Effect of crude oil extracts from trout offal as a replacement for fish oil in the diets of the Australian native fish Murray cod Maccullochella peelii peelii

The efficacy of trout oil (TO), extracted from trout offal from the aquaculture industry, was evaluated in juvenile Murray cod Maccullochella peelii peelii (25.4±0.81 g) diets in an experiment conducted over 60 days at 23.7±0.8 °C. Five isonitrogenous (48% protein), isolipidic (16%) and isoenergetic (21.8 kJ g^?1) diets, in which the fish oil fraction was replaced in increments of 25% (0–100%), were used. The best growth and feed efficiency was observed in fish fed diets containing 50–75% TO. The relationship of specific growth rate (SGR), food conversion ratio (FCR) and protein efficiency ratio (PER) to the amount of TO in the diets was described in each case by second‐order polynomial equations (P<0.05), which were: SGR=–0.44TO²+0.52TO+1.23 (r²=0.90, P<0.05); FCR=0.53TO²–0.64TO+1.21 (r²=0.95, P<0.05); and PER=–0.73TO²+0.90TO+1.54 (r²=0.90, P<0.05). Significant differences in carcass and muscle proximate compositions were noted among the different dietary treatments. Less lipid was found in muscle than in carcass. The fatty acids found in highest amounts in Murray cod, irrespective of the dietary treatment, were palmitic acid (16:0), oleic acid (18:1n‐9), linoleic acid (18:2n‐6) and eicosapentaenoic acid (20:5n‐3). The fatty acid composition of the muscle reflected that of the diets. Both the n‐6 fatty acid content and the n‐3 to n‐6 ratio were significantly (P<0.05) related to growth parameters, the relationships being as follows. Percentage of n‐6 in diet (X) to SGR and FCR: SGR=–0.12X²+3.96X–32.51 (r²=0.96) and FCR=0.13X²–4.47X+39.39 (r²=0.98); and n‐3:n‐6 ratio (Z) to SGR, FCR, PER: SGR=–2.02Z²+5.01Z–1.74 (r²=0.88), FCR=2.31Z²–5.70Z+4.54 (r²=0.93) and PER=–3.12Z²–7.56Z+2.80 (r²=0.88) respectively. It is evident from this study that TO could be used effectively in Murray cod diets, and that an n‐3:n‐6 ratio of 1.2 results in the best growth performance in Murray cod.     

Optimal chemical triploid induction in geoduck clams, Panopea abrupta, by 6-dimethylaminopurine

The development of geoduck culture techniques coupled with increased market demand during the past decade led to cultured intertidal geoduck beds, over which concerns have arisen regarding the potential genetic risk posed by the reproductive contribution of hatchery outplants to wild stocks. Although an ongoing study to determine the genetic stock structure of Puget Sound geoducks has yet to yield definitive results, sterile triploids would enable geoduck culture to proceed irrespective of any genetic differences found, and may increase rate of growth. At 15 °C and salinity of 30‰, we evaluated the suitability of cytochalasin B (CB) and 6-dimethylaminopurine (6-DMAP) for triploid induction in geoducks. Parallel tests of induction agent, start time, duration, and concentration were conducted on the same gamete pool. We found optimal triploid induction (92%) and suitable survivorship (30%) resulted from a 600 μM 6-DMAP treatment. This work enables the future examination of the efficacy of triploid induction for conferring sterility and increasing growth rate in this commercially valuable species.     

草鱼呼肠孤病毒VP6蛋白在毕赤酵母中表达的初步研究

根据GeneBank中草鱼呼肠孤病毒(grass carp reovirus,GCRV)104株VP6蛋白的全基因序列(HM234682)设计一对特异引物,以提取的GCRV-104核酸为模板,采用RT-PCR技术扩增VP6蛋白编码基因,并将其克隆到含强启动子AOXⅠ的毕赤酵母(Pichia pastoris)表达载体pPICZB上。重组酵母质粒pPICZB-VP6经SacⅠ线性化,电击转化到毕赤酵母KM71菌株中,Zeocin抗性平板上筛选高拷贝转化子。阳性转化子在30℃,0.5%(V/V)的甲醇添加量的条件下,连续诱导3 d,表达产物经SDS-PAGE和Western-Blotting检测,结果表明成功实现了GCRV-104 VP6蛋白在毕赤酵母中的胞内表达,重组VP6蛋白相对分子质量约46 000,与天然VP6蛋白相对分子质量接近,并且可与鼠抗草鱼GCRV-104 VP6蛋白的多克隆抗体特异性结合。     

草鱼呼肠孤病毒VP6蛋白与大肠杆菌LTB亚基植物融合表达载体的构建

根据GenBank中草鱼呼肠孤病毒(Grass Carp Reovirus,,CCRV)VP6蛋白的全基因序列(AF403394)和大肠杆菌不耐热肠毒素B亚单位(LTB)的基因序列(M17874),设计并合成特异性引物,从感染草鱼呼肠孤病毒(GCRV)09草鱼(Ctenopharyngodon idellus),肾细胞...     

6-二甲基氨基嘌呤诱导泥蚶三倍体实验

于2001年5月,用6-DMAP抑制泥蚶受精卵第二极体的释放诱导三倍体的产生。实验设三个6-DMAP浓度梯度,分别为300μmol/L、450μmol/L、600μmol/L,处理时机为受精卵第一极排放体30％,处理持续时间为10min。结果:三倍体诱导率300μmol/L时为35.5％,450μmol/L时为48.6％,600μmol/L时约为58.5％,另外本实验还就6-DMAP浓度对D形幼虫孵化率和畸形率的影响以及在染色体制片过程中的有关问题进行了初步探讨。     

中华鲟ASDIGIRR与ASTRAF6基因的克隆与表达

中华鲟是处在硬骨鱼类与软骨鱼类之间的中国古老的珍稀鱼类之一,但在人工繁殖和养殖过程中,容易受到不同疾病的危害,因此,需要深入研究其免疫调控,为其疾病预防提供理论依据。单个免疫球蛋白白细胞介素-1受体相关分子(SIGIRR)和肿瘤坏死因子受体相关因子6(TRAF6)是toll样受体(TLR)信号通路的2个重要的信号转导元件。本研究鉴定了中华鲟的SIGIRR和TRAF6的同源物,分别命名为ASDIGIRR (Acipenser sinensis DIGIRR)和ASTRAF6 (A. sinensis TRAF6),并研究它们在正常组织中的表达和Poly(I:C)诱导后的表达模式。结果显示,ASDIGIRR和ASTRAF6在健康鲟的10个组织中均有表达,且分别在肠道和头肾组织中表达量最高;用Poly (I:C)孵育中华鲟脾脏细胞后,ASDIGIRR在3 h时的表达量显著下调,在6 h时恢复至正常水平,后在24 h显著上调达到最高值,随后开始下调,至48 h时仍显著高于对照组,而ASTRAF6在6 h达到最高表达量,维持到24 h后再下调,48 h时下降至最低水平。研究表明,ASDIGIRR和ASTRAF6在中华鲟抵御病原入侵的免疫防御过程中起着重要作用。     

30％已·乙水剂对玉米产量和茎秆质量的影响

30%已.乙水剂处理极显著缩短穗下部节间长度,降低了植株和果穗的重心,提高了子粒形成期和灌浆期穗下部节间单位长度干重,极显著提高穗下部节间折断时的最大载荷和径向的碾碎强度,增加了穗下各茎节的粗度,总体提高玉米茎的抗倒伏性能。同时,化控处理降低了空秆率和秃尖长,提高了行粒数和穗粒重,显著提高了产量,化控措施使玉米子粒产量与茎秆质量得到了协同改善。     

超甜玉米单交种"吉甜6号"选育报告

超甜玉米品种"吉甜6号"是吉林农业大学以自选系"吉898"为母本、"吉908"为父本杂交育成的甜玉米单交种.1996-1998年吉林省专用型玉米品种区域试验平均鲜果穗产量为13 337.8 kg/hm2,比对照品种"吉甜3号"增产9.7%.1997-1998年吉林省生产试验平均鲜果穗产量为12 401.5 kg/hm2,比对照品种"吉甜3号"增产5.5%,2000-2001年国家东北、华北地区鲜食玉米品种区域试验平均鲜果穗产量13 196.3 kg/hm2.鲜籽粒含糖量18.73%,籽粒皮薄、甜而脆,有香味,口感好,品质优.高抗大斑病、弯孢菌叶斑病、丝黑穗病,抗灰斑病和玉米螟,中抗茎腐病.适宜在河北、山西、辽宁、吉林、新疆、黑龙江、内蒙等地区种植.于2003年通过国家农作物品种审定委员会审定.     

翘嘴红肝脏G6Pase催化亚基的克隆以及摄食和饲料中碳水化合物对其表达的影响

采用RT-PCR和RACE法分离、克隆了翘嘴红G6Pase催化亚基基因全长cDNA,共1900 bp ［不含poly(A)］, 包括49 bp 5′非翻译区,1068 bp阅读框以及含Poly(A)信号AATAAA的778 bp 3′非翻译区［不包括Poly(A)］。阅读框共编码355个氨基酸,分子量为39.89 ku。序列比对分析表明翘嘴红G6Pase与斑马鱼G6Pase的相似性高达95%,与鼠、狗、人G6Pase的相似性为63%,和光滑爪蟾、金头鲷、河豚等G6Pase的相似性分别为69%、55%、76%,并具有G6Pase特有的3个保守基序。为了研究摄食以及饲料中碳水化合物对G6Pase的影响,使用实时定量RT-PCR分别测定了饲喂等能但不含碳水化合物和含23.98%碳水化合物的饲料的翘嘴红肝脏G6Pase基因的表达水平,在使用上述饲料饲喂8周后,禁食48 h, 然后测定禁食和摄食后3、6、12、24 h G6Pase mRNA的表达量,结果显示摄食后12 h,两组G6Pase的表达明显增加,说明摄食影响G6Pase基因的表达,禁食和摄食后3～12 h,含糖组G6Pase基因的表达量为无糖组的2～4倍,这表明碳水化合物可以诱导G6Pase mRNA的表达。图5参21 关键词：快速扩增cDNA末端;葡萄糖6磷酸酶;碳水化合物;翘嘴红;实时定量PCR E-mail:gexp@ffrc.cn     

基于GF-6卫星影像多特征优选的酿酒葡萄精准识别

多源遥感信息和特征优选是提高农作物识别精度的重要支撑,高分六号（GF-6）卫星作为首次引入红边波段的国产卫星,其丰富的光谱信息为作物识别提供了新的思路和解决途径。该研究基于宁夏回族自治区银川市永宁县2018年6月-2019年3月的GF-6数据,充分利用红边优势提取光谱特征、纹理特征和植被指数特征,构建多种特征组合方案,并根据随机森林算法对特征重要性进行度量,选取最优特征组合对酿酒葡萄进行精准识别。结果表明,与单一特征相比,多源遥感特征的增加显著改善了酿酒葡萄分类效果,其中,植被指数贡献程度最大,光谱特征次之;基于随机森林的优选特征组合分类效果最佳,其中,总体分类精度为94.15%,酿酒葡萄用户精度为94.23%,制图精度为92.59%;以实地调查的4个酒庄为验证区,将酿酒葡萄提取结果与统计数据进行对比,面积相对精度均在70%以上,其中优选特征结果相对精度在90%以上,研究结果将为国产卫星红边波段在植被分类和识别方面的应用提供数据参考。