饲粮添加芦丁对肉仔鸡免疫功能和空肠形态、黏膜屏障、抗氧化功能的影响

Effects of dietary rutin supplementation on immune function,jejunum morphology,mucosal barrier function and antioxidant capacity of broilers

[目的]前期研究发现饲粮添加250~1000 mg·kg^(-1)芦丁可提高21日龄肉鸡生长性能,本试验进一步研究芦丁对其肠道形态结构、黏膜屏障和抗氧化功能的影响。[方法]试验选取1日龄健康且体重(43±1)g相近的雄性AA肉鸡256只,随机分为4组,每组8个重复,每个重复8只鸡。对照组饲喂基础饲粮,试验组在基础饲粮中分别添加250、500和1000 mg·kg^(-1)芦丁。21日龄时每个重复取1只肉鸡屠宰取样测定肠道屏障功能、免疫炎症、抗氧化等相关指标。[结果]与对照组相比,饲粮添加250 mg·kg^(-1)芦丁显著提高了肉仔鸡脾脏器官指数、空肠黏膜总超氧化物歧化酶(T-SOD)活性和总抗氧化能力(T-AOC),以及空肠黏膜中闭合小环蛋白1(ZO-1)、闭锁蛋白(OCLN)、核因子E2相关因子2(Nrf 2)和SOD mRNA的表达水平,同时显著降低了血清肿瘤坏死因子α(TNF-α)和D-乳酸(D-LA)水平、空肠黏膜TNF-αmRNA的表达水平(P T<0.05);与对照组相比,饲粮添加500 mg·kg^(-1)芦丁显著提高了肉仔鸡法氏囊器官指数、空肠VH/CD值,空肠黏膜T-SOD活性和T-AOC,空肠黏膜中B细胞淋巴瘤基因2(Bcl-2)、ZO-1和Nrf 2 mRNA的表达水平,并显著降低了血清TNF-α水平(P T<0.05);与对照组和250、500 mg·kg^(-1)芦丁组相比,饲粮添加1000 mg·kg^(-1)芦丁显著提高了血清中免疫球蛋白M(IgM)和免疫球蛋白G(IgG)含量(P T<0.05);与500 mg·kg^(-1)芦丁组相比,饲粮添加250 mg·kg^(-1)芦丁显著提高了肉仔鸡脾脏器官指数、血清脂多糖(LPS)水平和OCLN mRNA表达水平,并显著降低了血清D-LA水平(P T<0.05);与1000 mg·kg^(-1)芦丁组相比,饲粮添加250 mg·kg^(-1)芦丁显著提高了肉仔鸡脾脏器官指数,同时降低了空肠黏膜TNF-αmRNA的表达水平(P T<0.05);与1000 mg·kg^(-1)芦丁组相比,饲粮添加500 mg·kg^(-1)芦丁显著提高了肉仔鸡空肠黏膜中Bcl-2 mRNA的表达水平,并显著降低了血清中LPS水平(P T<0.05)。[结论]饲粮添加250 mg·kg^(-1)或500 mg·kg^(-1)芦丁均可以促进免疫器官发育,增强免疫能力和改善肉仔鸡空肠形态结构,提高空肠屏障功能,其对肉仔鸡空肠抗氧化功能的改善作用可能与激活Nrf2信号通路有关。本试验条件下推荐芦丁适宜添加剂量为250 mg·kg^(-1)。

[Objectives]Previous studies had found that dietary supplementation of 250-1000 mg·kg^(-1) rutin could improve the growth performance of broilers at 21 days of age.This study further investigated the effects of rutin on jejunal morphology,mucosal barrier function and antioxidant capacity of broilers.[Methods]A total of 2561-day-old male Arbor Acres(AA)broilers with similar body weight(43±1)g were randomly divided into 4 groups with 8 replicates per group and 8 chickens per pen.Broilers in the control group were fed a basal diet,and those in experimental groups were fed the basal diet supplemented with 250,500 and 1000 mg·kg^(-1) rutin,respectively.At 21 days of age,one broiler from each replicate was chosen and slaughtered to analyze the indices of intestinal barrier function,immune inflammation,and antioxidant capacity and other related indices.[Results]Compared with the control group,dietary 250 mg·kg^(-1) rutin significantly increased spleen organ index,total superoxide dismutase(T-SOD)activity and total antioxidant capacity(T-AOC)of jejunal mucosa and closed small cyclic protein-1(ZO-1)in jejunal mucosa of broilers,blocking protein(OCLN),nuclear factor E2-related factor 2(Nrf 2)and SOD mRNA expression levels,while serum tumor necrosis faction-α(TNF-α)and D-lactic acid(D-LA)levels,and the expression of TNF-αmRNA in jejunal mucosa significantly decreased(P T<0.05).Compared with the control group,dietary 500 mg·kg^(-1) rutin significantly increased bursal organ index,jejunum VH/CD value,T-SOD activity and T-AOC in jejunal mucosa,B-cell lymphoma gene-2(Bcl-2),ZO-1 and Nrf 2 mRNA expressions in jejunal mucosa of broilers.The serum TNF-αlevel significantly decreased(P T<0.05).Compared with the control group,250 and 500 mg·kg^(-1) rutin group,dietary 1000 mg·kg^(-1) rutin supplementation significantly increased the serum immunoglobulin M(IgM)and immunoglobulin G(IgG)contents(P T<0.05).Compared with 500 mg·kg^(-1) rutin group,dietary 250 mg·kg^(-1) rutin significantly increased spleen organ index,serum lipopolysaccharide(LPS)level and OCLN mRNA expression level,and serum D-LA level of broilers significantly decreased(P T<0.05).Compared with 1000 mg·kg^(-1) rutin group,dietary 250 mg·kg^(-1) rutin significantly increased spleen organ index,and TNF-αmRNA expression level in jejunal mucosa of broilers decreased(P T<0.05).Compared with 1000 mg·kg^(-1) rutin group,dietary 500 mg·kg^(-1) rutin significantly increased the expression of Bcl-2 mRNA level in jejunal mucosa,and the serum LPS level of broilers significantly decreased(P T<0.05).[Conclusions]Dietary supplementation of 250 mg·kg^(-1) or 500 mg·kg^(-1) rutin could promote the development of immune organs,enhance immune capacity,improve jejunum morphology,and enhance jejunum barrier function of broilers.The improvement of antioxidant function of jejunum of broilers might be related to the activation of Nrf2 signaling pathway.The optimum dosage of rutin was 250 mg·kg^(-1) under the experimental conditions.