在不同营养水平日粮中添加益生菌对肉鸡抗氧化功能、黏膜免疫及回肠菌群的影响

采用2×2因素设计,研究在不同营养水平日粮中添加益生菌对肉鸡免疫器官指数、血清和肠黏膜抗氧化性能、肠黏膜IgG和SIgA及回肠菌群的影响,评价益生菌在宿主内的免疫效应及其机理。试验选用1日龄AA肉鸡320只,分成4组,每组10个重复,每个重复8只,饲喂以下4种日粮:(1)正对照组(NC):基础日粮;(2)负对照组(LC):低能低蛋白日粮,使基础日粮的代谢能降低320 kJ/kg,粗蛋白均降低0.85%;(3)试验1组(NP):基础日粮+0.01%益生菌;(4)试验2组(LP):低能低蛋白日粮+0.01%益生菌。结果表明,在不同营养水平下,益生菌能提高21 d肉鸡的胸腺指数(P<0.01)、脾脏指数和法氏囊指数(P<0.05),但不影响42 d免疫器官指数(P>0.05),可显著提高肉鸡21 d血清和肠黏膜总超氧化物歧化酶(T-SOD)的活性(P<0.05),降低肉鸡21 d血清丙二醛(MDA)的含量(P<0.01),对21 d肠黏膜MDA含量也有降低趋势(P=0.057),能极显著提高42 d血清T-SOD活性和总抗氧化能力(T-AOC)(P<0.01),显著降低42 d血清和肠黏膜MDA的含量(P<0.05);在不同营养水平日粮中添加益生菌对肠黏膜IgG的含量有提高趋势(P=0.077),显著提高42 d肠黏膜IgG和SIgA含量(P<0.05),能显著降低21 d、42 d回肠大肠杆菌数量(P<0.05),极显著提高21 d回肠乳酸杆菌的数量(P<0.01),对42 d回肠乳酸杆菌数量没有显著影响(P>0.05)。结果提示,在不同营养水平下添加益生菌能促进肉鸡前期的免疫器官生长和发育,增强血液和肠黏膜的抗氧化功能,促进肠黏膜免疫球蛋白分泌,并能促进回肠乳酸杆菌增殖,抑制大肠杆菌增殖。

Effects of probiotics on antioxidant function, mucosal immunity and ileum microflora in broilers fed diets with different nutrient levels

A 2×2 factorial arrangement of treatments was used to determine the effects of probiotics (none or 100 mg/kg of diet) on immune organs, antioxidant function of serum and mucosa, IgG and SIgA content of mucosa, and ileum microflora in broilers fed diet with different nutrient levels, and evaluate the mechanism and immune effect of probiotics on host animals. 320 one-day-old AA broilers were randomly assigned to four dietary treatments, and each treatment had 10 replicates with 8 broilers per replicate. The treatments were as follows: (1) control with normal nutrient level(NC); (2) control with 320 KJ/kg less ME and 0.85% less CP than NC (LC); (3) NC supplemented with 0.01% probiotics (NP); (4)LC supplemented with 0.01% probiotics (LP). The result suggested that probiotics supplementation improved thymus index (P<0.01), increased spleen index and bursal index (P<0.05), but did not influence immune organ indexes. Probiotics promoted the activity of T-SOD in serum and musoca of broiler (21 d) (P<0.05), decreased MDA in serum (P<0.01), also tended to reduce the content of MDA in musoca (P=0.057), enhanced T-SOD activity and T-AOC in serum (P<0.01) and reduced MDA both in serum and musoca (P<0.05) (42 d). Probiotics addition to diets with different nutrient levels tended to improve IgG in musoca (21 d) (P=0.077), and improved the contents of IgG and sIgA in musoca (42 d) (P<0.05). The number of E. coli in ileum was diminished (P<0.05) at both 21 d and 42 d by probiotics supplementation. Probiotics promoted the number of lactobacillus in ileum (P<0.001) at 21 d, but there was no effect on the number of lactobacillus in ileum (42 d). The results implied that the probiotics added in diet with different nutrient levels promoted the growth and development of immune organs and the secretion of immunoglobulin in intestinal mucosa. In addition, Probiotics supplementation enhanced lactobacillus proliferation and attenuated E. coli proliferation in ileum.