Use of molasses as a carbon source during the nursery rearing of Farfantepenaeus brasiliensis (Latreille, 1817) in a Biofloc technology system

The present work evaluated the use of molasses as a carbon source during the nursery rearing of Farfantepenaeus brasiliensis in a Biofloc technology system. During a 30 days trial, three replicate tanks were randomly assigned to the following treatments: 1.) molasses (with molasses addition) and 2.) control (without molasses addition). Bacteriological analysis was used to quantify the abundance of presumptive Vibrio spp. between control and molasses treatment. The concentration of this microorganism was lower in molasses compared with control. For the immunological analysis, shrimp haemolymph was collected to determine the total haemocyte count and the total protein concentration. The immunological results were not different between treatments. The performance results of shrimp reared with molasses addition showed that the survival rate (88.87 ± 6.36), the mean final weight (1.22 ± 0.38) and the specific growth rate (0.0309 ± 1.06) were significantly higher compared with control (80.5 ± 2.42; 1.03 ± 0.13; 0.0256 ± 0.97 respectively). Moreover, the addition of molasses contributed to the maintenance of water quality and lower concentration of presumptive Vibrio spp. The control presented an unstable variation of Vibrio spp. reaching values of 80 × 10² CFU/ml, while the highest result of molasses was 20 × 10² CFU/ml, confirming the beneficial effects of molasses addition.     

Incentive for shifts in water management systems by shrimp culturists in southern Thailand

ABSTRACT:   Water management systems and other business situations of shrimp culturists were surveyed in two districts in southern Thailand. There were three types of water management systems in southern Thailand, namely closed, semiclosed and open systems, categorized by the frequency of exchange of pond water. Shrimp culturists in those districts tended to shift their system from the open system to the closed system of their own accord, and the average net income ratio decreased due to the change of water management system in a district from more than 2 to less than 1. The reason for this shift, in spite of the decrease in the profit rate, was prevention of infectious disease caused by water exchange. In conclusion, it was proven that independent shrimp culturists, such as medium and small scale shrimp pond owners in southern Thailand, would accept short-term decreases in profit rate in order to stabilize production.     

Fouling and predation; how do they affect growth and survival of the blacklip pearl oyster, Pinctada margaritifera, during nursery culture?

This paper reports on 5 experiments conducted to assess the effect of cleaning regime and predation on growth and survival of blacklip pearl oyster (Pinctada margaritifera) juveniles in north Queensland, Australia. P. margaritifera juveniles with a mean (±SE) dorso-ventral shell height (DVH) of 4.5 ± 0.1 mm were placed into plastic mesh trays and cleaned either every 4 or 8 weeks or left uncleaned for 16 weeks. Cleaning regime had a significant effect on growth and survival (P < 0.005). Lowest DVH (16.2 ± 1.0) was shown by oysters in uncleaned trays during 16 weeks compared to oysters in cleaned trays; however, there was no significant difference in DVH between oysters held in trays cleaned every 4 (19.4 ± 1.2) or 8 weeks (21.2 ± 0.8). In contrast lowest survival was shown by oysters held in trays that were cleaned every 4 weeks (30 ± 5%), but no differences were noted between oysters cleaned every 8 weeks (63 ± 4%) and oysters that were left uncleaned for 16 weeks (75 ± 8%). Predators of P. margaritifera in northern Australia included crabs, stomatopods, flatworms, gastropods and fish. The stomatopod, Gonodactylus falcatus, was the most destructive predator with individuals consuming in excess of 20 juvenile pearl oysters per week. The leather jacket, Paramonocanthus japonicus, did not kill pearl oysters, but trimmed the margin of oysters shells significantly reducing DVH when compared to control groups cultured without fish. Removing predators monthly had a significant effect on growth of pearl oysters compared to oysters in non-inspected trays; however monthly inspection of culture trays did not significantly improve oyster survival. This revised version was published online in August 2006 with corrections to the Cover Date.     

盐碱地渗水调配养殖南美白对虾技术

本文介绍了利用黄河三角洲地区丰富、闲置的重盐碱地,经过合理调配水质,在反复试验的基础上设计出一套合理的健康养殖技术方案,实施了大面积南美白对虾盐碱地健康养殖。尤其是通过在用盐碱地渗出的咸水与淡水混合调配成的,盐度为5～20的养殖用水中,添加一定浓度的钾离子,有效提高了虾苗的成活率。     

西狭文化旅游形象三重结构整合

西狭文化旅游资源是甘肃成县旅游开发的优势资源。由于对西狭文化理解上的不全面 ,导致西狭文化旅游区的建设存在一系列偏差 ,旅游形象不突出。文章提出了西狭文化旅游形象的三重结构整合的思路 ,即文化结构整合、空间结构整合与景观结构整合 ;并且认为 :文化结构整合是西狭文化旅游形象三重结构整合的前提、基础 ;空间结构整合是由文化结构整合向景观结构整合的过渡 ,而景观结构整合是西狭文化旅游形象三重结构整合的关键。     

鲫肠道上皮细胞原代培养方法的研究

探讨了健康鲫(Carassius auratus)幼鱼肠道上皮细胞的原代培养方法。结果显示,用含有抗生素、胶原蛋白酶Ⅰ、EDTA和胶原蛋白酶Ⅳ组成的D-Hanks液消化无菌分离的鲫肠道可以获得大量细胞团及绒毛隐窝;用含有抗生素、胎牛血清(FBS)、表皮生长因子(EGF)、胰岛素的DMEM培养液进行培养,并根据肠道上皮细胞与成纤维细胞贴壁时间的差异进一步纯化,连续培养12d后可以得到纯化的肠道上皮细胞。     

盐碱地池塘配置网箱养鱼试验

在盐碱地一个面积为2871m^2的鱼池中,配置4个网箱．分别放养罗非鱼、淡水白鲳和鲤,箱外放养鲢、草鱼和鲤。试验结果：罗非鱼箱(20m^2)出鱼525kg．平均单产26．3kg／m^2,淡水白鲳箱(12m^2)出鱼400kg,平均单产33.3kg／m^2,鲤鱼箱两个(各12m^2)分别出鱼488．5kg和522kg,平均单产为40．7kg／m^2和43．5kg／m^2。箱外出鲢516kg,草鱼130kg,鲤1125kg。总计全池出鱼3706．5kg,亩产鱼862kg,每亩纯盈利2173．85元。试验证明：池塘配置网箱养鱼．可同池主养几种鱼,起捕容易,管理方便。     

对虾白斑病围栏封闭预防技术

“对虾白斑病的围栏封闭预防技术”是一项针对沿海低位池塘、以切断传染病源为主旨、以设置防蟹围栏为特色的对虾白斑病综合预防技术。其主要措施为：首先在贮水(兼水处理)池和养殖池周围设置防蟹围栏，将该等池塘封闭起来，使杂蟹不会从陆地侵入池内；然后通过60目滤网进水，并用敌百虫或敌杀死处理上述两种池塘，杀灭以蟹类为主的一切甲壳动物；解毒后，放养经检测不带白斑症病毒的虾苗；采取封闭式养殖，养殖期中只向养殖池加水以补充渗漏和蒸发的水损失；加水时，先将海水在贮水池中用药物处理，杀灭其中的传染该病的媒介生物(主要是桡足类)，药物解毒后再注入养殖池。此外，作为辅助措施，在养殖期中从多方面尽量保证虾池中有一个良好的生态环境。该技术已经过预备研究、实验研究和扩大试验等阶段，均证明效果良好。已扩大试验了近33．33hm^2(其中实际养虾池约17．33hm^2)，成功率达96％左右。     

地被菊幼嫩花瓣组织培养研究

以地被菊幼嫩花瓣为试材,进行了组织培养的研究,结果表明地被菊幼嫩花瓣是诱导愈伤组织的良好材料。当培养基中2.4-D和NAA浓度为0.5～2mg·L-1时,愈伤组织诱导率均达87.2%以上,并且诱导出的愈伤组织结构疏松,易于分割。在分化培养基MS+KT2mg·L-1+IAA0.5mg·L-1上,芽分化率可达92.5%。不同接种方向对地被菊花瓣不定芽形成无显著影响。地被菊花瓣培养芽的分化率以基部组织为最高(94%),中部和上部组织分化率则逐渐变低。经培养得到的再生植株与原品种相比在形态上产生了一系列变化。     

Oyster greening by outdoor mass culture of the diatom Haslea ostrearia Simonsen in enriched seawater

Oyster greening was first described in the seventeenth century as a natural phenomenon. However, it has recently been discovered that the diatom Haslea ostrearia Simonsen causes greening by synthesis of a blue pigment designated as ‘marennine’. This phenomenon, which involves massive proliferation of H. ostrearia in oyster ponds, was not understood or controlled by oyster farmers in the Marennes‐Oléron region (Atlantic coast of France). As greening oysters improved their market value, they tried to develop empirical methods to guarantee oyster fattening and improve profits. In this context, the present study investigated the feasibility of mass culture of diatoms outdoors in 10‐m³ ponds, using enriched seawater. Different biotic and abiotic parameters were monitored daily to determine the influence of the day–night temperature range. After 8 days, H. ostrearia was the dominant diatom species (66%), reaching a mean cell concentration of 2 × 10⁵ cell mL^?1 and a marennine concentration of 3.4 mg L^?1. Although intensive greening was obtained, further studies are required to optimize the production stages before this technology can be transferred to oyster farmers.