3种优势牧草在不同生育期对干旱胁迫的响应

选择松嫩草地上的3种优势牧草羊草(Leymus chinensis)、碱蒿(Artemisia anethifolia)和全叶马兰(Kalimeris integrifolia) ,通过野外干旱胁迫试验、定点实时观测和隶属函数法,研究3种优势牧草在不同生育期内对不同等级干旱胁迫的响应,探究不同等级干旱胁迫对牧草在不同生育期内形态特性的影响及其抗旱能力。结果表明：在牧草同一生育期内,随干旱胁迫程度加剧,株高、叶长、叶绿素含量和产量受到的影响越大,在特旱程度下,3种牧草生长受干旱胁迫影响最严重;同一干旱胁迫处理下,随着生育期推移,株高、叶长、叶绿素含量和产量受干旱胁迫的影响总体呈减少趋势。3种牧草在其生育期内的抗旱性呈现出一定的规律性,羊草在开花期抗旱能力最强,其次是在返青期;全叶马兰在开花期抗旱能力最强,其次是在返青期,在抽穗期最差;碱蒿在开花期抗旱能力最强,其次是在抽穗期,在返青期最差。本研究结果对松嫩草地3种优势草种在不同生育期内遭受不同程度干旱胁迫时采取不同应急方案具有指导作用,也为培育优良耐旱草种及草地生态系统可持续发展提供了一定的参考。     

氮、磷添加对青藏高寒草甸土壤碳氮磷化学计量特征影响的Meta分析

为了解青藏高原高寒草甸土壤碳(Carbon,C)、氮(Nitrogen,N)、磷(Phosphorus,P)化学计量特征对氮、磷添加的响应,提高养分管理水平及草地生态系统的养分平衡。本研究严格筛选出21篇文章(612项数据)进行Meta分析,通过亚组分析分析了不同施肥方式(氮添加、磷添加、氮磷添加)、不同施肥强度(轻度、中度、重度)对青藏高原草地土壤C,N,P化学计量特征的影响。研究结果表明：养分添加显著增加了青藏高原草地土壤C,N,P含量;氮添加对土壤的增加效应随施肥强度增加而增加,磷轻度施肥(20g·m^-2以下)处理、氮磷添加轻度施肥处理下的土壤C,N,P含量及化学计量比增加效果最好。本研究结果总体反映出氮、磷添加对青藏高原高寒草甸土壤产生积极影响,研究结果可为青藏高原草地生态系统的保护提供科学依据。     

山东小尾寒羊研究概况

介绍了山东小尾寒羊的研究概况 ,主要内容包括该品种的繁殖性能、屠宰性能、杂交利用等方面的最新研究成果 ,比较全面地阐述了山东小尾寒羊的种质特性。     

Etiological Investigation of Diarrhea in Newborn Piglets and Molecular Characterization and Genetic Variation Analysis of ORF3 Gene of PEDV in North Guangdong

In order to understand the main pathogen of newborn piglets diarrhea in North Guangdong region, 31 diarrhea samples were collected from six pig farms in North Guangdong, the pathogen of porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV) and porcine rotavirus (PoRV) were detected by Real-time RT-PCR, meanwhile, ORF3 gene of PEDV amplified from positive samples were sequenced and analyzed. Pathogen detection results showed that 83.87%(26/31) samples were positive for PEDV, all herds and samples were negative for TGEV and PoRV. The sequence analysis revealed that the ORF3 gene of 5 epidemic strains of PEDV were all 675 bp, homologies of nucleotides were 98.7% to 100.0%, and homologies with reference sequences of nucleotides were 94.5% to 100.0%, and some gene mutation in common nucleotides site. The results of gene phylogenetic trees showed that PEDV could be divided into two groups, PEDV genetic relationship between field strains in North Guangdong and some regions in China, Southeast Asia, North America, Europe from 2013 to 2015 was closer, classed as a gene subgroup, from 2011 to 2012 main epidemic strains in our country and vaccine strains classed as other two gene subgroups. These results indicated that PEDV infection was the main pathogen of newborn piglets diarrhea in North Guangdong region, as time passed, the PEDV epidemic strains gene presented a tendency of evolution and variation.     

内蒙古红豆草黄萎病菌的分离鉴定及其生物学特性

依照柯赫氏法则,利用形态学结合分子生物学的方法首次对内蒙古自治区呼和浩特市中国农科院草原研究所沙尔沁基地红豆草疑似黄萎病的病样进行分离和鉴定,利用蘸根接种法对病原菌的致病性进行测定.同时,首次在室内条件下对病菌的生物学特性,如生长最适温度、酸碱度以及碳源、氮源对病原菌生长速率和产孢量的影响进行了研究.结果表明,引起沙尔...     

紧实度对青贮玉米有氧稳定期发酵品质、微生物数量的效应研究

本研究旨在分析不同紧实度对全株玉米青贮有氧暴露期间发酵品质和微生物变化的影响,为生产实践选择适宜的青贮紧实度提供参考。以新饲玉10号青贮玉米为材料,发酵装料密度设计为5个梯度(350,400,500,600,700 kg/m³),发酵期为50 d,检测开窖后各紧实度处理第12,24,36,60,108 h青贮发酵品质和主要微生物的变化,并用多通道温度记录仪监测温度变化。结果表明,有氧暴露时间与紧实度的交互作用对pH、乳酸、乙酸和氨态氮含量以及乳酸菌、霉菌、酵母菌和好氧细菌数量产生极显著影响(P<0.01)。开窖108 h后,紧实度为600 kg/m³青贮饲料的乳酸菌数量最多,达到8.17 lg cfu/g FW,其pH值和氨态氮含量最低,霉菌和酵母菌数量最少,分别为5.38和7.72 lg cfu/g FW;且紧实度600 kg/m³有氧暴露后稳定的时间显著高于其他处理(P<0.05),达到100 h。通过综合评价,在有氧暴露后紧实度为600 kg/m³的全株玉米青贮发酵品质及有氧稳定性最好,建议600 kg/m³为全株玉米最佳青贮紧实度。     

Carob pods (Ceratonia siliqua L.) improve growth performance,antioxidant status and caecal characteristics in growing rabbits

The objective of this study was to evaluate carob pods and their effect on growth performance, antioxidant activities, carcass and caecal characteristics and equilibrium modification of the caecal microbiota population of growing NZW rabbits. Eighty weaned rabbits (initial body weight: 625.00 ± 26.46 g) were randomly allocated into four dietary groups of 20 rabbits each until 90 days of age. Dietary groups were as follows: C (basal diet with no supplementation), CP1 (basal diet + 2.5% carob pods), CP2 (basal diet + 5% carob pods) and CP3 (basal diet + 10% carob pods). Rabbits given the CP2 diet had significantly higher daily and final body weights compared with the other experimental groups. The increase in inclusion rate of carob pods significantly decreased feed intake, whereas carob pods at 5% in the CP2 group recorded the best value of feed conversion ratio. Rabbits in the CP3 group showed the worst slaughter weight and carcass dressing percentage weight. No significant effect was found on meat protein and ash contents. Cholesterol, low‐density lipoprotein, high‐density lipoprotein and triglycerides decreased significantly (p < 0.05) in rabbits treated with carob pods compared with the control. Because of high content of the antioxidant compounds in CP2 and CP3 groups, the activities of glutathione peroxidase, glutathione S‐transferase, catalase and superoxide dismutase increased, whereas the concentration of thiobarbituric acid‐reactive substance decreased significantly. Rabbits given the CP2 diet had a significantly higher volatile fatty acid concentration and a lower pH in content of the caecum compared to the other groups. The data of microbial analysis for C group showed a significant increase in Escherichia coli and Clostridium counts. Lactobacillus and Bacillus counts increased significantly more in the CP2 and CP3 groups than in the other groups. In conclusion, 5% of carob pods in the diet stimulated the performance of growing rabbits, and thus, it has potential as an unconventional feed resource for rabbits without any adverse effects.     

Effects of Exogenous Glycine Betaine on the Physiological Characteristics in Medicago sativa Seedlings under Low-temperature Stress北大核心CSCD

In this study,the 'Ganong 5th' alfalfa (Medicago sativa L.) was used as experimental material,and two application methods (leaf application,root application) and six exogenous betaine concentrations (0,10,20,30,40 and 50 mmol·L-1) were used to treat the seedlings of alfalfa. Plant growth and related physiological indexes were measured after 7 days of low temperature (4?) stress,and the physiological mechanism of exogenous betaine to alleviate the low temperature stress of alfalfa was explored. The results showed that exogenous GB alleviated the loss of plant height,root length,leaf dry weight,root dry weight and chlorophyll content,and increase the content of soluble sugar (SS) and free proline (Pro),and reduced the increase in leaf relative membrane permeability and MDA content. Exogenous GB increased antioxidant enzyme activities and non-enzymatic antioxidant content. And also,exogenous GB enhanced the osmotic adjustment capacity of the plant by increasing endogenous GB accumulation and BADH activity. These results indicated that exogenous GB enhanced the resistance of Medicago sativa to low-temperature stress under low temperature adjustment. The membership function analysis indicated that spraying 30 mmol·L-1 GB on the leaves and spraying 40 mmol·L-1 GB on the roots had the best effect on alleviating the low-temperature stress of alfalfa seedlings. © 2019 Ｊｏｕｒｎａｌ ｏｆ Ｒｅｆｒｉｇｅｒａｔｉｏｎ. All rights reserved.     

猪两种腹泻病毒混合感染的病原诊断

对我省流行的疑似猪病毒性腹泻进行了病原诊断，通过细菌培养、ＲＮＡ电泳和电镜形态观察等辅助诊断和免疫萤光特异性诊断，确诊该病病原为猪传染性胃肠炎病毒（ＴＧＥＶ）与猪流行性腹泻病毒（ＰＥＤＶ）的混合感染，混合毒代号为ＴＰＶ３。     

Tick-borne encephalitis epidemic in Hungary 1951–2021: The story and lessons learned

The authors analysed epidemiological data of the Hungarian tick-borne encephalitis epidemic from the past seven decades. A total of 911 meningitis serosa cases were described from 1930-1950 s by local hospital physicians, indicating that the virus had been present in the country decades before its official identification in 1952. The virus spread freely in the 1950s–1960s, occupying almost all habitats where ticks occurred in large numbers. The increasing number of cases drove authorities to classify this illness as a notifiable disease in 1977 and to organize the first measures to stop the epidemic. Statistical analysis revealed that the large-scale vaccination launched from the 1990s was responsible for the sharp decrease in the number of human cases from 1997. A significant negative correlation was found between the number of vaccine doses sold and human cases 6 years later. The TBEV endemic area covers 16.57% of the territory and 16.65% of the population of the country. In the last 10 years, 186,000 vaccine doses/year in average were enough to keep the incidence of human TBEV infections between 0.45 and 0.06/100,000 persons. A 20-year-long study found evidence for easing clinical signs in TBEV-infected hospitalized patients. Statistics found a sharp decrease in the number of samples sent for TBEV diagnosis after 1989. Male dominance of patients was characteristic of the epidemics since the 1940s, but now analysis of detailed data from the 1981–2021 period (60.5%–87.5%) proved the statistical significance of this dominance. Obviously, the voluntary vaccination programme was the tool which broke the spread of the epidemic. Widespread public awareness of the disease and the tick vector, probable evolutionary spread of less pathogenic virus strains supplemented with the vaccination campaign led to a negligible level of human TBE cases in Hungary in the last years.