基于粪便DNA宏条形码的人工草地放牧绵羊采食组分研究  

Fecal DNA Metabarcoding-based Diet Composition Research of Grazing Lambs on Artificial Pasture

作　　者：郭艳萍 王月君[1] 彭思嘉 左淑贤 张英俊 罗海玲[1] GUO Yan-ping;WANG Yue-jun;PENG Si-jia;ZUO Shu-xian;ZHANG Ying-jun;LUO Hai-ling(State Key Laboratory of Animal Nutrition and Feeding,College of Animal Science and Technology,China Agricultural University,Beijing 100193,China;Research Institute of Forestry,Chinese Academy of Forestry,Beijing 100091,China;College of Grassland Science and Technology,China Agricultural University,Beijing 100193,China)

机构地区：[1]中国农业大学动物科学技术学院畜禽营养与饲养全国重点实验室,北京100193 [2]中国林业科学研究院林业研究所,北京100091 [3]中国农业大学草业科学与技术学院,北京100193

出　　处：《草地学报》2024年第10期3043-3051,共9页Acta Agrestia Sinica

基　　金：宁夏回族自治区重点研发项目(2017BY082);中国博士后科学基金面上项目(2019M660877);国家自然科学基金重大项目(32192463)资助。

摘　　要：准确获取食草动物食性数据有助于了解草地放牧家畜的营养状况,同时也对掌握草地植物群落的动态变化具有重要意义。本研究通过从滩羊粪便样本中提取DNA,利用ITS2条形码和粪便DNA宏条形码技术(fDNA metabarcoding),基于出现频率(Frequency of occurrence,FO)和相对序列丰度(Relative read abundance,RRA)两个指标快速分析获得粪便中的物种组成。分析获得的滩羊食物组成包含28个植物类群,主要有藜属(Chenopodium sp.)、苜蓿属(Medicago sp.)、蒿属(Artemisia sp.)等隶属于13科23属,其中27个鉴定到种水平,物种鉴定分辨率高达96%。藜属FO和RRA均最高,分别为100.0%和31.5%,其次为紫花苜蓿(Medicago sativa),分别为100.0%和26.9%。基于两种算法分析得到的食物比例具有差异性和一致性,其中紫花苜蓿是放牧滩羊的主要采食来源,但摄入比例需要校正。研究证明了基于ITS2片段的粪便DNA宏条形码技术在食草家畜快速准确食性分析中的可行性,为此类研究提供了有力借鉴。建议采用该技术时应完善潜在摄食植物DNA条形码数据库,准确分析目标家畜在特定区域内的采食种类。Acquiring accurate dietary composition information of herbivores is a valuable tactic in understanding their nutritional level and the function of the grassland ecosystem.This study collected Tan lambs fecal samples from three treatment groups:artificial pasture grazing(G),artificial pasture grazing with the indoor feeding group(GF),and the indoor feeding group(F).DNA was then extracted from the samples and the species were identified based on the ITS2 gene and DNA mebarcoding technique.Frequency of occurrence(FO)and Relative read abundance(RRA)were used to determine the diet composition.Using fecal DNA metabarcoding,we conducted diet analysis for the lambs and found 28 different plant operational taxonomics unites(OTUs)belonging to 13 families and 23 genera,of which 27 were identified to the species level,and the species identification resolution was 96%.The predominant categories were Chenopodium sp.,Medicago sp.,and Artemisia sp..Chenopodium sp.had the highest relative FO(100.0%)and RRA(31.5%)among all the ingested foods,followed by Medicago sativa(100.0%and 26.9%,respectively).Therefore,to some extent the proportion obtained by frequency of occurrence and relative read abundance showed consistent tendencies but also generated differences.The results revealed that M.sativa was the main diet component of lambs,however its accurately proportion needs further correction.In addition,we suggested that the usage of fecal DNA barcode analysis approach should consider feeding range,targeted herbivores,and improved barcode database,which favorable to accurately determination of species and ingestion proportion.Our study highlights the utilization of fecal DNA metabarcoding based ITS2 gene in fast and high-throughput diet analysis,and provides a technical guidance for future herbivore livestock nutrition surveys and food-web studies.

关 键 词：绵羊 食性 DNA宏条形码 ITS2 物种鉴定 

分 类 号：S541[农业科学—作物学]