Exploring the efficacy of vaccine techniques in juvenile sablefish,Anoplopoma fimbria

Wild sablefish, Anoplopoma fimbria, are a valuable commercial species whose populations are declining. Fortunately, sablefish are excellent species for commercial aquaculture. Sablefish raised under high‐density conditions in the marine environment require the use of efficacious vaccines to control disease. Sablefish impacted by disease in net pens may have poor flesh quality and high mortality during grow‐out. As a result, disease can cause financial hardship for sablefish aquaculture operators. The efficacy of a multivalent vaccine preparation for sablefish, administered either by intraperitoneal (i.p.) injection or by immersion, against atypical and typical Aeromonas salmonicida, the causative agents of atypical and typical furunculosis, respectively, was examined. A. salmonicida can affect sablefish at any age and size. Consequently, an efficacious vaccine that can be appropriately and optimally administered to all life stages is desirable. Sablefish vaccinated by immersion at ~1.5 or ~4.5 g with a whole‐cell multivalent vaccine were not protected against either typical or atypical A. salmonicida. Factors that may have contributed to the ineffectiveness of the immersion vaccine are discussed. By contrast, the relative per cent survival (RPS) or potency of the whole‐cell multivalent vaccine injected i.p. in juvenile sablefish at ~50 g against typical and atypical A. salmonicida was 94.3% and 81.7% respectively. The high RPS values indicated that the vaccine successfully initiated an immune response in sablefish upon a second encounter with the pathogen.     

Effects of photoperiod,light intensity,turbidity and prey density on feed incidence and survival in first feeding yellow tang (Zebrasoma flavescens)(Bennett)

Zebrasoma flavescens (Bennett) aquaculture is limited by high mortality during first feeding. Photoperiod, light intensity, turbidity and prey density are culture parameters that have been shown to affect feed incidence and survival in some food fish species, offering a logical starting point to improve first feeding in Z. flavescens. This study aimed to determine the effect of photoperiod, light intensity, turbidity and prey density on feed incidence and survival in larval yellow tang age 3 DPH to 5 DPH (days post hatch). Larvae were reared in four photoperiods (24L:0D, 16L:8D, 12L:12D, 0L:24D), four light intensities (1,500, 3,000, 4,500 and 6,500 lx), three turbidity ranges (0 cells/ml, 100,000–200,000 cells/ml and 400,000–600,000 cells/ml) and four prey densities (1, 3, 6 and 9 per mL). Photoperiod at 16L:8D and 12L:12D significantly increased feed incidence; 16L:8D significantly increased survival. Light intensities at 3,000 and 4,500 lx significantly increased feed incidence. Larvae reared in 400,000–600,000 cells/ml fed and survived significantly better than those in clear water. Larvae in 1 per mL fed and survived significantly less than those fed at 6 per mL.     

Eastern little tuna,Euthynnus affinis (Cantor, 1849) mature and reproduce within 1 year of rearing in land‐based tanks

Eastern little tuna (ELT, Euthynnus affinis) is expected to see use as a novel aquaculture species due to its rapid growth and high economic value. In this study, closing of the complete life cycle of ELT in land‐based tanks was successfully carried out. Seed production of a first generation (F1) derived from wild‐caught ELT broodstock was conducted in 2010, 2011 and 2012. Survival percentages of F1 ELT at 365 days post hatching for the 2010, 2011 and 2012 year classes were 0.9%, 0.4% and 6.3% respectively. On average, F1 ELT were approximately 40 cm in total length and weighed 1500 g by the time they reached 1 year of age. Successful artificial induction of spawning was achieved in 1‐year‐old F1 ELT using a gonadotropin‐releasing hormone analogue (GnRHa). Induction of spawning was successful at the first administration of GnRHa in the 2010, 2011 and 2012 year classes. First spawning was observed at 4 or 5 days post implantation, which indicated that oogenesis and spermatogenesis progressed within 1 year of rearing in land‐based tanks. During spawning periods, the average number of fertilized eggs and the average number of hatched larvae per spawning event in the 2010, 2011 and 2012 year classes were 20,480 eggs day^?1 and 177 larvae day^?1, 39,423 eggs day^?1 and 9347 larvae day^?1, and 819,555 eggs day^?1 and 674,445 larvae day^?1 respectively. Therefore, it was concluded that both male and female ELT reared in land‐based tanks were capable of reproduction at 1 year of age.     

Water quality,waste production,and off-flavor characterization in a depuration system stocked with market-size Atlantic salmon Salmo salar

Land-based Atlantic salmon, Salmo salar, grow-out facilities utilize depuration to remediate off-flavor. Water used in this process is either discharged or repurposed as supply water in recirculating aquaculture systems (RAS). Both approaches require an understanding of water quality and waste production for water treatment decisions and compliance with pollution discharge standards; however, these data were lacking. Therefore, a study was carried out to characterize these parameters. To begin, 311 salmon (5–6 kg) originally cultured in freshwater RAS were stocked at 100 kg/m³ in an 18 m³ depuration tank. Feed was withheld 1 day before transfer and throughout the 7-day study period. Hours after stocking, total suspended solids (TSS), total phosphorus (TP), and total ammonia nitrogen (TAN) levels spiked, and concentrations declined thereafter. Delta TSS and TP were negligible by the end of the trial; however, TAN plateaued, indicating that salmon began to catabolize somatic tissue in the absence of feeding. Geosmin and 2-methylisoboreol levels in water and fish were low throughout the study. This research indicates that residual waste production occurs while depurating Atlantic salmon. Procedural refinements and recommendations were gleaned including locality for introducing depuration system water within RAS and extension of the feed withholding period before depuration.     

反硝化技术对模拟养殖池塘修复的研究

浙江奉化市池塘的底泥经过反复培养、驯化.从中筛选、分离出反硝化细菌,在模拟实验条件下,研究其对不同浓度的硝酸盐氮和亚硝酸盐氮的去除情况,讨论反硝化菌种的生长情况.结果表明,在初始浓度为1、25、50 mg·L-1的硝酸盐氮和亚硝酸盐氮模拟池塘中,随着实验的进行,对污染物的去除效果逐渐提高.其中在1 mg·L-1的浓度组中,3 d内硝酸盐氮和亚硝酸盐氮去除率就分别达到了95.8%和90.2%;在25 mg·L-1的浓度组中,第6 d硝酸盐氮和亚硝酸盐的去除率分别为93.8%和87.8%;在50 mg·L-1的浓度组中,第6 d硝酸盐氮和亚硝酸盐的去除率分别为89.7%和78.7%.此外,反硝化菌对硝酸盐氮的去除效果略优于亚硝酸盐氮,而且硝酸盐氮和亚硝酸盐氮的浓度越低,对其去除效果越好,达到稳定状态的时间越短.在模拟池塘中,菌种的生长情况与硝酸盐氮和亚硝酸盐氮的浓度呈负相关,即污染物的浓度越高反硝化菌的生长情况越差.对反硝化菌的生态影响因子研究表明,其反硝化最适宜的pH值为6～7,温度为25～35℃;而且在同一pH值和温度条件下,硝酸盐氮和亚硝酸盐氮浓度越低,反硝化菌对其去除效果越好.     

基于Web服务的农产品企业管理平台研究与设计

在了解农产品企业使用管理软件的过程中出现的各种问题和Web Service关键技术与特点的基础上,阐述了如何应用Web Service技术来设计农产品企业管理平台,给出了系统框架,实现了在不同的客户端对Web服务的调用,实现异构系统简单信息集成共享,并结合开发实例进行了论述。     

应用耕水机养殖南美白对虾的试验

为探索一条新的水产养殖途径,该文利用耕水机进行南美白对虾养殖对比试验。在一个养殖周期内对溶解氧、温度、pH值和亚硝酸盐等水环境因子及南美白对虾生长情况、品质和经济效益进行了分析研究。试验结果表明：与非耕水机养殖比较,使用耕水机能够提高水体溶解氧均匀度和温度均匀度,增加池塘溶解氧含量;维持水体pH值在7.6～8.9之间;降低水体亚硝酸盐含量;对虾生长速度快且品质优良;节约耗电量56.9%、饵料15.5%、药费45.4%;提高单位面积产量20.1%。试验和分析结果证明使用耕水机能够改善水体环境,降低养殖成本,增加养殖收入,有较高的实际应用价值。     

复合微生物制剂在日本鳗鲡土池精养中的应用

本研究开展了对日本鳗鲡(Anguilla japonica) 精养殖土池,定期泼洒施用一种复合微生物制剂（Freshplus净水剂）的对比试验,定期监测了处理组和对照组池塘的水温、pH、溶氧、氨氮、亚硝酸盐氮、硝酸盐氮、COD、碱度等水质指标,并分析对比了鳗鱼养殖效果。结果表明：Freshplus净水剂的施用能显著降低鳗鱼土池水体氨氮浓度60.5% (p＜0.05)、显著提高鳗鱼生长速度33.0% (p＜0.05),降低饲料系数9.6% (p＜0.1)。     

Total and available tryptophan requirement of Nile tilapia,Oreochromis niloticus,fingerlings

The dietary total and available requirement of tryptophan of Nile tilapia fingerlings was determined using linear regression analysis. Six hundred fish (3.4 ± 0.0 g) were fed diets containing 296.4 g/kg of crude protein and 14.1 MJ/kg of digestible energy. Five extruded diets containing 2.5, 3.0, 3.4, 3.8 and 4.2 g/kg of total tryptophan were evaluated. Fish were fed four times a day during 45 days. Final body weight, weight gain, feed intake, feed conversion ratio and net protein utilization of fish fed Trp 3.4 and Trp 3.8 diets were improved compared to fish fed Trp 2.5 and Trp 4.2 diets. No significant differences in survival rate, whole‐body moisture and ash were observed. Whole‐body amino acid profile of fish fed different diets did not differ statistically (p > .05). Fish fed Trp 3.0 and Trp 3.4 diets showed higher tryptophan retention compared to fish fed Trp 2.5 and Trp 4.2 diets. Excepting blood glucose, no effects of dietary tryptophan on haematological parameters were observed. The dietary total tryptophan requirement of Nile tilapia fingerlings based on weight gain was estimated to be 3.4 g/kg (11.0 g/kg of dietary crude protein) or 3.0 g/kg of available tryptophan (11.0 g/kg of dietary digestible protein).