Combined effects of water temperature and daily food availability period on the growth and survival of tench (Tinca tinca) larvae

A 16‐day experiment was designed to find the best combination of water temperature (27, 30, 33°C) and daily duration of food availability (12, 18, 24 h) for larval tench (Tinca tinca) growth and survival. Larvae with an initial mean size of 5.7 mm total length (TL) and 0.7 mg wet body weight (BW) were stocked at 15 L^?1. Larvae were fed in excess with live Artemia nauplii with the period of food availability lasting 12, 18 or 24 h daily. The largest final larval size was recorded at 27 and 30°C in groups fed for 24 h a day (17.7 and 17.9 mm TL, 76.1 and 77.7 mg BW, respectively). The combination of the highest temperature and the longest daily food availability was the only set of conditions under which final larval survival was affected (95.4% survival; 98.7–99.9% under all other conditions). The combination of water temperature of about 28.6°C and continuous food availability is recommended as the optimum combination for rearing T. tinca larvae under controlled conditions. Providing continuous food supply to fish larvae under aquaculture conditions was also advantageous in helping to mitigate the effects of slower growth relative to developmental progress, which can occur at high water temperatures. However, should one wish to limit the daily feeding period to 12 h per day, the use of a water temperature between 27.4 and 27.9°C would be the best solution.     

Design and performance of a recirculating aquaculture system for oyster larval culture

The major objective of this study was to introduce a newly designed recirculating aquaculture system (RAS) for oyster (Crassostrea angulata) larval culture. The system includes a culture tank, a suspended circular inlet‐pipe, an upwelling aeration pipe, combined “banjo” sieves and a bioreactor chamber containing microalgae life keeping installation. The system was designed to resolve three problems: (i) stranding of larvae caused by water level changes and aeration, (ii) physical clogging of the screens and also (iii) deterioration of diet microalgae. The culture tank, “banjo” sieve size, water flow rate and light intensity for maintaining microalgae activity were all designed according to the pattern of larval movement and feeding behaviour. Results of this study showed the best average SGR for larval length was 6.36%/d (9.5 μm/d) and survival rate was 80%, with initial rearing density of 50 larvae/ml, indicating the problems above were fully resolved. Consequently, the system is fit for larval culture in mass production of oysters.     

啶氧菌酯对意大利蜜蜂幼虫生长发育及免疫应答的影响

为探究啶氧菌酯对意大利蜜蜂Apis mellifera ligustica幼虫生长发育和免疫应答的影响,使用田间推荐浓度（113、150、225和281 mg/L）的啶氧菌酯连续饲喂意大利蜜蜂工蜂幼虫,记录处理后工蜂幼虫的存活率、化蛹率、蛹重、羽化率和羽化初生重,并测量幼虫体内发育相关基因、营养相关基因及免疫相关基因表达情况。结果显示,不同浓度啶氧菌酯对意大利蜜蜂工蜂幼虫存活率、蛹重和羽化初生重均有显著影响,且具有显著的浓度效应;150、225和281 mg/L啶氧菌酯处理后意大利蜜蜂工蜂幼虫的化蛹率和蛹的羽化率均较对照显著下降。不同浓度啶氧菌酯均可诱导幼虫体内蜕皮激素受体（ecdysone receptor,Ecr）基因、卵黄原蛋白（vitellogenin,Vg）基因、蜜蜂防卫素（defensin 1,Def1）基因和膜翅抗菌肽（hymenoptaecin,Hym）基因的表达量上调,且大部分与对照差异显著;不同浓度啶氧菌酯均可显著抑制幼虫体内胰岛素样肽（insulin-like peptide 1,ILP1）基因的表达量;281 mg/L啶氧菌酯分别显著抑制和显著增加幼虫体内蜜蜂抗菌肽（apidaecin,Api）基因和蜂蛾抗菌肽（abaecin,Aba）基因的表达量,225 mg/L和281 mg/L啶氧菌酯可诱导幼虫体内ILP2的表达量显著上调,显著抑制幼虫体内储存蛋白（hexamerin,Hex）基因Hex70b的表达量,其他浓度处理对幼虫体内Api、Aba、ILP2和Hex70b无显著影响。表明啶氧菌酯对意大利蜜蜂工蜂幼虫有慢性毒性,长时间暴露会扰乱幼虫的生长发育和免疫应答。在生产实践中应当考虑啶氧菌酯对意大利蜜蜂的潜在风险。     

Winter monsoon promotes the transport of Japanese temperate bass Lateolabrax japonicus eggs and larvae toward the innermost part of Tango Bay,the Sea of Japan

Northwesterly cold winds characteristic of the East Asian Winter Monsoon (EAWM) dictate winter climatic conditions over the Japanese Archipelago. Japanese temperate bass Lateolabrax japonicus is a commercially important coastal fish that spawns offshore in winter and uses shallow waters as nursery habitats. To investigate the effects of EAWM on the planktonic period of L. japonicus, eggs, larvae, and juveniles were quantitatively collected in Tango Bay on the Sea of Japan side in winter and spring from 2007 to 2017. Although eggs occurred close to the mouth of the bay, planktonic larvae occurred further inside as they developed. The horizontal distribution of planktonic larvae, combined with water velocity data obtained from mooring observations, indicated that planktonic larvae are transported south‐ to westward through Ekman current and an anticyclonic circulation, which are driven by northwesterly winds. To evaluate survival during the planktonic period in each year class, the abundance of benthic larvae/juveniles was divided by winter total landings of Lateolabrax spp. (proxy of the spawning stock size). This survival index exhibited a positive correlation with the northwesterly component of winter winds, and a negative correlation with winter air temperature (average from December to February, Spearman's correlation, p < .05). There was, however, no significant correlation with winter water temperature or winter freshwater discharge in the bay. We conclude that northwesterly cold winds of EAWM play a critical role in transporting L. japonicus eggs and larvae toward nursery habitats, specifically beaches and estuaries fringing the innermost part of Tango Bay.     

番茄潜叶蛾成虫触角及幼虫头部感受器的超微结构

为明确番茄潜叶蛾Tuta absoluta(Meyrick)成虫触角及幼虫头部感受器的种类、分布和形态结构,采用扫描电镜法观察番茄潜叶蛾雌雄成虫触角和4龄雌雄幼虫触角及口器上的感受器种类和形状。结果显示,番茄潜叶蛾成虫触角上共有8种类型感受器,分别为B?hm氏鬃毛、毛形感受器、鳞形感受器、锥形感受器（Ⅰ型和Ⅱ型）、刺形感受器、腔锥形感受器、栓锥形感受器和耳形感受器。其中,雌成虫的Ⅰ型和Ⅱ型锥形感受器数量、刺形感受器数量、B?hm氏鬃毛长度、鳞形感受器长度及基部直径、Ⅰ型锥形感受器长度及基部直径、Ⅱ型锥形感受器长度、刺形感受器臼状窝直径、腔锥形感受器基部直径和耳形感受器基部直径均显著大于雄成虫;而雄成虫的毛形感受器数量和腔锥形感受器中心锥长度显著大于雌成虫。幼虫头部共计有6种类型感受器,主要着生在触角、下颚和下唇上,分别为毛形感受器、锥形感受器、刺形感受器、栓锥形感受器、指形感受器和感觉锥;幼虫触角、下颚和下唇的感受器类型和数量在雌雄间完全相同。而雌性幼虫触角鞭节上的锥形感受器SB5和下颚须上的锥形感受器SB2的长度显著大于雄性幼虫;雄性幼虫下颚茎节上的刺形感受器Sch1和下颚须上的锥形...     

甘蓝夜蛾人工饲料的研究

文章报道了以甘蓝叶、白菜叶、灰菜叶、大豆粉、菜豆粉、玉米粉、麦麸为主要原料配制的5种人工饲料对甘蓝夜蛾的饲养效果。结果表明,以甘蓝叶和大豆粉为主要原料配制的配方—人工饲料对甘蓝夜蛾饲养效果最好,甘蓝夜蛾不仅能正常生长发育,而且在产卵量、蛹重、幼虫存活率方面均优于天然饲料,用该人工饲料连续饲养4代甘蓝夜蛾,未发现饲养后代生命力减退现象,表明该人工饲料可用来室内大量连续饲养甘蓝夜蛾。     

基于松墨天牛种群动态及其影响因素分析的松材线虫病风险评价

【目的】分析重庆市綦江区松墨天牛种群发生动态及松材线虫病的灾变风险,为深入揭示该虫在当地的成灾机制及防控基础提供依据。【方法】对2015年和2016年APF-I型诱捕器诱捕松墨天牛成虫数据、环境因子、天牛携带线虫数和携带线虫天牛数及枯死松树数量等指标进行统计分析,在此基础上评估了重庆市綦江区松材线虫病的灾变风险。【结果】在年发生总量上,2015年以古南街道松墨天牛种群诱集量最多,其次是三江镇;而2016年以北部林场最多,数量显著增加,其次是篆塘镇。在年发生动态上,2015年和2016年多数林场/镇成虫高峰期主要集中在6月30日至8月1日,但北部林场2016年为9月1日。按提取的3个主成分综合值排序,对天牛成虫发生量影响力由大到小的关键环境因子依次是林型、胸径、郁闭度和树高。由于总方差49.93%的贡献率来自第1主成分,因此从第1主成分看,影响力大小依次是胸径、树高和林型。各地天牛发生量与天牛携带的线虫数以及枯死松树数量均呈显著正相关关系,天牛携带的线虫数与枯死松树数量也呈显著正相关关系。聚类分析结果表明,北部林场、古南街道和篆塘镇15个村子在松材线虫病灾变风险方面明显地聚为3类,其中古南街道花坝村、连城村、清水村和南山村聚为一类,北部林场荣农村、十隆村、顺山村、可乐村、长春村、狮岭村以及篆塘镇铁马村、群乐村、联合村、珠滩村聚为一类,篆塘镇葡萄村独成一类,分别为松材线虫病主发区、高风险区和低风险区。【结论】重庆市綦江区松墨天牛种群呈加速扩散态势,松材线虫病在各环境因素作用下流行灾变的风险高,应加强检疫管理和提高综合防控技术。     

松材线虫Bx-Daf-22基因鉴定及表达

[目的]为探究松材线虫(Bursaphelenchus xylophilus)抗逆态幼虫DL3(Dauer larvae3)形成的分子机理,对其鸟苷酸环化酶路径(cyclic guanosine monophosphate,cGMP)中的抗逆态基因daf-22进行了鉴定和表达研究。[方法]根据松材线虫基因组数据设计引物克隆松材线虫Bx-Daf-22基因。进一步对Bx-Daf-22基因编码的蛋白进行系统发育分析、保守结构域分析等生物信息学分析。应用BLAST比对技术在松材线虫基因组数据中鉴定得到固醇载体蛋白SCP2同源基因,命名为Bx-Daf-22。应用PCR技术扩增Bx-Daf-22完整蛋白编码区,分析同源序列系统进化和三维结构。[结果]结果表明,Daf-22作为路径的起点是cGMP路径中一个受体蛋白,可将起始信号传递到cGMP路径的膜结合受体上,再通过胰岛素相似信号途径(insulin like signaling,Insulin/IGF)中的β-胰岛素(β-insulin,Daf-28)以及转化生长因子β路径(transforming growth factor β,TGFβ-like)中的热激蛋白90(HSP90/Daf-21)连接从而调控线虫进入抗逆态。[结论]通过结构比对及基因表达量分析表明Bx-Daf-22与秀丽线虫Daf-22具有相近的功能。Bx-Daf-22编码的蛋白质具有固醇载体蛋白SCP2构域。因此松材线虫的cGMP路径与DL3形成具有直接相关。     

Effects of stocking density,ration and temperature on growth,survival and metamorphosis of auricularia larvae of the California sea cucumber,Parastichopus californicus

The combined effects of stocking density (0.2, 0.5, 1, 2, 4 and 8 inds/ml) and dietary microalgal ration (20,000 and 40,000 cells/ml) and the sole effect of temperature (10, 12, 14, 16, 18 and 22°C) on the specific growth rate (SGR), per cent survival and per cent metamorphosis of auricularia larvae of the California sea cucumber, Parastichopus californicus, were evaluated in two separate experiments. The SGR was not significantly affected by stocking densities in the range of 0.2 to 4 inds/ml, but was significantly reduced at 8 inds/ml. The SGR of larvae fed 20,000 cells/ml was significantly reduced in comparison to those fed 40,000 cells/ml. Larvae had significantly higher per cent survival and per cent metamorphosis when reared at densities of 0.2 and 0.5 inds/ml compared with those reared at 2–8 inds/ml. Microalgal ration level did not significantly impact survival or metamorphosis. Larvae reared at 16 and 18°C had significantly higher SGRs and per cent metamorphosis than those held at all other temperatures, while per cent survival was highest at 16°C. Based on these results, we recommend rearing auricularia larvae of P. californicus at a stocking density at or below 0.5 inds/ml, a dietary ration of 40,000 cells/ml, and a temperature of 16°C.     

光色对中华绒螯蟹幼体诱集与仔蟹摄食的影响

为揭示不同发育阶段中华绒螯蟹Eriocheir sinensis对光照颜色的行为反应,探究蟹类颜色视觉的特征,采用自制的试验装置,研究了蓝光(波长446~493 nm)、绿光(波长502~579 nm)、黄光(波长586~600 nm)、红光(波长620~644 nm)、白光(波长440~637 nm)对中华绒螯蟹Ⅱ~Ⅴ期溞状幼体与大眼幼体的诱集效果,以及对仔蟹摄食的影响。结果表明:在室内试验装置中,Ⅱ~Ⅴ期溞状幼体和大眼幼体在蓝光下的分布率最高,极显著高于其他光照组(P0.01),各期幼体在绿光下的分布率也不同程度地高于其他光照组;在室外土池中,采用容积为1 L的捕苗器,在蓝光下捕获大眼幼体的数量最多,为1097尾,极显著高于白光组(253尾)、红光组(121尾)和黄光组(35尾)(P0.01),显著高于绿光组(629尾)(P0.05);24 h内各光色组中仔蟹的昼夜摄食量结果显示,各组仔蟹的日摄食量无显著性差异(P0.05),白天摄食量平均值高于夜晚,但差异并不显著(P0.05)。