-10(P<0.05)in the liver.CSB at 600 mg/kg significantly increased the mRNA expression of TGF-βand IL-10(P<0.05).[Conclusion]Dietary CSB supplementation can improve the antioxidant capacity of broilers,effectively alleviate the inflammatory response caused by acute heat stress,and reduce the damage of liver function structure.In this study,900 mg/kg CSB was the best supplemental dosage.(1)To investigate the effects of dietary coated sodium butyrate(CSB)on serum antioxidant capacity and immune function,and liver function structure of broilers subjected to acute heat stress,the damage mechanism and nutritional regulation methods of broilers subjected to acute heat stress were interpreted.