Juvenile Freshwater Prawn Research Articles

Functional Mechanism of Antimicrobial Peptide Bomidin and Its Safety for Macrobrachium rosenbergii.

Macrobrachium rosenbergii is an economically important source of crustacean seafood worldwide. Vibrio parahaemolyticus is an important aquatic pathogen that causes epidemics of acute hepatopancreatic necrosis in shrimp populations, which results in significant economic losses to aquaculture farmers. To prevent the antibiotics abuse, which has become a serious threat to human health, novel anti-infective strategies are urgently required to control V. parahaemolyticus. Antimicrobial peptides, which exhibit favourable germicidal activity compared to traditional antibiotics, can be used as a key method to prevent and treat bacterial diseases. Herein, an antimicrobial peptide, bomidin, was expressed through genetic engineering technology. The minimum inhibitory concentration (MIC) of bomidin showed a significant inhibitory effect on V. parahaemolyticus that was equivalent to that of ampicillin. Subsequently, the mechanism of action of recombinant bomidin was explored using PNP and ONPG assays to investigate the effects on membrane permeability. These assays indicated that bomidin penetrated the germ membrane and induced the release of cytoplasmic contents and ultimately interacted with DNA to form a bomidin-DNA complex that inhibits bacterial survival. Transmission electron microscopy and scanning electron microscopy revealed that bomidin could cause damage and dysfunction to the cell wall and membrane. Bomidin was nontoxic to mouse red blood cells within a concentration range that was much larger than the MIC. Toxicity assays revealed that 0.02mg/mL bomidin was safe for use with juvenile freshwater prawns of M. rosenbergii and significantly inhibited the growth of V. parahaemolyticus in cultured water. These results demonstrated that synthetic peptide bomidin had great antibacterial effect against V. parahaemolyticus and therefore a therapeutic potential in aquaculture.

Modulation of growth, antioxidant status, hepatopancreas morphology, and carbohydrate metabolism mediated by alpha-lipoic acid in juvenile freshwater prawns Macrobrachium nipponense under two dietary carbohydrate levels

Carbohydrate is commonly used in aquatic organism as the cheapest energy source. However, most aquatic animals are low efficient in utilizing dietary carbohydrate for energy provision. Therefore, improving the utilization efficiency of high carbohydrate by aquatic organisms is important for sustainable aquaculture development. Alpha-lipoic acid (α-LA) is a cofactor of key enzymes involved in glucose metabolism. However, its role in regulation of carbohydrate metabolism in aquatic animals is currently unknown. This study investigated the effects of α-LA on growth, antioxidant status, hepatopancreas morphology, and carbohydrate metabolism of freshwater prawns Macrobrachium nipponense under two dietary carbohydrate levels. Six diets were formulated using casein and fish meal as the protein sources, fish oil and soybean oil as the lipid sources, and corn starch as the carbohydrate source, at two carbohydrate levels (15% and 30%) and three concentrations of α-LA supplementation (0, 700, and 1400 mg/kg). Each experimental diet was fed to juvenile prawns (mean weight 0.050 ± 0.003 g), twice daily to apparent satiation, in five replicates. In the 15% (low)-carbohydrate groups, weight gain was significantly reduced in prawns fed 1400 mg/kg α-LA compared with 0 or 700 mg/kg α-LA, but there was no significant effect in the 30% (high)-carbohydrate groups. Survival was significantly higher among prawns fed 700 mg/kg α-LA compared with 0 or 1400 mg/kg α-LA regardless of the carbohydrate level. The levels of dietary carbohydrate and α-LA also significantly affected the activities of key enzymes involved in glycolysis and the citric acid cycle. The activities of hexokinase and pyruvate kinase activities were highest in prawns fed l400 mg/kg α-LA, in both the low- and high-carbohydrate groups. Supplementation with 700 or 1400 mg/kg α-LA significantly increased the activities of 6-phosphofructokinase, pyruvate dehydrogenase, and succinate dehydrogenase regardless of the carbohydrate level. The level of malondialdehyde decreased significantly with increased α-LA supplementation; in contrast, the levels of superoxide dismutase, glutathione peroxidase, and glutathione were significantly higher in prawns fed 700 or 1400 mg/kg α-LA when compare with those fed no α-LA supplement. Dietary α-LA did not affect the overall morphology of the hepatopancreas, but 1400 mg/kg α-LA reduced the number of B (blister-like) cells. Thus, 700 mg/kg α-LA supplementation under either dietary carbohydrate level could improve the antioxidant status, carbohydrate metabolism, and morphology of the hepatopancreas in juveniles of M. nipponense. We conclude that α-LA supplementation can be used to improve the efficiency of carbohydrate utilization when a 30% carbohydrate diet is used for this prawn.

According to the issue of the giant freshwater prawn ((<i>Macrobrachium rosenbergii</i>)

Purpose: study the biotechnical features of rearing juvenile giant freshwater prawn (Macrobrachium rosenbergii) using recirculating aquaculture systems (RAS).Materials and methods. Two fish-farming modules RAS and aquarian complex were used for the work. One of them has a total volume of 6.5 m3, the second - 14.5 m3. Larvae were reared in gasite cages of 0.021 m3 in an aquarian complex of two 200-liter aquariums. Larvae of one female prawn were used in an amount of 8500 units. At each stage of prawns' development we used different versions of feed of both animal and plant origin: artemia, minced fish, boiled chicken eggs (protein + yolk), beef liver and oat flakes.Results. Brood fish were kept at an average planting density of 6.2 individuals/m2, with a sex ratio of 1:4.5 (males: females). The planting density of larvae in cages was 2,125 units/cage or 101.2 units/liter. The average weight of juveniles during rearing of postlarvae at 130 days was 3.19 g. Juvenile yield was 49.9%. Specific growth rate of biomass varied from 4.87 to 3.68 %. Planting density of juveniles varied from 1775,6 units/m2 to 660,9 units/m2. As a result, the feeding coefficient was 5.24 units. Growing productivity was 362.7 pcs/m2 or 1156.8 g/m2 in the RAS module.Conclusion. There were established biotechnical peculiarities and production possibilities of growing young giant freshwater prawn (Macrobrachium rosenbergii) using fish-breeding RAS and aquarian complex. Modernization of fish-feeding RAS and use of some recommendations on feeding suggest the possibility of their use for breeding and rearing of juvenile giant freshwater prawns in already existing warm-water enterprises, initially aimed at other objects of aquaculture.

Effects of mannan oligosaccharides and fructooligosaccharides on the growth and nonspecific immune responses of juvenile freshwater prawn Macrobrachium acanthurus

The freshwater prawn Macrobrachium acanthurus represents a valuable resource for fishermen's communities in Mexico, although the information of its culture conditions and nutrition is still scarce. Prebiotics are defined as non-digestible components that are metabolized by specific health-promoting bacteria in the host's digestive system, improving the health status and growth performance of cultured aquatic organisms. Fructooligosaccharides (FOS) and mannan oligosaccharides (MOS) are among the most used prebiotics in aquaculture. The present work aimed to determine the effects of dietary FOS and MOS in the growth performance, immune responses, and sexual maturity of juvenile freshwater prawn Macrobrachium acanthurus. Juveniles (0.06 ± 0.001 g) were fed with diets supplemented with a 3 g kg-1 diet of commercial FOS and MOS for 80 days. At the end of the feeding trial, the following indices were calculated: weight gain, specific growth rate, and feed conversion efficiency, as well as superoxide dismutase and lysozyme activities in hepatopancreas tissue. The growth performance, survival, juveniles' protein contents did no show significant differences among the groups. No differences were detected in superoxide dismutase and lysozyme activities among experimental groups. Around day 60 of the feeding trial, the females fed with the prebiotics maturated, and by the end of the trial, several of them were carrying eggs. It seems that prebiotics might have a role in sexual maturation, but further research is necessary to establish if prebiotics influences the early maturation of M. acanthurus.

Effects of graded levels of mineral mixtures (Aquamin® and Agrimin®) supplemented diets on growth, survival, proximate composition, and carcass mineralization of juvenile freshwater prawn, Macrobrachium malcolmsonii (H Milne-Edwards 1844).

The present study investigated the effects of Aquamin® mineral mixture (AQMM) and Agrimin® mineral mixture (AGMM) supplemented diets on growth and chemical composition of juvenile freshwater prawn Macrobrachium malcolmsonii (H. Milne-Edwards, 1844). Experimental diets containing 6 different AQMM levels (Trial 1: 0, 0.5, 1.0, 1.5, 2.0, and 2.5%) and 6 different AGMM levels (Trial 2: 0, 0.5, 1.0, 1.5, 2.0, and 2.5%) were formulated to feed juvenile prawn [initial body weight of 0.82 ± 0.05g (Trial 1) and 1.24 ± 0.03g (Trial 2)] for 60days. Prawn fed diets containing 1.0% of AQMM and AGMM showed significantly increased (P < 0.05) survival rate, weight gain, specific growth rate, protein efficiency ratio, edible flesh weight, and proximate composition (moisture, crude protein, crude fat, and ash), while feed intake and feed conversion ratio were significantly decreased (P < 0.05). Whereas, 1.5-2.5% of AQMM- and AGMM-supplemented diets fed prawn showed a reverse trend when comparing other groups. Moreover, the minerals (macro elements: Ca, P, Mg, Na, and K; trace elements: Cu, Zn, and Fe) were significantly increased (P < 0.05) in the carcass of prawn when fed with 2.5% AQMM- and AGMM-supplemented diets. The present results suggest that the optimal dietary supplementation of AQMM and AGMM at a concentration of up to 1.06 and 1.02%, respectively (based on polynomial regression analysis), improved growth and enhanced the crude protein level of juvenile prawn.

Myology of juvenile freshwater prawn Macrobrachium amazonicum (Decapoda, Caridea): Morphology and swimming implication

Little is known about the functional morphology of locomotion in prawns, and even fewer studies have succeeded in relating a specific muscular group to the movement of the body. The present study aimed to describe the morphology of the thoracoabdominal muscle system and its implications for swimming in juveniles of Macrobrachium amazonicum. Ten muscles were observed in the abdominal muscular system in juveniles of M. amazonicum. The complex arrangement of the anterior oblique muscle in association with the central muscles occupies most of the abdominal space. This muscular compound could promote a flexion movement of the abdomen for body propulsion as well as the tail movement during swimming. Morphofunctional continuity between thoracic and abdominal muscles could aid in locomotion and support the abdominal movement. Moreover, collagen plays a valuable role in connecting deep muscles not inserted in the carapace. Collagenous fascia could transmit the tension during the contraction of deep muscles for coordinated movement.

The effects of acute ammonia exposure on the immune response of juvenile freshwater prawn, Macrobrachium nipponense

The effects of acute ammonia exposure on juvenile Macrobrachium nipponense (De Haan, 1849) were evaluated. The LC50 values and 95% confident intervals for total ammonia nitrogen (TAN) after 24, 48, 72 and 96 hours’ exposure were 139.78 (108.77-179.63), 84.17 (50.40-127.87), 64.07 (44.78-91.66) and 40.42 (30.46-53.62) mg/l. Then a 96-hour acute toxicity experiment was conducted in five concentrations of TAN (0, 5, 10, 15 and 20 mg/l). The whole-body activities of alkaline phosphatase (AKP), acid phosphatase (ACP), superoxide dismutase (SOD), catalase (CAT), and the concentration of malonaldehyde (MDA) were measured. The results demonstrate that the concentrations used in this study induce the immune response and that damage may be accompanied by a depression of the antioxidant defense system and the accumulation of malonaldehyde (MDA). These results suggest that changes in whole-body immune parameters of juvenile prawns are effective to characterize overall prawn health and environmental conditions.

Preharvest Feeding Strategy to Enhance Long‐Chain Polyunsaturated and Polyunsaturated Fatty Acid Composition of the Tail Muscle of Freshwater Prawns Macrobrachium rosenbergii Grown in Earthen Ponds

AbstractThree independent experiments were sequentially conducted during separate growing seasons (2009, 2010, and 2012) to determine whether a preharvest change in feed could achieve a desired enhancement of the long‐chain (LC) polyunsaturated fatty acid (PUFA) content or the PUFA content of the tail muscle in freshwater prawns Macrobrachium rosenbergii. Juvenile freshwater prawns were stocked into 0.05‐ha earthen ponds, cultured for 111–122 d, and then harvested. For the first experiment, there were three treatments: exclusive feeding of a commercial prawn feed for 122 d after stocking; exclusive feeding of range cubes for 122 d after stocking; and administering range cubes for 84 d followed by prawn feed for the final 38 d prior to harvest. The second experiment consisted of four treatments: range cubes were fed exclusively for the entire growing season (116 d) or were fed until replaced by the prawn feed at 39, 24, or 17 d prior to harvest. The LC‐PUFA profile for the tail muscle of harvested prawns was equivalent between prawns given the prawn feed for the entire growing season and those given the range cubes substituted by the prawn feed for the final 38 or 39 d before harvest. The proportional levels of LC‐PUFA in the tail muscle of prawns that received the prawn feed during the final 24 or 17 d prior to harvest were slightly lower. In the third experiment (two treatments), range cubes were administered either throughout the growing season (112 d) or for 84 d followed by the feeding of range cubes sprayed with flaxseed oil (2% weight/weight) for the final 28 d. The percentage (as total fatty acids) of linolenic acid (18:3[n‐3]), the principal fatty acid in flaxseed oil, increased 7.8 times in the feed and 3.3 times in the tail muscle of harvested freshwater prawns.

Impacts of Inclusion of Column Feeder Rohu (Labeo Rohita) at Different Stocking Densities on Growth and Production in Freshwater Prawn-Finfish Polyculture System

Normal 0 false false false EN-US X-NONE BN-BD MicrosoftInternetExplorer4 An experiment was conducted to assess the impacts of inclusion of column feeder rohu ( Labeo rohita ) on growth and production in freshwater prawn-carp-mola polyculture system at the Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh for a period of 172 days (June - December, 2008). Four stocking densities of Rohu were maintained as 500, 1,000, 1,500 and 2,000 ha -1 in treatment R 500 , R 1000 , R 1500 and R 2000 , respectively in triplicates. All ponds each 120 m 2 were stocked with juvenile freshwater prawn ( Macrobrachium rosenbergii ), silver carp ( Hypophthalmichthys molitrix ), catla ( Catla catla ) and small fish mola ( Amblypharyngodon mola ) at the fixed stocking densities of 20,000, 1,500 , 1,000 and 20,000 ha -1 , respectively. Prawns were fed with pelleted feed twice daily started initially with 10% and gradually reduced to 3% of body weight and continued throughout the study period. All fish were fed with mixture of soaked rice bran and mustard oilcake (2:1) at the rate of 3% of the body weight daily. All the water quality parameters such as temperature, transparency, pH, dissolved oxygen, total alkalinity, NH 3 -N, NO 2 -N, NO 3 -N, PO 4 -P and chlorophyll- a did not differed significantly (&gt;0.05) among the treatments. The survival rate, mean individual weight and production of prawn were decreased with increasing density of rohu. Therefore, the density of rohu significantly (P&lt;0.05) influenced the growth and production of freshwater prawn. Catla and Mola production were affected adversely with increasing rohu density. The production of rohu increased with increasing density although the individual weight decreased. The combined production of all finfish was significantly lower in R 0 whereas, the combined production of all species including prawn did not differ significantly (P&lt;0.05) among the treatments. The treatments R 0 and R 500 fetched higher net profit without significant difference between them. Therefore, inclusion of rohu at a density of 500 ha -1 may be recommended for prawn-carp-mola polyculture.

Effect of Bacillus subtilis on Aeromonas hydrophila infection resistance in juvenile freshwater prawn, Macrobrachium rosenbergii (de Man)

This experiment was carried out to investigate the potential probiotics properties of Bacillus subtilis in protecting of juvenile freshwater prawn, Macrobrachium rosenbergii against Aeromonas hydrophila infection. A B. subtilis bacterium isolated from gut of juvenile prawns was added to the prawns feed at 108 cells g−1 feed. There were significant differences (P < 0.05) between B. subtilis-treated and control groups in growth and survival enhancement of juvenile prawns after 60 days of feeding trial. Sixty days after B. subtilis feeding trial, the prawns were challenged by bath exposure to A. hydrophila (107 cells mL−1) for 28 days. Four weeks after challenge, there was significant difference in the survival of prawns between B. subtilis-treated groups (88.33 %) and control groups (20.81 %; P < 0.05). In addition, the control groups had an unhealthy external appearance, while the treated groups, appeared healthy and normal. From this, it was concluded that the selected B. subtilis may be a promising probiotics for protection of prawns from A. hydrophila infection.

Probiotic activity of Bacillus subtilis in juvenile freshwater prawn, Macrobrachium rosenbergii (de Man) at different methods of administration to the feed

This experiment was carried out to investigate the potential probiotic properties of Bacillus subtilis and suitable methods of administration to the commercial feed in juvenile Macrobrachium rosenbergii (de Man) from 25 August to 25 November 2008. Putative Bacillus subtilis bacterium isolated from juvenile M. rosenbergii intestine was added to commercial prawn feed as a probiotic. Five types of diets were prepared by mixing B. subtilis at level of 108 cells g−1 with commercial feed using different methods consisting mixing, soaking, spraying and bathing. After 60 days, the prawns fed diets at soaking method treated group, showed a higher mean weight gain (2.09) or 328.84% increase in growth over control. There were significant differences (P 0.05) in water quality and biochemical composition among treated and control groups. Clearly, B. subtilis-treated diets appeared to enhance growth and survival of juveniles M. rosenbergii. It was concluded that the tested strain may be a promising probiotic for M. rosenbergii under soaking method of administration to the prawn commercial feed.

Toxicity of Rotenone to Giant River Freshwater Prawn Macrobrachium rosenbergii

AbstractAquaculturists have often suffered predation losses in the production of freshwater giant river prawn Macrobrachium rosenbergii due to the presence of wild fish species in culture ponds. The piscicide rotenone is widely used to remove undesirable fish species from ponds. Although evidence in the technical literature suggests that crustaceans generally have a higher tolerance to rotenone than fish, there are currently no data on the acute or chronic toxicity of rotenone to juvenile freshwater prawns. In this study, two static acute‐toxicity bioassays (96 h) were conducted using Prentox Prenfish (5% active ingredient) rotenone to determine the median lethal concentration (LC50) for juvenile freshwater prawns (average weight = 0.55 g, SD = 0.25; length = 41.43 mm, SD = 6.45). In bioassay 1, prawns were exposed to rotenone concentrations of 1.0, 3.0, 5.0, and 10.0 mg/L. In bioassay 2, prawns were exposed to rotenone concentrations of 2.2, 3.6, 6.0, 10.0, and 16.7 mg/L. All rotenone concentrations used in the study were based on the total product of the commercial rotenone formulation. The LC50 calculated in bioassay 1 was 6.2 mg/L, and the LC50 calculated in bioassay 2 was 7.5 mg/L. Freshwater prawns were able to tolerate 3.0 to 3.6 mg/L of rotenone with no mortality or apparent adverse effects during the study. Prawns held at the end of each bioassay for 5 d showed no signs of delayed effects from rotenone exposure. Data from this study indicate that juvenile prawns should be able to tolerate the concentrations of rotenone required to eradicate certain problematic wild fish species.Received April 29, 2010; accepted October 1, 2010

Pelleted Sources of Nutrition and the Effect of Stocking Size-graded Juveniles in Low-input Farming of the Freshwater Prawn Macrobrachium rosenbergii in Earthen Ponds

Nutrient sources in pelleted form and the effect of stocking size-graded juvenile freshwater prawns Macrobrachium rosenbergii for the low-input farming of the freshwater prawn in experimental earthen ponds (0.05–0.06 ha) have been studied. For each of 4 yr, experiments were sequentially conducted, having growout durations ranging from 111 to 135 d. Generally, graded juvenile prawns (0.26–0.29 g) were stocked into earthen ponds containing artificial substrate at a density that ranged from 21,690 to 34,580/ha. For all experiments, feeding rates ranged from 10.1 to 60.8 kg/ha/d during the growout season. Survival, mean weight, and total production were compared among the treatments. There were no significant differences in survival, mean harvest weight, or total production when corn gluten pellets fed exclusively were compared to corn gluten pellets in combination (1:1) with less expensive nutrient sources, wheat midds, and range cubes. Substitution of corn gluten pellets with a commercial prawn feed fed for the last 28 d of growout had no significant effect. A total level of feeding corn gluten pellets : range cubes (1:1) at 2802 kg/ha for the growout period was as effective as 3923 and 5044 kg/ha at a stocking density of 28,405/ha. The use of trout feed in combination with the feeding of the 1:1 corn gluten pellets to range cubes for 49 d prior to harvest was effective in maintaining mean harvest weight and production at a higher stocking density (34,580/ha vs. 28,405/ha). Poultry litter pellets were ineffective substitutes for the corn gluten pellet : ranges cubes (1:1) combination. The exclusive feeding of alfalfa pellets and soy hull pellets resulted in mean harvest weights and total production that were significantly less than what was achieved with the feeding of range cubes. Engineered enterprise budgets demonstrated positive economic benefits of the low-input strategy using pellet nutrient sources that contain no less than 20% crude protein (dry weight). Highest returns were realized with the upper grade of juveniles resulting from a 60/40 split (by number), even when lower grade animals were discarded. At stocking densities of approximately 22,000–28,000/ha, nutritional requirements of the prawns appear to be satisfied by the consumption of the fed nutrient sources combined with live, natural resident pond prey organisms enhanced by organic input resulting from the breakdown of the pellets. Production levels of 900–1000 kg/ha can be consistently achieved.

The juvenile freshwater prawn, Macrobrachium rosenbergii (Crustacea-Decapoda) as an effective zooplankton predator

Alaboratory study was carried out to examine the effectiveness of juvenile freshwater prawn, Macrobrachium rosenbergii (De Man, 1879), as a planktonic crustacean predator. The results showed that large juvenile prawns (body length 4.5-4.8 cm) ingested significantly more zooplankton than did smaller ones (1.1-1.5 c,) when zooplankton density was 5.3 prey /ml . The large juvenile specimens consumed 2705 zooplankton on average, after 12 h, while the medium sized prawn (3-3.5 cm, body length) , medium small (2.1-2.4 cm) and small (1.1-1.5 cm,) size groups ingested 1570, 1440 and 1258 zooplankton respectively. Large prawn consumed prey of larger body size than did smaller prawn .More zooplankton were consumed by the prawn when the zooplankton density was high (8.45-9.8 prey/ml.). The clearing rate (no of zooplankton ingested /no. of zooplankton offered) was, however, lower (69%) when the zooplankton density was high. The results indicate that juvenile M. rosenbergii can effectively ingest zooplankton which play an essential role in the food web of the prawn.

Effects of Dietary Protein Level on Growth, Feed Conversion, and Protein Efficiency Ratio of Freshwater Prawn, Macrobrachium rosenbergii, in Outdoor Concrete Tanks

ABSTRACT Isocaloric diets with 25,30, 35,40, and 45% protein levels were fed to triplicate groups of juvenile (1.96 ± 0.2 g) freshwater prawn, Macrobrachium rosenbergii, at 3% to 6% body weight per day for 168 days. No significant effect of dietary protein level on weight gain, specific growth rate, and survival was found (P > 0.05). Highest wet weight gain was recorded for prawns fed 35% protein diet and the poorest for prawn fed 25% and 45% protein diet. Protein efficiency ratio (PER) progressively and significantly (P < 0.05) decreased with increasing level of dietary protein. The results of the present study suggest that dietary protein requirement of freshwater prawn is 35%.

Comparative Efficacy of Anesthetics for the Freshwater Prawn Macrobrachiurn rosenbergii

— The freshwater prawn Macrobrachiurn rosenbergii is a commercially important culture species in the South Central United States. Two major constraints in the commercial culture of the freshwater prawn in the U.S. are poor survival during live transportation of seed-stock to growout ponds, and live transportation of pond harvested prawn to distant live markets due to the territorial and cannibalistic nature of prawn. The use of anesthetics could possibly improve transport survival; however, to date anesthetic agents have not been evaluated for use with prawn. Two trials were conducted with juvenile freshwater prawn to compare the efficacy of anesthetics commonly used on fish. The first trial was designed to identify the most promising candidates. In Study 1, tricaine methanesulfonate (MS-222), 2-phenoxyethanol, quinaldine sulfate (quinaldine), clove oil, and Aqui-STM were evaluated at 25 and 100 mg/L for 1 h in three replicate 10-L glass containers, containing five juvenile prawn each. Relative sedation level was determined every 3 min for 1 h, then recovery time and survival were measured. In Study 1, MS-222 and 2-phenoxyethanol were determined to be ineffective on prawn at all rates tested. Based on their performance in Study 1, quinaldine, clove oil, and AquiSTM were evaluated at 100, 200, and 300 mg/L in Study 2. Observations were determined as in Study 1. Clove oil and Aqui-STM induced anesthesia faster and at lower concentrations than quinaldine. At the highest treatment rate (300 mg/L) prawn suffered 60% mortality in the Aqui-STM treatment, 13% mortality in the quinaldine treatment, and 0% mortality in the clove oil treatment and control following a 1-h exposure to these concentrations. Based on these data, Aqui-STM and clove oil applied at 100 mg/L may be suitable anesthetic treatments for prawn. Additional research is needed to determine optimal time and dose relationships to minimize stress during holding, handling, and transportation of prawn.

The Effect of Biomass Density, Salinity, and Substrate on Transport Survival of Juvenile Freshwater Prawns Macrobrachium rosenbergii in Continuously Oxygenated, Vented Containers

AbstractDuring the stocking of grow‐out ponds, juvenile prawns are usually transported from regional nurseries by truck in vented tanks. Hauling stress and associated delayed mortality have been implicated as potential causes of low pond survival. An experiment was conducted to evaluate the effects of biomass density, substrate, and salinity on water quality and transport survival of juvenile freshwater prawns Macrobrachium rosenbergii. The trial was designed as a 3 × 2 × 2 factorial and evaluated three biomass densities (10, 20, and 30 g/L), the presence or absence of added substrate (plastic mesh to provide a 200% increase in surface area), and the presence or absence of added salt (0‰ or 6‰). Model transport tanks were 15‐L, open styrofoam containers aerated with pure oxygen and compressed air. Water quality analyses were performed prior to stocking. After 24 h, water quality analyses were again conducted and all prawns were removed, designated as alive or dead, weighed, and counted. After 24 h of simulated transport, three‐way analysis of variance indicated no significant interactions (P &gt; 0.05) between the main effects of density, substrate, or salinity for prawn survival or water quality. When the main effects were analyzed separately, survival was significantly influenced by density. Survival was significantly lower (P &lt; 0.05) in the high‐density treatment (30 g/L: 89% survival) than in the medium‐ (20‐g/L) and low‐density (10‐g/L) treatments, which were not significantly different (P &gt; 0.05) and averaged 95% survival overall. Total ammonia nitrogen and un‐ionized ammonia nitrogen concentrations significantly increased (P &lt; 0.05) as biomass density increased. The addition of salt to the transport water did not significantly affect survival (P &gt; 0.05) but did result in a significant decrease (P &lt; 0.05) in both pH and un‐ionized ammonia nitrogen. Added substrate had no significant (P &gt; 0.05) impact on any measured variable. These data indicate that good survival can be achieved at a biomass density of 20 g/L and that increased salinity appears to reduce the buildup of toxic metabolites. The addition of substrate to the transport tank appears to provide no benefit.

Effect of glycine betaine, a feed attractant affecting growth and feed conversion of juvenile freshwater prawn Macrobrachium rosenbergii

A feeding experiment was conducted to determine the effect of the feeding attractant, glycine betaine (betaine hydrochloride) on the growth and feed conversion of juveniles of Macrobrachium rosenbergii (deMan) (mean initial weight 1.12 g). Three types of diets were prepared with the incorporation of glycine betaine at 5, 10 and 15 g kg−1 levels along with an unsupplemented control. After 60 days, weight gain, feed intake and food conversion ratio (FCR) were higher in prawn fed the three glycine betaine-added diets compared with the control feed. Among the glycine betaine-added diets, prawn fed glycine betaine at 5 g kg−1 level showed highest weight gain (2.73 g) by registering 61.5% increase in growth over control and also higher feed intake (5.79 g) and good FCR (2.12). There were highly significant differences (P 0.05) in survival among treatments.

Acute Toxicity of Copper to Juvenile Freshwater Prawns, Macrobrachium rosenbergii

Copper sulfate is an algicide that is commonly used for phytoplankton and filamentous algae control and has been used as a therapeutant in aquaculture. The objectives of this study were to determine the acute toxicity of copper sulfate and the safe level for use in freshwater prawn, Macrobrachium rosenbergii, production ponds in a high calcium and alkalinity environment. Six concentrations of copper sulfate (0, 0.2, 0.4, 0.6, 0.8, 1.0 mg/L) were tested in 8-L glass aquaria for 48 hours with three replicate aquaria per treatment. Concentrations of calcium hardness and alkalinity were set at 100 mg/L using calcium chloride and sodium bicarbonate, respectively. After 48 hours, survival of the control treatment (0% CuSO4) averaged 97%, which was significantly higher (P< 0.05) than that of all other treatments. The survival in the 0.2 mg/L and 0.4 mg/L (70% and 73%, respectively) concentrations of CuSO4 were significantly greater (P< 0.05) than higher dose treatments; but were not significantly different from each other (P> 0.05). Treatments containing 0.6, 0.8, and 1.0-mg/L copper sulfate demonstrated a dramatic decrease in prawn survival, which averaged 30, 7, and 0%, respectively. Regression analysis of the data predicted 48-hour LC50 for copper sulfate tobe0.46 mg/L. Since recommended application rates for use of copper sulfate as an algicide are 1.0 mg/L or more for water with alkalinities of 100 mg/L, copper sulfate treatments are not recommended for prawn production ponds.

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.