Essential amino acids supplementation to practical diets affects growth,feed utilization and glucose metabolism‐related signalling molecules of blunt snout bream (Megalobrama amblycephala)

Six diets were formulated to investigate the success of fish meal (FM) replacement by plant proteins; diet 1 reflected a commercial feed (8% FM), diet 3 contained 4% FM, and diet 5 was devoid of FM. Whereas, diet 2, diet 4, and diet 6 reflected diet 1, diet 3, diet 5, respectively, and supplemented with essential amino acid (EAA). At the end of 8‐week trial, there was no significant difference in survival rate. Significantly higher final weight, weight gain rate, and specific growth rate were recorded in the group fed diet 2 compared with the other treatments (except diet 4) (p < 0.05). Feed conversion ratio of fish fed diet 2 was significantly lower than those fed diets 1, 3, and 5 (p < 0.05). The lowest feed intake and highest protein efficiency rate were found in fish fed diet 2 (p < 0.05). There was no significant difference in whole body compositions between treatments. Plasma aspartate transaminases, alanine aminotransferase, and glucose were significantly affected by dietary treatments (p < 0.05), while plasma protein and albumin contents were not influenced by the treatments. The relative expression of target of rapamycin (TOR) and phosphatidylinositol 3‐kinase, regulatory subunit 1 (alpha) (PIK3R1) in fish fed diet 3 (4% FM) were significantly down‐regulated compared with those fed diet 6 for TOR and diets 4 and 6 for PIK3R1 (p < 0.05). Insulin receptor substrate 1 (IRS‐1) and janus kinase 3 (JAK3) expressions were fluctuated, with the higher levels in fish fed diets 4 and 6. In conclusion, the findings of this study indicate that plant protein mixture supplemented with EAA could be used to substitute FM in practical diet for Megalobrama amblycephala.     

团头鲂tf和tfr1a基因启动子克隆及转录调控分析

为探索鱼类转铁蛋白基因tf和转铁蛋白受体基因tfr1a的转录调控机制,本实验以团头鲂为研究对象,在其全基因组数据库中获取tf和tfr1a基因序列,对2个基因候选启动子区转录因子结合位点及CpG岛进行预测,通过PCR方法克隆得到tf和tfr1a基因近端启动子区不同长度片段,连接至pGL3-Basic/pEGFP-1载体,瞬时转染入Hela细胞,并采用双荧光素酶报告基因检测系统进行检测。结果发现,团头鲂tf基因启动子区无CpG岛位点,而tfr1a基因启动子区有2个CpG岛位点。成功构建9个tf和10个tfr1a不同长度启动子片段的重组质粒,经双荧光素酶报告基因系统检测发现,tf启动子核心区域为-268^+56 bp,且-1 308^-1 102 bp片段可能存在正调控该基因表达的转录因子结合位点;tfr1a启动子核心区域为-224^+48 bp,且+48^+92 bp可能存在抑制该基因转录的负调控元件,而-1 229^-1 219 bp区域可能存在促进tfr1a基因表达的正调控转录因子结合位点。     

螺旋粉虱对不同甜椒品种的产卵选择性及与植物中化学物质的相互关系研究

［目的］ 明确螺旋粉虱对不同甜椒品种的产卵偏好性及其与甜椒体内化学物质含量的关系。［方法］ 采用非自由选择法测定了螺旋粉虱对不同甜椒品种的产卵偏好性,并测定不同甜椒品种体内单宁酸、总黄酮、可溶性糖、可溶性蛋白等化学物质含量,分析其与螺旋粉虱产卵选择的相关性。［结果］ 螺旋粉虱对‘古风7号’的选择性最强,产卵量显著高于‘特大型牟一号’、‘吉星’、‘京椒’、‘特大甜椒八号’等8个品种（α=0.05水平）,而与‘国禧205’、‘郑椒甜宝’、‘古风5号’等7个品种差异不显著。不同甜椒品种间的单宁酸含量、总黄酮含量、可溶性糖含量、可溶性蛋白含量存在显著差异。相关分析表明,螺旋粉虱对甜椒品种的选择性与单宁酸、总黄酮不相关,与可溶性蛋白呈负相关,与可溶性糖含量呈正相关。［结论］ 螺旋粉虱对不同甜椒品种的偏好性存在显著差异,这种差异与甜椒体内一些化学物质含量不同有关。     

Growth and ontogenetic development of digestive functionality in black Amur bream (Megalobrama terminalis)

The function of digestive physiology during ontogenetic development is essential to ensure high survival and growth rates. In order to evaluate the digestive physiological capacity of the black Amur bream (Megalobrama terminalis), changes of morphology and digestive enzyme activity (trypsin, lipase, amylase, pepsin, leucine aminopeptidase and alkaline phosphatase) in larvae were examined from hatching to 40 days after hatching (DAH). Results indicated that fluctuation patterns differed between the total and specific activities of the digestive enzymes. The total activities of these six enzymes gradually increased throughout the fish growth. The specific activity of trypsin peaked at 5 DAH and then decreased dramatically, while it increased remarkably again from 8 to 10 DAH and remained stable level after 20 DAH. Pepsin activity was first examined in M. terminalis at 15 DAH and gradually elevated towards the end of the experiment. The specific activity of lipase displayed obvious peaks at 5 and 20 DAH. For the amylase, its specific activity reached plateau at 4 DAH, underwent sharp decrease, and remained stable after 20 DAH. In addition, we found that the specific activity of alkaline phosphatase raised significantly from hatching to 5 DAH, and tended to keep slight fluctuation after 15 DAH. From the above, we concluded that the specific activities of digestive enzymes in the larvae varied constantly from 3 to 20 DAH and turned relatively stable after 20 DAH. The present study provides effective information that is useful to improve the seedling cultivation and the technology for healthy breeding.     

厚颌鲂外周血细胞形态及细胞化学特征研究

采用血细胞常规染色和细胞化学染色对厚颌鲂(Megalobrama pellegrini)外周血细胞形态及细胞化学特征进行观察。结果显示:厚颌鲂外周血细胞可分为红细胞、血栓细胞、单核细胞、淋巴细胞和三种类型粒细胞。红细胞有幼稚、成熟和衰老三种形态,其中幼稚和衰老红细胞较少见;血栓细胞数量最多,其次是淋巴细胞。粒细胞中Ⅰ型和Ⅱ型较常见,Ⅲ型粒细胞少有。细胞化学染色显示幼红细胞、血栓细胞和淋巴细胞均呈ACP弱阳性;单核细胞呈ACP和ANAE阳性;Ⅰ型粒细胞是嗜中性粒细胞,POX、ACP和ANAE阳性;Ⅱ型粒细胞是PAS-GL,PAS强阳性和ACP阳性;Ⅲ型粒细胞是Ⅰ型粒细胞的晚期形态。厚颌鲂的PAS-GL可能是嗜酸性/嗜碱性粒细胞,而不是嗜碱性粒细胞的前体。     

不同猪种ESR基因多态性的PCR-RFLP分析

运用PCR-RFLP方法,检测了杜洛克、约克夏、长白猪、皮特兰、梅山猪、二花脸猪、枫泾猪、荣昌猪、苏太猪等9个国内外猪种的ESR基因PvuⅡ位点多态性。结果表明,在约克夏猪、二花脸猪、枫泾猪和苏太猪中检测到了AA、AB、BB 3种基因型,在杜洛克猪、皮特兰猪中检测到AB、BB 2种基因型,在长白猪、梅山猪、荣昌猪中只检测到了AB基因型。在本研究中不同品种的A、B基因频率差异显著,总体上在国外猪群体中A等位基因为优势等位基因,而地方猪种中B等位基因为优势等位基因。     

坏死杆菌白细胞毒素作为腐蹄病亚单位疫苗候选抗原的研究前景

腐蹄病（foot rot）是侵害反刍动物趾间皮肤及深层软组织为主的,严重影响奶牛生产性能和产奶质量的一种常见疾病。由于传统的灭活菌苗具有免疫效果差、副反应严重及大量生产困难等缺点,使腐蹄病基因工程疫苗的研究成为热点。笔者对坏死杆菌白细胞毒素作为腐蹄病亚单位疫苗候选抗原研究的最新进展进行综述,希望为腐蹄病亚单位疫苗的研究提供参考。     

牛GHR10基因Hind Ⅲ酶切多态性与体尺、体重指标的相关性分析

采用PCR-RFLP技术检测生长激素受体基因外显子10 (GHR10) 730 bp在南阳牛、利木赞、盖洛威中的单核苷酸多态性,同时分析不同基因型与3个品种体尺、体重指标的关系。结果表明,GHR10基因的730 bp突变（A/G）对体尺、体重等12个指标并无显著影响。     

细粒棘球蚴Eg95s基因的串联表达及表达系统优化

为研制新型棘球蚴病基因工程疫苗,根据GenBank公布的细粒棘球蚴Eg95基因序列,针对其中一段348 bp高度亲水的优势表位序列设计引物,扩增Eg95s基因,利用同尾酶法基因同向串联方案,获得3拷贝Eg95s串联体。分别用两种表达载体pGEX-6p-1和pET-32a构建重组质粒,转化入3种大肠杆菌表达宿主BL21(DE3)、Rosseta(DE3)和Origami (DE3),对其进行IPTG诱导表达,经免疫印迹分析结果表明,均能正确表达具有免疫原性的Eg95s蛋白。通过重组蛋白的表达量、可溶性、纯化方法等方面的比较,对Eg95s重组表达系统的载体及宿主菌进行了优化,结果表明,3拷贝的串联Eg95s在以pET-32a为表达载体,Rosseta(DE3)为宿主菌的系统中表达最佳。最终获得了表达量高、可溶性好、纯化方便的Eg95s重组蛋白表达系统,为大规模生产棘球蚴病基因工程疫苗提供了科学依据。     

猪繁殖与呼吸综合征病毒M基因RT-LAMP检测方法的建立

本研究根据GenBank中登录的猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus, PRRSV)M基因保守序列6个特异性部位设计了 2对引物,建立了PRRSV的环介导逆转录等温检测方法。结果表明,该方法灵敏度比RT-PCR高100倍;全部反应可在1 h内完成并可得到其特有的阶梯状条带,而且猪圆环病毒、猪瘟病毒、猪伪狂犬病毒的扩增结果均为阴性;在反应体系中添加SYBR GREENⅠ染料后,可通过肉眼观察有无荧光而直接判定结果。该方法灵敏度高、特异性好,可作为猪繁殖与呼吸综合征病毒的快速诊断方法。