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Journal of Zhejiang University (Agriculture and Life Sciences)  2023, Vol. 49 Issue (6): 863-872    DOI: 10.3785/j.issn.1008-9209.2022.10.081
Animal sciences & veterinary medicines     
Effects of aboveground parts of Tetrastigma hemsleyanum on the intestinal microflora, immune function and growth performance of broilers
Jing WANG1,2(),Tao LIU2,Minjie ZHAO2,Fengqin FENG1,2,Xiaoying DAI3,Haijun QIAO3,Xin PENG1,4()
1.Ningbo Innovation Center, Zhejiang University, Ningbo 315100, Zhejiang, China
2.College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, Zhejiang, China
3.Ningbo Shengwang Biotechnology Co. , Ltd. , Ningbo 315000, Zhejiang, China
4.Ningbo Research Institute of Traditional Chinese Medicine, Ningbo 315010, Zhejiang, China
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Abstract  

The effects of aboveground parts of Tetrastigma hemsleyanum, T. hemsleyanum leaves (THL), on the growth performance, immune function and intestinal microflora of broilers were evaluated. A total of 240 broilers were randomly divided into four groups: the control group (fed with a basal diet) and low dose group, medium dose group and high dose group (fed with a basal diet supplemented with 1%, 3% and 5% THL powder, and denoted as THL-L, THL-M and THL-H, respectively). The body masses of broilers at 21 and 42 days of age in each group was measured, and the immune organ indexes and the contents of immunoglobulin A (IgA), IgG and IgM in serum and the relative abundance of intestinal microflora in cecum contents of broilers at 42 days of age were determined. The results showed that compared with the control group, the supplementation of THL powder significantly enhanced the average daily feed intake (P<0.05) and average daily gain (P<0.05) of broilers at 42 days of age, and the promoting effect of the THL-M group was the best. At the same time, compared with the control group, the thymus index and the bursa of fabricius index of broilers in THL-L and THL-M groups were significantly increased (P<0.05). The contents of IgA and IgM in serum of broilers in THL-L, THL-M and THL-H groups were significantly higher than those in the control group (P<0.05). However, IgG content in THL-M and THL-H groups was significantly higher than that in the control group (P<0.05). The relative abundances of Lachnospiraceae and Clostridiaceae were significantly increased by the supplementation of appropriate amount of THL powder (3%) (P<0.05). This study indicated that T. hemsleyanum leaf powder could significantly improve the immune function, the intestinal microflora composition and the growth performance of broilers, and the most significant effect was found with supplementation of 3% THL powder.



Key wordsTetrastigma hemsleyanum leaf      growth performance      immune function      intestinal microflora     
Received: 08 October 2022      Published: 25 December 2023
CLC:  S831.5  
Corresponding Authors: Xin PENG     E-mail: wangjzju@zju.edu.cn;pengx@nit.zju.edu.cn
Cite this article:

Jing WANG,Tao LIU,Minjie ZHAO,Fengqin FENG,Xiaoying DAI,Haijun QIAO,Xin PENG. Effects of aboveground parts of Tetrastigma hemsleyanum on the intestinal microflora, immune function and growth performance of broilers. Journal of Zhejiang University (Agriculture and Life Sciences), 2023, 49(6): 863-872.

URL:

https://www.zjujournals.com/agr/10.3785/j.issn.1008-9209.2022.10.081     OR     https://www.zjujournals.com/agr/Y2023/V49/I6/863


三叶青地上部分对肉鸡肠道菌群、免疫功能和生长性能的影响

为探究三叶青地上部分(三叶青藤叶)对肉鸡生长性能、免疫功能和肠道菌群的影响,将240只健康肉仔鸡随机分成4组,分别为对照组(饲喂基础日粮)和低剂量组、中剂量组、高剂量组(分别饲喂添加1%、3%、5%三叶青藤叶粉的基础日粮)。测定各组21日龄与42日龄试验鸡只体质量,42日龄试验鸡只免疫器官指数和血清免疫球蛋白A(immunoglobulin A, IgA)、IgG、IgM含量以及盲肠内容物的肠道菌群相对丰度。结果表明:与对照组相比,添加三叶青藤叶粉可显著提高42日龄肉鸡的平均日采食量(P<0.05)和平均日增重(P<0.05),且中剂量组促进效果最明显。同时,低、中剂量组肉鸡胸腺指数和法氏囊指数较对照组显著升高(P<0.05)。各剂量组的肉鸡血清中IgA、IgM含量均显著高于对照组(P<0.05),中、高剂量组的IgG含量显著高于对照组(P<0.05)。添加适量三叶青藤叶粉(3%)可显著增加毛螺菌科(Lachnospiraceae)和梭菌科(Clostridiaceae)的相对丰度(P<0.05)。上述结果表明,三叶青藤叶粉可显著提高肉鸡的免疫功能,改善肉鸡肠道菌群组成,提高肉鸡生长性能,其中,以添加3%三叶青藤叶粉的促进效果最为显著。


关键词: 三叶青藤叶,  生长性能,  免疫功能,  肠道菌群 

日粮组成

Diet ingredient/%

CKTHL-LTHL-MTHL-H
玉米 Corn60.560.560.560.5
小麦麸 Wheat bran5.04.02.00.0
三叶青藤叶粉 T. hemsleyanum leaf powder0.01.03.05.0
豆粕 Soybean meal23.023.023.023.0
玉米蛋白粉 Corn gluten meal6.06.06.06.0
大豆油 Soybean oil1.51.51.51.5
磷酸氢钙 CaHPO41.51.51.51.5
石灰石 Limestone1.21.21.21.2
氯化钠 NaCl0.30.30.30.3
预混料1) Premix1)1.01.01.01.0
总计 Total100.0100.0100.0100.0

营养指标

Nutritional index

CKTHL-LTHL-MTHL-H
粗蛋白 Crude protein/%18.8918.9118.9318.95
代谢能 Metabolic energy/(MJ/kg)12.5512.5712.5812.59
钙 Ca/%0.890.890.890.89
总磷 Total P/%0.600.610.620.63
赖氨酸 Lysine/%0.950.960.960.97
蛋氨酸 Methionine/%0.400.400.400.50
蛋氨酸和胱氨酸混合物 Mixture of methionine and cystine/%0.720.730.750.76
Table 1 Ingredients and nutritional indexes of diets in different experimental groups

指标

Index

日龄

Days of age

CKTHL-LTHL-MTHL-H

平均日采食量

Average daily feed intake/(g/d)

21日龄54.78±3.35a55.00±2.50a56.33±1.32a56.78±1.86a
42日龄121.11±4.81b125.44±3.71a126.56±4.67a123.11±1.76b

平均日增重

Average daily gain/(g/d)

21日龄32.22±1.86c34.56±1.59b37.22±3.11a36.89±1.62a
42日龄74.33±3.77c77.78±2.63b82.56±1.81a78.44±2.35b

料重比

Feed to gain ratio

21日龄1.70±0.08a1.59±0.11b1.51±0.16c1.54±0.04c
42日龄1.63±0.09a1.61±0.07a1.53±0.07c1.57±0.06b
Table 2 Effects of THL powder on growth performance of broilers

指标

Index

CKTHL-LTHL-MTHL-H
胸腺指数 Thymus index/(g/kg)2.31±0.22c2.62±0.17b2.88±0.15a2.45±0.19c
脾脏指数 Spleen index/(g/kg)1.47±0.17a1.56±0.19a1.57±0.15a1.53±0.14a
法氏囊指数 Bursa of fabricius index/(g/kg)1.26±0.17c1.46±0.12b1.57±0.15a1.33±0.21c
IgA/(mg/mL)0.92±0.07c1.15±0.08b1.25±0.07a1.18±0.07b
IgG/(mg/mL)0.90±0.04c0.93±0.06c1.03±0.07b1.16±0.05a
IgM/(mg/mL)0.99±0.09c1.09±0.09b1.12±0.14b1.32±0.10a
Table 3 Effects of THL powder on immune indexes of broilers
Fig. 1 PCoA results between the THL-M group and the control groupThe scales of horizontal and vertical axes represent relative distance and have no practical significance, and the percentage represents the explanation value of each principal axe for the difference in sample composition. Each point in the figure represents a sample, and the closer the distance between the samples, the smaller the difference in intestinal microflora composition between the samples.
Fig. 2 Comparison of community structure of intestinal microflora between the groups
Fig. 3 Analysis of key phylotypes of intestinal microflora between the groupsA. Cladogram from LEfSe; B. LDA score distribution histogram for differential microorganisms (LDA score>3).
[1]   高爱荣.动物源性食品安全问题及对策浅析[J].现代农村科技,2022(8):9. DOI:10.3969/j.issn.1674-5329.2022.08.005
GAO A R. Analysis on the safety problems and countermeasures of animal-derived food[J]. Xiandai Nongcun Keji, 2022(8): 9. (in Chinese)
doi: 10.3969/j.issn.1674-5329.2022.08.005
[2]   楚云开.中药添加剂在动物饲养中的作用[J].畜禽业,2021,32(10):24-25. DOI:10.19567/j.cnki.1008-0414.2021.10.013
CHU Y K. The roles of traditional Chinese medicine additives in animal feeding[J]. Livestock and Poultry Industry, 2021, 32(10): 24-25. (in Chinese)
doi: 10.19567/j.cnki.1008-0414.2021.10.013
[3]   李者,周昌和,杜向标,等.三叶青研究和生产现状及发展对策[J].浙江林业科技,2020,40(6):87-92. DOI:10.3969/j.issn.1001-3776.2020.06.015
LI Z, ZHOU C H, DU X B, et al. Current situation and countermeasures on research and development of Tetrastigma hemsleyanum [J]. Journal of Zhejiang Forestry Science and Technology, 2020, 40(6): 87-92. (in Chinese with English abstract)
doi: 10.3969/j.issn.1001-3776.2020.06.015
[4]   廖淑彬,陈丹,余文静,等.三叶青地上部分抗炎提取物效应组分群不同生理状态体内组织分布规律及特性研究[J].中国中药杂志,2021,46(5):1224-1249. DOI:10.19540/j.cnki.cjcmm.20200707.204
LIAO S B, CHEN D, YU W J, et al. Study on patterns and characteristics of in vivo tissue distribution of anti-inflammatory extract of Tetrastigma hemsleyanum aerial part in healthy and inflammatory pathological model rats[J]. China Journal of Chinese Materia Medica, 2021, 46(5): 1224-1249. (in Chinese with English abstract)
doi: 10.19540/j.cnki.cjcmm.20200707.204
[5]   姜文娟,陈文云,徐田放,等.三叶青研究现状及其在畜牧兽医领域的前景展望[J].中兽医学杂志,2018(4):96-98.
JIANG W J, CHEN W Y, XU T F, et al. Current research status of Tetrastigma hemsleyanum and its prospect in animal husbandry and veterinary field[J]. Chinese Journal of Traditional Veterinary Science, 2018(4): 96-98. (in Chinese)
[6]   蔡韦炜,陈丹,范世明,等.三叶青地上部分化学成分分析[J].福建中医药大学学报,2013,23(5):34-35. DOI:10.13261/j.cnki.jfutcm.002859
CAI W W, CHEN D, FAN S M, et al. Component analysis of aerial parts of Tetrastigma hemsleyanum [J]. Journal of Fujian University of TCM, 2013, 23(5): 34-35. (in Chinese with English abstract)
doi: 10.13261/j.cnki.jfutcm.002859
[7]   靳二辉,陈耀星,周金星,等.黄芪、枸杞、金银花等中草药复方制剂对肉鸡免疫器官发育及免疫功能的影响[J].畜牧兽医学报,2017,48(6):1128-1139. DOI:10.11843/j.issn.0366-6964.2017.06.018
JIN E H, CHEN Y X, ZHOU J X, et al. The effect of compound Chinese herbal medicine preparation of Astragalus, wolfberry and honeysuckle flower on immune organ development and immune functions of broiler[J]. Acta Veterinaria et Zootechnica Sinica, 2017, 48(6): 1128-1139. (in Chinese with English abstract)
doi: 10.11843/j.issn.0366-6964.2017.06.018
[8]   谢全喜,崔诗法,徐海燕,等.复合微生态制剂与饲用抗生素对肉鸡生长性能、免疫性能和抗氧化指标的影响[J].动物营养学报,2012,24(7):1336-1344. DOI:10.3969/j.issn.1006-267x.2012.07.019
XIE Q X, CUI S F, XU H Y, et al. Effects of compound probiotics and antibiotics on growth performance, immune function and antioxidant indices of broilers[J]. Chinese Journal of Animal Nutrition, 2012, 24(7): 1336-1344. (in Chinese with English abstract)
doi: 10.3969/j.issn.1006-267x.2012.07.019
[9]   韩金恒,李鹏升,姜云瑶,等.复方中草药添加剂对AA+肉鸡生产性能及肠道菌群结构的影响[J].黑龙江畜牧兽医,2022(5):115-118. DOI:10.13881/j.cnki.hljxmsy.2021.04.0383
HAN J H, LI P S, JIANG Y Y, et al. Effect of compound Chinese herbal medicine additives on production performance and intestinal microflora structure of AA+ broilers[J]. Heilongjiang Animal Science and Veterinary Medicine, 2022(5): 115-118. (in Chinese with English abstract)
doi: 10.13881/j.cnki.hljxmsy.2021.04.0383
[10]   JI W W, PENG X, LOU T L, et al. Total flavonoids from Tetrastigma hemsleyanum ameliorates inflammatory stress in concanavalin A-induced autoimmune hepatitis mice by regulating Treg/Th17 immune homeostasis[J]. Inflammopharmacology, 2019, 27(6): 1297-1307. DOI: 10.1007/s10787-019-00599-0
doi: 10.1007/s10787-019-00599-0
[11]   JI T, JI W W, WANG J, et al. A comprehensive review on traditional uses, chemical compositions, pharmacology properties and toxicology of Tetrastigma hemsleyanum [J]. Journal of Ethnopharmacology, 2021, 264: 113247. DOI: 10.1016/j.jep.2020.113247
doi: 10.1016/j.jep.2020.113247
[12]   王建烽.可溶性纤维日粮对福建黄兔生产性能、免疫机能以及肠道内环境的影响[D].福建,福州:福建农林大学,2018.
WANG J F. Effect of soluble fiber diet on performance, immune function and internal cecum of Fujian rabbit[D]. Fuzhou, Fujian: Fujian Agriculture and Forestry University, 2018. (in Chinese with English abstract)
[13]   陈加红.药用植物三叶青藤蔓在肉牛养殖中的应用[J].智慧农业导刊,2022,2(1):21-23.
CHEN J H. Application of medicinal plant trifoliate vine in beef cattle breeding[J]. Journal of Smart Agriculture, 2022, 2(1): 21-23. (in Chinese with English abstract)
[14]   张娟.丁酸梭菌对肉鸡生长性能、肠道生理及盲肠菌群的影响[D].浙江,杭州:浙江大学,2015.
ZHANG J. Effects of Clostridium butyricum on growth performance, intestinal physiology and cecal microflora in broiler chickens[D]. Hangzhou, Zhejiang: Zhejiang University, 2015. (in Chinese with English abstract)
[15]   周雪雁,李琼毅,丁功涛,等.鸡肠道微生物菌群的建立发育、分布和生理学意义[J].微生物学报,2020,60(4):641-652. DOI:10.13343/j.cnki.wsxb.20190376
ZHOU X Y, LI Q Y, DING G T, et al. Establishment, distribution and physiological significance of the intestinal microbiota in chicken[J]. Acta Microbiologica Sinica, 2020, 60(4): 641-652. (in Chinese with English abstract)
doi: 10.13343/j.cnki.wsxb.20190376
[16]   STANLEY D, HUGHES R J, MOORE R J. Microbiota of the chicken gastrointestinal tract: influence on health, productivity and disease[J]. Applied Microbiology and Biotechnology, 2014, 98(10): 4301-4310. DOI: 10.1007/s00253-014-5646-2
doi: 10.1007/s00253-014-5646-2
[17]   张莉,尹德凤,向建军,等.日粮中添加蓝藻粉对崇仁麻鸡肠道菌群结构的影响[J].江西农业学报,2022,34(3):73-79. DOI:10.19386/j.cnki.jxnyxb.2022.03.012
ZHANG L, YIN D F, XIANG J J, et al. Effects of cyanobacteria powder in diet on intestinal microflora structure of Chongren partridge chicken[J]. Acta Agriculturae Jiangxi, 2022, 34(3): 73-79. (in Chinese with English abstract)
doi: 10.19386/j.cnki.jxnyxb.2022.03.012
[18]   段智璇,田维毅.中药对肠道菌群及肠黏膜屏障功能的影响[J].内蒙古医学杂志,2016,48(9):1053-1057. DOI:10.16096/J.cnki.nmgyxzz.2016.48.09.010
DUAN Z X, TIAN W Y. Influence of traditional Chinese medicine on intestinal floras and intestinal mucosal barrier function[J]. Inner Mongolia Medical Journal, 2016, 48(9): 1053-1057. (in Chinese with English abstract)
doi: 10.16096/J.cnki.nmgyxzz.2016.48.09.010
[19]   王小宁.飞机草总黄酮对肉鸡生长和免疫及肠道菌群的影响[D].广东,湛江:广东海洋大学,2016.
WANG X N. Effect of total flavonoids extract from Eupatorium odoratum on growth performance, immunity and intestinal flora in broiler[D]. Zhanjiang, Guangdong: Guangdong Ocean University, 2016. (in Chinese with English abstract)
[20]   纪丽丽,祁根兄,王传宝,等.中草药提取物对肉鸡生长性能、器官发育、免疫功能及肠道菌群的影响[J].中国饲料,2018(22):32-36. DOI:10.15906/j.cnki.cn11-2975/s.20182208
JI L L, QI G X, WANG C B, et al. Effect of the herbal extracts on growth performance, organ development, immunity and intestinal microbial population of broilers[J]. China Feed, 2018(22): 32-36. (in Chinese with English abstract)
doi: 10.15906/j.cnki.cn11-2975/s.20182208
[21]   韩金恒.复方中草药添加剂对AA+肉鸡生产性能及肠道菌群的影响[D].吉林,长春:吉林农业大学,2021.
HAN J H. Effect of compound Chinese herbal medicine additives on production performance and intestinal microflora structure of AA+ broilers[D]. Changchun, Jilin: Jilin Agricultural University, 2021. (in Chinese with English abstract)
[22]   BÄUMLER A J, SPERANDIO V. Interactions between the microbiota and pathogenic bacteria in the gut[J]. Nature, 2016, 535(7610): 85-93. DOI: 10.1038/nature18849
doi: 10.1038/nature18849
[23]   MUKHOPADHYA I, HANSEN R, EL-OMAR E M, et al. IBD—what role do Proteobacteria play?[J]. Nature Reviews Gastroenterology & Hepatology, 2012, 9(4): 219-230. DOI: 10.1038/nrgastro.2012.14
doi: 10.1038/nrgastro.2012.14
[24]   ZENG A P, ROSS A, BIEBL H, et al. Multiple product inhibition and growth modeling of Clostridium butyricum and Klebsiella pneumoniae in glycerol fermentation[J]. Biotechnology and Bioengineering, 1994, 44(8): 902-911.
[25]   BIDDLE A, STEWART L, BLANCHARD J, et al. Untangling the genetic basis of fibrolytic specialization by Lachno-spiraceae and Ruminococcaceae in diverse gut communities[J]. Diversity, 2013, 5(3): 627-640. DOI: 10.3390/d5030627
doi: 10.3390/d5030627
[26]   彭喜春,黄嘉成.肠道梭菌在机体能量过度摄入中的作用[J].现代食品科技,2014,30(3):262-265. DOI:10.13982/j.mfst.1673-9078.2014.03.048
PENG X C, HUANG J C. The functions of gut Clostridum spp. in over-ingesting energy of body[J]. Modern Food Science and Technology, 2014, 30(3): 262-265. (in Chinese with English abstract)
doi: 10.13982/j.mfst.1673-9078.2014.03.048
[27]   孔繁刚.月桂酸甘油酯与丁酸甘油酯对肉种鸡生产性能、血清生化指标及肠道健康的影响[D].广东,佛山:佛山科学技术学院,2020.
KONG F G. Effects of glycerol laurate and glycerol butyrate on production performance, serum biochemical indexes and intestinal health of broiler breeders[D]. Foshan, Guangdong: Foshan University, 2020. (in Chinese with English abstract)
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