Influence of recombinant duck follistatin protein on embryonic muscle development and gene expressions

Follistatin (FST) acts as a positive regulator of muscle development by inhibiting the activities and expression of myostatin. The recombinant duck FST protein was injected into hatching eggs and was also added to the medium of duck myoblast to study its role on duck embryonic muscle development and gene expressions. Duck embryo weight increased 3.49% (p > 0.05) in FST treatment group as compared with control group, but minor effects were found on leg or breast muscle weights of ducklings at 2 days post‐hatching (p > 0.05). Relative expression of Pax7 was upregulated in both leg and breast muscle tissues (p < 0.05), while MyoD was only upregulated in leg muscle (p < 0.05), and Myf5 was only upregulated in breast muscle (p < 0.05). Relative expression of myostatin was downregulated in both muscle tissues researched (p < 0.05). In vitro studies also showed some maker genes relevant to protein synthesis and degradation, cells’ proliferation and differentiation had significant changes in myoblasts after treated with FST. These results suggested that in ovo feeding of recombinant FST protein to duck hatching eggs had an effect on duck embryo development but have less roles on the duck embryonic muscle development.     

检测鸭呼肠孤病毒抗体间接ELISA方法的建立

RT—PCR扩增鸭呼肠孤病毒（Duckreovirus,DRV）的dB基因,克隆到pET-32a（＋）表达载体,再转化大肠杆菌Transetta（DE3）;含有重组质粒pET—σB的大肠杆菌经IPTG诱导,获得大小为55000的以包涵体形式表达的σB重组蛋白。Westernblotting显示,σB重组蛋白能够与兔抗DRV多抗血清特异性结合。以高亲和NI—NTA树脂在变性条件下纯化、梯度尿素复性的σB重组蛋白为包被抗原,建立了检测DRV抗体的间接ELSIA方法。分别以间接ELSIA方法和血清中和试验对DRV感染鸭血清和SPF鸭血清进行检测,两者的符合率为100％。该间接ELSIA方法对鸭瘟病毒、鸭病毒性肝炎病毒和禽流感病毒阳性血清均无交叉反应。     

赤麻鸭（Tadorna ferruginea）的人工孵化初探

2011年4—5月,对徐州金桥禽业发展有限公司养殖的赤麻鸭所产的44枚卵进行了人工孵化研究。其中43枚卵受精,出雏35枚,4枚在孵化中期死胚,5枚为27d落盘后啄壳困难而死亡,受精卵的孵化率为81．40％。孵化温度前期为38．5℃;中期为38．2℃;后期为37．8℃,落盘后温度降为37．5℃。赤麻鸭卵鲜重为（79．80±6．72）g,长径为（66．10±2．53）mnq,短径为（46．40±1．45）／mm,卵形指数为1．43±0．06,出雏后的卵壳等剩余物质重（12．60±1．07）g,新生雏鸟重占鲜卵重的（67．20±3．71）％。卵总失重率为17％。孵化期间的卵重（Y）与孵化天数（x）之间的线性方程为Y=一0．9071x＋81．019（R2=0．9997,P〈0．01）,根据卵失重方程可以比较准确地推算出赤麻鸭卵的孵化天数。     

中华绒螯蟹养殖期间细菌性疾病流行情况调查研究

1999~2004年对安徽省巢湖市6个乡镇的池塘、稻田养殖的中华绒螯蟹(Eriocheir sinensis)的细菌性疾病流行情况进行了调查研究。结果表明:中华绒螯蟹细菌性疾病发生与流行存在着季节性,其发病率年平均依次为47.3%、59.6%、51.9%、46.7%、60.0%、29.9%,逐月比较发病率最大峰值出现在每年的8月份;感染率年平均分别为66.6%、75.8%、57.8%、52.0%、86.0%、39.3%,死亡率年平均依次为38.3%、44.6%、36.3%、29.6%、43.5%、21.6%;中华绒螯蟹细菌性疾病发病率与出现的最高气温、最低气温以及气温、水温持续偏高呈正相关(r=0.7657、r=0.7385、r=0.7237,P<0.01)。     

不同羽色和性别番鸭屠宰性能及肌肉成分比较研究

研究旨在比较不同羽色及性别番鸭在屠宰性能及肌肉成分上的差别,为选育优良番鸭品种提供依据。试验选取1日龄黑羽番鸭、白羽番鸭及黑白花番鸭公、母共324羽,按羽色、性别分为6个处理,每处理设6个重复,每重复9只鸭,各处理饲喂相同日粮,试验期90d。结果表明：雄性黑羽番鸭屠宰率、全净膛率显著高于雄性白羽及黑白花羽番鸭（P〈0．05）,而雌性黑白花番鸭及白羽番鸭的胸肌率和瘦肉率相近且均显著高于雌性黑羽番鸭（P〈0．05）;各处理番鸭肌肉中汞、镉、砷、铅含量无显著差异（P〉0．05）,且均很微量;各同羽色雄性番鸭肌肉水分、无氮浸出物和粗蛋白质含量均基本略高于其同羽色雌性番鸭,而各处理雌性番鸭肌肉粗脂肪、粗灰分含量则高于其同羽色的雄性番鸭;雄性白羽番鸭和黑白花番鸭肌肉粗蛋白质含量相近且均显著高于雄性黑羽番鸭（P〈0．05）;各同羽色番鸭中基本上肌肉氨基酸含量均以雄性高于雌性,而同性别的番鸭比较,雄性白羽番鸭肌肉中多种氨基酸的含量显著高于雄性黑羽及雄性黑白花羽番鸭（P〉0．05）;同时雌性各羽色番鸭肌肉中多种氨基酸含量呈现出：黑白花番鸭〉黑羽番鸭〉白羽番鸭,但该趋势不显著（P〉0．05）。试验结果表明,雄性黑羽番鸭屠宰性能有一定优势,白羽番鸭肌肉养分和氨基酸含量优势明显。     

新型鸭呼肠孤病毒RT-PCR检测方法建立与初步应用

为建立一种能够快速检测新型鸭呼肠孤病毒（NDRV）的方法,本研究参考GenBank上登录的NDRV S3基因保守序列设计特异性引物.经条件优化后,建立了检测NDRV的RT-PCR方法.对其特异性、敏感性和重复性进行检验.结果显示：该方法仅能从NDRV分离毒中扩增到与预期大小相符,长度为298 bp的特异性目的片段,检测灵敏度达到83.4 pg病毒RNA;而其它病毒：番鸭呼肠孤病毒、禽呼肠孤病毒、鸭病毒性肝炎病毒、鸭瘟病毒、鸭新城疫病毒和禽流感病毒等样品的扩增结果均为阴性.采用该方法对在广东不同地区采集的15份鸭病料样品进行检测,NDRV阳性率为53.33％.表明建立的RT-PCR方法特异性强、敏感度高,可用于NDRV的临床诊断和流行病学调查.     

饲粮代谢能和粗蛋白质水平对蛋鸭产蛋性能的影响

本试验旨在研究饲粮代谢能(ME)和粗蛋白质(CP)水平对蛋鸭产蛋期不同阶段产蛋性能的影响。采用3×3两因子完全随机试验设计,ME水平分别为10.88、10.46和10.04 MJ/kg,CP水平分别为18.26%、17.07%和16.42%,选取刚开产的福建龙岩麻鸭1 674羽,随机分为9个组,每组6个重复,每个重复31羽。试验共持续32周。结果表明:1)产蛋初期(16~18周龄),饲粮ME和CP水平均未显著影响蛋鸭产蛋率、平均蛋重、日产蛋重和料蛋比(P>0.05)。饲粮ME和CP水平对蛋鸭平均蛋重有显著的交互作用(P<0.05)。2)产蛋高峰期(19~39周龄),饲粮ME水平显著影响蛋鸭平均蛋重(P<0.05)。饲粮ME水平为10.88和10.46 MJ/kg组的平均蛋重显著高于10.04 MJ/kg组(P<0.05)。饲粮CP水平未显著影响蛋鸭产蛋率、平均蛋重、日产蛋重和料蛋比(P>0.05)。饲粮ME和CP水平对蛋鸭产蛋率、平均蛋重、日产蛋重和料蛋比没有显著的交互作用(P>0.05)。3)产蛋后期(40~47周龄),饲粮ME水平为10.46 MJ/kg组的产蛋率和日产蛋重显著高于10.04 MJ/kg组(P<0.05);10.88 MJ/kg组的平均蛋重显著高于10.46和10.04 MJ/kg组(P<0.05)。饲粮CP水平为18.26%组的产蛋率、日产蛋重显著高于17.07%和16.42%组(P<0.05),料蛋比显著低于17.07%和16.42%组(P<0.05)。饲粮ME和CP水平对蛋鸭日产蛋重有显著的交互作用(P<0.05)。综合考虑产蛋性能指标,产蛋初期、高峰期和后期龙岩麻鸭饲粮适宜的ME和CP水平分别为10.88、10.46、10.46 MJ/kg和17.07%、17.07%、18.26%,每日ME和CP需要量分别为1.47、1.60、1.48 MJ和22.96、26.16、25.81 g,饲粮的蛋能比分别为15.62、16.35、17.44 g/MJ。     

Analysis of the Genetic Diversity and Origin of Some Chinese Domestic Duck Breeds

Twelve fluorescence-labeled microsatellite markers were used to analyze the genetic diversity of 12 domestic duck breeds and 2 wild duck breeds to determine the relationship and origin of Chinese domestic duck breeds. Gene frequency, effective number of alleles （Ne）, expected heterozygosity （He）, polymorphism information contents （PIC）, inbreeding coefficient in population （Fis）, standard genetic distance （Ds）, and genetic distance （DA） were calculated by FSTAT and distance and phylogenetic analysis after the dates which were output from the Microsatellite-Toolkit software. Genetic distances between 12 domestic duck breeds and 2 wild duck breeds were analyzed by variance analysis. Unweighted pair group method with arithmetic mean （UPGMA） and phylogenetic trees used for cluster analysis were structured. The results indicated that 11 loci had medium- or high-level genetic diversity among the 12 loci, which could be efficiently used in the detection of the genetic parameters of each population. The values of He were 0.5414 to 0.7343, those of PIC proved similar, and those of Fis were 0.1101 to 0.3381 among all populations. All breeds were clustered into three groups by UPGMA phylogenetic trees. Banzui duck was clustered into a separate group. Differences of the DA were analysed by t-test. The results showed that difference in DA between the 12 domestic duck breeds and Lvtou duck and the Banzui duck were very significant （P〈0.01）, indicating that these 12 domestic duck breeds originated from Lvtou wild duck, but not Banzui duck.     

鸭多巴胺受体D1基因CDS区多态性与生长性状的关联性分析简

本研究采用PCR-SSCP法与DNA直接测序技术相结合对兴义鸭和樱桃谷鸭多巴胺受体D1 (dopamine receptor D1,DRD1)基因编码序列(coding sequence,CDS)区130－587 bp区域的多态性进行检测,并分析其多态性对樱桃谷鸭生长性状的影响。结果表明,在樱桃谷鸭和兴义鸭DRD1基因编码区130－587 bp区域内均检测到3种基因型：AA、BB和AB,2个等位基因：A和B;AA基因型均为优势基因型,频率分别为0.7416和0.5643,等位基因A均为优势等位基因,频率分别是0.8539和0.7204;多态信息含量分别为0.2184和0.3217,分别处于低度多态和中度多态位点,樱桃谷鸭群体中该座位基因型分布处于Hardy-Weinberg平衡（P>0.05）,兴义鸭群体则偏离了Hardy-Weinberg平衡（P<0.05）;序列比对发现2个SNPs位点,其中c.189 T＞C为同义突变,c.507 T＞A为错义突变,导致丝氨酸（S）变成精氨酸（R）。关联分析结果显示,BB基因型樱桃谷鸭个体的8周龄重和12周龄体斜长显著高于AB基因型（P<0.05）,10周龄重、12周龄重和12周龄胸深显著高于AA和AB基因型（P<0.05）。研究结果揭示该多态座位可能是影响鸭生长性状的一个标记辅助选择位点。     

Association Analysis between Differences of GnRHR-Ⅱ Gene Expression with Reproduction Traits Heterosis in Duck Populations

The objective of this study was to clone the sequence of duck type Ⅱ gonadotropin releasing hormone receptor (GnRHR-Ⅱ) gene, and to analyze the association of its expression levels with reproduction trait heterosis. RT-PCR method was used to clone GnRHR-Ⅱ gene fragments, and the expression levels during early laying days and laying fastigium period in Gaoyou duck, Jinding duck and crossed populations were tested by Real-time PCR method. Sequencing and homology analysis showed that the cloned duck GnRHR cDNA was about 500 bp in length, and it belonged to the avian type Ⅱ GnRHR isoforms. It was 96% identical to the cGnRHR-Ⅱ sequence reported in domestic chicken. From the early laying days to laying fastigium period, expression levels of GnRHR-Ⅱ gene in pituitary increased for Jinding duck, Gaoyou duck and crossed populations, with the highest expression levels in Jinding×Gaoyou hybrid group (P<0.01) . The expression levels of GnRHR-Ⅱ gene in hypothalamus also increased for Jinding duck, Gaoyou duck, however, it decreased in two crossed populations. The expression levels of GnRHR-Ⅱ gene in ovary were significantly higher for Jinding duck and two crossed populations than Gaoyou duck (P<0.01), but it decreased during laying fastigium period. Compared to Jinding duck and Gaoyou duck breeds, the two crossed populations had positive heterosis in 42-week production and 42-week egg fertilization percent, and negative heterosis in the first laying age and 42-week fertilized egg hatching rate traits. It suggested that the short-lived higher expression of ovary GnRHR-Ⅱ gene before early laying days be correlated with heterosis of the first laying age and 42-week production traits, and its higher expression levels in pituitary could aid to keep laying fastigium.