Gene Expression in Black Tiger Prawns Following Intramuscular Injection of β-gal Plasmid

Gene expression in black tiger prawns (Penaeus monodon) was studied following intra-muscular injection of CMVGal plasmid into the second abdominal segment. We used an in situ staining technique to detect -gal expression in one- and three-month-old injected prawns. We found that only one of the three-month-old prawns expressed the marker gene (2 days after injection), and the site of expression was confined to the sixth abdominal segment away from the injection site. We repeated the experiment on a new batch of three-month-old prawns, but using fluorometric determination technique. This time we found that -gal expression was detected (6/42) at the site of injection after 2, 7, and 14 days. In two other test samples, transgene expression was detected in the sixth abdominal segment only, further confirming the possibility of injected DNA dispersal. The results of the study also suggest that direct gene transfer is a feasible technique in black tiger prawns.     

中国对虾育苗中几项新的技术措施

本文针对目前中国对虾苗种生产中幼体病害日益严重的问题，提出了采用卵子消毒和生态防病作为预防疾病的重要手段，并介绍了几种消毒剂用于对虾幼体不同时期的安全浓度，为对虾育苗生产中防治病害提供了几项新的技术措施。     

磁化海水在对虾育苗中的应用研究

经过磁场处理的海水;应用在中国对虾人工育苗和短期养成的研究中,产生了良好的生物效应,使用1600G、2400G、3000G三种磁感应强度的磁化装置处理的海水,对于仔虾的成活率都有较明显的提高,平均提高17.90％;在对虾短期养成(室内)中,使成活率和体长都比对照高,平均提高51.88％和10.56％。这主要因为     

日本对虾活体干法运输技术研究

介绍了日本对虾无水保活运输的捕捞、暂养、包装、贮放、运输等技术。     

中国水产苗种进口特征及其对养殖产业发展的影响分析——基于2013—2018年的数据

水产种业是水产养殖业的战略性、基础性核心产业,水产苗种引进是促进水产养殖业绿色发展的一个重要途径。中国水产苗种引进品种繁多,水产观赏动物成为新宠,通过分析2013—2018年水产苗种进口贸易数据,其主要特征为:进口额呈下降趋势,进口种类涉及24种,部分种类的进口频率达到100%,用于水产养殖的苗种和受精鱼卵进口额分别为14061.19×104美元和632.02×104美元。从进口额数据来看,小虾及对虾、鳗鱼、受精鱼卵及其他鱼种等主要进口苗种种类对水产养殖业发展的影响较大,其中鳗鱼增养殖业对进口鳗苗的依赖程度较高,平均依赖度为50.86%。提出构建养殖鱼类苗种进口预警机制,谋划养殖鱼类品种的替代策略,提高对虾苗种控制能力,做好水产苗种进口质量安全防范等建议,以保障水产养殖产业健康稳定发展。     

亲虾暂养,卵子消毒与生态防病技术研究

研究了亲虾暂养中温度，盐度突变对卵子孵化率的影响，提出了卵子消毒和生态防病等新的技术手段。     

Possible effects of the recent Australian ban on prawn imports

Australia banned imports of uncooked prawns from Asia in early 2017 after an outbreak of the deadly white spot disease in southern Queensland. The ban expired after 6 months, and it remains unclear what the source of the epidemic was, or the mechanism through which it may have entered the country. The Queensland State Government offered financial assistance to selected producers, although as a group, producers benefit from the higher prices resulting from the ban. In fact, the major cost of the ban is borne by domestic consumers and foreign producers. The major impact is a transfer from Australian consumers to Australian producers. These transfers are quantified in this analysis, as are the impacts on developing country exporters.     

The effects of dietary lipid sources and lecithin on the production of giant freshwater prawn <Emphasis Type="Italic">Macrobrachium rosenbergii</Emphasis> larvae in the Mekong Delta region of Vietnam

The giant freshwater prawn, Macrobrachium rosenbergii, is cultured widely in the Mekong Delta region of Vietnam but it is often difficult or expensive for hatchery operators to purchase commercial diets used as a feeding supplement to Artemia nauplii. Therefore, in the present study, the effects of lipid sources and lecithin on the growth and survival rate of M. rosenbergii larvae were examined in order to develop suitable hand-prepared larval diets for seed production of M. rosenbergii in this area. Six egg custard diets consisting of various ratios of lipid (originating from soybean oil and squid oil) and lecithin were used for rearing Macrobrachium rosenbergii larvae. Treatments in which larvae were fed diets containing squid oil exhibited the highest body length and survival rates (7.14–7.43 mm and 51.1–68.1%, respectively), and differed significantly from other treatments (P<0.05). Use of dietary soybean oil yielded the lowest body length and survival rates (6.29–6.75 mm and 22.0–48.7%), respectively). The supplementation of dietary lecithin did not increase final body weight but did improve larval survival rates. The n-3 HUFA content of prawns fed dietary squid oil was higher than those of animals provided with other diets. These results indicated that the most appropriate diet for rearing M. rosenbergii larvae is the diet containing 3% squid oil and 1.5% lecithin.     

Targeted species substitution in giant freshwater prawn trade revealed by genotyping

This study presents the molecular barcoding results of giant freshwater prawns and allied products collected from inland landing centres, markets and stores of Vembanad Lake (Kerala state, India) which is recognized as a natural abode for Macrobrachium rosenbergii. Prawns collected from landing centres of the lake could be easily identified as the above with their large size and morphological characters. There were certain ‘alien’ prawns and prawn products (headless shell on, peeled and deveined) traded in the markets and stores of this region as M. rosenbergii. Genotyping of all these samples using COI and 16S rRNA gene sequences confirmed the speciation of individuals from inland landing centres as M. rosenbergii, ‘alien’ prawns and certain prawn products as M. malcolmsonii. To ensure the same and to detect the presence of any other congeners of genus Macrobrachium inhabiting Vembanad Lake, additional homologous COI and 16S rRNA sequences available in NCBI were acquired and incorporated for molecular analyses. Results generated from NJ tree and genetic distance data confirmed the trade of non‐indigenous Macrobrachium species M. malcolmsonii in Kerala for the first time and its use as a species substituent for M. rosenbergii.     

The effect of Penaeus merguiensis densovirus on Penaeus merguiensis production in Queensland, Australia

Penaeus merguiensis densovirus (PmergDNV) is currently present on several Queensland prawn farms culturing Penaeus merguiensis. Densoviruses have been linked to mortality and stunting that has caused significant financial loss to prawn farms in Asia. A histopathological study for PmergDNV was initially undertaken to compare broodstock to grow out factors from 60 broodstock animals from each of 22 ponds. There was a significant negative correlation (r = -0.61) between the number of animals with PmergDNV lesions and healthy animals. Furthermore, a higher number of septic hepatopancreatic tubules was correlated (r = 0.48) to high PmergDNV loads. Hence, a polymerase chain reaction analysis of 10-day-old post-larvae (PL) was conducted to determine whether PmergDNV infection was resulting in production losses. An attributable risk analysis of PL from 190 ponds over a 2-year period revealed that 28-29% of ponds with below average survival will have at least average survival following the removal of or decreased levels of PmergDNV. P. merguiensis culture facilities in Queensland should have at least a 14.5% increase in production, equating to an increase of $2.25 million within the first year alone, following the removal or reduction of PmergDNV in their ponds. Hence, focussing efforts on prevention, better management practices and maintaining healthy stock should be of top priority.