Effects of Size and Age of Juvenile Freshwater Prawns Macrobrachium rosenbergii at Stocking on Population Structure and Production in Polyculture Ponds

Effects of size and age of juvenile freshwater prawns on their growth in polyculture ponds were investigated. Post-larvae were nursed at two commercial nurseries, during either 66 or 129 days, to final mean weights of about 0.25 and 0.5 g, for each age group. Nursed prawns were stocked in ponds at a density of 2/m² and polycultured with carps and tilapias for 148 days.
No significant effect of age or size, or their interaction, was detected in mean harvest weight and gross income, although small age effect was noted in survival and total yield.     

Effects of Stocking Density on Nursery Production and Economics of the Freshwater Prawn,Macrobrachium rosenbergii

ABSTRACT

In temperate regions, post-larvae freshwater prawn, Macrobrachium rosenbergii, are grown to more advanced sizes in tanks prior to pond stocking. This intermediate stage of culture is referred to as the nursery period. Little research has been conducted on different management practices on juvenile prawn growth and survival during this 30-60 day period. Survival during the nursery stage has been highly variable and may be related to the cannibalistic behavior of juvenile freshwater prawn when cultured at high densities in the nursery. The objective of this study was to evaluate the effect of stocking density, relative to the provision of artificial substrate (number of prawns/m² of substrate), on growth, survival, and economic variables for freshwater prawn juveniles during nursery production. Post-larvae (0.01%0.00 g, n = 300) were stocked into nine 1900 L tanks, each provided with 20.5 m² of artificial substrate in the form of horizontal layers of black plastic mesh (10 mm) spaced 5 cm apart. Tanks were randomly assigned one of three prawn densities (215, 430, or 860 post-larvae/m² of substrate), which equated to 2.3,4.6 and 9.2 prawn/L, respectively. Juvenile prawn were fed a commercial trout diet (42% protein) at a percentage of body weight according to a feed rate table. Water quality was maintained using a flow rate of 8 L/min in each tank from a reservoir pond. Temperature was maintained at approximately 28°C using heat pumps. After 56 days there was no significant difference (P >0.05) in average weight of juvenile prawn stocked at the three densities (0 = 0.58%0.12 g, n = 9). Survival was significantly lower (P <0.05) for prawn stocked at 860 m² (62%) than in those stocked at 430/m² (78%) and 215/m² (94%), which were not statistically different (P >0.05). Even with reduced survival, the highest stocking density produced the greatest number of nursed juveniles based on both tank volume (5.5/l) and surface area (530/m²), at the lowest average cost.     

Polyculture of Macrobrachium rosenbergii and Notemigonus crysoleucas

A polyculture study was conducted in southwest Louisiana comparing production of Malaysian prawns, Macrobrachium rosenbergii , in monoculture and polyculture with Golden shiners, Notemigonus crysoleucas .
This test revealed stocking of shiners at 24.7/m² with prawns at 4.4/m² resulted in increased total pond production over monoculture of prawns at 4.4/m² with equal prawn yields in both systems and little increase in labor. Feeding rates were based on prawn biomass. Food conversion ratios ranged from 0.5 to 1.0 in polyculture and 0.9 to 1.1 in monoculture when total production was considered. Prawn production averaged 640 kg/ha in polyculture and 629 kg/ha in monoculture. Mean size of prawns was 19 g in polyculture and 20 g in monoculture. The polyculture of shiners with prawns added an average of 307 kg/ha of the bait fish to pond production.
Shiners did not compete seriously with prawns when stocked at these rates. This practice could result in added revenues to producers culturing these species together.     

Growth, Survival, Yield, and Size Distributions of Freshwater Prawn Macrobrachium rosenbergii and Tilapia Oreochromis niloticus in Polyculture and Monoculture Systems in Puerto Rico

Abstract.— Tilapia and freshwater prawn production in Puerto Rico for monoculture and polyculture systems were compared. The experiment consisted of three treatments with three replicates each. The stocking rates for the prawn monoculture, fish monoculture and polyculture treatments were respectively: 7 prawns/m², 1 tilapia/M², and 7 prawns with 1 tilapia/ m². The mean stocking size for tilapia and prawn were respectively, 7–8 g and 1–1.3 g. After 145 d of culture, yields and mean weight of tilapia in monoculture and polyculture system were not significantly different. Total yields were 2,942 and 2,769 kg/ha, respectively. Mean weights were 348 g in monoculture and 331 g in polyculture. Yields and mean weight of prawns in monoculture and polyculture were significantly different. Total yields were 1,367 and 951 kg/ha, respectively. Mean weights were 55 g in monoculture and 31 g in polyculture. Total yield in polyculture was 3,720 kg/ha showing an increase over the production separately obtained in prawn and fish monoculture.     

Production of Nile Tilapia Oreochromis niloticus and Freshwater Prawn Macrobrachium rosenbergii Stocked at Different Densities in Polyculture Systems in Brazil

Abstract.— The effect of stocking prawns Macrobrachium rosenbergii at increasing densities in ponds with Nile tilapia Oreochromis niloticus reared at low density was evaluated. Twelve 0.01-ha earthen ponds were stocked with 1 tilapia/m² and 0, 2, 4, or 6 postlarvae prawn/m². Three replicates were randomly assigned to each prawn density. Postlarval prawns were stocked a week prior to tilapia juveniles and both were harvested 175 d after the beginning of the experiment. Tilapia final average weight, survival, production, and food conversion rates did not differ significantly among treatments ( P > 0.05); the averages were 531 g, 67%. 3,673 kg/ha, and 1.91, respectively. Prawn survival rates did not differ for the three stocking densities (mean 90%). However, final weight and production were significantly different ( P < 0.05) as follows: 34.0, 23.0, and 14.7 g and 639, 909, and 818 kg/ha, respectively for 2. 4, and 6 prawns/m² densities. Stocking densities up to 6 prawn/m² did not affect tilapia production and required neither additional feeding nor significant changes in management. The polyculture system allowed an increase in total production with the same amount of supplied feed, thus improving the system sustainability.     

Effects of Stocking Density and Monosex Culture of Freshwater Prawn Macrobrachium rosenbergii on Growth and Production in Concrete Tanks in Saudi Arabia

Abstract This study was conducted to evaluate the effects of stocking density and monosex culture on growth, survival, yield and feed conversion ratio of freshwater prawn Macrobrachium rosenbergii in concrete tanks. Juvenile prawns with an average weight of 1.8 g were stocked into triplicate tanks at densities of 5, 10, 15 and 20 prawns/m², grown for 168 d and fed a 34% tilapia diet. Stocking density had significant effect on prawns. Final mean body weight decreased with the increasing density, being highest at 5 prawns/m² (29.6 9). and lowest at 20 prawns/m² (17.4 g). Total yield increased from 135 g/m² (1,350 kg/ha) at a density of 5 prawns/m² to 261 g/m² (2,610 kg/ha) at density 15/m^z to 245 g/m² (2,450 kg/ha) at 20/m^z. Feed conversion ratios were high and ranged from 3.7 (5 prawns/m²) to 5.6 (20 prawns/m²).
In monosex culture of freshwater prawns stocked in triplicate tanks at a density of 5 prawns/m² for 112 d, the all-male population had the best growth performance and feed conversion ratio, followed by the mixed-sex and all-female populations. The all-male population had 99% marketable prawns (>20 g) with an average yield of 159 g/m² (1,590 kg/ha); the mixed-sex population had 90% marketable prawns and the yield was 135 g/m^z (1,350 kg/ha); and the all-female population had 75% marketable prawns with an average yield of 108 g/m² (1,080 kgha).     

混养鲫鱼对罗氏沼虾种虾培育效果的影响

在3口面积各为0.3 hm^2、深度2.0 m的长方形池塘(1#、2#、3#)中放入体长0.7～0.8 cm的罗氏沼虾"南太湖2号"无特定病原种虾,密度为3.0×10~5尾/hm^2;养殖30 d时,2#、3#池塘分别混养质量3～4 g/尾的鲫鱼450、900尾,1#池塘不混养作对照组。经过近110 d的培育,1#、2#、3#池塘"南太湖2号"种虾的平均体质量分别达18.36、18.95、22.6 g,收获量分别达931.5、898.4、842.95 kg,饵料系数分别为1.36、1.53和1.71。试验结果表明,罗氏沼虾"南太湖2号"种虾培育池塘混养合理密度的鲫鱼,虽然影响种虾养殖产量,饲料系数增大,但培育出的种虾个体较大,饱满度较高,作为亲本可以为后期育苗工作的顺利开展打下良好基础。     

积温和放养规格对网箱养殖罗非鱼的影响

利用大秋房水库网箱养罗罗非鱼的６年生产记录，以放养规格以及每天大于１５℃、大于２０℃的积温和天数作为自变量、以个体增肉倍数、饵料系数作为变量，进行一元和二无回归分析。结果发现：每天大于１５℃的积温和天数与增肉倍数相关最显著；第天大于１５℃的天数和放养规格与饵料系数相关也较显著。     

Effects of Stocking Density on Growth of Tilapia nilotica Cultured in Cages in Ponds

Reported maximum carrying capacities of Tilapia nilotica reared in cages are Iow ranging from 10 to 70 kg/m³. This may be related to total numbers of caged fish reared in a body of water and not simply density per cage volume. An experiment was conducted to demonstrate such effects.
Sixteen cages in a 0.77 ha pond were stocked with T. nilotica at either 250, 500, 750, or 1,000 fish/cage for a total of 12,987 fish/ha. One cage in each of four 0.13 ha ponds was stocked with either 250 or 1,000 fish/cage for a total of 1,923 or 7,692 fish/hectare, respectively. Fish were fed a 32% protein diet at equal rates for 169 days. In the 0.77 ha pond, yield per cage was positively correlated with stocking density, while individual mean weights were negatively correlated with stocking density. However, among equal densities per cage between ponds, fish in the 0.13 ha ponds gained about 26% more than in the 0.77 ha pond. An interaction of the effects of density per cage volume and per pond area may have occurred.     

卤虫的营养强化及其对罗氏沼虾幼体培育的影响

用小球藻强化培育卤虫，研究不同时间后卤虫体内脂肪酸的变化，并用此卤虫投喂罗氏沼虾幼体，研究其对罗氏沼虾幼体发育及成活的影响。实验结果表明，卤虫在强化12h后EPA及HUEA含量最高，强化时间延长至24h，EPA和HUFA含量反而下降。卤虫经营养强化可明显地促进罗氏沼虾幼体的生长发育并提高育苗成活率，而且在24h内随着强化时间的延长，效果越明显。     

Effects and Interactions of Stocking Density and Added Substrate on Production and Population Structure of Freshwater Prawns Macrobrachiurn rosenbergii

The effects and interactions of added artificial substrate with different stocking densities of prawns were evaluated. Juvenile prawns (0.2 ± 0.1 g) were stocked into 12 0.04-ha ponds at 60,000ha and 120,000/ha with and without substrate. Added substrate consisted of horizontal plastic mesh and strips of oyster netting sutlicient to increase available surface area 80%. There were no statistically significant ( P > 0.05) interactions between stocking density and presence of added substrate, allowing these main effects to be compared separately. Increasing stocking density produced a significant increase ( P < 0.01) in total production but a significant decrease ( P < 0.01) in average prawn size and production ( P < 0.05) of market size prawns (>20 g, -27%; > 30 g, -56%). Added substrate also produced a significant increase ( P < 0.05) in total production (18%). However, average prawn size was not decreased and production of marketable shrimp was increased (>20 g, 25%; >30 g, 19%). Feed conversion ratios were significantly decreased (P < 0.01) by the presence of substrate. Increased stocking density significantly increased ( P < 0.05) the percentage of males which were small males (SM) and decreased ( P < 0.01) the percentage of orange claw males (OC), but had no impact ( P > 0.05) on numbers of reproductive (RF) and virgin (VF) female morphotypes. Increased stocking density also produced a significant decrease ( P < 0.05) in average size of OC, RF, and VF morphotypes while the addition of substrate had no statistically significant impact (P > 0.05) on the number or size of different morphotypes. The mathematical relationship between available surface area and average prawn size should be determined to produce recommended inclusion rates for added substrate based on desired levels of total production, stocking rates, and optimum market sizes.     

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.     

罗氏沼虾与河蟹、鲢、鳙池塘混养试验

为充分利用水体资源 ,大力推广健康养殖新技术 ,作者于 2 0 0 1年实施了临沂市河东区科技局下达的《罗氏沼虾与河蟹、鲢、鳙池塘混养技术》试验项目 ,在当年取得良好效果的基础上 ,接着于2 0 0 2年进行了大面积推广。该项目在饲养技术及产量方面显示了一定的先进性 ,并达到了预期效果 ,现归纳报道如下。池塘及设置　　 1 .池塘条件　　为当年开挖或已养过 2年鱼的池塘 ,面积 2 0 0 0～ 5 0 0 0m2 ,坡比 1∶2 .5～ 3 ,水深1 .5～ 2m ,池底无淤泥。水源为农田灌溉用水和地下井水 ,水质符合渔业用水标准。苗种放养前半个月用生石灰清塘消毒 ,并…     

超低温保存对罗氏沼虾胚胎几种酶活性的影响

研究了超低温冷冻保存(-196℃)对罗氏沼虾胚胎内总三磷酸腺苷酶(ATPase)、肌酸激酶(CK)、琥珀酸脱氢酶(SDH)、乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)、丙二醛(MDA)等酶活性的影响。运用试剂盒分别测定了冷冻前后罗氏沼虾胚胎内酶活性的变化。结果表明,经过超低温冷冻保存后,胚胎内7种酶的活性均显著下降(P0.05),其中总ATPase、CK、LDH和SDH的活性分别从冻前的1.322±0.162 U/mg prot、0.404±0.015 U/mg prot、352.225±23.214 U/gprot和2.067±0.139 U/mg prot下降到0.087±0.003 U/mg prot、0.010±0.002 U/mg prot、5.890±0.658 U/gprot和0.552±0.138 U/mg prot;SOD、CAT和GSH-Px的活性分别从冻前的19.217±0.677 U/mg prot、3.587±0.233 U/mg prot和7.626±1.106 U/(min.mg)下降至3.579±0.234 U/mg prot、1.773±0.227 U/mg prot和1.524±0.096 U/(min.mg);MDA的活性从1.015±0.038 n mol/mg prot上升到20.937±0.320 n mol/mgprot,超低温冷冻对罗氏沼虾胚胎酶活性有显著性影响。     

罗氏沼虾与青虾轮养技术

罗氏沼虾具有食性杂、生长快、产量高的优势 ,但是不耐低温 ,在我国江淮流域 ,虾池的利用实际只有半年时间 (5～ 1 0月 )。青虾适温范围广 ,生长快。它具有繁殖力强、肉味鲜美、经济价值高的特点。为了提高池塘的养殖效益 ,在实际生产过程中 ,可以通过增大放养规格 ,加强饲养管理 ,来缩短罗氏沼虾生长周期(1 0 0天以内 )。另一方面采取二级放养的措施 ,来延长青虾生长时间 ,从而实现罗氏沼虾、青虾的二茬轮养。下面就我们 1 999年开展的这一试验做一初步总结。1　条件和方法1 1　试验池 :为马鞍山市前庄水产良种场2 2 #、2 3#成虾池 ,面积…     

Effects of Diffused Aeration and Stocking Density on Growth, Feed Conversion, and Production of Florida Red Tilapia in Cages

The effects of four levels of diffused aeration (0, 6, 12, and 24 hours/day) and two stocking densities (400 and 600 fish/m³) on the culture performance of caged Florida red tilapia were evaluated in 1 m³ cages in a 2 ha watershed pond on St. Croix, U.S. Virgin Islands. Fish obtained a nutritionally-complete (36% protein), floating feed from demand feeders for 143 to 146 days. Diffused aeration had no significant ( P > 0.05) effect on fish growth, survival, feed conversion, and production in cages. Combined across all levels of diffused aeration, fish stocked at 400/cage had a greater growth rate (2.21 vs. 1.97 g/day), larger final body weight (370 vs. 335 g), and a lower feed conversion ratio (1.69 vs. 1.80) than fish stocked at 600/cage ( P < 0.05). The final biomass of fish stocked at the higher density (181 kg/m³) was greater than at the lower density (140 kg/m³). The enhancement of water exchange rates by diffused aeration did not increase tilapia growth rate or production in cages.     

三丁基锡对罗氏沼虾卵黄蛋白原（VTG）表达和性腺发育的影响

将罗氏沼虾成虾浸浴于含三丁基锡（Tributyltin, TBT） (0.1、0.2、0.4mg/L）的水体中,研究TBT对其肝胰脏和性腺中卵黄蛋白原(VTG)表达和性腺发育的影响。结果表明,罗氏沼虾在TBT中浸浴10d,TBT能够诱导雌虾的肝胰腺VTG基因表达,而对卵巢VTG基因的表达则表现为抑制作用;TBT对雄虾的肝胰腺VTG基因表达有抑制作用,而对精巢VTG基因的表达无明显影响。性腺组织切片显示,TBT浸浴能够促进罗氏沼虾精巢的发育,且随浸浴剂量的增加对精巢发育的促进作用逐步增强,但TBT对罗氏沼虾卵巢发育无明显影响。     

VC聚磷酸酯对罗氏沼虾生长的影响

随着动物营养和饲料科学的研究进展,ＶＣ在水产养殖中的作用逾来逾受到人们的关注和重视。水产动物机体本身不能合成ＶＣ,必需由饵料供给,当ＶＣ缺乏时,水产动物则表现出厌食,抗病力差,生长迟缓等症状。由于ＶＣ在空气中、高温下极不稳定,容易被氧化而失去活性,因此目前国内外都在研究稳定型ＶＣ,其中ＶＣ聚磷酸酯的研究及应用较为广泛。为了考察饲料中添加ＶＣ聚磷酸酯对罗氏沼虾生长的影响,我们于１９９８年７月进行了如下试验。１　材料与方法１－１　试验饲料试验饲料基础配方如表１,各组饲料除复合维生素中ＶＣ含量不同外,…     

罗氏沼虾工厂化育苗试验

利用对虾育苗场的设计进行罗氏沼虾工厂化育苗试验，于１３６ｍ＾３水体中投放状幼体１４３８万尾，育出商品仔虾９６４万尾，幼体培育成活率为６７％，平均每尾亲虾出苗４７２５尾，单位水体平均出苗量为７．０９万尾，最高为１０．２万尾／ｍ＾３。从４月上旬到５月下旬，罗氏沼虾雌性亲虾可抑卵三次以上，前后抱卵批次所孵出的幼体质量没有明显差异。试验还证明，幼体培育池内氨氮浓度高达１０５６．４μｇ／ｌ对成活率没有多大曩