浅海养殖环境复合生态净化菌群的筛选及其净化功能

本研究由浅海网箱区富营养沉积物经多步富集和筛选获得高效复合生态净化菌群,对浅海养殖区的有机物、氨氮和亚硝酸氮有明显去除效果.研究了不同条件对复合菌液去除养殖水体中氨氮、亚硝酸氮和有机物能力的影响,并确定了最佳净化条件.结果表明,复合菌添加量、葡萄糖添加量,处理时间、温度、pH和盐度对复合菌的去除效果均有影响,实验条件确定为复合菌的添加量为3%、处理时间为4 d、温度为30±2 ℃、pH值为8.1±0.2、葡萄糖添加量为2 g/L和盐度为(30±10) g/L 时,去除效果达到最佳,此时氨氮、亚硝酸氮和溶解有机物的去除率可分别达到79.1%、85.2%和88.7%.     

流沙湾浮游植物群落特征季节变化及其与养殖活动的关系

流沙湾是中国海水珍珠“南珠”的主产区和广东省重要的贝类养殖区。为评估湾内养殖活动的环境效应,于2015~2016年对流沙湾海区进行了夏(8月)、秋(11月)、冬(2月)、春(5月) 4个季节的浮游植物和海水理化因子调查。共检出浮游植物171种,包括硅藻门43属122种、甲藻门 10属44种、蓝藻门2属2种、金藻门2属2种和裸藻门1属1种。流沙湾内湾浮游植物细胞丰度为(0.05~79.04)×104个/L,夏季>春季>秋季>冬季,且夏季丰度远大于其他三季,内湾和外湾差异不显著。春季须状角毛藻(Chaetoceros crinitus)、红海束毛藻(Trichodesmium erythraeum)和明壁圆筛藻(Coscinodiscus debilis)为主要优势种,夏季优势种主要为中肋骨条藻(Skeletonema costatum),秋季优势种主要为拟弯角毛藻(Chaetoceros pseudocurvisetus)、奇异棍形藻(Bacillaria paradoxa)、洛氏角毛藻(Chaetoceros lorenzianus),冬季主要优势种为威氏圆筛藻(Coscinodisus wailesii)、柔弱根管藻(Rhizosolenia delicatula)、岛脆杆藻(Fragilaria islandica)。其中,奇异棍形藻为春、秋、冬季的优势种,红海束毛藻为春、夏、秋季的优势种。冗余分析表明,流沙湾浮游植物优势种在春季与水温和氨氮密切相关,夏季受透明度显著影响,而在秋、冬季受亚硝酸氮含量影响显著。流沙湾不同养殖区的浮游植物多态性和丰度有明显季节差异。与2012年相比,流沙湾外湾的养殖覆盖率提高了近50%,内湾的珍珠贝养殖减少了近90%,养殖品种、规模和分布格局都发生了明显变化,目前流沙湾的浮游植物群落特征正是对其变化的一种响应。夏季鱼类网箱养殖提高了水域营养盐水平并降低了浮游植物多样性。大规模的扇贝养殖则导致了扇贝养殖区浮游植物丰度的降低。     

Measurement of 5-day biochemical oxygen demand without sample dilution or bacterial and nutrient enhancement

A direct method for measuring the 5-day biochemical oxygen demand (BOD₅) of aquaculture samples that does not require sample dilution or bacterial and nutrient enrichment was evaluated. The regression coefficient (R²) between the direct method and the standard method for the analyses of 32 samples from catfish ponds was 0.996. The slope of the regression line did not differ from 1.0 or the Y-intercept from 0.0 at P = 0.05. Thus, there was almost perfect agreement between the two methods. The control limits (three standard deviations of the mean) for a standard solution containing 15 mg/L each of glutamic acid and glucose were 17.4 and 20.4 mg/L. The precision of the two methods, based on eight replicate analyses of four pond water samples did not differ at P = 0.05.     

云斑尖塘鳢研究进展与前景展望

云斑尖塘鳢原产于东南亚地区,自20世纪80年代末引进我国,并实现人工繁育和养殖,已发展成为重要的名特优水产鱼类品种。随着养殖规模快速扩大,原有引进品种已经无法满足产业发展的需求,因此迫切需要加快云斑尖塘鳢种质资源研究,培育出能够适应人工配合饲料、生长速率快、抗寒、抗病能力强的适宜本土养殖新品种。本文综述了国内外半个世纪以来云斑尖塘鳢相关的研究进展;首先阐述了云斑尖塘鳢生殖和生长发育等生物学特征及研究进展,探讨了温度、盐度、溶解氧等环境条件对云斑尖塘鳢的影响;然后进一步总结和探讨了云斑尖塘鳢人工养殖领域的进展和面临的饲料、种质资源开发、病害防治等问题;同时也探讨了云斑尖塘鳢未来发展方向。     

《水产养殖概论》课程建设的探索与实践

按照精品课程建设的内容和要求,以培养高素质人才为目标,对《水产养殖概论》课程在教学内容、教学方法与手段、实验教学、课程考核等4个方面进行了探索与实践,并取得了较好的教学效果。     

病原检测基因芯片应用及在水产病害检测的前景

基因芯片技术是近年来迅速发展起来的一项新技术,已成为国内外研究的热点。作为生物芯片技术发展中最完备的一个分支,基因芯片以其高通量、高灵敏性、高特异性的特点,在细菌、病毒、真菌等病原检测和鉴定方面发挥着越来越重要的作用。本文介绍了基因芯片的原理和作为检测手段的优越性,并综述了基因芯片技术在细菌和病毒检测方面的应用,分析了现有水产动物病原检测技术,提出了在现有水产动物病原生物信息学的基础上,研发水产养殖动物病害诊断基因芯片的策略。     

Dietary carbohydrate/lipid ratios and nutritional condition in juvenile southern rock lobster, Jasus edwardsii

The availability of formulated diets is considered economically imperative if rock lobster aquaculture, based on the collection and ongrowing of puerulus, is to progress. Central to the development of diets is an understanding of the nutritional requirements of the species. This study determined the effect of different dietary carbohydrate/lipid ratios (17:1, 5:1, 2:1, 0.8:1) on the growth and nutritional condition of juvenile southern rock lobsters, Jasus edwardsii, by measuring standard growth parameters, proximate composition of the whole body and digestive gland, and from a histological investigation of the digestive gland. Four replicate groups of eight lobsters (initial weight 5.08±0.98 g (mean±S.D.)) per diet treatment were held in 50 l tanks, in a recirculating system at 18 °C for 84 days. Maximum growth and the highest levels of lipid and dry matter in digestive glands and whole bodies was found in lobsters fed a diet containing 27% carbohydrate and 13.5% lipid (2:1 ratio) suggesting that of the four experimental diets, this diet provided the best balance of lipid and carbohydrate. Digestive gland histology supported this conclusion and lobsters fed low carbohydrate, high lipid diets were in the best nutritional condition, with high lipid accumulation, and structurally sound epithelial cells. Digestive gland epithelial cells of lobsters fed the high carbohydrate, low lipid diets were compressed, of inconsistent shape and size, with low lipid accumulation. Histology is therefore seen as a feasible method, in addition to growth and proximate composition data, to further examine the effect of diets in nutritional studies of crustaceans.     

养殖尾水处理系统填料生物膜氮循环微生物功能特征

为探讨填料生物膜在养殖尾水处理中对水体氮循环的影响机制,采用16S rRNA基因扩增子测序和宏基因组测序技术,对填料生物膜、水体细菌的群落结构及其与氮循环相关的功能基因丰度差异特征进行了研究。结果显示,填料生物膜微生物主要参与氮代谢活动。在属水平上,Pseudomonas、Spirochaeta、Opitutus和Syntrophus是填料生物膜氮素转化过程的重要功能微生物类群。与水体相比,填料生物膜的碳代谢活动能力较强（P<0.05）;填料生物膜上固氮功能基因nifH、硝化功能基因hao、反硝化和异化硝酸盐功能基因napA、nirS、norB、norC、nrfA、nirB和氮代谢调控基因ntrC及其相应的关键酶均显著高于周围水体（P<0.05）,且对含氮污染物有显著去除效果。研究表明,养殖尾水处理系统内复合填料生物膜具有比周围水环境更强的氮周转能力,主要通过关键功能物种介导的固氮和反硝化作用实现养殖尾水氮素的转化和迁移。研究结果作为野外实验证据,可为复合填料生物膜系统在水产养殖尾水治理中的应用提供理论依据。     

Wood chips and wheat straw as alternative biofilter media for denitrification reactors treating aquaculture and other wastewaters with high nitrate concentrations

This study evaluated wood chips and wheat straw as inexpensive and readily available alternatives to more expensive plastic media for denitrification processes in treating aquaculture wastewaters or other high nitrate waters. Nine 3.8-L laboratory scale reactors (40 cm packed height × 10 cm diameter) were used to compare the performance of wood chips, wheat straw, and Kaldnes plastic media in the removal of nitrate from synthetic aquaculture wastewater. These upflow bioreactors were loaded at a constant flow rate and three influent NO₃–N concentrations of 50, 120, and 200 mg/L each for at least 4 weeks, in sequence. These experiments showed that both wood chips and wheat straw produced comparable denitrification rates to the Kaldnes plastic media. As much as 99% of nitrate was removed from the wastewater of 200 mg NO₃–N/L influent concentration. Pseudo-steady state denitrification rates for 200 mg NO₃–N/L influent concentrations averaged (1360 ± 40) g N/(m³ d) for wood chips, (1360 ± 80) g N/(m³ d) for wheat straw, and (1330 ± 70) g N/(m³ d) for Kaldnes media. These values were not the maximum potential of the reactors as nitrate profiles up through the reactors indicated that nitrate reductions in the lower half of the reactors were more than double the averages for the whole reactor. COD consumption per unit of NO₃–N removed was highest with the Kaldnes media (3.41–3.95) compared to wood chips (3.34–3.64) and wheat straw (3.26–3.46). Effluent ammonia concentrations were near zero while nitrites were around 2.0 mg NO₂–N/L for all reactor types and loading rates. During the denitrification process, alkalinity and pH increased while the oxidation–reduction potential decreased with nitrate removal.

Wood chips and wheat straw lost 16.2% and 37.7% of their masses, respectively, during the 140-day experiment. There were signs of physical degradation that included discoloration and structural transformation. The carbon to nitrogen ratio of the media also decreased. Both wood chips and wheat straw can be used as filter media for biological denitrification, but time limitations for the life of both materials must be considered.     

Comparison of Spore Inoculated and Vegetative Propagated Cultivation Methods of <Emphasis Type="Italic">Gracilaria chilensis</Emphasis> in an Integrated Seaweed and Fish Cage Culture

In Chile the integration of Gracilaria chilensis with salmon culture has shown high potential. Seaweed integrated aquaculture is of great interest as it allows waste recycling within fed cage aquaculture. The development of economically feasible suspended methods of seaweed cultivation is therefore of high importance. Hence, production and performance of two suspended Gracilaria cultivation methods, spore inoculated ropes and ropes with twined field collected seaweed, were studied in open water. The production from spore-seeded ropes was comparable to that of twined ropes for the first month of culture. Thereafter, the twined ropes had a significantly higher productivity. Fish farm wastes had no significant fertilizing effect upon Gracilaria growth rate. In addition, spore-originated thalli and field collected thalli were compared under laboratory conditions and in suspended culture using the same cultivation method. Spore-originated thalli had a 50% lower growth rate than the field collected thalli under laboratory conditions; however, no significant differences were detected in the field. Also, the occurrence of spore coalescence growth enhancement was not significant on the spore-seeded ropes. It was concluded that spore-originated cultivation techniques could be of interest for an integrated open seawater aquaculture system due to the high levels of Gracilaria polymorphism. This would result in greater adaptability to environmental variations, and a continuous supply of restocking material.