甜菜碱在养殖业中的营养机理

甜菜碱作为饲料添加剂已经在养殖业上得到了广泛的应用，它具有调节动物脂肪代谢、改善家禽的生产能力、促进动物的生长和抗球虫病等疗效。本文对甜菜碱在脂肪代谢和甲基代谢中的机理进行了阐述，对甜菜碱与甲硫氨酸和胆碱在添加荆中的添加效果进行了比较，并就其对饲料中维生素的保护作用和在水产养殖中的营养机理进行了综述。甜菜碱作为安全高效的营养性饲料添加剂，具有广阔的应用前景。     

甜菜碱在水产饲料中的应用实践探讨

甜菜碱是一种分布在动植物中的天然物质,它存在的载体包括:微生物、水生无脊椎动物、麦麸、甜菜、小麦胚芽、菠菜等.基于甜菜碱貌似甘氨酸,具备3个另外的甲基,也被称之为三甲甘氨酸.尽管甜菜碱在饲料添加剂中已经应用几十年了,但对它在代谢中的功能以及在饲料配方中的使用还认知不足.只是在近年,人们对甜菜碱的作用机理和使用价值才有深入的研究,并开始在饲料中广泛应用,尤其在水产饲料中的应用比例也日趋增大.本文对甜菜碱的来源和剂型进行介绍和分析,探讨甜菜碱在水产饲料中的应用实践路径.     

寡糖在水产动物饲料上的应用

寡糖是一种绿色的水产动物饲料添加剂,能够促进水产动物肠道内有益菌增殖,抑制有害菌生长,维持正常的消化道环境,提高水产动物机体的免疫力、抗病力、饲料利用效率以及促进脂类的代谢等,本文就寡糖对水产动物的作用及其在水产动物饲料中的应用现状进行综述,并探讨应用中存在的问题,尝析寡糖在水产动物饲料中的应用前景。     

新型绿色水产饲料添加剂——二氢吡啶

二氢吡啶作为我国农业部批准的新兽药类添加剂，因其促进畜禽生长繁育功效．受到普遍关注。但是在水产饲料中应用不多，近年来一些研究表明其对水产动物也具有促进生长；改善产品品质；提高免疫力等优点，且其代谢快，在动物体内几乎无残留，作为饲料添加剂，安全性极佳。该文概述二氢吡啶的理化性质、特点．以及对动物的营养免疫学作用机理．概述关于二氢吡啶在水产饲料中应用的现有研究资料，针对目前二氢吡啶在研究中存在的问题，提出对策。     

L-肉碱的生物学功能及其在鱼类营养代谢中的作用

L－肉碱是一种具有生物活性的饲料添加剂，对于动物的营养代谢具有非常重要的作用。在水产动物饲料中添加适量的L－肉碱，不但可以提高饵料利用率，增加体重，还能节约蛋白质，提高肉质。综述了L－肉碱的吸收利用和代谢机制，生物学功能及其在鱼类营养代谢中的应用效果。     

绿色饲料添加剂低聚糖在动物生产上的应用

本文阐述了抗生素替代品之一──绿色饲料添加剂低聚糖在动物生产中应用的主要类型,对动物保健的作用、作用机理,在畜禽业中的应用效果及在未来饲料工业中的应用前景。     

非营养性饲料添加剂在水产养殖中的应用及发展态势

在现代水产养殖业中，高密度集约化的发展趋势十分迅猛。同时，随着人民生活水平的 不断提高，水产养殖业正面临着从追求产量增长转向以追求质量为主、高产优质高效并举的 重大转折。为了降低饲料成本，提高经济效益和生态效益，生产高品位、低消耗的水产动物 ，饲料添加剂尤其是非营养性饲料添加剂的作用愈来愈被业主所认识和重视。本文就某些重 要的非营养饲料添加剂在国内水产养殖中的应用现状及其发展态势作一综述，以资参考。1 诱食剂1.1 三甲胺已内酯 是一种天然化合物，商品名称为甜菜碱(Betaine)。近年来的研究表 明，甜菜碱是动物…     

几种新型饲料添加剂在水产养殖中的应用

近年来,随着水产养殖业的迅速发展,一批具有较高效益的鱼类饲料添加剂相继被研制和应用并取得了很好的效益.本文介绍了复合酶制剂、甜菜碱、植酸梅、大蒜素在水产养殖中的应用.希望能对诸水产养殖户在认识和应用此类添加剂方面有所帮助.     

中草药饲料添加剂在我国水产中的应用

作为绿色饲料添加剂之一的中草药饲料添加荆,近年来已成为动物营养研究的一大热点,研究结果发现:中草药饲料添加剂的免疫活性物质能增强机体免疫机能,提高动物抗应激、抗疾病能力,改善动物生产性能,而其本身又具有毒副作用小、无残留、无耐药性的特殊优点.本文综述了中草药饲料添加剂的特点、作用机理、分类及其在我国水产中的应角,并对其发展前景进行了展望.     

饲料添加剂在水产动物生长、营养及免疫中的应用进展

饲料添加剂是在基础饲料的生产加工或使用过程中添加微量物质,具有强化基础饲料营养价值,节省饲料成本,提高动物生产性能,改善肌肉品质等作用。目前国内外对饲料添加剂的研究众多,为突出饲料添加剂对水产动物在不同方面的影响,本文综述了饲料添加剂对水产动物生长性能、营养成分及免疫中的应用进展。     

我国蟹类土池育苗技术研究进展

蟹类养殖产业已成为我国水产养殖的支柱产业之一。中华绒螯蟹(Eriocheir sinensis,以下简称河蟹)、三疣梭子蟹(Portunus trituberculatus,以下简称梭子蟹)、拟穴青蟹(Scylla paramamosain,以下简称青蟹)是我国主要的养殖蟹类。目前3种蟹类土池育苗技术发展不平衡,河蟹、梭子蟹土池育苗技术较为成熟,已经普及推广并在养殖生产中发挥重要作用;青蟹土池育苗尚未有成功的报道。本文综述了我国河蟹、梭子蟹、青蟹苗种生产技术,尤其是土池育苗技术的研究进展,并对河蟹、梭子蟹土池育苗关键技术进行分析,旨在探讨蟹类土池育苗技术应用于青蟹土池育苗的可行性。     

Multispecies biomass dynamics models reveal effects of ocean temperature on predation of juvenile pollock in the eastern Bering Sea

Walleye pollock (Gadus chalcogrammus) supports one of the largest commercial fisheries in the world. Juvenile pollock are important forage fish in the eastern Bering Sea (EBS) ecosystem, often representing the largest fraction in the diets of major Bering Sea piscivores. Large variability in the EBS pollock stock biomass in recent years has been attributed primarily to fluctuations in recruitment. It has been hypothesized that predation rates on forage fishes increase when the cold pool (a body of cold water < 2°C) is extensive and covers much of the middle continental shelf, which tends to concentrate larger predatory fishes in the outer shelf and slope regions. In contrast, young pollock appear to tolerate colder temperatures than older fish and can stay in the cold pool, thereby reducing predation. We used a multispecies modeling approach to examine the effects of the cold pool size on predation of juvenile pollock. We found that predation on age‐1 pollock by age‐3+ pollock decreased, and predation on age‐1 and age‐2 pollock by arrowtooth flounder increased with increasing bottom temperature, which was used as a proxy for the cold pool size. These results suggest that the cold pool creates spatial separation between juvenile pollock and arrowtooth flounder, but not between adult and juvenile pollock. The model developed in this study could be used to examine the effects of other covariates on interspecific interactions, help explain observed changes in fish communities, and understand implications of climate change on ecosystems and their productivity.     

海带“三海”品系栽培试验初报

在浙江沿浦湾进行了“三海”海带新品系与“福建种”海带的对比养殖测试,经过了6,f,-月试验,在3个测试海区中,“三海”与“福建种”海带对比,其耐高温能力强,薄嫩期生长快,厚成期干物质积累快,增产达到了10％以上,能够进行大规模养殖生产应用;在养殖生产中,应充分发挥其前期生长较快和后期干物质积累能力强的特点,在流速较小的海区进行即食海带养殖生产,而在流速较大的海区进行淡干海带的养殖生产。     

肉用仔鸡早期限食饲养试验

试验对7日龄肉用仔鸡进行了10d限食饲养,限食量分别为对照组的70%、60%、55%和50%,到56日龄时,除限食量为50%组日增重较低外,其它各试验组分别比对照组提高8.5%(P〈0.05)、7.5%(P<0.05)和6.79%,饲料报酬和心脏病发生率以限食量为60%和55%的试验组较好。试验就肉用仔鸡实施限制性饲养进行初探,旨在提供一个降低养鸡成本的途径。     

The global contribution of forage fish to marine fisheries and ecosystems

Forage fish play a pivotal role in marine ecosystems and economies worldwide by sustaining many predators and fisheries directly and indirectly. We estimate global forage fish contributions to marine ecosystems through a synthesis of 72 published Ecopath models from around the world. Three distinct contributions of forage fish were examined: (i) the ecological support service of forage fish to predators in marine ecosystems, (ii) the total catch and value of forage fisheries and (iii) the support service of forage fish to the catch and value of other commercially targeted predators. Forage fish use and value varied and exhibited patterns across latitudes and ecosystem types. Forage fish supported many kinds of predators, including fish, seabirds, marine mammals and squid. Overall, forage fish contribute a total of about $16.9 billion USD to global fisheries values annually, i.e. 20% of the global ex‐vessel catch values of all marine fisheries combined. While the global catch value of forage fisheries was $5.6 billion, fisheries supported by forage fish were more than twice as valuable ($11.3 billion). These estimates provide important information for evaluating the trade‐offs of various uses of forage fish across ecosystem types, latitudes and globally. We did not estimate a monetary value for supportive contributions of forage fish to recreational fisheries or to uses unrelated to fisheries, and thus the estimates of economic value reported herein understate the global value of forage fishes.     

A review of the environmental effects and alternative production strategies of marine aquaculture in Chile

In Chile, fish, mussel and seaweed cultivation has expanded significantly over the last decade. This review considers the accumulated knowledge on the environmental effects of aquaculture in Chilean coastal areas, analyses the capacity of the industry to treat its waste and also gives some insight into new culture technologies and strategies that are currently under research and discussion in Chile. Data relating to the environmental impact of aquaculture in Chile are scarce and much is subject to severe methodological restrictions with regard to sampling design. Results related to the environmental effects show that seaweed cultivation can have an impact on sedimentation processes, increase of invertebrate assemblages and algal epiphytic abundances. It has also been ascertained that mollusc farming causes biodeposition, faunal changes and possible effects related to the introduction of new species, as well as pathogens and other unforeseen species. It has been affirmed that fish cultivation, in particular that of salmon species, also has an environmental impact related to organic sedimentation and changes in the fauna. However, these results indicate that, in general, the current dynamics of bays and fjords seem to be an important factor for the environmental sustainability of the salmon culture areas. Salmon cultivation has also been associated with phytoplankton blooms, but this point was not supported by a monitoring programme in southern Chile. Furthermore, there is concern related to new pathogen introduction and therapeutical applications to the fish cultures, and further research is required in this field. Regulations to protect the environment from the consequences of aquaculture activities have been adopted during the last couple of years. The main regulations are provided by international market standards. Nevertheless, these regulations can only be effective if other human activities, such as urban discharge, intensive agriculture fertilisation and pesticide utilisation, are taken into consideration, in an integrated perspective. On the other hand, the Chilean salmon farming industry in particular, would be in a position to cover the costs involved in the treatment of waste waters, if feeding management were improved in the future. Finally, active research is currently being undertaken into new cultivation strategies, such as the use of integrated cultivation and the recycling of nutrient-rich waters, which should permit the diversification of this economic activity in Chile, while minimising the environmental impact.     

Biogeography of pelagic food webs in the North Pacific

The tufted puffin (Fratercula cirrhata) is a generalist seabird that breeds throughout the North Pacific and eats more than 75 different prey species. Using puffins as samplers, we characterized the geographic variability in pelagic food webs across the subarctic North Pacific from the composition of ~10,000 tufted puffin meals (~56,000 prey items) collected at 35 colonies in the Gulf of Alaska (GoA) and Aleutian Archipelago. Cluster analysis of diet species composition suggested three distinct forage fish communities: (i) in the northern GoA, multiple age‐classes of coastal and shelf residents such as capelin, sand lance and herring dominated the food web, (ii) in the western GoA to eastern Aleutians, the shelf community was dominated by transient age‐0 walleye pollock, and (iii) in the western Aleutians, shelf‐edge and mesopelagic forage species such as squid, lanternfish, and Atka mackerel were prevalent. Geographic patterns of abundance of capelin and sand lance in tufted puffin diets were corroborated by independent research fisheries and diets of piscivorous fish, indicating that puffin diets reflect the local abundance of forage species, not just selection of favored species. Generalized additive models showed that habitat characteristics predict, in a non‐linear fashion, forage species distribution and abundance across two large marine ecosystems. We conclude that major biogeographic patterns in forage fish distribution follow gradients in key habitat features, and puffin diets reflect those patterns.     

Natural mortality augments population fluctuations of forage fish

Forage fish are a vital part of marine ecosystems, partly by supporting some of the largest fisheries worldwide, but also due to their role in food webs as prey for larger fish and other predators. One of the unresolved questions about forage fish dynamics is the causes of their significant temporal fluctuations. These fluctuations are often attributed to changes in environmental conditions, but direct correlations have proven hard to find. Here, we show how time‐varying predation mortality additionally plays a substantial role in forage fish population fluctuations. By analysing 10 stocks that have estimates of natural mortality changes through time, we find that natural mortality on average increases as population biomass declines towards a trough, and to a lesser degree decreases, when their biomass is growing towards a peak. While depensatory mortality was dominant on average in biomass dynamics leading up to peaks or troughs, some of the stocks exhibited compensatory mortality emphasizing variation between stocks. Furthermore, we show that the magnitude of natural mortality and productivity is generally higher than fishing mortality. The results underscore the importance of top‐down control on the dynamics of forage fish. We conclude that a holistic ecosystem analysis is required for a better ecological understanding of forage fish dynamics.     

工厂化循环水培育菲律宾鳗鲡苗种试验

采用分级微生物净化、曝气增氧、有效控温等循环水养殖系统对菲律宾鳗鲡进行苗种培育试验.鳗苗放养密度为3 000尾/m2和3 050尾/m2,约为传统模式的5～6倍.试验结果显示：在水温27～30℃范围内,对个体体重0.15～0.20 g（平均0.17g）的菲律宾鳗鲡苗进行培育,经过71d培育,个体平均体重为2.95 g,增重17.7倍,日均增加重量0.04g,鳗苗养殖成活率达到98.81％,高于传统养殖模式,水蚯蚓饲料系数7.14.试验表明,工厂化循环水养殖系统适用于菲律宾鳗苗培育,并具有节能减排优点,为开发新的鳗鲡养殖品种及环境友好型的鳗鲡育苗模式提供参考.     

河蚌外套膜的组织培养

本文报道了褶纹冠蚌和背角无齿蚌外套膜的组织培养结果。试验表明，河蚌外套膜的上皮细胞和结缔组织的成纤维细胞能在离体培养条件下生长繁殖。在试验中还能观察到所培养的组织块上皮细胞，能分泌出茶褐色的有机珍珠质，使组织块逐渐变成茶褐色。