桑叶水提物对大肠杆菌攻毒肉鸡生长性能、抗氧化能力和肠道健康的影响

Effects of Mulberry Leaf Water Extract on Growth Performance,Antioxidant Capacity and Intestinal Health of Broilers Challenged with Escherichia coli

本试验旨在研究饲粮中添加桑叶水提物对大肠杆菌攻毒肉鸡生长性能、抗氧化能力和肠道健康的影响。选取256羽8日龄雌性黄羽肉鸡,随机分为4组,每组8个重复,每个重复8羽。对照组(CON组)和大肠杆菌攻毒组(EC组)饲喂基础饲粮;桑叶水提物组(MWE组)和桑叶水提物+大肠杆菌攻毒组(ECMWE组)在基础饲粮中添加1 200 mg/kg桑叶水提物。试验期28 d(8~35日龄)。33~35日龄时,EC组和ECMWE组肉鸡灌服2 mL大肠杆菌K88菌液(1.0×109CFU/mL),CON组和MWE组肉鸡灌服2 mL无菌生理盐水。结果显示:1)大肠杆菌攻毒使肉鸡的平均日采食量(ADFI)显著降低(P<0.05),腹泻率显著升高(P<0.05)。添加桑叶水提物极显著提高了肉鸡的平均日增重(ADG)(P<0.01),极显著降低了肉鸡的料重比(F/G)和腹泻率(P<0.01)。添加桑叶水提物与大肠杆菌攻毒对肉鸡的ADFI表现出极显著的交互作用(P<0.01),对腹泻率表现出存在交互作用的趋势(P=0.07)。2)大肠杆菌攻毒显著降低了血清中谷胱甘肽过氧化物酶(GSH-Px)的活性(P<0.05),极显著降低了血清中过氧化氢酶(CAT)的活性(P<0.01);添加桑叶水提物有提高肉鸡血清中CAT活性的趋势(P=0.09)。3)添加桑叶水提物能显著增加肉鸡空肠绒毛高度与隐窝深度的比值(P<0.05)。4)添加桑叶水提物和大肠杆菌攻毒均能明显改变肉鸡盲肠菌群结构。在门水平下,添加桑叶水提物有降低肉鸡盲肠菌群中厚壁菌门(Firmicutes)相对丰度的趋势(P=0.09),有升高变形菌门(Proteobacteria)相对丰度的趋势(P=0.08);在属水平下,添加桑叶水提物能显著提高另枝菌属(Alistipes)、链球菌属(Streptococcus)和毛螺菌科UCG-004(Lachnospiraceae_UCG-004)的相对丰度(P<0.05),极显著降低瘤胃球菌科UCG-011(Ruminococcaceae_UCG-011)和瘤胃球菌科UCG-013(Ruminococcaceae_UCG-013)的相对丰度(P<0.01)。添加桑叶水提物与大肠杆菌攻毒在沙特尔沃思菌属(Shuttleworthia)、消化球菌属(Peptococcus)和毛螺菌科UCG-004的相对丰度上存在显著的交互作用(P<0.05)。综上可知,饲粮中添加1 200 mg/kg桑叶水提物能降低肉鸡腹泻率,提高生长性能,增强抗氧化能力,改善肠道形态和盲肠菌群结构,有效缓解大肠杆菌攻毒对肉鸡造成的不利影响。

This experiment was conducted to investigate the effects of dietary supplementation of mulberry leaf water extract on growth performance,antioxidant capacity,intestinal health of broilers challenged with Esche⁃richia coli.Two hundred and fifty⁃six 8⁃day⁃old female yellow⁃feathered broilers were randomly divided into 4 groups with 8 replicates per group and 8 broilers per replicate.Broilers in control group(CON group)and Escherichia coli challenge group(EC group)were fed a basal diet;broilers in mulberry leaf water extract group(MWE group)and mulberry leaf water extract+Escherichia coli challenge group(ECMWE group)were fed the basal diet supplemented with 1200 mg/kg mulberry leaf water extract.The experimental period was 28 days(8 to 35 days of age).At 33 to 35 days of age,broilers in the EC group and ECMWE group were given 2 mL Escherichia coli K88 bacterial solution(1.0×109 CFU/mL),while broilers in the CON group and MWE group were given 2 mL sterile saline.The results showed as follows:1)after the test broilers were challenged with Escherichia coli,the average daily feed intake(ADFI)of EC group was significantly de⁃creased(P<0.05),and the diarrhea rate was significantly increased(P<0.05).Adding mulberry leaf water extract could extremely significantly increase the average daily gain(ADG)(P<0.01),and extremely signifi⁃cantly reduce the feed/gain ratio(F/G)and diarrhea rate of broilers(P<0.01).Adding mulberry leaf water extract and Escherichia coli challenge showed a extremely significant interaction on ADFI of broilers(P<0.01),and showed a trend of interaction on diarrhea rate of broilers(P=0.07).2)After Escherichia coli challenge,the activity of glutathione peroxidase(GSH⁃Px)in serum was significantly decreased(P<0.05),and the activity of catalase(CAT)in serum was extremely significantly decreased(P<0.01).Adding mul⁃berry leaf water extract tended to increase serum CAT activity of broilers(P=0.09).3)Adding mulberry leaf water extract significantly increased the jejunal villus height/crypt depth(V/C)ratio of broilers(P<0.05).4)Adding mulberry leaf water extract and Escherichia coli challenge both could obviously change the cecal micro⁃flora structure of broilers.At the phylum level,adding mulberry leaf water extract tended to reduce the relative abundance of Firmicutes(P=0.09),and tended to increase the relative abundance of Proteobacteria(P=0.08);at the genus level,adding mulberry leaf water extract could significantly increase the relative abun⁃dances of Alistipes,Streptococcus and Lachnospiraceae_UCG⁃004(P<0.05),and extremely significantly de⁃crease the relative abundances of Ruminococcaceae_UCG⁃011 and Ruminococcaceae_UCG⁃013(P<0.01).There was a significant interaction between adding mulberry leaf water extract and Escherichia coli challenge in the relative abundances of Shuttleworthia,Peptococcus and Lachnospiraceae_UCG⁃004(P<0.05).In summa⁃ry,it can be seen that adding 1200 mg/kg mulberry leaf water extract to the diet of broilers can reduce the di⁃arrhea rate,improve the growth performance,enhance the antioxidant capacity,improve the intestinal mor⁃phology and cecal microflora structure of broilers,and then effectively alleviate the adverse effects of Esche⁃richia coli challenge on broilers.