Effects of feeding regime and probionts on the diverting microbial communities in rotifer Brachionus culture

Rotifer growth performance and microbial community changes associated with rotifer cultures were monitored while different feed types (Nannochloropsis oculata paste and the commercial yeast based feed CS-3000), different regimes (daily changes, changes per batch and no changes) and mixtures of three probionts (Phenylobacterium sp.; Gluconobacter sp. and Paracoccus denitrificans) were provided. It was shown that the dominant bacterial species in the cultures receiving either N. oculata or CS-3000 were different. However, in cultures receiving both feeds (either switching between feeds on a daily basis or on a batch basis), a high similarity in microbial community fingerprint was found. The presence of probionts was detected by the end of four batch culture cycles in spite of strong shifts of the bacterial community. By group discriminant analysis, it was found that Phenylobacterium sp. and Paracoccus sp. contributed positively to the CS-3000-fed group, while Gluconobacter sp. contributed positively to the N. oculata-fed group, although they did not appear as very dominant species.     

Benthic microbial indicators of fish farm impact in a coastal area of the Tyrrhenian Sea

We studied the impact of organic loads due to the biodeposition of a fish farm in a non-impacted coastal area of the Tyrrhenian Sea (Western Mediterranean). Sediment chemistry and benthic microbial community were investigated from July 1997 to February 1998 on monthly basis at two stations: one was located under the fish farm, while the second was about 1 km away, and served as a reference site. The presence of the cage induced rapid changes in the benthic conditions: the sediments were rapidly (after 6 weeks) reduced. A significant accumulation of biopolymeric carbon was observed beneath the cage both 2 weeks after the initial cage deployment, on non-impacted sediments, and 5–7 months after, and appeared to be related to the fish farm production cycle. The density of microbial communities beneath the fish farm increased only during the first month of farming activity (July) and partially 7 months after cage disposal (i.e. in January), when there was a significant sediment organic enrichment. Additional evidence of rapid impact of the fish farm on the benthic bacterial communities is provided by the increase in the numbers of autofluorescent microbial cells. The photosynthetic eukaryotic cells displayed a highly reduced contribution to total autofluorescent microbial density, indicating that their decrease is related with biopolymeric carbon accumulation, and probably was due also to “shadow effect” induced by suspended material, coming from the fish farm, on the environment below. We propose here, to apply the ratio of culturable heterotrophic bacteria to microbial direct counts (CFU/MDC) to detect fish farm impact. In cage sediments, organic enrichment and the consequent modification of the characteristics of the benthic environment, determined an increase in aerobic heterotrophic bacteria and vibrio density indicating that they are efficient colonizers of organic-rich sediments. Densities of Escherichia coli and Enterococci were not significantly higher than in the reference site, and are likely of terrestrial origin. Thus they cannot be used as specific indicators of fish farm impact.     

大力发展“第二代生物燃料”

办为满足国民经济高速持续发展对新型能源日益增长的需求,适应改善我国能源消费结构、节能减排、发展低碳经济的需要,加快发展生物质能源是一项战略选择。文章阐述了大力发展新兴生物燃料产业具有的重大经济社会意义,提出以大批粮食、食用油为原料生产生物燃料,是第一代生物燃料,在我国发展中遭遇到不可逾越的障碍。认为大力发展第二代生物燃料,即纤维素燃料乙醇和木本油料生物柴油具有多种优越性,将开辟我国生物燃料持续发展的广阔途径,特别是开发利用广袤的“边际性土地”,即开辟最普遍、最丰富的生产生物燃料的资源,既可改善生态脆弱地区的生产与生活环境,还可点燃农业农村新经济增长点,有利于解决“三农”问题,效用重大。最后提出我国发展生物燃料的五条必要措施,包括：大力开发广袤的“边际性土地”;尽快攻克纤维素燃料乙醇的技术难关;建立健全生物燃料能源市场体系,以市场机制优化资源配置;建立专业生物能源资源产销合作社,建立社会化服务体系;加大财政扶持力度,把发展第二代生物燃料列入国家“十二五”经济社会发展规划。     

Physiological responses of pink abalone Haliotis corrugata (Gray, 1828) exposed to different combinations of temperature and salinity

Physiological responses of pink abalone Haliotis corrugata were determined under different temperature and salinity conditions. Oxygen consumption rate was not affected by temperature and salinity. Ammonium excretion of pink abalone was inversely related to salinity. The O:N ratio indicated that abalone maintained in lower salinities had an interval of 4.9–7.7, which is indicative of a protein‐dominated metabolism, whereas the O:N in 35‰ was 28.8–35.5 for both temperatures, suggesting that carbohydrates were used as energy substrate. Haemolymph osmolality of abalone exposed to 20 and 24 °C was slightly hyperiso‐osmoconformic in salinity ranges of 20–35‰. The results of this study suggested that for optimized culture, pink abalone should be cultivated at 24 °C at a salinity of 35‰.     

海洋胶红酵母Y2产类胡萝卜素发酵促进剂的研究

研究了几种添加物对海洋胶红酵母（Rhodotorulamucilaginosa）Y2发酵产类胡萝卜素的促进作用。在摇瓶条件下,发酵培养基中分别添加不同量的番茄汁、花生油、大豆油、玉米浆、谷氨酸钠和生物素,培养72h后取样分别测定类胡萝卜素产量及生物量。结果显示,当分别添加2mL·L-1番茄汁、1．5mL·L-1花生油和3mL·L-1玉米浆时,类胡萝卜素产量比对照组提高14．2％、30．3％和21．3％;谷氨酸钠和生物素会抑制海洋胶红酵母Y2类胡萝卜素的合成。因此,番茄汁、花生油和玉米浆是较为经济适用的海洋胶红酵母Y2产类胡萝卜素发酵促进剂,具有广阔的开发应用潜力。     

Changes in density of under-yearling masu salmon <Emphasis Type="Italic">Oncorhynchus masou</Emphasis> in a natural stream after release

ABSTRACT:   The relation between the density of fish and parameters such as body weight, condition factor and the hepatic triglyceride (TG) content of masu salmon Oncorhynchus masou juveniles after release into a natural stream were studied. Hatchery-reared juveniles of different sizes and numbers were released in May 1999, 2000 and 2001, and investigations were carried out from July to September each year. The density of fish was relatively high in 1999, when juveniles of the largest size and number were released, but then continued to decrease during the investigation. The hepatic TG content remained considerably low in 1999, and there was a significant negative correlation between the density of fish and the hepatic TG content of the juveniles caught over three years. The initial fish size and number at release as well as the nutritional condition of the juveniles may affect the density of fish after release.     

Photosynthetic suspended-growth systems in aquaculture

Standardized evaluation and rating of biofilters for aquaculture should be assessed in the context of the economic efficiency of ecological services (waste assimilation, nutrient recycling, and internal food production) provided by earthen ponds, and the availability and cost of land, water, and electrical energy resources required to support particular classes of production systems. In photosynthetic suspended-growth systems, water quality control is achieved by a combination of natural and mechanical processes. Natural processes include photosynthesis of oxygen, algal nutrient uptake, coupled nitrification–denitrification, and organic matter oxidation; mechanical processes include aeration and water circulation. Ammonia is controlled by a combination of phytoplankton uptake, nitrification, and immobilization by bacteria. Unlike biofilters for recirculating aquaculture systems, unit processes are combined and are an integral part of the culture unit. The important design and operational considerations for photosynthetic suspended-growth systems include temperature effects, aeration and mixing, quantity and quality of loaded organic matter, and fish water quality tolerance limits. The principle advantages of photosynthetic suspended-growth systems are lower capital costs relative to other recirculating aquaculture systems and increased control over stock management relative to conventional static ponds. The main disadvantage is the relatively low degree of control over water quality and phytoplankton density, metabolism, and community composition relative to other recirculating aquaculture systems. Examples of photosynthetic suspended-growth systems include semi-intensive ponds, intensively aerated outdoor lined ponds, combined intensive–extensive ponds, partitioned aquaculture systems, greenwater tanks, greenwater tanks with solids removal, and greenwater recirculating aquaculture systems.     

勤得利湾浮游植物群落结构特征

2003年5、7、9、11月对勤得利湾浮游植物的种类组成结构特征进行了研究。结果表明:浮游植物共计7门69种,以绿藻、硅藻为主,分别占52.36%和20.11%。近亲鱼腥藻、铜绿微囊藻、普通小球藻、柱形栅列藻、四尾栅列藻、颗粒直链藻、细长锥囊藻、四角十字藻、浮球藻、含糊囊裸藻、针形纤维藻、尺骨针杆藻等为优势种。浮游植物数量为1750.8×104ind./L,以硅藻为主,数量为517.3×104ind./L,占29.55%;生物量为16.082mg/L,硅藻最高,为7.285mg/L。浮游植物季节变化比较明显,数量夏季最高为2801.4×104ind./L,生物量以夏季最高28.235mg/L;水平分布采样点Ⅲ最高,平均为2158.6×104ind./L,采样点Ⅳ生物量最高为12.296mg/L。多样性指数变化是夏季>秋季>冬季>春季。均匀度指数变化是秋季>夏季>冬季>春季。     

烟杆生物质燃灰替代硫酸钾的研究

[目的]为了研究不同替代比例的烟杆生物质燃灰对烟叶质量的影响.[方法]设置1个对照和3个处理,对烟叶的农艺性状、常规化学成分与经济效益进行对比分析.[结果]不同代替比例的烟杆生物质燃灰对烟株生长有不同的影响,主要对烤烟的最大叶面积与项叶面积有较大影响;随着烟叶着生部位的降低,烟杆生物质燃灰的不同替代比例对化学成分的影响逐渐增强;其中,T3处理相比对照可以提高产值8 717.72 元/hm2.[结论]生产上,可以通过添加一定比例的生物质燃灰代替硫酸钾肥料以提高烟叶品质,充分提高生物质燃料的利用率.     

鸭流感病毒4/2004-H6N2亚型毒株的血凝素基因全序列克隆与分析

2004初从正常鸭群中分离到一株鸭源禽流感病毒，命名为A／Duck／HN／4／2004(H6N2)。经对血凝素基因(HA)序列分析发现HA基因全长为1744bp，共编码566个氨基酸，在裂解位点仅含一个碱性氨基酸-精氨酸(R)，符合LPAIV的标准。将所得基因序列与已发表的同一亚型参考序列分析表明，与H6亚型流感HA基因同源性为89．2％-97．1％，经分子遗传演化分析表明本次分离株与香港分离株A／Duck／Hong Kong／3600／99(H6N2)、A／Duck／Hong Kong／3600／99(H6N2)最近。