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Freshwater Prawn (freshwater + prawn)
Kinds of Freshwater Prawn Terms modified by Freshwater Prawn Selected AbstractsAn Economic Analysis of Freshwater Prawn, Macrobrachium rosenbergii, Farming in Mymensingh, BangladeshJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2008Nesar Ahmed This paper deals with production systems, cost structure, and profitability of freshwater prawn, Macrobrachium rosenbergii, farming in a new area of Mymensingh district in the north-central part of Bangladesh. In the study area, prawn farming practice is still extensive, and only a few farmers (20%) cultivate semiintensively. The costs and returns of extensive and semiintensive farming systems are compared. All farmers in different farming systems made a profit, with seed and feed dominating variable costs. Considerable variation in production costs and profitability was observed. Based on the Cobb,Douglas production function model, return to scale indicates that there is scope to increase production and income from prawn farms in extensive and semiintensive systems by applying more inputs (i.e., seed, feed, and fertilizer). [source] Effect of Dietary Administration of 17,-methyltestosterone on the Sex Ratio of Postlarval Freshwater Prawn, Macrobrachium rosenbergii, During the Nursery Stage of CultureJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 3 2006Cortney L. Ohs First page of article [source] Culture-based fisheries in non-perennial reservoirs in Sri Lanka: production and relative performance of stocked speciesFISHERIES MANAGEMENT & ECOLOGY, Issue 4 2005W. M. H. K. WIJENAYAKE Abstract, In Sri Lanka, there is a great potential for the development of culture-based fisheries because of the availability of around 12 000 non-perennial reservoirs in the dry zone (<187 cm annual rainfall) of the island. These reservoirs fill during the north-east monsoonal period in October to December and almost completely dry up during August to October. As these non-perennial reservoirs are highly productive, hatchery-reared fish fingerlings can be stocked to develop culture-based fisheries during the water retention period of 7,9 months. The present study was conducted in 32 non-perennial reservoirs in five administrative districts in Sri Lanka. These reservoirs were stocked with fingerlings of Indian (catla Catla catla Hamilton and rohu Labeo rohita Hamilton) and Chinese (bighead carp Aristichthys nobilis Richardson) major carps, common carp Cyprinus carpio L., genetically improved farmed tilapia (GIFT) strain of Nile tilapia, Oreochromis niloticus (L.) and post-larvae of giant freshwater prawn, Macrobrachium rosenbergii De Man, at three different species combinations and overall stocking densities (SD) ranging from 218 to 3902 fingerlings ha,1, during the 2002,2003 culture cycle. Of the 32 reservoirs stocked, reliable data on harvest were obtained from 25 reservoirs. Fish yield ranged from 53 to 1801 kg ha,1 and the yields of non-perennial reservoirs in southern region were significantly (P < 0.05) higher than those in the northern region. Naturally-recruited snakehead species contributed the catches in northern reservoirs. Fish yield was curvilinearly related to reservoir area (P < 0.05), and a negative second order relationship was evident between SD and yield (P < 0.05). Chlorophyll- a and fish yield exhibited a positive second order relationship (P < 0.01). Bighead carp yield impacted positively on the total yield (P < 0.05), whereas snakehead yield impact was negative. Bighead carp, common carp and rohu appear suitable for poly-culture in non-perennial reservoirs. GIFT strain O. niloticus had the lowest specific growth rate among stocked species and freshwater prawn had a low return. [source] Extra small virus-like particles (XSV) and nodavirus associated with whitish muscle disease in the giant freshwater prawn, Macrobrachium rosenbergiiJOURNAL OF FISH DISEASES, Issue 9 2003D Qian Abstract A disease of Macrobrachium rosenbergii, the giant freshwater prawn, farmed in China was recently recorded in Zhejiang, Jiangsu, Shanghai, Guangxi and Guangdong provinces. The clinical sign of the disease, which develops in post-larvae (PL), is a whitish appearance of the muscles, particularly noticeable in the abdomen. Mortalities may reach 100% in some hatcheries. Investigations by transmission electron microscopy after negative staining of diseased PL homogenates showed the presence of two types of viral particles: one, unenveloped, icosahedral in shape, 26,27 nm in diameter, the second, much smaller, about 14,16 nm in diameter, designated extra small virus particle (XSV). The large virus has a genome with two pieces of ssRNA (RNA-1 and RNA-2), of 3 and 1.2 kb, respectively. Hybridization tests confirmed that this large virus is closely related to M. rosenbergii nodavirus (MrNV) which was isolated from diseased prawns in a hatchery in the French West Indies. Its very small size and hypothesized biochemical and biological characteristics suggest XSV is a new type of crustacean virus. As XSV has always been found associated with the larger virus (nodavirus) and is located in muscle and connective cells of diseased animals, it could be an autonomous virus, a helper-type virus or a satellite-like virus. [source] A sandwich enzyme linked immunosorbent assay (S-ELISA) for detection of MrNV in the giant freshwater prawn, Macrobrachium rosenbergii (de Man)JOURNAL OF FISH DISEASES, Issue 2 2003B Romestand Abstract A sandwich enzyme-linked immunosorbent assay (S-ELISA) was developed to improve diagnosis of white tail disease of the giant freshwater prawn, Macrobrachium rosenbergii, caused by the nodavirus, Mr NV. Polyclonal antibodies were produced by immunization of Balb/C mice using a purified suspension of the virus and IgG anti- MrNV were purified from ascitic fluid. A sandwich method was successfully developed, coating first with unlabelled antibody and detecting trapped antigens with a second biotinylated antibody. Reaction was demonstrated using an avidin,peroxidase conjugate. Tissue extracts from M. rosenbergii infected with MrNV or purified viral extracts (control) were successfully identified in an individual ELISA, thus confirming the validity of the method. This S-ELISA should be the technique of choice for epidemiological studies of this disease and is a rapid and inexpensive assay with high specificity and sensitivity. [source] Experimental susceptibility of different life-stages of the giant freshwater prawn, Macrobrachium rosenbergii (de Man), to white spot syndrome virus (WSSV)JOURNAL OF FISH DISEASES, Issue 4 2002R B Pramod Kiran Studies were conducted by injecting/feeding white spot syndrome virus (WSSV) derived from infected shrimp, Penaeus monodon (Fabricius), to different life-stages, namely post-larvae, juveniles, sub-adults and adults of Macrobrachium rosenbergii (de Man). The disease was also induced in brood stock, and the eggs and larvae derived from these animals were subsequently tested for WSSV infection. All the stages except egg used for the experiment were found WSSV positive in histopathology, cross infection bioassay and polymerase chain reaction (PCR) analysis. Experimentally infected post-larvae and juveniles showed a high percentage of mortality and an increased rate of cannibalism. The cumulative mortality in post-larvae was up to 28%; with 28,40% cannibalism resulting in a maximum loss of up to 68%. In juveniles, observed mortality and cannibalism were 10,20% and 6.7,30.0%, respectively, and the maximum loss recorded was 50%. In sub-adults, mortality ranged from 2.8 to 6.7%, cannibalism was up to 20% and the total loss was up to 26.7%. Sub-adults and adults were found to be more tolerant to the infection as evidenced by the mortality pattern. A nested (two-step) PCR resulted in a 570-bp product specific to WSSV in all stages, except the eggs. [source] Using the Sustainable Livelihoods Framework to Identify Constraints and Opportunities to the Development of Freshwater Prawn Farming in Southwest BangladeshJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 5 2008Nesar Ahmed A conceptual framework, drawn from an approach to poverty reduction known as the sustainable livelihoods approach (SLA), is applied to understanding the role of freshwater prawn, Macrobrachium rosenbergii, farming in gher (modified rice fields with high, broad peripheral dikes) systems in southwest Bangladesh. Gher farming potentially allows incorporation of a wide variety of crops together with prawn, fish, dike crops, and rice culture. The analysis shows how, in a gher farming context, sustainable livelihoods are achieved through access to a range of livelihood assets, which are combined in the pursuit of prawn farming strategies. The study used the SLA framework as a diagnostic tool to identify ways of strengthening the livelihoods of the prawn farmers. [source] An Economic Analysis of Freshwater Prawn, Macrobrachium rosenbergii, Farming in Mymensingh, BangladeshJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2008Nesar Ahmed This paper deals with production systems, cost structure, and profitability of freshwater prawn, Macrobrachium rosenbergii, farming in a new area of Mymensingh district in the north-central part of Bangladesh. In the study area, prawn farming practice is still extensive, and only a few farmers (20%) cultivate semiintensively. The costs and returns of extensive and semiintensive farming systems are compared. All farmers in different farming systems made a profit, with seed and feed dominating variable costs. Considerable variation in production costs and profitability was observed. Based on the Cobb,Douglas production function model, return to scale indicates that there is scope to increase production and income from prawn farms in extensive and semiintensive systems by applying more inputs (i.e., seed, feed, and fertilizer). [source] Effects of Two Densities of Caged Monosex Nile Tilapia, Oreochromis niloticus, on Water Quality, Phytoplankton Populations, and Production When Polycultured with Macrobrachium rosenbergii in Temperate PondsJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 3 2007Jason J. Danaher The effects of different densities of caged Nile tilapia, Oreochromis niloticus, on water quality, phytoplankton populations, prawn, and total pond production were evaluated in freshwater prawn, Macrobrachium rosenbergii, production ponds. The experiment consisted of three treatments with three 0.04-ha replicates each. All ponds were stocked with graded, nursed juvenile prawn (0.9 ± 0.6 g) at 69,000/ha. Control (CTL) ponds contained only prawns. Low-density polyculture (LDP) ponds also contained two cages (1 m3; 100 fish/cage) of monosex male tilapia (115.6 ± 22 g), and high-density polyculture (HDP) ponds had four cages. Total culture period was 106 d for tilapia and 114 d for prawn. Overall mean afternoon pH level was significantly lower (P , 0.05) in polyculture ponds than in CTL ponds but did not differ (P > 0.05) between LDP and HDP. Phytoplankton biovolume was reduced in polyculture treatments. Tilapia in the LDP treatment had significantly higher (P , 0.05) harvest weights than in the HDP treatment. Prawn weights were higher (P , 0.05) in polyculture than prawn monoculture. These data indicate that a caged tilapia/freshwater prawn polyculture system may provide pH control while maximizing pond resources in temperate areas. [source] Limnology and culture-based fisheries in non-perennial reservoirs in Sri LankaLAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 3 2005U. Asanka D. Jayasinghe Abstract This study was carried out to investigate the possibility of using the limnological characteristics of non-perennial reservoirs in Sri Lanka for the future management of culture-based fisheries. Forty-five reservoirs were randomly selected to study their limnology, out of which 32 were stocked with fish fingerlings of Chinese and Indian carps, tilapia and freshwater prawn at stocking densities ranging from 218,4372 fingerlings ha,1. Of these, 23 reservoirs were harvested at the end of the culture period (6,10 months). Thirteen limnological parameters were measured during the water retention period of each of the 45 reservoirs between November 2001 and January 2004. The mean values of the limnological parameters were used to ordinate the reservoirs through principal component analysis. Ordination showed a productivity gradient among reservoirs where Secchi disc depth, total phosphorus, chlorophyll- a, inorganic turbidity and organic turbidity were identified as key factors. The total fish yield of culture-based fisheries was positively correlated to the scores of the first principal component axis. This study reveals that it is possible to classify non-perennial reservoirs in Sri Lanka based on the above limnological parameters in order to develop culture-based fisheries and that they could be applicable in comparable water bodies elsewhere in the tropics. [source] Liver oil of pharaoh cuttlefish Sepia pharaonis Ehrenberg, 1831 as a lipid source in the feed of giant freshwater prawn, Macrobrachium rosenbergii (De Man 1879)AQUACULTURE NUTRITION, Issue 3 2009G. SHYLA Abstract The efficacy of pharaoh cuttlefish (Sepia pharaonis Ehrenberg, 1831) liver lipid in the feed for juveniles of giant freshwater prawn Macrobrachium rosenbergii (De Man 1879) was tested by feeding five experimental diets prepared using clam meat, groundnut oil cake, wheat bran, tapioca powder, vitamin,mineral mixture and cellulose powder as the major ingredients. The test diets T1, T2, T3, T4 and T5, containing five levels (1, 2, 3, 4 and 5%, respectively) of lipid, extracted from the liver of pharaoh cuttlefish, were fed to 30-day-old prawn juveniles for 60 days, in triplicates and compared against a control. Analysis of variance of the growth parameters showed that the juveniles fed with T2, containing 2% cuttlefish liver lipid with a total lipid content of 9.85% and lipid,carbohydrate ratio of 1 : 3.8, showed significantly better growth (P < 0.05) with the highest weight gain of 118%, greatest food conversion and protein utilization efficiency, and the highest body protein content, although the survival rates remained unaffected among treatments. Growth of the juveniles, however, declined at lipid levels >2%. Addition of cuttlefish liver lipid led to an increase of ,-3 and ,-6 fatty acids in T2, the proportion of ,-6 being higher than the former. The crude lipid content of the body of test animals also increased with the increase in dietary lipid from 1.51% in T1 to 3.27% in T5. The present study indicates that cuttlefish liver lipid can be successfully used as a substitute for conventional lipid sources in rearing juveniles of giant freshwater prawn, an eco-friendly practice in recycling cuttlefish waste , a discarded fishery by-product. [source] Effects of selective harvesting and claw ablation of all-male freshwater prawn (Macrobrachium rosenbergii ) on water quality, production and economics in polyculture pondsAQUACULTURE RESEARCH, Issue 10 2010Sheikh Md. Abstract The effects of selective harvesting (SH) and claw ablation (CA) of blue-clawed (BC) prawns on an all-male freshwater prawn,finfish polyculture system were compared with control (Co) in quadruplicate. Ponds were stocked with all-male freshwater prawn Macrobrachium rosenbergii, silver carp Hypophthalmichthys molitrix, catla Catla catla and mola Amblypharyngodon mola at 12 000, 2000, 500 and 20 000 ha,1 respectively. Prawns were fed with pelleted feed. Ponds were fertilized regularly with urea, triple super phosphate and cow-dung. SH of BC prawns in treatment SH and CA in treatment CA started on the 60th day during a 137-day culture and continued at 15-day intervals until the final harvest. Water quality parameters and plankton abundance did not vary significantly (P>0.05) among the treatments. Treatment SH resulted in a higher (P<0.05) net production of freshwater prawn (437 kg ha,1), with better survival and mean weight, followed by CA (354 kg ha,1) and Co (322 kg ha,1). The combined net production of prawn plus finfish was also higher in SH (1244 kg ha,1) as compared with CA (1161 kg ha,1) and Co (1137 kg ha,1), although the finfish production did not differ significantly. The periodic SH of BC prawns showed a better economic return with a BCR of 1.71. [source] Density effects of silver carp Hypophthalmichthys molitrix and catla Catla catla on the production system in all-male freshwater prawn,finfish polyculture pondsAQUACULTURE RESEARCH, Issue 10 2010Sheikh Md. Abstract The effects of three different combinations of silver carp Hypophthalmichthys molitrix and catla Catla catla density on the production system in all-male freshwater prawn,finfish polyculture ponds were evaluated in triplicate. The stocking density of silver carp and catla, respectively, were maintained at 2000 and 500 ha,1 in treatment SC2000C500, 1500 and 1000 ha,1 in treatment SC1500C1000 and 1000 and 1500 ha,1 in treatment SC1000C1500. Male freshwater prawn Macrobrachium rosenbergii and small fish mola Amblypharyngodon mola densities were fixed in all treatments at 12 000 and 20 000 ha,1 respectively. Management practices were same for all treatments. Blue-clawed male prawns were harvested twice during the 122-day culture at 15-day intervals before the final harvest. Plankton and macro-benthos abundance and water quality parameters (except transparency and chlorophyll a) did not vary significantly (P>0.05) among treatments. Mean final weights of both silver carp and catla were decreased with the increasing of their own stocking density. The treatment SC1500C1000 resulted in 25,32% increased net production of silver carp plus catla (461 kg ha,1) and 20,21% increased net production of all species combined (874 kg ha,1) as compared with the other treatments, although the differences in production of prawn and mola among treatments were not significant. [source] Osmoregulation, growth and moulting cycles of the giant freshwater prawn (Macrobrachium rosenbergii) at different salinitiesAQUACULTURE RESEARCH, Issue 9 2010Do Thi Thanh Huong Abstract The giant freshwater prawn, Macrobrachium rosenbergii, is a species with a high commercial value in aquaculture. Two experiments were performed to determine the effects of salinities on the osmoregulation, growth and molting cycles of M. rosenbergii during growout. The first experiment was designed to determine whether these animals are capable of adapting to the changes in salinity seen in salinity intrusions in tropical deltas, with an incremental increase in salinity of 3, per day from 0, to 30, Haemolymph osmolality was rapidly regulated up to salinities of 15, , whereas animals conformed at higher salinities. The second experiment determined the growth, moulting cycle, osmolality, muscle water content and mortality during a 4-month experiment at 0,, 15, or 25, salinity. The weight gains in 0, and 15, were not significantly different and were comparable to the growth rates achieved in production farms with body mass increases of 2.6 and 2.3-fold their initial body mass, respectively, after 4 months. The 25, group suffered from low growth, high mortality and a significantly lower moulting frequency. These data show that this species can be reared in brackish water up to 15,, allowing for farming in the large areas impacted by salt water intrusions in tropical deltas. [source] Effects of different dosages of astaxanthin on giant freshwater prawn Macrobrachium rosenbergii (De Man) challenged with Lactococcus garvieaeAQUACULTURE RESEARCH, Issue 1 2009Isagani P Angeles Jr Abstract The effects of astaxanthin (AX) injected at 0.67 and 1.34 nmol g,1 BW,1 on the survival, antioxidant capacity, total haemocyte count (THC) and hepatopancreas astaxanthin content of giant freshwater prawn, Macrobrachium rosenbergii, challenged with Lactococcus garvieae were evaluated. AX-injected M. rosenbergii at 1.34 nmol g,1 BW,1 had significantly (P,0.05) higher survival rates. However, AX showed no significant effects on the capacity of certain antioxidant indicators (superoxide dismutase, glutathione peroxidase and glutathione reductase). This implies that L. garvieae infection suppressed the activity of the haemolymph antioxidant system of infected M. rosenbergii. This result suggests that the two different dosages used in this study could not exert significant effects on the tested antioxidant capacity of L. garvieae -infected M. rosenbergii. On the other hand, AX-injected M. rosenbergii at either dose showed a significant increase in the THC and hepatopancreas AX content when compared with the challenged control group. Overall, the results of this study indicate that the injected AX led to an improvement in M. rosenbergii's resistance against L. garvieae infection. [source] Effects of all-male, mixed-sex and all-female freshwater prawn in polyculture with major carps and molas in the fallow rice fieldsAQUACULTURE RESEARCH, Issue 1 2009Mrityunjoy Kunda Abstract This study was conducted to evaluate the effects of all-male, mixed-sex and all-female freshwater prawn (Macrobrachium rosenbergii) in a polyculture with major carps (Catla catla and Labeo rohita) and self-recruiting small fish molas (Amblypharyngodon mola) in the fallow rice fields of Bangladesh. There were three treatments with three replicates. All ponds were stocked with carps and molas plus either all-male prawns (treatment MP), mixed-sex prawns (MFP) or all-female prawns (FP). Prawn, mola, catla and rohu were stocked 20 000, 20 000, 1750 and 750 ha,1, respectively, in all treatments. The prawns were fed twice daily, starting at 8% body weight and gradually reduced to 3% body weight. The fish were fed in the morning with mustard oil cake and rice bran (1:2 ratios) at 3% body weight. Significantly higher production of prawns (697 kg ha,1) was obtained in treatment MP, which yielded 34.7% and 56.2% more production than MFP and FP respectively. Significantly higher total production of 1620 kg ha,1 and a higher benefit,cost ratio of 2.10:1 were also obtained in treatment MP. It can be concluded that an all-male prawn culture is economically more viable than all-female and mixed-sex prawn cultures, along with other fish like major carps and the nutrient-dense molas in the polyculture. [source] Effects of including catla and tilapia in a freshwater prawn,mola polyculture in a rotational rice,fish culture systemsAQUACULTURE RESEARCH, Issue 9 2009Mrityunjoy Kunda Abstract An on-farm trial was carried out from February to June 2006 to evaluate the growth and production performance of catla (Catla catla) and tilapia (Oreochromis niloticus) with freshwater prawn (Macrobrachium rosenbergii) and mola (Amblypharyngodon mola) in farmer's rice fields. In all treatments, 20 000 mola ha,1 and 20 000 prawn ha,1 were stocked. Besides, stocking included 2500 catla ha,1 in treatment-I, 2500 tilapia ha,1 in treatment-II and catla and tilapia at 1250 ha,1 each in treatment-III . Prawns were fed in the evening with pellets at a feeding rate of 3,8% body weight (initially 8% and gradually decreased to 3%). Catla and tilapia were fed in the morning with a paste of mustard oil cake and rice bran at a feeding rate of 3% body weight. Significantly higher combined production of fish and prawn observed was 2142 kg ha,1 in treatment-I. The benefit:cost ratio was found to be significantly higher in treatment-I than in treatment-II and there were no differences between treatments I and III. From the production and economic point of view, treatment-I was found to be the best proposition for the rotational rice,fish culture systems. [source] Identification and partial characterization of selected proteolytic enzymes in the digestive system of giant freshwater Prawn Macrobrachium rosenbergii (De Man) PostlarvaeAQUACULTURE RESEARCH, Issue 5 2009Mohamed Ayaz Hasan Chisty Abstract Biochemical assays and substrate SDS-PAGE were conducted to partially characterize and identify various types of proteases present in the digestive tract of PL15 giant freshwater prawn (Macrobrachium rosenbergii). Casein hydrolytic assay of the enzyme extracts showed major proteolytic activities at pH 3.0, 6.0 and 9.0, while assay of preincubated enzyme extracts with phenylmethylsulphonyl fluoride (PMSF), a serine protease inhibitor produced a 33.17% reduction in alkaline protease activity. When specific inhibitors tosyl-lysine chloromethyl ketone and tosyl-phenylalanine chloromethyl ketone were used, they resulted in a reduction in activity of proteases in the enzyme extracts by 82.41% and 55.03%, respectively, confirming the presence of trypsin and chymotrypsin, while ethylenediamine tetraacetic acid produced protease activity reduction in 33.92% showing the presence of metalloproteases in the digestive tract of the prawn. Further characterization of the alkaline proteases using SDS-PAGE technique, after incubating the extract in the presence or absence of specific inhibitors, produced six bands corresponding to molecular masses of between 13.48 and 136.1 kDa; two trypsin bands of 13.48 and 36.4 kDa, three chymotrypsin bands in the range of 23.0,73.4 kDa and one for metalloprotease of 136.1 kDa, all of which were identified from a zymogram. This study suggests that protein digestion in M. rosenbergii is initiated by an acid protease followed by a combination of action of alkaline proteases: trypsin, chymotrypsin and metalloproteases. [source] Freshwater prawn farming in Bangladesh: history, present status and future prospectsAQUACULTURE RESEARCH, Issue 8 2008Nesar Ahmed Abstract Within the overall agro-based economy in Bangladesh, freshwater prawn (Macrobrachium rosenbergii) farming is currently one of the most important sectors of the national economy. During the last two decades, its development has attracted considerable attention for its export potential. Freshwater prawn farming offers diverse livelihood opportunities for a large number of rural poor. Although the prospects for prawn farming are positive, it requires some research and development activities for long-term sustainability. This paper provides an overview of freshwater prawn farming in Bangladesh. [source] Growth and carcass composition of giant freshwater prawn, Macrobrachium rosenbergii (De Man), fed different isonitrogenous and isocaloric dietsAQUACULTURE RESEARCH, Issue 13 2007Akhil Gupta Abstract 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. [source] Low-cost diet for monoculture of giant freshwater prawn (Macrobrachium rosenbergii de Man) in BangladeshAQUACULTURE RESEARCH, Issue 3 2007Md Arshad Hossain Abstract An experiment was conducted for 3 months in 12 experimental ponds, each of 30 m2, with a view to develop a low-cost diet for monoculture of Macrobrachium rosenbergii in ponds. Three experimental diets (30% protein) were formulated using fish meal, meat and bone meal, mustard oilcake, sesame meal and rice bran in different combinations partially replacing fish meal by meat and bone meal and sesame meal and assigned to treatments T1, T2 and T3 respectively. A commercial golda feed (Starter-III) was assigned to T4 (reference diet). Each treatment had three replicates. Juveniles of M. rosenbergii (2.90±0.21 g) were stocked at the rate of 40 000 ha,1. Prawns were fed three times daily at the rate of 10% and 5% of their body weight at the beginning and for the last 2 months respectively. The ponds were provided with aeration during the night using air pumps. The ranges of water quality parameters recorded in different ponds were: temperature 28.9,32.5°C, dissolved oxygen 5.1,8.1 mg L,1 and pH 6.4,7.7. The results showed that the weight gain of prawns fed diet 1 was significantly higher (P<0.05) than those fed diets 2 and 3, but was not significantly different from those fed diet 4 (reference diet). The feed conversion ratio (FCR) values of diets ranged between 2.21 and 2.96 with diets 1 and 4 showing significantly lower (P<0.05) FCR values. The survivals (%) ranged between 68% and 78% with prawns fed diets 1 and 4 showing significantly higher survival. The production of prawn ranged between 921 and 1428 kg ha,1 and diet 1 resulted in a significantly high (P<0.05) production. A simple economic analysis showed that diet 1 generated the maximum net profit of Tk 159 178 ha,1. The results of the study showed that a diet containing 20% fish meal, 10% meat and bone meal, 15% mustard oilcake, 15% sesame meal, 35% rice bran, 4% molasses and 1% vitamin,mineral premixes may be recommended to the farmers for monoculture of M. rosenbergii in ponds. [source] Economic analysis of monosex culture of giant freshwater prawn (Macrobrachium rosenbergii De Man): a case studyAQUACULTURE RESEARCH, Issue 9 2006C Mohanakumaran Nair Abstract All-male monosex culture of Macrobrachium rosenbergii (De Man) has emerged as a popular practice in India, especially in the state of Andhra Pradesh. A study was conducted to compare the economics of all-male, mixed and all-female culture in 15 adjacent, rectangular ponds of 4000 m2 each by stocking juveniles previously reared in a nursery for 60 days. The experiment was conducted using a completely randomized design with three treatments; T1 (all male), T2 (mixed) and T3 (all female), and five replicates for a period of 5 months after the nursery phase. Statistical analysis showed highly significant (P<0.01) differences among the three types of culture. The cost of production was estimated and the economic feasibility of the culture methods was evaluated by cost-return and partial budgeting analysis. The average weight, productivity and specific growth rate were the highest for all male culture, being 80.92±2.41 g, 1532 kg ha,1 and 1.97±0.02 respectively. All-female culture registered significantly higher survival (89.16±0.77%) and the best apparent feed conversion ratio of 1.26±0.02. The economic analysis revealed that all-male monosex culture of M. rosenbergii was 63.13% and 60.20% more profitable than mixed and all-female cultures respectively. [source] Macrobrachium rosenbergii nodavirus infection in M. rosenbergii (de Man) with white tail disease cultured in TaiwanJOURNAL OF FISH DISEASES, Issue 6 2008C S Wang Abstract White tail disease (WTD) is a serious problem in Macrobrachium rosenbergii hatcheries and nursery ponds in Asia. The causative agents have been identified as M. rosenbergii nodavirus (MrNV) and its associated extra small virus. This is the first report demonstrating MrNV virus in M. rosenbergii displaying WTD signs in Taiwan by reverse transcriptase-polymerase chain reaction (RT-PCR). Amplified fragments of 850 and 425 bp for RNA-1 and RNA-2 of MrNV, respectively, were obtained by RT-PCR. RT-PCR products of about 850 and 1121 bp for RNA-1 and RNA-2 of MrNV were also obtained using different primer pairs. The amplicons were individually cloned into pGEM-T vector and sequenced. Using this recombinant plasmid of MrNV RNA-2 as DNA template, the non-radioactive DNA probes were prepared by PCR amplification with DIG,11-dUTP. The probes were used to successfully detect MrNV infection in the striated muscle tissues of WTD-diseased prawns using in situ hybridization. The 1121 bp genomic fragment of RNA-2 of MrNV consisted of a unique open reading frame with 1116 nucleotides, and it encoded a structural protein with 371 amino acids. The nucleotide sequence of the partial genome of MrNV RNA-2 revealed a 97% identity with an Indian isolate. A phylogenetic tree constructed using the nucleotide sequence of the viral capsid gene from insect and fish nodaviruses revealed that the MrNV Taiwan isolate could be interpreted as a new genus within the family Nodaviridae. However, its position showed more affinity with Alphanodavirus than with Betanodavirus. The study confirmed the presence of MrNV infection in freshwater prawns cultured in Taiwan suffering from WTD. [source] | ||||||||||