生物絮团对罗氏沼虾体组成和消化酶活性的影响

通过向养殖水体中泼洒糖蜜构建生物絮团养殖模式,分析生物絮团营养组成,并探讨生物絮团对罗氏沼虾体组成和消化酶活性的影响。试验分对照组和试验组(生物絮团组),其中试验组在养殖过程中泼洒糖蜜。试验在室内水泥池内(2 m×2 m×0.6 m)进行,每个处理有3个重复,每个重复225尾虾(0.26 g±0.02 g),试验周期为90 d。养殖过程中不换水,糖蜜的泼洒量根据饲料投喂量进行计算(C/N为20)。结果显示:添加糖蜜能够显著促进生物絮团的形成,到第90天时,试验组的絮团体积达21.22 mL/L;而对照组为6.03 mL/L;试验组絮团粗蛋白含量为29.47%,粗脂肪含量为4.32%,二者均显著高于对照组,而粗灰分含量为11.36%,显著低于对照组;泼洒糖蜜对罗氏沼虾体组成的影响不显著,对照组和试验组肌肉粗蛋白含量分别为21.09%和21.20%,粗脂肪含量分别为2.91%和3.06%;另外,向水体中泼洒糖蜜对罗氏沼虾消化酶活性影响显著。试验组罗氏沼虾肠脂肪酶活性、胃脂肪酶活性和胰脂肪酶活性均显著高于对照组;试验组罗氏沼虾糜蛋白酶活性、胰蛋白酶活性也均显著高于对照组。但泼洒糖蜜对肠淀粉酶、胃蛋白酶、胃淀粉酶、胰淀粉酶和纤维素酶活性没有显著影响。试验表明,生物絮团营养组成丰富,能够有效提高消化酶活性。     

玉米蛋白粉部分替代鱼粉饲料对日本沼虾生长的影响及效益分析

以27%鱼粉组饲料为对照组,用6.0%的玉米蛋白粉替代对照组饲料中的部分鱼粉(相应替代对照组饲料配方中22.2%的鱼粉),配制成2种等氮等能的饲料。在室外4口池塘进行日本沼虾(Macrobrachiumnipponensis)生产性养殖试验。经过一茬养殖,结果发现:投喂玉米蛋白粉饲料组与投喂鱼粉饲料组的日本沼虾在生长速度上无显著差异,投喂两种饲料对池塘水质影响也无明显差异,投喂两种饲料的日本沼虾的总产量分别为1 219.5 kg/hm2和1 033.5 kg/hm2,投喂两种饲料的投饲系数分别为2.4和2.2。使用玉米蛋白粉饲料养殖日本沼虾比使用鱼粉饲料可增收毛利润2 669.00～2 717.30元/hm2。     

亚硝态氮对罗氏沼虾存活率、生长及能量代谢的影响

采用单因子6处理设计,对照组亚硝态氮(NO_2~--N)质量浓度为0. 04 mg/L,试验组NO_2~--N质量浓度分别为2、4、6、8、10 mg/L,研究了亚硝酸盐对罗氏沼虾存活、生长及能量代谢的影响。试验结果:2、4mg/L NO_2~--N试验组罗氏沼虾的存活率和特定生长率(SGR_d)均显著高于其它试验组(P 0. 05);随着亚硝态氮质量浓度的升高,罗氏沼虾的SGR_d和饲料转化效率(FEf_d)均呈下降趋势,显著低于对照组(P 0. 05);对照组的摄食能(C)显著高于试验组(P 0. 05),生长能占摄食能的比例(G/C)显著高于除2、4mg/L组之外的试验组(P 0. 05),10 mg/L NO_2~--N试验组虾的摄食能(C)、生长能占摄食能的比例(G/C)显著低于其它组(P 0. 05)。结果表明,在罗氏沼虾养殖中,需将NO_2~--N的质量浓度控制在4mg/L以下,以确保摄食能转化为生长能达到最优。     

罗氏沼虾性早熟原因及预防措施

在罗氏沼虾养殖过程中，普遍存在性早熟问题，很多体长在5～6cm的雌虾抱卵腔内已充满了卵。关于罗氏沼虾性早熟问题，一般认为是由以下两个原因造成的：(1)有效积温过高：在现行的池塘养殖过程中，由于水体较小，水位较低，水温的回升比河道、水库要快得多，而且罗氏沼虾的养殖一般都在高温季节，水温长时间过高，加速了罗氏沼虾的性腺发育，从而产生了性早熟现象；(2)营养过剩：营养过剩主要是指蛋白质过剩。在罗氏沼虾养殖过程中，所投喂的饵料几乎全部是高品质的商品饲料。投喂过多过精的商品饲料，一方面加速了罗氏沼虾的生长，另一方面…     

华群2号罗氏沼虾与螺蛳混养技术

<正>罗氏沼虾是目前世界上养殖面积最大的三大虾种之一。全国养殖面积曾高达40 000 hm~2,里下河地区养殖面积近20 000 hm~2,是一个非常有潜力的养殖品种。江苏地区养殖罗氏沼虾主要采用在五月中下旬水温稳定在20℃以上后放苗,也有采用在池塘中修建小温棚,在3—4月放苗,5月水温稳定后撤去温棚,提升水位大塘养殖。罗氏沼虾环境适应能力强,投喂大量饲料后,水质变差,水色变得很浓,养殖后期常常爆发蓝藻。10月以后虾全部上市后,池塘常常闲置较长时间,而且在饲养过程中     

罗氏沼虾的养殖技术

六、影响养虾高产的因素影响罗氏沼虾池塘养殖取得高产的原因很多，也很复杂，但从总体上说可分成人为因素和自然环境因素两大类。１．自然环境因素（１）池塘面积　　养罗氏沼虾的池塘不宜太小，太小的池塘水温不稳定，水质不易控制；太大的池塘饲料投喂困难，池中央的虾不能正常摄食；过深的池塘往往底层缺氧造成罗氏沼虾栖息环境不良。（２）池塘水质　　池塘水质不良，溶氧不足，罗氏沼虾长期处于低氧环境中，会导致生长缓慢，甚至浮头和泛塘。（３）敌害生物　　池塘中敌害生物，如凶猛鱼类、鸟、蛇等会大量捕食罗氏沼虾；又如各种水草…     

国外简讯

虾池内设置网箱饲养罗非鱼　　为提高池塘养殖效益 ,降低饲料成本 ,美国水产科研人员进行了在罗氏沼虾主养池内设置网箱饲养尼罗罗非鱼的试验。投喂的是酒糟饲料。虾池面积 0 .2ｈｍ2 ,放养罗氏沼虾苗80 0 0尾 ,池内设置 1ｍ3 的网箱 9个 ;分别放养 2 0 0尾平均体重 2 6 ｇ的尼罗罗非鱼。日投饲 2次 ,试验时间为 12周。非颗粒酒糟饲料含蛋白质 2 6 % ,颗粒酒糟饲料含蛋白质2 3% ,对照饲料为鲇鱼商品饲料 ,含蛋白质 31%。结果表明 :投喂鲇鱼商品饲料的尼罗罗非鱼 ,体重增长快 ,产量最高 ,但饲料成本高 ,每增重1ｋｇ需花成本 0 .6 6美元 ;而投…     

生态塘对养殖池塘水氨氮和亚硝态氮去除的研究

<正>近年,我国的池塘水产养殖密度日益增大,甚至超过池塘本身的容纳能力,造成养殖水体富营养化。水质污染导致鱼体生长缓慢、成品品质下降,已经不符合绿色健康生态养殖的发展需求。池塘养殖密度过大,养殖饵料投喂增多,相应造成养殖水体的氨氮和亚硝态氮增多。有研究表明,在池塘养殖投喂的饲料中,有5%～10%未被鱼类食用,而被养殖鱼类食用的饲料中又有25%～30%以粪便形式排出体外,而且养殖池塘的尾水、     

罗氏沼虾与河蟹混养技术

高邮市是罗氏沼虾养殖大市,全市养殖近10 000 hm2,平均每667 m2产量约300 kg,通常采用虾苗分批放养、幼虾分级培育、成虾轮捕上市的养殖方式,这种方式放苗量大(近两年罗氏沼虾苗供不应求,价格较高),投饲量大,池水富营养化严重,蓝藻水华频发,严重制约了罗氏沼虾养殖的发展.为此我们进行了罗氏沼虾与河蟹混养模式探索,以降低养殖池塘的虾苗放养量,通过实施种草养殖,降低饲料投喂量,改善了养殖环境,取得了很好经济效益和生态效益.现将其养殖技术介绍如下.     

放养不同数量白鲢对罗氏沼虾池塘蓝藻水华及水质的影响

该文旨在探讨在罗氏沼虾养殖后期放养白鲢对池塘水质及浮游植物种类与数量的影响。试验选取规格为80尾/kg白鲢鱼种,按放养数量分别为0(1号塘)、1000尾/667m^2(2号塘)、1500尾/667m^2(3号塘)、2000尾/667m^2(4号塘),投放到4个养殖条件相近的罗氏沼虾池塘中,每隔10d检测池塘水质指标和浮游藻类,共5次。结果显示,池塘pH值呈先下降后稳定的趋势;各组溶氧均有显著的提升;2号和4号池塘透明度提升速率明显高于对照组;各组氨氮、亚硝含量变化不明显。各组化学需氧量(CODCr)、总氮、总磷、修正营养状态指数(TSIM)均呈下降趋势,且试验组下降幅度高于对照组,其中4号池塘下降最为明显。试验组池塘蓝藻下降幅度均高于对照组,且随着投放鲢鱼数量的增大,蓝藻占水体浮游植物的百分比越小。结果表明,在罗氏沼虾养殖后期放养白鲢,能够改善养殖水体环境,降低水体富营养化程度,有效控制蓝藻水华的发生。     

Spent brewer's yeast as a replacement for fishmeal in diets for giant freshwater prawn (Macrobrachium rosenbergii), reared in either clear water or a biofloc environment

A 90‐day feeding experiment was conducted in order to test spent brewer's yeast as a replacement for fishmeal in diets for giant freshwater prawn (Macrobrachium rosenbergii) reared in either a recirculating aquaculture system (RAS) or a biofloc system. Triplicate groups, each of 20 prawn (6.7 ± 0.03 g), were randomly assigned to 24 identical tanks. Twelve tanks were connected to the RAS, and the other 12 tanks were connected to the biofloc system which were initially supplemented with Bacillus subtilis, molasses and blood meal to achieve a C:N ratio of 20:1. Four iso‐nitrogenous (350 g/kg) and iso‐energetic (19 MJ/kg) diets where 0%, 20%, 40% and 60% of fishmeal protein was replaced by spent brewer's yeast. Neither growth nor survival was affected (p > 0.05) by increasing levels of brewer's yeast. The exception, being fish given 60% replacement with brewer's yeast, reared in biofloc, which displayed a higher (p < 0.05) growth than fish given 40% replacement, reared in clear water. The feed conversion ratio of prawn reared in the biofloc environment was lower than in the clear water. We concluded that spent brewer's yeast represents a possible 60% substitute for fishmeal in giant freshwater prawn diets, especially for prawn reared in a biofloc environment.     

A Preliminary Evaluation of Naturally Occurring Organisms,Distillery By-Products,and Prepared Diets as Food for Juvenile Freshwater Prawn Macrobrachium rosenbergii

The relative acceptability and suitability of naturally occurring pond organisms identified as likely natural food items for juvenile freshwater prawn, Macrobrachiurn msenbergii, were evaluated under controlled conditions. The potential of direct consumption of materials used as organic pond fertilizer (distillers dried grains with solubles [DDGS] was also evaluated. Growth and survival of prawn fed gastropods, oligochaetes, zooplankton, or DDGS were compared with those fed a nutritionally-complete pellcted diet (control). Groups of five juvenile prawn (average weight 1.66 ± 0.10 g) were stocked into eighteen 7.5-L glass aquaria. Dietary treatments were evaluated in triplicate aquaria for 21 days. Prawn fed live zooplankton exhibited a significantly higher rate of weight gain (P < 0.05) than drawn in other treatments, as measured by differences in slopes of regression lines for weight gain over time. There were no significant differences (P > 0.05) in rates of gain for prawn fed a complete diet and those fed DDGS or gastropods. Prawn fed oligochaetes grew significantly slower (P < 0.05) than those fed the prepared diet. Results indicate that juvenile prawn as large or larger than 2g can utilize live zooplankton and that DDGS may be consumed directly by prawn. Thus, DDGS may serve a dual role as a feed and pond fertilizer. Additional research in pond management strategies that maximize zooplankton and gastropod numbers and the potential of DDGS as a combination food/fertilizer in freshwater prawn production ponds should be conducted.     

左旋咪唑对罗氏沼虾免疫功能及抗病力的影响

以0(对照)、50、100和150 mg/kg饲料的剂量将左旋咪唑(LMS)添加于基础饲料中制成颗粒饲料投喂罗氏沼虾(Macrobrachium rosenbergii)14 d,采样测定了罗氏沼虾血细胞吞噬活性、血清酚氧化酶(PO)、溶菌酶(LSZ)及超氧化物岐化酶(SOD)活性,并以6×105cells/mL浓度的致病性嗜水气单胞菌(Aerom onas hydrophila)对罗氏沼虾进行肌肉注射(20μL/尾),记录接种7 d后罗氏沼虾的累积死亡率。结果表明,3个LMS处理组的罗氏沼虾血细胞吞噬百分比和吞噬指数、血清PO、LSZ及SOD活性均显著地高于对照组(P<0.05);LMS处理组的罗氏沼虾对嗜水气单胞菌的抵抗力明显增强。因此,饲喂适量的LMS能促进罗氏沼虾的免疫力和抗病力;在本试验条件下,100 mg/kg饲料的剂量为最适添加剂量。     

Optimal protein replacement of fish meal by mackerel condensate in diet for giant freshwater prawn (Macrobrachium rosenbergii)

The optimal protein replacement of fish meal (FM) by mackerel condensate (MC) was investigated in giant freshwater prawn, Macrobrachium rosenbergii (0.90 ± 0.01 g initial weight) over a 12‐week trial. The experimental diets replaced the FM partially in a baseline FM‐based diet (0MC), by substituting MC for 10% (10MC), 20% (20MC), 30% (30MC), 40% (40MC), 50% (50MC) and 60% (60MC) of the FM, and a commercial diet (CD) was included for comparison. The prawn fed with 40MC had superior growth performance and feed utilization. Significant increases in amylase and cellulase‐specific activities indicated improved carbohydrate utilization in this dietary group (P < 0.05). The proteolytic activity was maintained through the key gastrointestinal enzymes (pepsin, trypsin and chymotrypsin). A slight improvement in carcass compositions was also observed in the prawns fed 40MC, and the total haemocyte count was significantly increased by this diet, without negative effects on the hepatopancreatic histology. These findings indicate that a 40% protein replacement of FM by MC is optimal for giant freshwater prawn, and similar use of it in the aquafeed of other species appears worth further studies.     

Growth, Survival, and Body Composition of Cage-Cultured Nile Tilapia Oreochromis niloticus Fed Pelleted and Unpelleted Distillers Grains with Solubles in Polyculture with Freshwater Prawn Macrobrachium rosenbergii

Abstract.— A 12‐wk feeding trial was conducted in cages with juvenile Nile tilapia Oreochromis niloticus to evaluate distillers grains with solubles (DDGS) as a direct feed, the effects of pelleting on its utilization, and the compatibility of caged tilapia and prawns in polyculture. Nine 1.0‐m³ cages were stocked with 200 juvenile (26 ± 0.9 g) tilapia. Cages were suspended in a 0.2‐ha pond stocked with juvenile freshwater prawns Macrobrachium rosenbergii at 40,000/ha. Three replicate cages were randomly assigned to each dietary treatment. In one dietary treatment DDGS was fed as an unpelleted loose grain ration (26% protein). In a second dietary treatment fish were fed DDGS that had been steam‐pelleted (23% protein). Fish in a third dietary treatment were fed a commercial catfish diet (31% protein) for comparison. After 12 wk, individual weight, individual length, and specific growth rate were significantly higher (P < 0.05) and feed conversion ratio was significantly lower (P < 0.05) for fish fed the commercial catfish diet than for fish fed either unpelleted or pelleted DDGS. Specific growth rate was significantly higher (P < 0.05) for fish fed pelleted DDGS than for fish fed unpelleted DDGS. Survival did not differ significantly (P > 0.05) among treatments (>95%). Although growth was increased in fish fed the commercial diet, their cost of production (<0.66/kg gain) was significantly higher (P < 0.05) than in fish fed unpelleted and pelleted DDGS (<0.26/ kg gain and <0.37/kg gain, respectively). The costs of gain in fish fed unpelleted DDGS was significantly lower (P < 0.05) than in fish fed the pelleted DDGS. Prawn production was 1,449 kg/ha and addition of tilapia in polyculture increased total pond productivity approximately 81 %. These data suggest that DDGS provides economical growth in tilapia when fed as a direct feed and that polyculture of tilapia may improve overall pond efficiency in freshwater prawn production ponds, even at temperate latitudes.     

罗氏沼虾肌肉白浊病发病池和未发病池水质状况比较

对罗氏沼虾肌肉白浊病发病与未发病育苗池以及发病与未发病大棚培育土池 ,进行了 pH值、氨氮、亚硝酸盐氮、硝酸盐氮、化学耗氧量和可溶性磷酸盐检测 ,结果显示 ,发病池与未发病池之间这些水质因子均无显著差异 (P(0 .0 5 )。对罗氏沼虾苗有较大毒性的非离子态氨氮和亚硝酸盐氮含量都在安全浓度范围内 :淡化前 ,发病育苗池中两者的平均值分别为 0 .173mg/L、0 .0 83mg/L ,未发病育苗池中分别为 0 .2 0 1mg/L、0 .10 3mg/L ;淡化后 ,发病育苗池中两者的平均值分别为 0 .0 33mg/L、0 .0 4 0mg/L ,未发病育苗池中分别为 0 .0 2 7mg/L、0 .0 39mg/L ;在发病大棚培育土池中 ,两者的平均值分别为 0 .114mg/L、0 .0 6 1mg/L ,在未发病大棚培育土池中分别为 0 .112mg/L、0 .0 76mg/L。检测结果表明 :罗氏沼虾肌肉白浊病与所测的这些水质因子无关。     

Effects of C/N ratio and periphyton substrates on pond ecology and production performance in giant freshwater prawn Macrobrachium rosenbergii (De Man, 1879) and tilapia Oreochromis niloticus (Linnaeus, 1758) polyculture system

The production performances of giant freshwater prawn Macrobrachium rosenbergii and Nile tilapia Oreochromis niloticus in C/N‐controlled periphyton‐based polyculture systems were evaluated in triplicate. Three different management practices were compared: the traditional practice without addition of periphyton substrates and carbohydrate (Control), addition of maize flour to maintain a carbon: nitrogen rate of 20:1 (treatment CN) and addition of both maize flour and periphyton substrates (treatment CN+P). This experiment used a pre‐optimized stocking density of tilapia and freshwater prawn by Asaduzzaman et al. Aquaculture [286 (2009) 72]. All ponds were stocked with prawn (3 m²) and monosex Nile tilapia (1 m^?2). Bamboo side shoots were posted vertically into the pond bottoms as periphyton substrate covering an additional area of 171 m² for periphyton development. A locally formulated and prepared feed containing 17% crude protein with C/N ratio close to 15:1 was applied twice daily in all ponds considering the body weight of freshwater prawn only. Water quality parameters, except total alkalinity did not vary significantly (P > 0.05) among treatments. Both, organic matter and total heterotrophic bacterial loads (THB) in the sediment were significantly (P < 0.05) higher in treatment CN+P followed by treatment CN and control. Periphyton biomass in terms of dry matter and chlorophyll a values constantly decreased during the culture period. Substrates contributed 66% and 102% higher net yield of freshwater prawn than CN and control treatment respectively.     

Evaluation of a Biofloc System for Intensive Culture of Fathead Minnows,Pimephales promelas

This study was carried out to test the suitability of biofloc technology to improve the productivity of the fathead minnow, Pimephales promelas, a commercially important baitfish in North America. Biofloc growth was induced in treatment tanks by periodic additions of a carbon source (glucose) to maintain a C : N ratio of 12:1. Control tanks (no aeration and no carbon addition) accommodated densities equivalent to 1 million fish/ha, while treatment tanks (biofloc) had densities of 1, 2, 4, and 8 million fish/ha. Fish were fed 4% body weight using a 32% protein commercial diet. There were no significant differences in condition of fish harvested from control and treatment densities (P < 0.05). However, fish growth indicators such as final individual weight, feed conversion efficiency, and specific growth rate were significantly impaired at higher stocking densities. Survival rate was significantly lower in the 8 million/ha treatment (P < 0.05). Results were indicative of possible production efficiencies of twofold higher in biofloc systems stocked at or below 4 million/ha compared with traditional ponds. Although biofloc systems maintained the desired water‐quality parameters, biofloc microbial biomass did not seem to significantly enhance feed conversion and specific growth rates of fathead minnows.     

Growth and carcass composition of giant freshwater prawn, Macrobrachium rosenbergii (De Man), fed different isonitrogenous and isocaloric diets

A feeding experiment was conducted for 135 days to observe the effect of different isonitrogenous (35% crude protein) and isocaloric (385 kcal) diets on the growth and carcass composition of giant freshwater prawn, Macrobrachium rosenbergii ( De Man 1879 ). Three experimental diets (ED1, ED2 and ED3) were prepared using locally available ingredients. These diets differed mainly in terms of percent contribution of major protein sources such as fish meal, soybean meal, groundnut oil cake and mustard oil cake. Experimental diets were evaluated against a commercial diet, which served as the control (CD). Juveniles 1.87–2.44 g in size were stocked at a population density of 40 000 ha⁻¹ and fed thrice daily at 10% in the beginning and reducing gradually to 7% and 5% of the body weight during the experimental period. No significant differences (P>0.05) in the growth performance were observed; however, a significantly (P<0.05) higher yield (721.9 kg ha⁻¹ 135 days⁻¹) was recorded for prawn fed with control diet, followed by experimental diet 2 (676.5 kg ha⁻¹ 135 days⁻¹, having soybean meal as a major protein source). The survival ranged between 63.8% and 77.7%, with different diets showing significantly higher survival. The apparent feed conversion ratio values of diets ranged between 3.15 and 3.49, with experimental and control diets showing non‐significantly lower AFCR values. At the end of the experiment, representative specimens from each treatment were collected and their carcass composition was measured. Analysis of variance showed that carcass protein and total carbohydrate contents were significantly (P<0.05) higher in prawns fed on a fish–soybean meal‐based diet (ED3) and a control diet. The total lipid contents of prawns, however, did not differ significantly among the various dietary treatments. The results of our study suggest that the experimental diets could be used effectively for M. rosenbergii without compromising growth and flesh quality.     

A Comparison of Two Feeding Technologies in Freshwater Prawns,Macrobrachium rosenbergii,Raised at High Biomass Densities in Temperate Ponds

ABSTRACT

Recent developments in prawn production technologies (i.e., added substrate, increased stocking densities, size grading, and increased feed rates) have increased production rates from 900-1,000 kg/ha to over 2,500 kg/ha. While prawn can receive substantial nutritional benefit from natural foods at the lower biomass densities, at higher production rates prawn are likely to be more dependent on prepared diets. To ensure that maximum production is being achieved by these new production technologies, production rates must not be nutritionally constrained. This study was conducted to compare the current recommended technology of phase feeding of different quality feedstuffs to prawns of different sizes with the feeding of a high-quality penaeid diet throughout the production season. Two treatments were evaluated: Treatment 1 was phase feeding (current technology-control) where prawns were fed unpelleted distillers' grains with solubles (DDGS) for the first four weeks, then a 28%-protein prawn diet for weeks 5-12, and finally a 40%-protein penaeid diet for weeks 13-16. In Treatment 2, prawn were fed the 40%-protein penaeid diet throughout the entire production period. Feeding rates in both treatments were based upon a feeding table. Three 0.04 ha ponds were used for each treatment. All ponds were stocked at 59,280 juveniles/ha and were provided with artificial substrate in the form of a polyethylene “safety fence” oriented vertically to increase available surface area by 50%. After 106 culture days, no significant differences (P >0.05) were observed between treatments in terms of yield, average individual weight, food conversion ratio (FCR), or survival, which averaged 2,575 kg/ha, 46 g, 2.3, and 94%, respectively, overall. Due to the higher cost of the penaeid diet (US$0.84/kg), feeding costs for the penaeid diet treatment (Treatment 2) were 38% higher than those for Treatment 1. No benefit to using higher protein diets during the first 12 weeks of prawn pond production was observed.