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1.
White tail disease (WTD) is found to cause immense economic losses in hatcheries, with mortalities often reaching 100% within 4 or 5 days. The pathogenic agents have been identified as Macrobrachium rosenbergii nodavirus (MrNV) associated with extra small virus (XSV), which are 27 and 15 nm in diameter respectively. The effects of some chemical disinfectants hydrogen ions (pH), heat and ultraviolet (UV) irradiation on the inactivation of MrNV and XSV were investigated. The viral inoculum exposed to UV irradiation for a period of 5 min and more was totally inactivated and failed to cause mortality in postlarvae of prawn. The viruses were totally inactivated by this high pH (8.5, 9 and 10). The viral suspension treated with sodium hypochloride, formalin, Benzalkonium chloride and Benzethonium chloride at the concentration of 200 ppm caused 100% mortality in postlarvae of prawn. Iodine was found to be effective to inactivate MrNV and XSV at the concentration of 100 ppm or more, whereas the viral suspension treated with iodine at the concentration of 50 ppm or less caused mortality in postlarvae. The infected postlarvae in treated and positive control groups showed positive by RT‐PCR for these viruses.  相似文献   

2.
White tail disease (WTD) caused by Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV) is a serious problem in prawn hatcheries. The gene for capsid protein of MrNV (MCP43) was cloned into pRSET B expression vector. The MCP43 protein was expressed as a protein with a 6‐histidine tag in Escherichia coli GJ1158 with NaCl induction. This recombinant protein, which was used to raise the antiserum in rabbits, recognized capsid protein in different WTD‐infected post‐larvae and adult prawn. Various immunological methods such as Western blot, dot blot and ELISA techniques were employed to detect MrNV in infected samples using the antiserum raised against recombinant MCP43 of MrNV. The dot blot assay using anti‐rMCP43 was found to be capable of detecting MrNV in WTD‐infected post‐larvae as early as at 24 h post‐infection. The antiserum raised against r‐MCP43 could detect the MrNV in the infected samples at the level of 100 pg of total protein. The capsid protein of MrNV estimated by ELISA using anti‐rMCP43 and pure r‐MCP43 as a standard was found to increase gradually during the course of infection from 24 h p.i. to moribund stage. The results of immunological diagnostic methods employed in this study were compared with that of RT‐PCR to test the efficiency of antiserum raised against r‐MCP43 for the detection of MrNV. The Western blot, dot blot and ELISA detected all MrNV‐positive coded samples as detected by RT‐PCR.  相似文献   

3.
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4.
The present study evaluated the role of recombinant RNA‐dependent RNA polymerase (RdRp) protein of Macrobrachium rosenbergii nodavirus (MrNV) in modulating the immune response and in reducing MrNV load in infected prawn. In the first experiment, prawns (25–30 g) were injected with recombinant RdRp protein (RP) at a concentration of 0, 1.0 and 10 μg, and immune parameters and expression of some immune‐related genes were measured up to 14 days post injection (p.i.). In the second experiment, early juveniles were injected with a similar dose of RdRp and animals were challenged by immersion with MrNV. The infection status was detected in muscles by nested RT‐PCR up to 21 days post challenge. Prawn injected with higher concentration of RP showed significantly higher total haemocyte count at different period post injection. Significant up‐regulation of immune‐related genes was observed within 24 h in prawn treated with lower dose of RP and after 7 days p.i. at higher level of RP injection compared with adult control. Most of the tested samples (63%) were found to be RT‐PCR positive for MrNV at 48 h of post‐immersion challenge. After 14 days, MrNV was detected only in control prawn, while both RP‐injected groups were MrNV negative. This study elucidated the potential viral load reduction role played by RdRP in MrNV‐infected prawn.  相似文献   

5.
Haemocyanin is a multi‐subunit protein complex found in the haemolymph and is involved in the immune system of crustaceans. In this study, a haemocyanin gene of Macrobrachium rosenbergii, designated MrHc, was successfully isolated. The MrHc gene contained an open reading frame (ORF) of 1,992 nucleotides, encoding a protein of 663 amino acid residues with a molecular mass of 76.5 kDa. The deduced amino acid sequence contained distinct structural motifs of the haemocyanin superfamily, including an all‐alpha domain, a copper‐containing domain and an immunoglobulin‐like domain. Based on the phylogenetic analysis, the MrHC protein demonstrated a close relationship with the haemocyanins of Palaemon carinicauda and Macrobrachium nipponense. The MrHc gene was expressed in various shrimp tissues, including the hepatopancreas, gill, haemocytes, stomach and muscle. After Macrobrachium rosenbergii nodavirus (MrNV) challenge tests, the MrHc gene was up‐regulated 237‐fold at day 2. A recombinant protein of the MrHc immunoglobulin‐like domain exhibited antibacterial activity against Vibrio vulnificus, V. parahaemolyticus, Aeromonas caviae, A. veronii, A. hydrophila and Bacillus cereus. This study suggested that MrHc may play important roles in the shrimp innate immune response to MrNV infection and bacterial infection.  相似文献   

6.
A 50‐day growth trial was conducted to evaluate the efficacy of Chlorella vulgaris (Beijerinck) as an ingredient in the diets of giant freshwater prawn Macrobrachium rosenbergii (De Man) postlarvae (PL30). Immune response (total haemocyte count and prophenoloxidase activity) was also assessed by subjecting postlarvae to a challenge test against Aeromonas hydrophila (Chester) for 14 days. Iso‐nitrogenous and iso‐lipidic test diets were prepared using a fishmeal‐based‐positive control diet (D0) and four basal diets with inclusion levels of 2% (D2), 4% (D4), 6% (D6) and 8% (D8) C. vulgaris. Postlarvae of M. rosenbergii were randomly stocked (mean initial body weight of 0.19 ± 0.02 g) in 30‐L tanks in three replicates per dietary treatment for evaluation of growth performance. Another set of postlarvae (mean initial body weight of 1.25 ± 0.02 g) was randomly distributed in 95‐L tanks in three replicates per dietary treatment for the assessment of immune response. Results showed that specific growth rate was significantly higher (P < 0.05) in postlarvae fed D4 and D6. Variations in values for carcass protein, lipid, moisture and ash were also evident. Postlarvae fed diets with Chlorella showed increased prophenol oxidase activity and total haemocyte counts. Moreover, survival rate after challenge with A. hydrophila was significantly increased (P < 0.05). Inclusion of C. vulgaris in diets enhanced immune response and resistance of M. rosenbergii postlarvae against A. hydrophila infection.  相似文献   

7.
The freshwater prawn, Macrobrachium rosenbergii naturally lives in the freshwater, though it migrates to the brackish water environment during spawning that claimed to be resistant on a broad range of saline fluxes. However, little is known about the osmoregulatory patterns and the effect of an enzyme glutamine synthetase (GS) in M. rosenbergii under stress. Here, we described the identification and functional characterization of GS from M. rosenbergii (Mr‐GS) at molecular and protein levels. The identified Mr‐GS was comprised of 361 amino acids that phylogenetically shared the highest identity with other crustaceans and predicted to contain Gln‐synt_C and Gln‐synt_N domains at the respective terminal regions. Tissue distribution analysis in M. rosenbergii revealed that the Mr‐GS was highly expressed in muscle, and commonly existed in other examined tissues in the following order gills > heart > stomach > brain > haemolymph. Whereas, the mRNA of Mr‐GS was significantly up‐regulated in the muscle and gill tissues following challenges with either hyper (0 → 13‰), or hypo (13 → 0‰) osmotic stress at 3, 6 and 12 hr. Furthermore, the level of Glutamine concentration was positively correlated with the GS mRNA and protein expression patterns in hyper‐osmotic stress, whereas in hypo‐osmotic stress a slight decrease in the gills and maintained a level in the muscle tissues at 3, 6 and 12 hr post‐treatments. Our findings suggest that Mr‐GS potentially exhibited the osmoregulation responses in the gill and muscle tissues of M. rosenbergii throughout the time of osmotic stress, which will benefit for future study on osmoregulation.  相似文献   

8.
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9.
This study was conducted to evaluate the influence of herbs such as Ocimum sanctum, Phyllanthus amarus and Solanum trilobatum on the freshwater prawn, Macrobrachium rosenbergii, postlarvae (PL). These herbs were powdered and incorporated at 5% with the basal diet separately and in a combination. The M. rosenbergii was fed with these feeds for a period of 90 days. Results indicated that significant (P < 0.05) improvements were observed in the survival, nutritional indices (weight gain, specific growth rate and protein efficiency ratio), proximate muscle biochemical constituents (total protein, amino acid, carbohydrate and lipid), profiles of essential amino acids and fatty acids of prawns fed with herb‐incorporated feeds. Among these herbs supplemented, P. amarus produced significantly (P < 0.05) better performance followed by S. trilobatum and O. sanctum. However, prawns fed with these herbs combination showed an insignificant (P > 0.05) improvement in survival and growth performance when compared to individual supplementation. Hence, this study suggests that the herbs (O. sanctum, P. amarus and S. trilobatum) can be used as a supplementary feed for a sustainable development of freshwater prawn culture.  相似文献   

10.
Nutritional efficacy of fairy shrimp (Streptocephalus sirindhornae) nauplii, as a live food, was studied for growth performance and survival rate of giant freshwater prawn (Macrobrachium rosenbergii) postlarvae. A feeding experiment was designed with four different feeds: dry commercial feed, fairy shrimp nauplii, Artemia sp. nauplii and adult Moina macrocopa. Results from the nutritional composition revealed that fairy shrimp nauplii had protein and lipid contents of 54.58 ± 2.8 g kg?1 and 255 ± 2.8 g kg?1, respectively. The highest value for an individual amino acid in fairy shrimp was lysine (140.7 ± 1.6 g kg?1). The essential amino acids content in the whole body of the larval prawns was in the range of 66.7–67.5 g kg?1. Fairy shrimp nauplii had the highest essential amino acid ratio (A/E) of lysine, similarly, in musculature of prawn larvae. Weight gain and specific growth rate of the postlarvae fed with fairy shrimp nauplii were significantly higher than those fed with Artemia nauplii, adult Moina and dry commercial feed. The presented results suggest that S. sirindhornae nauplii can be used as a nutritionally adequate food for freshwater prawn M. rosenbergii postlarvae.  相似文献   

11.
The effect of dietary supplementation of probiotic bacterium Bacillus licheniformis on the histopathological changes in Macrobrachium rosenbergii juveniles (4.0 ± 0.02 g) challenged with known pathogenic strain of Vibrio alginolyticus are reported. Two isocaloric basal diets supplemented with probiotic bacteria B. licheniformis (1.0 × 109 cfu/g feed) and other without probiotic supplementation were fed to the M. rosenbergii juveniles for 45 days. The histological observations revealed no significant changes in the hepatopancreas and gut tissues of both the experimental and the control groups which indicate that the present bacterium is a safe candidate probiont for the host. Prawns were challenged with V. alginolyticus after 45 days of feeding with probiotic diet. The histopathological studies of the hepatopancreas revealed that M. rosenbergii fed with probiotic‐supplemented diet showed less changes as compared to the prawns fed with control diet on second and fourth day of post‐experimental challenge with V. alginolyticus. Histopathological observations revealed that the gills of the prawns fed with control diet were severely affected in comparison to the prawns fed with probiotic‐supplemented diet after challenging with V. alginolyticus. Results from this study revealed the improved protection by dietary incorporation of B. licheniformis in reducing the histopathological manifestations due to V. alginolyticus infection in freshwater prawn.  相似文献   

12.
The different products of Eichhornia crassipes leaves including dried E. crassipes powder (DEP), hot‐water treated E. crassipe (HTE), hot‐water extract of E. crassipe (ECE) and dreg of hot‐water extract of E. crassipe extract (dECE) were produced and incorporated into the diet of the prawn, Macrobrachium rosenbergii, as an immunostimulant. Results showed that prawn fed the HTE‐, ECE‐ and dECE‐containing diets for 4 months had increased total haemocyte count, different haemocyte count, phenoloxidase activity, respiratory bursts, superoxide dismutase activity, glutathione peroxidase activity especially in HTE and ECE treatments. The phagocytic activity and clearance efficiency against Lactococcus garvieae of prawn fed the HTE‐ and ECE‐containing diets were significantly higher than those of prawn fed the control diet at 2–4 months. The relative percentage survival of prawn fed the DEP‐, HTE‐, ECE‐ and dECE‐containing diets for 4 months following 144 h challenging with L. garvieae were 19.0%, 38.1%, 38.1% and 33.3%. It was concluded that E. crassipes leaves containing an active component which was easily extracted by hot water can enhance innate immunity and resistance against pathogen of M. rosenbergii by dietary long‐term administration, and the administration of HTE in the diet was the best strategy due to the availability and convenience.  相似文献   

13.
Freshwater prawn production in India that includes farming and wild capture of the giant freshwater prawn, Macrobrachium rosenbergii and the monsoon river prawn, M. malcolmsonii has increased steadily since 1999 reaching a peak output of 42 780 t in 2005, but then declined to 6568 t in 2009–2010. Stunted growth and diseases in ponds because of poor seed quality and the broodstock which had been inbred over several generations; pond water quality issues; and increased cost of production on account of feed, labour and the mandatory certification requirements are suggested to be some of the factors leading to the production declines. While majority of the output occurs in Andhra Pradesh, single crop paddy–prawn production systems in the low‐lying fields of Kerala have helped gradual transformation to a sustainable, organic mode of farming of both rice and prawns, suitable for other states of India. Although the trends by June 2011 indicate that the sector is set to a revival, future prospects of freshwater prawn farming in India will also depend on the expansion of whiteleg shrimp Litopenaeus vannamei that was introduced recently in India and provided a more profitable opportunity for farming.  相似文献   

14.
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15.
A feeding trial was conducted to investigate the complete substitution of either fish oil (FO) or squid liver oil (SLO) with crude palm oil (CPO), canola oil (CO) sunflower oil (SFO) or linseed oil (LO), as the sole added lipid source in diets fed to triplicate groups of giant freshwater prawn, Macrobrachium rosenbergii (initial weight = 0.42 ± 0.01 g) for 6 weeks. Prawns fed the CO or SLO diets showed significantly higher (P < 0.05) specific growth rate than those fed the FO or CPO diets. The feed conversion ratio of the prawns was significantly better when fed the CO diet, compared with the FO, CPO, SFO and LO diets. The muscle eicosapentaenoic acid content of prawns fed the vegetable oil (VO) diets were not significantly different (P > 0.05) from those fed the FO diet, although all VO‐based diets led to a significantly lower docosahexaenoic acid content compared with prawns fed the FO or SLO diet. The whole‐body total carotenoid content was significantly lower for prawns fed the SLO diet compared with prawns on the CO or CPO diets. The successful use of VO instead of marine‐based oils in prawn diets will likely reduce feeding costs associated with M. rosenbergii aquaculture.  相似文献   

16.
The aim of this study was to compare two rearing systems for freshwater prawn Macrobrachium rosenbergii: one with use of a recirculating aquaculture system with biofilters (RAS) and another with use of microbial flocs (F). Thirty postlarvae of freshwater prawn with an initial average weight of 0.13 ± 0.05 g were randomly stocked in six experimental units with 0.20 m² and volume of 50 L. The experiment lasted thirty days. Dissolved oxygen, temperature and pH were monitored daily; ammonia concentration was determined three times per week; nitrite concentration, alkalinity and hardness were measured weekly. For the formation of microbial floc, molasses was used to keep the ammonia concentrations within safe levels for prawn farming. The variables of water quality remained within the suitable range for the production of the species, except for ammonia concentrations at the F treatment, which exceeded the safe levels. At the end of the experiment, the following parameters were evaluated: survival, specific growth rate, weight gain and feed conversion rate. Differences were found only in feed conversion rate with better values on RAS treatment. The microorganisms present in the RAS and F treatment were also evaluated. The densities of rotifers, amoebas and total bacteria were higher at the F treatment although the same organisms were found at the RAS treatment. The results of this study showed the possibility of rearing M. rosenbergii in biofloc system technology.  相似文献   

17.
The medicinal herbs such as Alternanthera sessilis, Eclipta alba and Cissus quadrangularis were used to assess the growth promoting ability, enhancement of muscle biochemical constituents and profiles of amino acid in the freshwater prawn, Macrobrachium malcolmsonii. The herbal powders were separately incorporated with basal diet, and these diets were fed to M. malcolmsonii postlarvae for a period of 90 days. At the end of experiments, the survival of prawn significantly improved in herbal incorporated feed. In addition, the growth parameters, such as weight gain, specific growth rate and protein efficiency rate were significantly (P < 0.05) higher in herbal diets fed groups when compared with control. The activities of digestive enzyme, biochemical constituents, profile of amino acid, energy utilization parameters, concentrations of vitamin C and E were significantly (P < 0.05) elevated in experimental diets fed groups when compared with control. The profiles of essential amino acids were also found elevated in herbal incorporated diets fed PL. Among the three herbs tested, C. quadrangularis incorporated diet fed group showed better performance followed by the E. alba and A. sessilis. The present study suggests that these herbs can be incorporated in artificial feed formulations for Macrobrachium culture.  相似文献   

18.
The effects and commercial implications of aquatic plant addition, and variable prawn stocking density and supply of commercial aquafeed on water quality, prawn production and economic benefit, are investigated in a prawn (Macrobrachium rosenbergii) + plant (Hydrilla verticillata) co‐culture system. Our experimental design includes a control (PM, prawn monoculture without H. verticillata, with 30 prawns/m2) and four treatments with 15% plant cover of total pond area in each replicate. Dissolved oxygen, pH, N, P, total ammoniacal nitrogen, nitrite and nitrate in this co‐culture system were significantly lower than those of PM. Prawn survival (96.2 ± 14.9%), average final weight (68.5 ± 4.9 g) and yield (879.1 ± 102.4 kg/ha) in treatment 20W80%A (20 prawns/m2, 80% of control aquafeed) were obviously greater than in PM and other treatments. Despite small males (SM) and immature females (IF) being predominant in prawn + plant cultures, more than 77.2% of prawns reached or exceeded 40 g on completion of trials, and by six months were of appropriate size for market. We report culture of M. rosenbergii with H. verticillata to be both feasible and profitable. The optimal treatment, a stocking density of 20 prawns/m2 with these plants, enabled reduction of commercial aquafeed to 20% conventional culture levels. For this optimal treatment, we estimate total gross revenue, profit and internal rate of return to be US$ 6,593.3 ± 103.3 ha?1, US$ 3,095.5 ± 42.6 ha?1 and 127.5 ± 20.7% for 20W80%A respectively; we estimate U.S. Dollar (US$) invested generates 3.87 times conventional culture revenue. Co‐culture of M. rosenbergii and plants renders prawn production ecologically and economically feasible on larger farms.  相似文献   

19.
RNA‐dependent RNA polymerase (RdRp), B2 and capsid genes of Macrobrachium rosenbergii nodavirus (MrNV) of Indian isolate were polymerase chain reaction amplified, cloned and sequenced. Expression of the MrNV fusion recombinant proteins of RdRp (44.5 kDa), B2 (32.2 kDa) and capsid (58.4 kDa) was confirmed by Western blot analysis using anti‐His mouse monoclonal antibodies. Polyclonal antibodies specific to purified recombinant MrNV capsid protein showed specificity against the capsid protein by Western blot. The protein sequence analysis of the partial RdRp gene of MrNV revealed the signature sequence along with the conserved core residues of the catalytic domain and indicated the presence of active sites, metal ion‐binding site and nucleic acid‐binding site residues. The Indian isolate of MrNV showed high RdRp and capsid gene sequence homology with the other MrNV geographical isolates. However, the Belize isolate was found to be the most distinct among the different geographical prawn nodavirus isolates due to the host specificity. Secondary structure prediction analysis of the MrNV capsid predicted it to be a DNA‐binding protein consisting of α helix (22.91%), extended strand (24.80%), β turn (5.39%) and random coil (46.90%) regions.  相似文献   

20.
Macrobrachium rosenbergii, known as the giant freshwater prawn or Malaysian prawn, is the sixth largest aquaculture species in Asia. Knowledge of genetic diversity of M. rosenbergii is important to support management and conservation programmes, which will subsequently help in sustainable production of this economically important species. This study aimed to analyse the genetic diversity and population structure of five M. rosenbergii populations using 11 microsatellite loci. In analysing 240 samples, the number of alleles, observed heterozygosity (HO) and expected heterozygosity (HE) ranged from 3 to 20, from 0.250 to 0.978 and from 0.556 to 0.944 respectively. The five stocks of M. rosenbergii displayed high level of genetic diversity. Both the FST and amova analyses showed that there was significant genetic differentiation among all populations. The UPGMA dendrogram based on Nei's genetic distance matrix revealed that the Narmada and Mahi populations were in one cluster and Mahanadi and Subarnarekha populations in another single major branch, whereas the Kerala population clearly showed a separate cluster. This information on genetic variation will be useful for genetic improvement and conservation of Indian populations of giant freshwater prawn M. rosenbergii.  相似文献   

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