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对虾配合颗粒饲料水中稳定性的测试方法 总被引:1,自引:0,他引:1
阐述了对虾配合颗粒饲料中稳定性的概念,介绍并讨论了各种评价及测试方法的优缺点,包括感官法、光度法、COD法、干燥称重法。作者指出,应采用多项参数对对虾配合颗粒料水中稳定性进行综合评价。 相似文献
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水产颗粒饲料的水中稳定性是指:饲料在水中受到水流的冲击和浸泡,一定时间内能够保持其组分不被溶解和饲料不散失的性能。一般以单位时间内饲料在水中的散失量与饲料质量之比的百分数(即散失率)表示,也可用饲料在水中不散失的最小时间表示。 相似文献
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水产颗粒饲料的水中稳定性是指:饲料在水中受到水流的冲击和浸泡,一定时间内能够保持其组分不被溶解和饲料不散失的性能.一般以单位时间内饲料在水中的散失量与饲料质量之比的百分数(即散失率)表示,也可用饲料在水中不散失的最小时间表示. 相似文献
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微生态制剂对虾池水质影响的研究 总被引:14,自引:0,他引:14
以虾为研究对象来探讨微生态制剂对虾池水质的改良效果。在养虾池中分别加入光合细菌、芽孢杆菌以及不同浓度的微生态制剂,待其生长繁殖后测定氨氮、亚硝酸盐、溶解氧、COD值和pH值等各项水质指标。结果表明,微生态制剂对虾池水质具有较好的改善作用,其最适使用浓度约为2 0×1010个/m3。 相似文献
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溶解氧是指以分子状态溶存于水中的氧气单质。水中的溶解氧含量通常很低,只有百万分之一。水中有机物分解、生物呼吸、气压、盐度等许多因素,都对水中溶解氧产生影响。所以掌握水中溶解氧的动态规律,熟悉缺氧的 相似文献
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苗种是水产养殖业发展的重要物质基础,也是保证高产、稳产的重要前提,而幼体开口饲料则是确保苗种生产的关键。有不少国家(如日本等)自70年代起已开始着手研究和开发微粘、微膜和微囊等微颗粒饲料,目前日本、英国、俄罗斯、比利时等国家在微颗粒饲料应用技术方面已趋成熟,并形成一定的商业性生产规模。我国自80年代后期、90年代初开始,先后有大连水产研究所、上海水产大学和江苏省淡水水产研究所等开始研制开发微颗粒饲料,并有少量产品投放市场。近几年来,杭州高成生物营养技术有限公司、山东海洋水产研究所、升索渔用饲料开… 相似文献
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4种微生态制剂对虾池水质及青虾生长性能的影响 总被引:2,自引:0,他引:2
在测定养殖水体pH值、溶解氧、氨态氮、亚硝态氮等水质指标和养殖青虾肥满度、平均规格、饲料系数等生长性能指标的基础上,比较研究了全池泼洒复合芽孢杆菌、EM菌、类球红细菌、超浓缩光合细菌微生态制剂对养殖水质的改善情况及提高杂交青虾"太湖1号"生长性能的效果。结果表明,4种微生态制剂均可改善水质;其中,芽孢杆菌与EM菌具有较强的降亚硝态氮功能,类球红细菌和EM菌具有较强的降氨态氮作用。4种试验菌剂的调水效果排序为:类球红细菌>EM菌>复合芽孢杆菌>超浓缩光合细菌。4种菌剂不同程度提高了青虾的生长性能;其中,类球红细菌效果最为显著,其次为EM菌、复合芽孢杆菌,而光合细菌的效果不显著。 相似文献
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This study investigated the effects of three microscreen mesh sizes (100, 60 and 20 μm) on water quality and rainbow trout (Oncorhynchus mykiss) performance compared to a control group without microscreens, in triplicated recirculating aquaculture systems (RAS). Operational conditions were kept constant during a 6-week period where the microscreens were manually rinsed three times a day. The effects of microscreen cleaning frequency and nitrification performance were subsequently assessed.Compared to the control group, microscreens removed particles, reduced particulate organic matter, and increased β-values. Particulate parameters reached steady-state in all treatment groups having microscreens at the end of the trial. The time to reach equilibrium seemingly increased with increasing mesh size but the three treatment groups (100, 60 and 20 μm) did not significantly differ at the end of the trial. Increased backwashing frequency over a 24-h period had no further significant effects on the parameters measured. The results demonstrated the role and importance of a microscreen, and showed that mesh size, within the range tested, is less important at long operations under constant conditions.Fish performed similarly in all treatments. Preliminary screening of trout gills did not reveal any pathological changes related to microscreen filtration and the resulting water quality. Biofilter performance was also unaffected, with 0′-order nitrification rates (k0a) being equivalent for all twelve systems (0.148 ± 0.022 g N m−2 d−1).Mechanisms for RAS equilibrium establishment, within and between systems with different mesh sizes, are discussed. 相似文献
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We studied the effect of rearing densities of Pacific white shrimp, Litopenaeus vannamei in three densities with three replicate treatments [T1: 0.4 million post-larvae (PL) ha−1, T2: 0.5 million PL ha−1, T3: 0.6 million PL ha−1] and water cutback approach on rearing environment, water use efficiency, water footprint and production performance. Conditional water exchange was carried out based on water quality parameters. Water quality suitability index was very good (7.5–9.0) up to 13th, 10th and 5th week of culture in T1, T2 and T3, respectively; which was attributed to rearing density, smaller-sized shrimp and low early feed input. Optimum rearing density of 50 PL m-2 (T2) led to total water use of 3.25 × 104 m3. It was seeming as a way to improve shrimp productivity (10.58 t ha−1 120 d−1), consumptive water use index (1.72 m3 kg-1 biomass), total water footprint (1229 m3 t−1 biomass) and net consumptive water productivity (USD 1.28 m-3). L. vannamei culture with low to moderate water exchange as in T2, helped uphold water quality suitable for the shrimp growth, improved water use efficiency (0.58 kg biomass m-3 water), minimized sediment load (45.3 m3 t-1 biomass), effluent outputs (0.63 × 104 m3), pumping cost (USD 30.1 t−1 biomass produced), and ratio of output value to the cost of cultivation (1.97). The findings and advancement in knowledge would offer the basis to augment shrimp rearing efforts and the water management approaches will help in preventing the production of waste and effluent while increasing water use efficiency and production performance. 相似文献
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根据对秦皇岛市新开河口实地采集水样 ,进行了重金属、总氮和总磷含量分析 ,发现新开河口水污染严重 ,多超过地表水IV类标准 ,主要污染物为氮、磷和油类 ,其他污染物含量均在II类标准以内 ,河口水体中氮、磷含量均达到水体富营养化危险负荷 ,可见陆源污染是秦皇岛近岸海域富营养化日趋严重、赤潮日趋增多的主要原因 相似文献
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不同放养量与水交换率对大菱鲆幼鱼的养殖效果及水质条件的影响 总被引:3,自引:0,他引:3
经过 6 0d的试验养殖 ,在每日 2、 4、6个循环水量的条件下 ,研究放养量从 0 .74~ 1.99kg/m2 大菱鲆 (Scophthalmusmaximus)幼鱼的平均体重增长、养殖成活率、饵料系数和养殖水中的溶解氧、氨氮含量等养殖生态状况。结果表明 ,日水循环量为 2个全量时 ,放养量为 1.5 4kg/m2 的实验组的平均体重增重与放养量低的实验组 (0 .75kg/m2 、1.0 1kg/m2 、1.31kg/m2 )平均体重增重无显著差异 (P >0 .0 5 ) ,而与高于此实验组 (1.74kg/m2 、1.99kg/m2 )的增重比较则差异显著 (P <0 0 5 ) ;水循环量的增加可以改善水质条件 ,加快幼鱼的生长速度 ,但对幼鱼的饵料系数影响不大。 相似文献
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牡丹江水质监测与评价 总被引:1,自引:0,他引:1
我们于1993-1995年对牡丹江进行了污染源监测,沿江不同江段设采样点采样进行水质分析,本根据数理统计的方法,结合水质参数各自对水环境质量的影响,采用半集均方差模式对该江进行污染现状评价,其 结果:WQI值为10.285,该江已污染。 相似文献
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为探讨短期内Nualgi营养素对池塘水质和藻类群落结构的影响,本研究在池塘中的不透水有底帆布围隔内共设计了4个试验组,依次分别添加Nualgi营养素(M1组)、补充硅藻藻种(M2组)、同时添加Nualgi营养素并补充硅藻藻种(M3组)、不做任何处理的空白对照(C组)。经过近一个月的试验,结果显示:各组的pH值、DO、TN、TP之间没有显著性差异;Nualgi可以显著降低水体中IP的含量,M1组和M3组的IP显著低于M2组和C组;M1组、M2组和M3组中的NH_4~+-N、NO_2~--N和CODMn含量显著低于C组,表明Nualgi和硅藻藻种都可以显著降低水体中NH_4~+-N、NO_2~--N和CODMn的含量,对养殖水质具有显著的调控效果。试验各组的藻类种群极为丰富,试验期间共检出浮游植物7门109属186种,其中绿藻门47属86种,硅藻门26属48种,蓝藻门18属27种,裸藻门11属17种,甲藻门3属3种,隐藻门2属3种,金藻门2属2种。结果显示:添加Nualgi和补充硅藻藻种都可以有效提高水体中硅藻的生物量并抑制绿藻和蓝藻的生长,同时可以改变水体中浮游植物的群落结构,试验进行到第20天时,M1组、M2组和M3组中硅藻的生物量均显著高于C组,绿藻和蓝藻的生物量显著低于C组。试验中,颗粒直链藻在M1组、M2组和M3组中成为优势藻种,但并未在C组中成为优势藻种,小空星藻和四足十字藻仅在C组中成为优势藻种,四尾栅藻在M1组、M2组和C组中均成为优势藻种。在试验期内,各试验组之间的多样性指数没有显著差异,香农-威纳指数均在2.00以上,表明Nualgi和硅藻藻种并没有影响到水体中藻类的多样性。 相似文献
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The aquaculture industry is growing fast but facing two major challenges: a shortage of suitable locations for growth and the need to reduce environmental impacts. One solution for both these challenges is inland production through recirculating aquaculture systems (RAS). The RAS technique is rather new, and several practical issues need to be solved. In this study, an experimental platform, consisting of ten individual RAS units, was built for small-scale testing of different RAS designs and operation methods, and two preliminary experiments were conducted. In the first experiment, the capability of different chemical additions (sodium nitrite, ammonium chloride and/or cane sugar) to fasten the startup of the nitrification bioreactor was tested. In addition, the suitability and reliability of an online water measurement system in monitoring nitrification process with was evaluated. We demonstrated that when using a combination of sodium nitrite and ammonium chloride in a concentration of 5 mg l−1, nitrification started one week before than when using only ammonium chloride or a clean start with rainbow trout (Oncorhynchus mykiss). In the second experiment, the effect of different relative water renewal rates (RWR) on water quality, rainbow trout growth and feed conversion ratio (FCR) were examined at 16 °C. Based on the results, FCR increased when RWR went below 478 l kg−1, and the specific growth rate decreased when RWR went below 514 l kg−1. Furthermore, when RWR decreased, nitrate, nitrite and organic material accumulated in the circulating water. In conclusion, we showed using experimental RAS platform that online water quality monitoring is a useful tool in following the effect of different management practices. Furthermore, we demonstrated that chemical substrate additions provide the fastest biofilter startup, and that water management is still in the key role in defining the fish production in RAS. 相似文献