Sodium alginate supplementation modulates gut microbiota,health parameters,growth performance and growth‐related gene expression in Malaysian Mahseer Tor tambroides

This study investigated the effects of sodium alginate supplementation on gut microbiota composition, health parameters, growth performances and growth‐related gene expression of Malaysian mahseer. Five test diets were formulated by supplementing 0%, 0.1%, 0.2%, 0.4% and 0.8% sodium alginate. Triplicate groups of juvenile Tor tambroides (2.19 ± 0.05 g) were stocked in 15 aquaria (20 individuals per aquarium) and fed at 3.0% body weight per day for 60 days. PCoA and UPGMA analysis showed that gut bacterial community were more convergence in higher sodium alginate‐supplemented diets. The percentage of Porphyromonadaceae, Bacteroides, Plesiomonas and Shewanella were substantially higher and Aeromonas, Entomoplasmatales and Prevotellaceae were drastically lower in higher sodium alginate (0.2%–0.8%) diets. Sodium alginate supplementation (≥0.2%) significantly improved the haematocrit value and respiratory burst activity of T. tambroides. Growth performances and feed utilization were significantly higher in 0.2%–0.4% sodium alginate‐supplemented diets. The increased growth rate of T. tambroides was governed by both hyperplastic and hypertrophic muscle growth. Real‐time PCR data demonstrated that most of the growth‐related genes were significantly upregulated in 0.2%–0.4% sodium alginate‐supplemented diet. Finally, it can be concluded that sodium alginate should be supplemented at 2 g/kg in practical fish feed formulation.     

Cloning and expression analysis of innate immune genes from red sea bream to assess different susceptibility to megalocytivirus infection

As suggested by the Office International des Epizooties (OIE), fishes belonging to the genus Oplegnathus are more sensitive to megalocytivirus infection than other fish species including red sea bream (Pagrus major). To assess the roles of the innate immune response to these different susceptibilities, we cloned the genes encoding inflammatory factors including IL‐8 and COX‐2, and the antiviral factor like Mx from red sea bream for the first time and performed phylogenetic and structural analysis. Analysed expression levels of IL‐1β, IL‐8 and COX‐2 and the antiviral factor like Mx genes performed with in vivo challenge experiment showed no difference in inflammatory gene expression or respiratory burst activity between red sea bream and rock bream (Oplegnathus fasciatus). However, the Mx gene expression levels in red sea bream were markedly higher than those in rock bream, suggesting the importance of type I interferon (IFN)‐induced proteins, particularly Mx, during megalocytivirus infection, rather than inflammation‐related genes. The in vitro challenge experiments using embryonic primary cultures derived from both fish species showed no difference in cytopathic effects (CPE), viral replication profiles, and inflammatory and Mx gene expression pattern between the two fish species.     

Study on the glass transition for several processed fish muscles and its protein fractions using differential scanning calorimetry

ABSTRACT:   The glass transition behavior of processed fish muscles (bonito, tuna, mackerel, sea bream, cod) and its muscle protein fractions (sarcoplasmic and myofibrillar proteins) were studied using differential scanning calorimetry. Each dried processed fish muscle and the extracted protein fractions showed clear glass transition phenomenon. The T _g values of muscles and myofibrillar proteins from red muscle fishes tended to be lower than those from white muscle fishes though there was no difference on T _g of sarcoplasmic proteins. The T _g value of whole muscle was considerably lower than that of extracted protein fractions because of the plasticizing effects of low molecular weight materials contained in the muscle.     

虾源哈维氏弧菌的致病性与生物学特性比较分析

哈维氏弧菌(Vibrio harveyi)是导致养殖对虾暴发弧菌病的重要病原之一。从我国南方养殖凡纳滨对虾(Penaeus vannamei)分离、鉴定了10株哈维氏弧菌(Vh00947、Vh00949、Vh11011、Vh11014、Vh21217、Vh21218、Vh21220、Vh21229、Vh21231和Vh31487),分别肌注感染健康凡纳滨对虾后发现,菌株Vh21229致病性很弱,Vh00949其次,其它菌株毒力较强;对8种哈维氏弧菌常见毒力基因(Vh1、Vh2、Vh3、Vh4、tox S、hcp、zot和pap6)的检测显示,南方虾源哈维氏弧菌无论强弱毒株都很少携带zot、pap6、toxs和4种Vh基因(≤10%),表明这10个菌株的致病性与这7种常见毒力因子的相关度很低;hcp基因在所有菌株中均有检出,其中强毒株中检出率较高(50%),在较弱毒株(Vh00949)中也存在,表明hcp基因与这些菌株的致病性密切相关,但不是决定性因子。因此,这10株南方虾源哈维氏弧菌菌株的致病性差异应由这8种常见毒力因子以外的未知或未检测到的因子所决定。生化特征分析显示,所有菌株中只有弱毒株Vh21229不能利用D-甘露糖、蔗糖、D-海藻糖,而且只有其赖氨酸脱羧酶反应至阳性,而其它菌株均为阴性,推测导致哈维氏弧菌菌株生化特性改变的某种因子可能对菌株的致病性也产生了影响。药敏实验表明,10株哈维氏弧菌均对环丙沙星、氯霉素、恩诺沙星、美罗培南、头孢曲松、多西环素、头孢吡肟、诺氟沙星敏感,而对氨苄西林耐受性强,表明在虾类养殖过程中应当严格规范和控制抗菌药物尤其是青霉素类药物的使用。     

乌鳢和斑鳢EST序列微卫星信息分析

乌鳢(Channa argus,♂)、斑鳢(Channa maculatus,♀)是杂交鳢"杭鳢1号"的亲本。利用高通量测序技术对乌鳢和斑鳢的肝脏进行转录组测序获得大量EST序列后,利用MISA软件进行微卫星信息分析,结果表明,通过转录组测序获得乌鳢EST序列59 959条,长度45 mb,发现15 428个SSR,出现频率为25.73%;获得斑鳢EST序列44 337条,长度27 mb,发现8 439个SSR,出现频率为19.03%。在乌鳢和斑鳢EST-SSR中,重复单元以1~2碱基重复为最多,并以长度小于16 bp的短重复序列为主,间隔SSR和复合SSR的EST序列RPKM均值要低于单纯型SSR的EST序列RPKM均值,且在单纯型SSR中SSR长度越长,其RPKM均值则越低。     

Changes in selected stress and immune‐related genes in Atlantic cod,Gadus morhua,following overcrowding

Using Atlantic cod, Gadus morhua, as a model for the stress response in gadoid fish, the changes in the expression of some stress and immune genes as well as the profiles of plasma cortisol were examined. Adult fish were kept at a density of ca. 100 kg m^?3 by lowering the water level in the rearing tank for 1 h and this short‐term crowding stress was repeated thrice over a 12‐h interval period. Blood samples were collected before exposure and at 2, 24 and 72 h post crowding. Plasma cortisol level significantly increased at 2 h post crowding but returned to pre‐crowding levels 24 h after exposure. The relative expression of the stress response genes, glucose transporter‐3 and a putative heat shock protein 70 significantly increased at 2 and 24 h post crowding respectively. Significant up‐regulation of the pro‐inflammatory cytokines, interleukin (IL)‐1β and IL‐8, as well as anti‐bacterial genes, g‐type lysozyme and bactericidal permeability‐increasing protein/lipopolysaccharide‐binding protein (BPI/LBP) was also observed at 2 h and the levels were maintained until 72 h post exposure, except for BPI/LBP which had maximum up‐regulation at 24 h. The present observations have implications with respect to fish welfare and assessment of the health status of the farmed fish.     

利用抑制消减杂交技术分离辣椒细胞质雄性不育育性恢复相关EST

 以辣椒(Capsicum annuum L. ) 细胞质雄性不育系23A、121A, 和其相应的近等基因恢复系23C、121C为试验材料, 利用抑制消减杂交( SSH) 技术成功构建了CMS恢复基因诱导表达的消减cDNA文库。结合高密度点阵膜杂交差异筛选, 获得了282个阳性克隆。通过测序, 除去重复序列共得到175个Unique ESTs。在GenBank上进行BLAST分析, 55个EST片段未找到对应的同源序列, 可能代表了新基因;120个EST片段找到了对应的同源序列, 包括103个已知功能基因和17个未知功能基因。按照MIPS功能分类法, 将其分为14个功能组, 涉及代谢、胁迫应答、蛋白活性、转录因子、信号转导等多方面的功能。     

小麦不同抗白粉病基因及品种在成都平原抗病的有效性

为了解小麦含已知抗白粉病基因材料及审定品种在成都平原对白粉病的抗性表现,2015-2017年在四川省江油市武都镇(104.47°E,31.52°N)和广汉市连山镇(104.18°E,30.59°N)设置病圃,种植42份含已知抗白粉病基因的材料以及85份小麦审定品种,于2016-2018年乳熟后期调查病害级别、普遍率和严重度。结果表明,已知抗白粉病基因材料中,Coker983(Pm5+6)、Wembley(Pm12)、Brigand(Pm16)、南农9918(Pm21)、赤牙糙(Pm24)、NCD7(Pm34)、NCD3(Pm35)、NCD4(Non-Pm1)、复壮30(Pm5e)和Tabasco(Pm46)在两个病圃(2016和2018年)均表现抗白粉病,而Kavkaz(Pm8)、W150(Pm3e)、Hope/8cc(Pm5a)、Timgalen(Pm6)和5P27(Pm30)在两个病圃内均表现感病。85份小麦审定品种中,国豪麦3号、蜀麦375、蜀麦482、杏麦2号、绵阳29号、绵阳33、绵麦228、西科麦5号和良麦4号9个品种连续三年(2016-2018年)在两地均表现抗病,有37个品种三年在两地均表现感病。其余27个含已知抗性基因材料和39个小麦审定品种的抗病性表现则在不同地点和年份并不稳定。     

油料作物油脂合成调控研究进展

植物油脂不仅是人类可食用油的主要来源,也是人类生产生活中重要的可再生原料.本文概述了植物油脂的生物合成途径,从母体效应、QTL、GWAS等多个方面总结了油料作物油脂合成的遗传学研究进展,同时探讨了已知的油脂合成调控相关基因的功能.本文综述了该领域的研究现状,为深入了解油料作物油脂合成调控网络提供了参考,也为油料作物的分...