EwE模型在水生态系统中的应用研究及长潭水库案例分析

EwE(Ecopath with Ecosim)模型是一种用于定量研究水生态系统食物网结构和能量流动特征的模型。总结了EwE模型中Ecopath、Ecosim、Ecospace和Ecotracer模块的原理,综述了该模型在不同类型水生态系统中的应用研究进展,发现Ecopath可用来评估海洋和淡水生态系统的成熟度并确定关键种和生态容量,明确浮游植物生产量(P)对生态系统总通量(TST)的重要贡献;Ecosim用于在时间尺度上揭示关键种捕捞、港口建设等人类活动对生态系统结构和功能的影响机制;Ecospace可用来阐明海上平台建设、发电厂运行、火山爆发等外部因素影响下渔业经济和生态系统结构的空间差异性;Ecostracer可用来追踪同位素、重金属和新型污染物等物质在食物网中的迁移过程。采用Ecopath分析了长潭水库的营养结构和能量流动,结果表明,长潭水库营养级介于1.000~3.093,食物网结构简单,TPP/TR为2.445,是一个相对成熟的生态系统,能量传递效率较低。未来应加强气候变化和人类活动对水生态系统结构演替的影响研究,推进新污染物在食物网中富集特征研究,为水域生态系统健康状态评估和渔业经济发展政策的调整提供支撑。

基于海洋生态系统管理的EwE建模技术要点

Ecopath with Ecosim (EwE)模型因具有功能完善、使用方便等特点,近年在海洋生态系统管理和研究中得到越来越广泛的应用。基于相关案例,分析并总结了EwE模型应用于海洋生态系统研究与管理的技术要点:Ecopath模型的系统边界在空间上一般应包含系统主要物种的所有生境,在时间上应能体现主要物种的完整生命周期;通常需要将几个具有相似功能的物种合并成一个功能组来简化生态系统;模型参数设置的合理与否需结合生态系统实际加以判断,模型平衡更是需要遵循基本的生态学和热力学规则;使用生态网络方法比较不同模型时需对模型参数进行标准化处理;Ecosim模型对初始参数的变化非常敏感,利用Monte Carlo拟合程序可以有效解决输入参数的不确定性问题;模型建成后建议参照相关标准对模型质量进行定期校验。

基于EwE模型的玄武湖水生物操纵模拟

使用Ecopath with Ecosim(EwE)构建了玄武湖生态系统模型,探究了玄武湖生态系统特征并针对富营养化问题进行了生物操纵模拟。结果表明:玄武湖食物网结构简单,连接指数(CI)、系统杂食性指数(SOI)、总初级生产量/总呼吸量(TPP/TR)、Finn’s循环指数(FCI)和Finn’s循环平均能流路径长度(FCL)均表明玄武湖生态系统正处于发育阶段;对鲢、鳙、枝角类及桡足类进行了生物操纵模拟,在生物操纵期间蓝藻、绿藻、硅藻相对于操纵前生物量削减百分比分别达到18%、5%、4%,表明生物操纵对富营养化有一定的控制效果。

草鱼-鲢-鲤混养生态系统的EwE模型分析

采用EwE模型软件,构建了一个具有14个生物功能组的草鱼、鲢和鲤混养生态系统EwE模型,对草鱼、鲢和鲤混养生态系统的结构和功能进行综合量化分析。研究表明,草鱼、鲢和鲤混养生态系统主要由3个营养级构成。从营养物质流量看,营养级Ⅰ流量最大,占系统总流量(TST)的56.90%;营养级Ⅱ、Ⅲ、Ⅳ、Ⅴ的流量随营养级的增加而递减,分别占总流量的34.45%、8.20%、0.44%和0.003%。食物网和营养级之间营养流动分析表明,系统营养流通的主要途径为从浮游植物开始的牧食链、从碎屑开始的腐食链和从饲料开始的饲料链。从生态营养学效率(EE值)看,除螺类的EE值为零外,大部分功能组的EE值都较高,表明系统中大部分功能组都得到了较好的利用。碎屑在草鱼、鲢和鲤混养生态系统中具有十分重要的作用,其主要来源是细菌、原生动物和浮游植物,且碎屑的EE值较高(水中为0.903,底泥为0.551),表明大部分碎屑重新进入食物链循环,碎屑得到了再利用。研究结果表明,草鱼、鲢和鲤混养的模式可以进一步优化,建议增加放养鱼类的密度,同时引进一些其他鱼类(如青鱼和鳙鱼),以提高系统的综合效益。

珠江口EwE模型功能组划分研究

对珠江口水域生态系统进行EwE模型功能组划分研究。在总结功能组划分方法的基础上,对珠江口水域生态系统进行了功能组划分。功能组的划分结果基本可以覆盖珠江口水域生态系统的能量流动过程,为进一步构建珠江口生态系统的营养模型,研究珠江口渔业发展变化,促进EwE软件在我国的推广应用具有重要意义。

EwE模型在评价渔业水域生态系统中的应用

渔业影响了水域生态环境,如过度捕捞、鱼类生存环境变迁等都使得原有渔业水域生态系统越来越脆弱。科学开发有限的渔业资源需要正确的理论指导。构建生态系统模型可以更完整地认识水域生态系统的结构和功能。Ecopath with Ecosim(EwE)模型是以生态系统中的能量流动和物质平衡为理论基础,融合了生态学的相关基础理论知识,主要用于探讨生态学的基本问题、评估渔业对生态系统的影响、提出渔业管理政策、评估海洋保护区域的效果和位置确定、评估环境变化对渔业的影响。该模型为海洋渔业和淡水渔业提供了分析和管理工具。

基于EwE模型的三疣梭子蟹、凡纳滨对虾和梭鱼混养系统的能流分析

以三疣梭子蟹(Portunus trituberculatus)、凡纳滨对虾(Litopenaeus vannamei)和梭鱼(Liza haematocheli)混养池塘生态系统为研究对象,利用Ecopath with ecosim(EwE)模型软件,构建了由17个生物功能组组成的能量流动模型。研究表明,系统由5个营养级组成,其中第Ⅰ、Ⅱ营养级的能量流通量占系统总能量流通量的比例分别为63.47%和35.39%。系统大部分消费者位于营养级Ⅱ左右,食物链结构多呈"线状"。系统总能量流中碎屑功能组占74.58%,初级生产者占25.42%,其中,碎屑功能组中的人工饵料生物能占系统总能量来源22.31%,在系统总能量流中起重要作用。系统Finn’s循环指数(FCI)为21.24%,连接指数(CI)和系统杂食指数(SOI)分别为0.28和0.06,相对聚合度(A/C)为0.45。从生态营养学效率(EE)值来看,系统对来自碎屑功能组的能量利用率较高,对来自初级生产者微型、微微型浮游植物的能量利用效率较低。大量初级生产者能量未被利用而直接流向碎屑功能组,表明该系统的营养级结构还能进一步优化。建议提高梭鱼的放养密度或引入合适的滤食性生物进行搭配养殖,进一步提高系统的能量利用效率和混合养殖效益。

Comparative analysis between endometrial proteomes of pregnant and non-pregnant ewes during the peri-implantation period

Background： Early pregnancy failure has a profound impact on both human reproductive health and animal production. 2/3 pregnancy failures occur during the peri-implantation period; however, the underlying mechanism（s） remains unclear. Well-organized modification of the endometrium to a receptive state is critical to establish pregnancy Aberrant endometrial modification during implantation is thought to be largely responsible for early pregnancy loss. Result： In this study, using well-managed recipient ewes that received embryo transfer as model, we compared the endometrial proteome between pregnant and non-pregnant ewes during implantation period. After embryo transfer, recipients were assigned as pregnant or non-pregnant ewes according to the presence or absence of an elongated conceptus at Day 17 of pregnancy. By comparing the endometrial proteomic profiles between pregnant and non-pregnant ewes, we identified 94 and 257 differentially expressed proteins （DEPs） in the endometrial caruncular and intercaruncular areas, respectively. Functional analysis showed that the DEPs were mainly associated with immune response, nutrient transport and utilization, as well as proteasome-mediated proteolysis. Conclusion： These analysis imply that dysfunction of these biological processes or pathways of DEP in the endometrium is highly associated with early pregnancy loss. In addition, many proteins that are essential for the establishment of pregnancy showed dysregulation in the endometrium of non-pregnant ewes. These proteins, as potential candidates, may contribute to early pregnancy loss.

Identification of Sheep Endogenous Beta-Retroviruses with Uterus-Specific Expression in the Pregnant Mongolian Ewe

The sheep genome harbours approximately 20 copies of endogenous beta-retroviruses （enJSRVs）, and circumstantial evidence suggests that enJSRVs might play a role in mammalian reproduction, particularly placental morphogenesis. This study was aimed to assess the expression of mRNAs of an enJSRV and its receptor, HYAL2, in the uterus and conceptuses of Mongolian ewes throughout gestation, using real-time reverse transcription polymerase chain reaction and in situ hybridization analysis. The results showed that enJSRV and HYAL2 mRNAs were found to be expressed throughout gestation in the endometrium, chorion, placenta, and conceptus. The enJSRV mRNA was most abundant in the placenta on day 90 of pregnancy, in the endometrium on day 30 and 50, and in the chorion on day 70 and 110. However, HYAL2 mRNA was most abundant in the endometrium on day 30. These differences were all significantly different from each other （P〈0.01）. In situ hybridization showed that enJSRV and HYAL2 mRNAs were specifically expressed in endometrial luminal epithelium and glandular epithelium, trophoblastic giant binucleated cells （BNCs）, endometrial caruncles, placental cotyledons, stroma, trophectoderm, as well as multinucleated syncytia of the placenta and blood vessel endothelial cells. Collectively, little is known about the molecular mechanisms by which trophoblastic differentiation and multinucleated syncytia formation are regulated by enJSRVs. However, the temporal and spatial distributions of enJSRV expression in the uterus and conceptus indicate that differentiation of BNCs and the formation of a multinucleated syncytiotrophoblast involve enJSRV and possibly its cellular receptor, HYAL2. Therefore, enJSRV and HYAL2 appear to play important roles in the female reproductive physiology in this breed of sheep.

Effect of CD14/TLR4 antagonist on GnRH/LH secretion in ewe during central inflammation induced by intracerebroventricular administration of LPS

Background: Immune stress induced by lipopolysaccharide(LPS) influences the gonadotropin-releasing hormone(GnRH)/luteinizing hormone(LH) secretion. Presence of LPS interacting Toll-like receptor(TLR) 4 in the hypothalamus may enable the direct action of LPS on the GnRH/LH secretion. So, the aim of the study was to investigate the influence of intracerebroventricular(icv) injection of TLR4 antagonist on GnRH/LH secretion in anestrous ewes during LPS-induced central inflammation. Animals were divided into three groups icv-treated with: Ringer-Locke solution, LPS and TLR4 antagonist followed by LPS.Results: It was demonstrated that TLR4 antagonist reduced LPS-dependent suppression of GnRH gene expression in the preoptic area and in the medial basal hypothalamus, and suppression of receptor for GnRH gene expression in the anterior pituitary gland. It was also shown that TLR4 antagonist reduced suppression of LH release caused by icv injection of LPS. Central administration of LPS stimulated TLR4 gene expression in the medial basal hypothalamus.Conclusions: It was indicated that blockade of TLR4 prevents the inhibitory effect of centrally acting LPS on the GnRH/LH secretion. This suggests that some negative effects of bacterial infection on the hypothalamic-pituitary-gonadal axis activity at the hypothalamic level may be caused by central action of LPS acting through TLR4.

Effect of supplementation of allicin on methanogenesis and ruminal microbial flora in Dorper crossbred ewes

Background： Garlic extracts have been reported to be effective in reducing methanogenesis. Related mechanisms are not well illustrated, however, and most studies have been conducted in vitro. This study investigates the effects of supplementary allicin（AL） in sheep diet on in vivo digestibility, rumen fermentation, and shifts of microbial flora.Methods： Two experiments were conducted using Dorper × thin-tailed Han crossbred ewes. In experiment 1,eighteen ewes（60.0 ± 1.73 kg BW） were randomly assigned for 29 days to either of two dietary treatments： a basal diet or the basal diet supplemented with 2.0 g AL/head？day to investigate supplementary AL on nutrient digestibility and methane emissions. In experiment 2, six ewes（65.2 ± 2.0 kg BW） with ruminal canulas were assigned to the same two dietary treatments as in experiment 1 for 42 days to investigate supplementary AL on ruminal fermentation and microbial flora. The methane emissions were determined using an open-circuit respirometry system and microbial assessment was done by q PCR of 16 S r RNA genes.Results： Supplementary AL increased the apparent digestibility of organic matter（P 〈 0.001）, nitrogen（P = 0.006）,neutral detergent fiber（P 〈 0.001）, and acid detergent fiber（P = 0.002）. Fecal nitrogen output was reduced（P = 0.001）but urinary nitrogen output was unaffected（P = 0.691）, while nitrogen retention（P = 0.077） and nitrogen retention/nitrogen intake（P = 0.077） tended to increase. Supplementary AL decreased methane emissions scaled to metabolic bodyweight by 5.95 %（P = 0.007） and to digestible organic matter intake by 8.36 %（P = 0.009）. Ruminal p H was unaffected（P = 0.601） while ammonia decreased（P = 0.024） and total volatile fatty acids increased（P = 0.024） in response to supplementary AL. Supplementary AL decreased the population of methanogens（P = 0.001） and tended to decrease that of protozoans（P = 0.097）, but increased the populations of F. succinogenes（P 〈 0.001）, R. flavefaciens（P = 0.001）, and B. fibrisolvens（P = 0.001）.Conclusions： Supplementation of AL at 2.0 g/head？day effectively enhanced OM, N, NDF, and ADF digestibility and reduced daily methane emissions（L/kg BW0.75） in ewes, probably by decreasing the population of ruminal protozoans and methanogens.

Primary Establishment of EWE Model in Caohai Nature Reserve

According to environmental data,Ecopath with Ecosim (EWE) model can quantitatively describe the energy flow in the production and consumption of function components of system by using trophodynamics,and accurately assess the biomass and stable state of aquatic ecosystem.In the paper,the basic principle and parameters of EWE model were introduced firstly,and the relationship between Q/B (the important parameter of EWE model) and basic life indices of fish was discussed,then the current study and typical results of EWE model were analysed,finally the related parameters of EWE model in Caohai Nature Reserve were analysed.

Effect of Diet Supplementation with Combinations of Soybean and Linseed Oils on Milk Production and Fatty Acid Profile in Lactating Dairy Ewes

Thirty-six Pampinta ewes were used in a completely randomized design to examine the effectiveness of soybean (SO) and linseed (LO) oils to reduce the concentration of the atherogenic fatty acids (FA) of milk (C12:0 to C16:0) and increase the content of conjugated linoleic (cis-9, trans-11 C18:2) also called rumenic acid (RA) and vaccenic acids (trans-11C18:1, VA). Six ewes per treatment received a Control diet alone (71% alfalfa hay and 29% concentrate) or supplemented (0.24 kg/ewe·day) with pure oils (SO100 or LO100) or their blend at (%) SO75-LO25, SO50-LO50 and SO25-LO75. Milk yield, milk fat content and milk fat secretion were not affected. Milk protein content resulted higher in SO75-LO25, SO50-LO50 and SO25-LO75 without changes in milk protein yield. Total solid content of milk tended (p p p < 0.001) by oils reaching a minimum value of 1.89 in LO100. Feeding polyunsaturated oils at 7% of total dry matter (DM) intake did not affect the productive response of dairy ewes resulting in an effective tool to improve the healthy value of milk fat. The SO50-LO50 blend showed the highest number of healthy changes in milk FA composition.

Energy requirements of Dorper×thin-tailed Han crossbred ewes during non-pregnancy and lactation

This experiment was conducted to investigate the energy requirement of Dorper×thin-tailed Han crossbred ewes during non-pregnancy and lactation. Fifteen ewes after parturition were randomly assigned to three treatments： ad libitum（100%） feed intake and 80 or 60% ad libitum intake, and another nine non-pregnant ewes were assigned to a blank control group. Digestibility trials were performed in the non-pregnant ewes and in the lactating ewes on the 20 th, 50 th, and 80 th d of lactation. In parallel with the digestibility trial, a respirometry experiment was conducted to determine the methane and carbon dioxide production with an open-circuit respirometry system that was equipped with respiratory chambers. The net energy（NE） and metabolizable energy（ME） requirements for maintenance and growth were calculated using the carbon and nitrogen balance method. The results revealed that the carbon（C） and nitrogen（N） excretions and energy losses at faeces and urine, as well as the output of methane and CO2, increased significantly with decreasing feed intake（P〈0.01）. The apparent digestibilities of C in th e stages of non-pregnancy and early, middle and late lactation were 55.8–58.3%, 62.5–73.8%, 64.8–71.3%, and 61.7–65.0%, respectively, and the apparent digestibilities of N were 45.2–51.3%, 73.7–82.7%, 72.8–80.5%, and 73.6–76.5%, respectively. The corresponding energy apparent digestibilities were 52.0–56.3%, 60.7–76.6%, 61.0–68.8%, and 61.4–67.7%, respectively. The ME/DE（digestible energy） values were 79.5–85.9%, 79.4–83.5%, 81.0%–85.3% and 78.6–82.9%, respectively. The maintenance requirements of NE, ME, and the efficiencies of ME utilisation for maintenance during the stages of non-pregnancy and early, middle and late lactation were 215.5, 253.1, 247.7, and 244.7 k J kg^（–1） BW0.75 d, and 372.4, 327.1, 320.9, and 362.0 k J kg^（–1） BW0.75 d, and 0.58, 0.77, 0.77, and 0.68, respectively. The ME requirement for the growth of non-pregnant ewes was 31.3 MJ kg^（–1） BW gain.

Comparative analysis of proteomic profiles between endometrial caruncular and intercaruncular areas in ewes during the peri-implantation period

The endometrium of sheep consists of plenty of raised intercaruncular areas （IC）. In order to better understand aglandular areas called caruncular （C）, and intensely glandular the endometrium involved mechanisms of implantation, we used LC-MS/MS technique to profile the proteome of ovine endometrial C areas and IC areas separately during the peri-implantation period, and then compared the proteomic profiles between these two areas. We successfully detected 1740 and 1813 proteins in C areas and IC areas respectively. By comparing the proteome of these two areas, we found 170 differentially expressed proteins （DEPs） （P 〈 0.05）, functional bioinformatics analysis showed these DEPs were mainly involved in growth and remodeling of endometrial tissue, cell adhesion and protein transport, and so on Our study, for the first time, provided a proteomic reference for elucidating the differences between C and IC areas, as an integrated function unit respectively, during the peri-implantation period. The results could help us to better understand the implantation in the ewes. In addition, we established a relatively detailed protein database of ovine endometrium, which provide a unique reference for further studies.

Control of Ewe and Goat Cheeses Labelling on the Croatian Market

The aim of the research was to examine ewe and goat cheese labelling on the market of the Republic of Croatia. During the four years (2012-2016) of the research, 133 cheeses from retail supermarket chains were selected by the random-choice method by the responsible inspection of the Republic of Croatia and analysed at the Reference Laboratory for Milk and Dairy Products of the Department of Dairy Science at the Faculty of Agriculture University of Zagreb. To check the correct labelling of cheeses, the chemical composition of cheese was examined: the fat content, the dry matter content, the fat in dry matter content, and the water content in the fat-free cheese compound were calculated according to the Ordinance on Cheeses and Cheese Products, which refers to cheeses manufactured in the Republic of Croatia, and Regulation EU (2011) of the European Parliament and the Council on providing information to consumers about food products, which covers foreign cheeses. The presence of cow milk in cheeses labelled as products manufactured exclusively from ewe or goat milk was tested by the reference method using iso-electric focusing to determine any adulteration according to Commission Regulation (2008). The results of analysis in this research show the condition of the quality and correct labelling of ewe and goat cheeses on the market of the Republic of Croatia. Of the 133 cheeses analysed, 67 cheeses (50%) did not correspond to the values stated on the declaration or to legal regulations, while the presence of cow milk was found in 30% of the cheeses analysed. The research results indicate the need to carry out continuous systematic control in the interest of protecting consumers and those manufacturers who are following good manufacturing practices.

基于CiteSpace的EwE模型文献计量学与可视化分析

为探究EwE(Ecopath with Ecosim)模型的历史演变和应用现状,本文通过Web of Science主题检索和引文链接法获得1984—2020年间的研究文献构成核心数据集和扩展数据集,并以此为数据源,从论文分布、研究力量、研究主题、热点演化等方面进行科学文献计量分析,利用CiteSpace软件绘制相关图谱。结果表明:EwE模型的系列研究成果产出总体呈上升态势,且广泛分布于多学科交叉领域, Christensen、Walters、Pauly等学者在模型应用和国际合作中起到重要推动作用。过去,EwE模型通过建立功能组间的营养关系,主要用于解决生态系统结构和功能的时空变化、捕捞对生态系统影响等问题。当前,研究主题聚焦于海洋资源管理、生态系统模拟、海洋保护区、生态系统指标等重点群组。研究热点从模型开发和食物网结构向生态系统预测和资源管理研究演变,从而为基于生态系统的水域资源管理和海洋保护区建设等提供科学依据。

竺山湾湖泊缓冲带湿地生态系统EWE模型构建与分析

湖泊缓冲带在湖泊流域空间布局中具有特殊地位,缓冲带内的湿地对于保障流域生态健康和湖泊水环境质量具有十分重要的意义.本研究以太湖竺山湾湖泊缓冲带内的竺山湖湿地生态系统为研究对象,将生物组分划分为16个功能组,构建了生态通道(EWE)模型,并分析了生态系统的特征、状态以及功能组之间的相互关系.结果表明:竺山湖湿地生态系统的有效营养级范围在1~3.72,营养流动主要发生在前4个营养级,开始于沉水植物和有机碎屑的食物链较多.湿地生态系统的总的能量转换效率为5.1%,并未达到"1/10定律",说明当前的能量转换效率较低.物质流量在生态系统中的平均传输效率为4.3%.系统的总生产量为2496.66 t·km^(-2)·a^(-1),总流量为10145.2 t·km^(-2)·a^(-1).生态系统的多种特征参数表明当前生态系统处于幼态化阶段.

Okara as a protein supplement affects feed intake and milk composition of ewes and growth performance of lambs

Evaluating the feeding value of wet okara as a protein supplement for lactating ewes with twin lambs was the objective. A 4 x 4 Latin square replicated 2 x(4 sheep, 4 treatments, 4 periods per square; 2 squares) was conducted to examine the influence of concentrate mix(okara or not) and type of forage(silage or hay) on ewe milk composition and growth of their lactating lambs. Treatment periods were 14 days(7 days adaptation and 7 days collection). Ewes(55 to 74.8 kg BW) were fed 1 of 4 diets: wheat middling and corn concentrate with mixed grass hay(TSH), okara and corn with mixed grass hay(OSH),soybean and wheat middlings with hay crop silage(TSS), and okara and corn with hay crop silage(OSS).Ewes fed hay diets had lower forage dry matter intakes than ewes fed silage. Intake of okara supplement was higher(P < 0.05) with OSH(3.64 kg/d) than with OSS(1.70 kg/d). There was no difference in supplement intake between TSH and TSS. There were no differences among diets for lamb daily gains or in ewe milk compositions among the diets. Okara is an effective source of protein for lactating ewes and their twin lambs.

Dystocia due to schistosomus reflexus(cojoined twins)in a Yankassa ewe

A two years'old,white and brown Yankassa ewe,weighing 20 kg was presented with dystocia of about 48 h duration at Mabs Veterinary Centre Ltd,Lagos.On thorough physical and vaginal examination,there were evidences of feotal parts and foul smelling discharges per vagina.A systematic and calculated traction and retropulsion revealed schistosomus reflexus cojoined twins.There was a complete recovery of the ewe 3 days post operative management.Finally,this case reported a true schistosomus reflexus cojoined twins in Yankassa ewe which was successfully relieved through traction and retropulsion despite the supposedly small birth canal which precluded the procedure in ewes except for caesarian section or fetotomy.