发酵玉米-豆粕饲料对蛋鸡小肠组织形态、消化酶活性和屏障功能相关基因表达的影响

Effects of Fermented Corn-Soybean Meal Feed on Small Intestine Morphology,Digestive Enzyme Activities and Barrier Function Related Genes Expression of Laying Hens

本试验旨在研究添加不同水平发酵饲料对蛋鸡小肠组织形态、消化酶活性和屏障功能相关基因表达的影响,为发酵饲料在蛋鸡生产中的应用提供参考。以玉米、豆粕和麸皮作为发酵底料,采用复合益生菌进行好氧和厌氧发酵,并通过16s rRNA高通量测序技术,分析发酵前后饲料菌群结构的变化。选取360只健康、体况和产蛋性能基本一致的22周龄京粉6号蛋鸡,随机分为4个组,发酵饲料添加水平分别为0(对照组)、4%、6%和8%,每组6个重复,每个重复15只鸡。试验期29周,其中预试期4周,正试期25周。35和50周龄时测定小肠食糜消化酶活性;试验期末测定小肠绒毛高度和隐窝深度,计算绒隐比(绒毛高度/隐窝深度),并检测空肠黏膜屏障功能相关基因mRNA相对表达量。结果表明:1)与发酵前相比,发酵后饲料菌群Shannon和Simpson指数显著降低(P<0.05),表明菌群多样性和丰富度下降;发酵后饲料优势菌群发生改变,在门上水平优势菌为厚壁菌门(Firmicutes),在属水平上优势菌为魏斯氏菌属(Weissella)。2)与对照组相比,6%和8%发酵饲料添加组蛋鸡十二指肠隐窝深度显著降低(P<0.05),绒隐比显著提高(P<0.05);各发酵饲料添加组蛋鸡空肠隐窝深度显著降低(P<0.05),绒隐比显著提高(P<0.05)。3)35周龄时,与对照组相比,饲粮中添加发酵饲料可以显著提高蛋鸡十二指肠食糜淀粉酶以及空肠食糜胰蛋白酶和脂肪酶活性(P<0.05)。4)与对照组相比,8%发酵饲料添加组蛋鸡空肠黏蛋白2(MUC2)mRNA相对表达量显著提高(P<0.05)。综上所述,发酵饲料能改善蛋鸡的小肠组织形态,提高小肠消化酶活性,上调空肠MUC2基因表达,增强蛋鸡肠道健康;其中,以6%发酵饲料添加水平的效果较佳。

This experiment was conducted to investigate the effects of different supplemental levels of fermented feed on small intestine morphology,digestive enzyme activities and barrier function related gene expression of laying hens,and to provide reference for the application of fermented feed in the production of laying hens.Corn,soybean meal and bran were used as fermentation substrates,and compound probiotics were used for aerobic and anaerobic fermentation.The changes of feed microbial community structure before and after fermentation were analyzed by 16S rRNA high-throughput sequencing technology.Three hundred and sixty healthy Jingfen No.6 laying hens with the same body condition and laying performance at 22 weeks of age were randomly divided into 4 groups with 6 replicates in each group and 15 hens in each replicate,and fed the diets supplemented with 0(control group),4%,6%and 8%fermented feed,respectively.The experiment lasted for 29 weeks,including 4 weeks of pre-experiment and 25 weeks of formal experiment.Digestive enzyme activities in small intestinal digesta were measured at 35 and 50 weeks of age.At the end of the experiment,the villus height and crypt depth of the small intestine were determined,the villus height/crypt depth(V/C)was calculated,and the mRNA relative expression levels of jejunal mucosa barrier function-related genes were detected.The results showed as follows:1)compared with before fermentation,the Shannon and Simpson indexes of the feed microflora were significantly decreased after fermentation(P<0.05),indicating that the diversity and richness of the feed microflora were decreased.After fermentation,the dominant flora in feed was changed,Firmicutes was the dominant bacteria at phylum level,and Weissella was the dominant bacteria at genus level.2)Compared with the control group,the crypt depth in duodenum in 6%and 8%fermented feed supplemental groups was significantly decreased(P<0.05),and the V/C was significantly increased(P<0.05);the crypt depth in jejunum in each fermented feed supplemental group was significantly decreased(P<0.05),and the V/C was significantly increased(P<0.05).3)At 35 weeks of age,compared with the control group,dietary supplemented with fermented feed significantly increased the amylase activity in duodenal digesta and the activities of trypsin and lipase in jejunal digesta of laying hens(P<0.05).4)Compared with the control group,the mucin 2(MUC2)mRNA relative expression level in jejunum of laying hens in 8%fermented feed supplemental group was significantly increased(P<0.05).In conclusion,fermented feed can improve the small intestine morphology,improve the intestinal digestive enzyme activities,up-regulate the MUC2 gene expression in jejunum,and enhance the intestine health of laying hens.Among them,the effect of 6%fermented feed is better.