暗管与竖井排水工程改良新疆盐渍土的设计与效果评价

为探讨干旱区盐渍化农田水利改良措施的可行性,在新疆玛纳斯河流域安集海灌区进行了田间暗管与竖井排水工程试验,分别在距离暗管0.5 m（P1）、7.5 m（P2）,距离竖井0.5 m（S1）、30 m（S2）和60 m（S3）,以及未铺管区（CK）域设置7处观测区,评估农田排水措施在盐渍土改良期间的排水功能、土壤脱盐效果,同时监测棉花生长与地下水位动态。结果表明：5 a排水改良期间,0～80 cm深度土壤含盐量的总体降幅达到29.2 g/kg,棉花干物质量和籽棉产量年际增幅分别为22%和28%,浅层地下水位年际降幅1.16 m;改进的暗管与竖井协同排水相比单独应用暗管排水量与地下水位年际降幅分别增加了118%,进一步减少了盐分淋溶时期的深层渗漏量。研究结果可为干旱盐渍区的水土资源合理利用提供科学和理论依据。     

基于IOE和SVM模型的府谷镇滑坡易发性分区

将陕西省府谷县府谷镇作为研究区,通过野外实地调查,圈定了47个滑坡点,制作了研究区滑坡编录图。以GIS软件和统计分析模型为基础,开展研究区滑坡易发性分区研究。首先通过GIS软件将滑坡点随机分成训练样本（70%）和测试样本（30%）两组。然后选择坡度、坡向、高程、距断层的距离、距道路的距离、距河流的距离、岩性、土地利用、NDVI、降雨量作为影响因子,提取因子图层。分别应用熵权模型（IOE）和支持向量机模型（SVM）计算滑坡易发性指数,利用自然间断点法将研究区划分为低易发区、中易发区、高易发区和极高易发区。最后利用ROC敏感度曲线下的面积（AUC）分别检验两种模型所得到的分区结果,结果表明,成功率曲线和预测度曲线的AUC值均在0.70～0.90,表明两种模型所得到的分区结果具有较高的精度,都可以为研究区的滑坡防治提供参考。在训练样本和测试样本中SVM模型的AUC值均最高,说明SVM模型比IOE模型适合在研究区开展滑坡预测研究。     

黄鳍金枪鱼垂直移动及水层分布研究进展

黄鳍金枪鱼(Thunnus albacares)为大洋性高度洄游鱼种,具有高速和深水游动能力,能够快速下潜至温跃层(20℃等温线)以下冷水区域觅食,最大深度甚至超过1000 m[1-4]。黄鳍金枪鱼垂直分布受海洋环境和饵料生物影响,进而影响渔船捕捞和效率[5]。因此获悉黄鳍金枪鱼垂直分布特征,不仅能辅助远洋渔场作业,对了解黄鳍金枪鱼鱼群垂直移动规律、分布习性和资源评估也至关重要。笔者综合国内外研究进展,综述了黄鳍金枪鱼垂直活动研究方法、垂直活动和水层分布及其影响因素在渔业生产和改进资源评估中应用,并对未来的研究内容进行展望。     

Cloning,characterization and transcription analysis of fatty acyl desaturase (Δ6Fad‐like) and elongase (Elovl4‐like,Elove5‐like) during embryos development of Strongylocentrotus intermedius

Strongylocentrotus intermedius has high nutritional value because it is rich in proteins, amino acids and long‐chain polyunsaturated fatty acids (LC‐PUFA). LC‐PUFA are essential nutrients that not only determine the nutritional value of sea urchins but also guarantee normal growth and reproduction performance. To better understand the molecular basis of LC‐PUFA biosynthesis in S. intermedius, the Δ6Fad‐like, Elovl4‐like and Elovl5‐like genes were cloned and fatty acid compositions during the early developmental stages of sea urchins were detected. The full‐length of Δ6Fad‐like was 2,199 bp, with a putative open reading frame of 1,248 bp encoding a polypeptide of 415 amino acid (AA). The Elovl4‐like and Elovl5‐like genes encoded 310 and 234 AA, respectively, which exhibited all of the characteristics of the Elovl family, such as a histidine box motif and putative transmembrane‐spanning domains. Tissue distribution analysis revealed that Δ6Fad‐like, Elovl4‐like and Elovl5‐like genes were expressed at the highest levels in the gonads and intestine, and the expression levels gradually increased in embryos during development. These results can help to understand the role of the Δ6Fad‐like, Elovl4‐like and Elovl5‐like genes in the different developmental stages of the sea urchin and to clarify the biosynthetic pathways of LC‐PUFA during the development of the sea urchin and provide a theoretical basis for improving the quality and breeding of excellent traits in sea urchins.     

四川彭州地区养殖虹鳟传染性造血器官坏死病病毒的分离、鉴定及病理学观察

近期,四川省成都彭州市某虹鳟养殖场暴发流行疾病,导致养殖虹鳟死亡率高达90%。现场采样观察发现患病鱼主要症状为背部发黑,鳔壁、腹膜严重出血,心包积液,空肠、空胃和显著肠炎。同时对病鱼进行细菌学与组织病理学检测,细菌学检查结果为阴性,病理学观察发现脾脏有典型凝固性坏死,肝脏组织广泛变性、坏死,肠道黏膜下层水肿,肠上皮充血及上皮细胞脱落坏死,脑膜和心外膜水肿。将病鱼的脾组织研磨过滤除菌后,腹腔注射60尾健康虹鳟,注射组均表现为急性死亡(累计死亡率达85%),试验鱼出现与自然发病鱼相同的症状而对照组无异常。取病鱼的脾脏组织研磨过滤后接种胖头鲤细胞(fathead minnow cell,FHM),细胞感染3 d后出现典型的细胞病变效应(CPE)。针对编码IHNV糖蛋白(Glycoprotein,G)基因进行逆转录-聚合酶链反应(RTPCR)检测显示,患病鱼、人工感染病鱼和病变细胞均为IHNV阳性,扩增序列与IHNV糖蛋白基因同源性为98.2%。对该病毒分离株的G基因进行系统发育分析,结果显示,该分离株与亚洲分离株聚为一簇,属于JRt基因型。     

2009年秋冬季东南太平洋智利竹筴鱼的渔业生物学特征

根据2009年秋冬季(3~6月)东南太平洋智利竹筴鱼的渔业调查资料,对其群体组成、叉长与体重关系、性腺成熟度、摄食等级和渔获量作了初步研究。结果表明:叉长范围为100~650 mm,优势叉长组350~400 mm;体重范围为100~2 600 g,优势体重组400~800 g;3~5月性腺成熟度大部分为Ⅱ期,6月则有52%个体为Ⅲ期。3~5月总产量和CPUE(t/h)呈逐渐增加趋势,6月份均显著下降,仅为5月的38.7%和51.4%。冬季(6月)总产量的大幅下降,暗示该渔场的空间分布出现了一些新的变化。     

基于CNKI的我国野鸟粪便研究文献计量与可视化分析

为从定量角度了解我国野鸟粪便研究现状,分析该研究领域存在的问题,采用文献计量学方法,基于"中国知网"CNKI数据库1987—2021年文献进行统计分析.结果显示:我国野鸟粪便研究总体呈增长趋势,且与禽流感病毒关系密切;研究内容日益丰富,研究热点由禽流感病毒和野生鸟类,逐步转向粪便污染、标记物、分离鉴定、肠道微生物、时空...     

Dietary histidine affects intestinal antioxidant enzyme activities,antioxidant gene expressions and inflammatory factors in juvenile blunt snout bream (Megalobrama amblycephala)

Six semipurified diets of graded histidine levels (from 4.1 to 14.2 g/kg) were fed to fish for 8 weeks. The results showed that the intestinal content of malondialdehyde (MDA), activities of total superoxide dismutase (T‐SOD) and glutathione peroxidase (GPx) were noticeably lower in 8.0 g/kg diet compared to control group. While the lowest activities of copper–zinc superoxide dismutase (Cu/Zn‐SOD) and manganese superoxide dismutase (Mn‐SOD) were observed in 9.9 g/kg diet, the intestinal activities of total antioxidant capacity (T‐AOC) and catalase (CAT) in 14.2 g/kg diet were noticeably higher than those in 8.0 and 9.9 g/kg diets. Plasma biochemical indexes were not significantly affected by dietary histidine levels. In the intestine, the Kelch‐like ECH‐associated protein 1 (Keap1) mRNA levels were increased in 8.0 g/kg diet, which suppressed the nuclear translocation of nuclear factor E2‐related factor 2 (Nrf2), and subsequently decreased CAT, GPx1, Cu/Zn‐SOD and Mn‐SOD expression levels. The lowest mRNA levels of interleukin 8 (IL‐8) and tumour necrosis factor‐α (TNF‐α) were observed in 8.0 g/kg diet, whereas the highest mRNA levels of transforming growth factor‐β (TGF‐β) and interleukin 10 (IL‐10) were observed in 8.0 g/kg diet. These results indicated that dietary histidine plays a major role in maintaining intestinal health in juvenile blunt snout bream.     

Evaluation of soybean meal as alternative to fish meal in diet for juvenile Asian red‐tailed catfish (Hemibagrus wyckioides)

A feeding trial was conducted to determine the amount of soybean meal (SBM) that could replace fish meal (FM) without compromising growth and health of Asian red‐tailed catfish (Hemibagrus wyckioides). Five isonitrogenous and isoenergetic diets (S0, S15, S30, S45 and S60) were formulated with SBM to replace 0%, 15%, 30%, 45% and 60% of FM. The replacement level up to 30% improved daily growth coefficient, plasma adenosine monophosphate deaminase (AMPD) and alanine aminotransferase (ALT) activities and IgM content, and hepatic ALT, aspartate aminotransferase (AST) and glutathione reductase activities, whereas these were depressed by a further inclusion. The highest protein efficiency ratio and lowest feed conversion ratio were observed in fish fed the S15 diet. Replacement of FM with SBM generally decreased plasma insulin and insulin‐like growth factor 1 (IGF‐1) contents and hepatic catalase activity, whereas no significant differences were observed among fish fed the S0, S15 and S30 diets. In contrast, replacing FM with SBM generally increased blood urea nitrogen content, and that was higher in fish fed the S60 diet compared to fish fed the S0 diet. The highest growth hormone (GH) and glutamate dehydrogenase (GDH) activities were observed in fish fed the S30 diet. Fish fed the S30 and S45 diets exhibited the highest hepatic AMPD, GDH, IGF‐1 and target of rapamycin mRNA levels and muscle AMPD and GDH mRNA levels, whereas those were lowest in fish fed the S60 diet. These results indicate that under the reported conditions SBM may be included in the diet up to 222 g/kg as a substitute for FM, replacing about 30% of FM protein in juvenile H. wyckioides.     

基于网箱控制法和模型法的长江4种淡水鱼目标强度研究

目标强度(target strength,TS)是将回波积分值转换成绝对资源量的关键参数,同时也是渔业声学技术的热点研究内容。2012年12月及2013年6―7月,在三峡水库中华鲟基地网箱内使用BioSonics DT-X(199 kHz)分裂波式科学回声仪测定了4种共计31尾不同鳔室构造和体型的长江淡水鱼类背腹方向的目标强度,并将此结果与基尔霍夫近似模型法测定结果进行比较。实验鱼包括鳊(Parabramis pekinensis) 6尾、鲢(Hypophthalmichthys molitrix) 8尾、鲇(Silurus asotus)10尾及长江鲟(Acipenser dabryanus)7尾。结果表明,模型法测定结果与网箱控制法所测结果无显著性差异。构建4种鱼TS值(dB)与体长(BL, cm)的标准方程分别为鳊:TS=20lg(BL)-70.1 (R~2=0.94);鲢:TS=20lg(BL)-67.0 (R~2=0.80);鲇:TS=20lg(BL)-74.5 (R~2=0.80)及长江鲟:TS=20lg(BL)-66.1 (R~2=0.94)。模型法获得实验鱼目标强度的分布表明,鱼类不同的形态学特征及鳔室数量会影响目标强度的大小与分布特征。低频(38 kHz)下鳊、鲇及长江鲟目标强度最大值对应的姿态倾角出现在-10°～0°,而鲢目标强度最大值出现在-20°～-10°,且不同种类鱼的目标强度最大值所对应姿态倾角的位置各不相同。本研究通过网箱控制法和模型法测定了4种不同鳔室构造和体型的长江淡水鱼类目标强度,可为长江淡水鱼类目标强度研究提供有益借鉴,为采用渔业声学方法进行长江淡水鱼类垂直原位监测评估资源量提供相关参数。