浙江鱼粉和秘鲁鱼粉氨基酸对鸡的消化率比较

本试验以去盲肠鸡和正常鸡各１６只测定了浙江鱼粉和秘鲁鱼粉的氨基酸表观消化率（ＡＡＡＤ）和真消化率（ＴＡＡＤ）。结果表明，以去盲肠鸡测定，浙江鱼粉多数氨基酸的ＡＡＡＤ和ＴＡＡＤ超过秘鲁鱼粉（Ｐ＜０．０５）。以正常鸡测定，两者大多数氨基酸消化率无显著差异（Ｐ＞０．０５）。说明新鲜优质浙江鱼粉的氨基酸可消化性与进口鱼粉相当，甚至更优     

Community-based conservation results in the recovery of reef fish spawning aggregations in the Coral Triangle

In the Coral Triangle community-based marine protected areas (MPAs) are being established at a prolific rate. Their establishment can benefit both fisheries and biodiversity, and they provide both a socially and economically acceptable means of managing coral reefs in developing nations. However, because such MPAs are typically small (usually <0.5 km²), they will rarely provide protection to large mobile fishes. An exception to this limitation may exist when community-based MPAs are established to protect small sites where vital processes occur, such as fish spawning aggregations (FSAs). To test the effectiveness of small (0.1–0.2 km²) MPAs for protecting FSAs, we monitored three FSA sites where brown-marbled grouper (Epinephelus fuscoguttatus), camouflage grouper (Epinephelus polyphekadion) and squaretail coralgrouper (Plectropomus areolatus) aggregate to spawn. Sites were monitored during peak reproductive periods (several days prior to each new moon) between January 2005 and November 2009. All three sites are located in New Ireland Province, Papua New Guinea, and had been exploited for decades, but in 2004 two sites were protected by the establishment of community-based MPAs. The third site continued to be exploited. Over the monitoring period densities of E. fuscoguttatus and E. polyphekadion increased at both MPAs, but not at the site that remained open to fishing. At one MPA the densities of E. polyphekadion increased tenfold. Our findings demonstrate that community-based MPAs that are appropriately designed and adequately enforced can lead to the recovery of populations of vulnerable species that aggregate to spawn.     

A decision-analytic approach to the optimal allocation of resources for endangered species consultation

The resources available to support conservation work, whether time or money, are limited. Decision makers need methods to help them identify the optimal allocation of limited resources to meet conservation goals, and decision analysis is uniquely suited to assist with the development of such methods. In recent years, a number of case studies have been described that examine optimal conservation decisions under fiscal constraints; here we develop methods to look at other types of constraints, including limited staff and regulatory deadlines. In the US, Section Seven consultation, an important component of protection under the federal Endangered Species Act, requires that federal agencies overseeing projects consult with federal biologists to avoid jeopardizing species. A benefit of consultation is negotiation of project modifications that lessen impacts on species, so staff time allocated to consultation supports conservation. However, some offices have experienced declining staff, potentially reducing the efficacy of consultation. This is true of the US Fish and Wildlife Service’s Washington Fish and Wildlife Office (WFWO) and its consultation work on federally-threatened bull trout (Salvelinus confluentus). To improve effectiveness, WFWO managers needed a tool to help allocate this work to maximize conservation benefits. We used a decision-analytic approach to score projects based on the value of staff time investment, and then identified an optimal decision rule for how scored projects would be allocated across bins, where projects in different bins received different time investments. We found that, given current staff, the optimal decision rule placed 80% of informal consultations (those where expected effects are beneficial, insignificant, or discountable) in a short bin where they would be completed without negotiating changes. The remaining 20% would be placed in a long bin, warranting an investment of seven days, including time for negotiation. For formal consultations (those where expected effects are significant), 82% of projects would be placed in a long bin, with an average time investment of 15 days. The WFWO is using this decision-support tool to help allocate staff time. Because workload allocation decisions are iterative, we describe a monitoring plan designed to increase the tool’s efficacy over time. This work has general application beyond Section Seven consultation, in that it provides a framework for efficient investment of staff time in conservation when such time is limited and when regulatory deadlines prevent an unconstrained approach.     

Network thinking in riverscape conservation – A graph-based approach

Graph theoretic approaches have received increased interest recently in landscape planning and conservation in the terrestrial realm, because these approaches facilitate the effective modelling of connectivity among habitats. We examined whether basic principles of graph theory can be extended to other ecosystems. Specifically, we demonstrate how a network-based context can be used for enhancing the more effective conservation of riverine systems. We first show how to use graph theoretic techniques to model riverscapes at the segment level. Then we use a real stream network (Zagyva river basin, Hungary) to examine the topological importance of segments in maintaining riverscape connectivity, using betweenness centrality, a commonly used network measure. Using the undirected graph model of this riverscape, we then prioritize segments for conservation purpose. We examine the value of each of the 93 segments present in the Zagyva river basin by considering the conservation value of local fish assemblages, connectivity and the size of the habitat patches. For this purpose we use the ‘integral index of connectivity’, a recently advocated habitat availability index. Based on the results the selection of the most valuable habitat segments can be optimized depending on conservation resources. Because of their inherent advantage in the consideration of connectivity relationships, we suggest that network analyses offer a simple, yet effective tool for searching for key segments (or junctions) in riverscapes for conservation and environmental management. Further, although the joint consideration of aquatic and terrestrial networks is challenging, the extension of network analyses to freshwater systems may facilitate the more effective selection of priority areas for conservation in continental areas.     

Growth rates,establishment, and effects on herbage yield of introduced earthworms in grassland on reclaimed cutover peat

Summary Lumbricus terrestris L. juveniles confined in nylon mesh bags grew at mean rates of 6–12 mg ind^–1 day^–1 in reclaimed peat grassland soil, while the growth rates of Aporrectodea caliginosa (Sav.) juveniles were 1.5–2.1 mg ind^–1 day^–1. Earthworm population densities exceeding 700 m² had become established within 1 year adjacent to sods transplanted from an old pasture, while microplots enclosed in nylon mesh cages had mean population densities of 318–408 earthworms m^–2 and biomass of 89–111 g m^–2 3–4 1/2 years after inoculation. Herbage yields were 25% greater in the 2nd year and 49% greater in the 3rd year in earthworm-inoculated microplots which received an annual application of cattle slurry compared with similarly fertilized, non-inoculated cages.Dedicated to the late Prof. Dr. M.S. Ghilarov     

不同新鲜度金枪鱼肉蒸煮品质的研究

热加工是一种传统的食品加工技术,热煮是其中的重要方式之一。鱼肉经过热煮处理会产生组织脆弱化、结构松散等问题,对其食用品质造成负面影响,因此提高鱼肉的耐煮性是开发水产系列加工产品的基础。文章总结了近几年关于热煮对鱼肉质构影响的研究进展,深入分析了热煮引起质构变化的作用机制,并结合变化原理分别从改善蛋白质热稳定性、提高肌肉持水性和提高肌肉凝胶特性3个方面阐述保持鱼肉质构的方法,提出将食品加工新技术与传统加工方法相结合以提高鱼肉耐煮性的研究方向,旨在为鱼肉热煮过程中的质构保持技术及食用品质控制提供参考。     

膨化大豆替代鱼粉对乌苏里貉毛皮质量的影响

选取150只健康乌苏里幼貉(Nyctereutes ussurienusis Matschie),随机分成1个对照组和4个试验组.各试验组按25%、50%、75%、100%比例用膨化大豆替代鱼粉饲料进行饲养试验,通过对针、绒毛的长度、粗细和皮板长度等反映毛皮质量各项指标的测定与分析得出:彭化大豆代替鱼粉能满足乌苏里貉冬毛生长的需要,不影响乌苏里貉毛皮质量.     

践行大食物观: 以科技创新引领渔业高质量发展

深海抗风浪网箱养殖区别于传统近海网箱、围栏等养殖方式,适合发展高经济价值的鱼类养殖,现已成为沿海渔民转产转业的重要方向。为缓解近岸养殖压力、拓宽深海水域养殖,基于中国海域养殖条件,设计了一种可以应对恶劣海况条件的新型复式抗风浪深海养殖网箱。该网箱放弃了传统的浮架和浮圈结构,采用双浮筒可调节结构,以适应不同海域海浪状况,减少因刚性连接而发生的中拱和中垂现象;此外,浮筒与立体浮框连接而成的垂荡体可以提供较大的垂荡以及纵向摇摆阻尼,控制网箱的运动幅度。同时采用莫里森公式和伯努利方程对网箱承受的风、浪、流等环境载荷进行受力计算,并与传统高密度聚乙烯 (High density polyethylene, HDPE) 网箱进行对比,结果显示新型复式抗风浪网箱比传统HDPE网箱更能承受海洋中的环境负载。研究结果为后续研究和发展大型抗风浪网箱养殖提供了设计参考。

     

深水网箱和池塘养殖凡纳滨对虾肌肉营养成分的比较分析

对深水网箱和池塘养殖凡纳滨对虾(Litopenaeus vannamei)肌肉常规营养成分、氨基酸和脂肪酸质量分数进行了比较分析。结果显示:1)网箱养殖对虾肌肉粗蛋白质量分数显著高于池塘养殖(P0.05),而水分、粗脂肪和粗灰分质量分数无显著差异(P0.05);2)肌肉中检测到18种常见氨基酸,网箱养殖对虾肌肉氨基酸总量(TAA)、天门冬氨酸(Asp)、异亮氨酸(Ile)、精氨酸(Arg)和脯氨酸(Pro)质量分数显著高于池塘养殖(P0.05),而必需氨基酸(EAA)、半必需氨基酸(HEAA)、鲜味氨基酸(DAA)和虾味氨基酸(PFAA)两者无显著差异(P0.05);3)肌肉中检测到30种常见脂肪酸,两者的饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)、多不饱和脂肪酸(PUFA)、n-3多不饱和脂肪酸(EPA和DHA)质量分数差异显著(P0.05),以网箱养殖对虾较高;两者的棕榈酸(C16∶0)质量分数最高,且网箱养殖对虾EPA+DHA质量分数是池塘养殖的1.90倍。结果表明,网箱养殖对虾营养成分要优于池塘养殖,具有较高的营养价值。     

Live microbial feed supplement in aquaculture for improvement of stress tolerance

Two bacterial strains, Lactobacillus fructivorans, isolated from sea bream (Sparus aurata) gut, and Lactobacillus plantarum, isolated from human faeces, were administered simultaneously, during sea bream development, using Brachionus plicatilis and/or Artemia salina as vectors. The probiotic treatment significantly affected gut colonization. To test the probiotic influence on stress responsiveness, sea bream fry, 47 days post-hatching (p.h.), were subjected to pH stress (from 8.6 to 6.3) and cumulative mortality, cortisol levels and HSP70 gene expression were analysed. Cortisol was selected, since under stress conditions its level increases. HSP70 was selected with consideration of its wide involvement in response to a great number of injuries, and because it protects cells probably by binding and refolding damaged proteins. The results obtained indicated that the administration of probiotic to sea bream fry induced higher HSP70 levels, indicating a greater potentiality to respond to the harmful conditions possibly present in fish farms. This hypothesis is supported by the fact that the levels of cortisol found were significantly lower (P < 0.05) in both groups under probiotic treatment. When pH was used as a stressor, it induced a higher cumulative mortality in the control; the mortality was found to be significantly lower in both treated groups. Interestingly, a significant increase (P < 0.05) in HSP70 gene expression was observed in all stressed groups. These results suggest an improvement in tolerance to acute stress of fry fed with probiotics.