林麝放牧区野生饲用植物叶营养成分的综合分析

在测定林麝（Moschus berezovskii）喜食野生植物叶的常规养分及矿物质元素的基础上,利用简单线性相关、营养类型及聚类分析,对植物叶成分含量进行了综合分析与归类,以期明析24种野生植物叶的养分含量特点和营养类别,为林麝日粮中青粗料的合理搭配及饲草资源的开发提供参考依据。结果表明,24种植物叶粗纤维(CF)含量均能满足林麝需要;粗蛋白(CP)含量仅构树（Broussonetia papyrifera）、葎草（Humulus scandens）及野桑（Morus alba）能满足其需要;钙含量均超过需要;磷含量部分超过需要;杜仲（Eucommia ulmoides）、苦木（Picrasma quassiodes）、葎草（Humulus scandens）及木姜子（Litsea pungens）等的钙磷比低于7.00,铁、锰含量超过林麝营养需求,铜、锌不足;灰分（Ash）与CP呈显著正相关（P＜0.05）,Ash与无氮浸出物（NEF）呈极显著负相关(P＜0.01）, CF与NEF呈显著负相关（P＜0.05), CP与NEF呈极显著负相关(P＜0.01）;金钱槭（Dipteronia sinensis）、野桑、木姜子C/N均小于3.75,属于N型,葛萝槭（Acer grosseri）C/N为7.27,属于C N型,蛇葡萄、构树、葎草属于灰分 N型,金银忍冬（Lonicera maackii）、铁箍散（Schisandra propinqua var. sinensis）、丛花南蛇藤（Celastrus rosthornianus var.loeseneri）属于NC 灰分型,其余属于N C型;按常规养分含量可将植物叶分为6类,按矿物质元素含量可将植物叶分为7类。     

大力推广方格蔟,提高蚕茧质量

本文在总结湖州雠主格蔟成绩的基础上,针对当前在方格蔟推广上存在的问题,提出了大力推广方格蔟,提高茧质的建议。     

Characterization of porcine circovirus type 2 (PCV2) infection in swine lymphocytes using mitogen-stimulated peripheral blood lymphocytes from healthy PCV2-carrier pigs

Information regarding the susceptibility of swine lymphocytes to PCV2 is rather limited. To further explore and characterize the PCV2 infection in swine lymphocytes, an in vitro model using concanavalin A (Con A)-stimulated peripheral blood lymphocytes (PBLs) obtained from clinically healthy PCV2-carrier pigs was introduced. It was found that the PCV2 antigen-containing rate was below 2% in PBLs from healthy PCV2-free pigs following treated simultaneously with Con A and PCV2. However, significantly higher PCV2 antigen- and nucleic acid-containing rates could be seen in Con A-stimulated PBLs from clinically healthy PCV2-carrier pigs. Prior to Con A treatment, both of the PCV2 antigen- and nucleic acid-containing rates in PBLs from healthy PCV2-carrier pigs were less than 1%; however, they reached 22.1+/-5.7% by flow cytometry and 27.1+/-6.5% by in situ hybridization, respectively, at 4-day post-incubation with Con A. Phenotyping of PCV2 antigen-containing cells revealed that PCV2-positive cells could be detected in both T and B lymphocyte populations within which IgM-positive B lymphocytes appeared to have a relatively higher positive rate. The Con A-stimulated PBLs also displayed a significantly higher viral load by the measurement of either PCV2 DNA copy number or viral titer when compared with the non-treated PBLs from healthy PCV2-carrier pigs. The results indicate that PBLs, especially IgM-bearing B lymphocytes, are indeed susceptible to PCV2 infection and PCV2 is capable of replicating in dividing lymphocytes. This activation-induced replication may explain in part the pathogenesis of lymphoid depletion in PMWS-affected pigs.     

湖羊胚胎和精液超低温保存效果的评价

【目的】 检验长期保存在国家家畜基因库的湖羊冷冻胚胎和冷冻精液的质量,评价超低温冷冻保存技术保种的效果。【方法】 对保存于国家家畜基因库的冷冻胚胎（保存20年）和冷冻精液（保存20和30年）进行复苏,进行相应鉴定后分别进行胚胎移植和人工授精,同时以0年冷冻精液和新鲜精液为对照,测定其受胎率和后代的羔皮性能、生长性能及繁殖性能,检验保存效果。【结果】 本试验共解冻胚胎36枚,其中,A级胚胎22枚,B级胚胎7枚,C级胚胎5枚,D级胚胎2枚,冷冻胚胎复苏利用率达到94.44%（34/36）,A级胚胎率达到61.11%（22/36）,移植34枚,产羔17只,冷冻胚胎复苏移植产羔率达50.00%;保存30年的冷冻精液复苏后平均精子活力达35%,受胎率为58.57%,平均产羔1.90只;保存20年冷冻精液复苏后平均精子活力达31%,受胎率为53.66%,平均产羔1.95只;胚胎复苏移植羊、30和20年冷冻精液后代体型外貌鉴定均符合纯种湖羊特征,没有畸形个体;羔羊一级羔皮率分别是31.25%、42.03%和23.81%,保持了当年湖羊的羔皮特性;生长发育及繁殖性能与现有湖羊群体性能基本保持一致。【结论】 利用超低温冷冻技术长期保存湖羊冷冻胚胎和冷冻精液的方法是可行的,对地方品种保种具有重要意义。     

冬油菜茬后复种青贮玉米品种比较

为了开辟饲料生产新途径,在冬油菜（Brassica napus）茬后复种青贮玉米（Zea mays）,开展品种筛选试验。对9个参试品种生育期、植株形状、产草量等指标的调查和测定,结果表明,饲粮2号和文玉5号属中熟品种,茎秆最粗,且饲粮2号鲜草产量最高,为79 303.7 kg·hm-2,其干物质为18 855.9 kg·hm-2;文玉5号鲜草产量次之,其干物质产量最高,为20 127.6 kg·hm-2。综合分析认为,饲粮2号和文玉5号具有较高的生物产量,适于在当地冬油菜茬后复种推广种植。     

Novel avian orthoavulavirus 13 in wild migratory waterfowl: biological and genetic considerations

Avian orthoavulavirus 13 (AOAV-13), formerly known as Avian paramyxovirus 13 (APMV-13), is found scatteredly in wild birds around the world. Although four complete genome sequences of AOAV-13 had been identified since the first discovery in Japan in 2003, the information available on the genetic variation and biological characteristics of AOAV-13 is still limited. In the present study, we isolated six AOAV-13 strains from fecal samples of wild migratory waterfowls during annual (2014–2018) viral surveillance of wild bird populations from wetland and domestic poultry of live bird markets (LBMs) in China. The phylogenetic analyses based on the HN and F genes showed that they had very close relationship and the molecular clock estimations showed a low evolutionary rate of AOAV-13. However, Bean goose/Hubei/V97–1/2015 is 1953 nt in size (ORF, 1, 776 nt), which is a unique size and longer than other reported AOAV-13 strains. Additionally, four repeats of conserved sequences “AAAAAT” was presented in the 5′-end trailer region of Swan goose/Hubei/VI49–1/2016, which is unprecedented in the AOAV-13. These findings highlight the importance of continuous monitoring the specific species of APMVs.

     

梅山猪与杜洛克猪中等卵泡差异表达基因的鉴定

本试验采用抑制性消减杂交技术构建了卵泡期第4天梅山猪和杜洛克猪中等卵泡M2组织差异表达的消减cDNA文库,从中筛选差异表达的基因,并通过实时荧光定量PCR对其进行验证,利用DAVID软件对差异表达的基因进行聚类分析。结果表明,从梅山猪和杜洛克猪M2卵泡消减文库中筛选得到了148和75个差异表达的ESTs,分别含有125和60个已知的基因。实时荧光定量PCR验证结果与筛选结果相符。GO功能分类注释到调控代谢、细胞循环、生物合成、胞内转运、类固醇雌激素受体和刺激等生物学过程。KEGG Pathway分析表明有6个基因参与TGF-beta信号通路,5个基因参与卵母细胞减数分裂信号通路,7个基因参与类固醇雌激素受体信号通路,推测TGF-beta信号通路中的基因可能调控猪卵泡的发育。研究结果为深入探讨卵泡发育机理和对繁殖性状影响的遗传机理奠定了基础。     

乙酸镁对氟烷基因杂合子育肥猪肌肉加工品质的影响

育肥猪屠宰前饲粮中短期添加乙酸镁,研究其对氟烷基因杂合子育肥猪肌肉加工品质的影响。选用体重相近的氟烷基因杂合子(HalNHaln)大长猪(大白猪×长白猪)36头随机分为2组,即对照组、乙酸镁组,每组18头。乙酸镁组在屠宰前5 d,基础日粮中添加镁1 500mg/kg(以乙酸镁形式),对照组饲喂基础日粮。试验表明:在猪屠宰前饲粮中短期添加1 500 mg/kg水平的镁对试验猪的平均日采食量没有明显影响(P>0.05);可以显著降低肌肉的滴水损失(P<0.05),提高猪肉的熟肉率,从而提高猪肉的加工品质。