Rosenbergii Culture Research Articles

Assessment of different grass species extracts as source of micronutrients in prawn Macrobrachium rosenbergii feeds

The present research is an attempt to screen five perennial indigenous grass species for their biochemical constituents seasonally for one year in order to determine the exact season for the harvest of the target species which will be used as feed ingredient. Among them, Cynodon dactylon has shown better result compared to other grass species and was hence incorporated as micronutrient in the formulated feed. Macrobrachium rosenbergii culture was carried out by feeding conventional and formulated feed (prepared from grass species) in tanks and ponds filled with spring water for 180 days in 2020 in the Eastern Ghats region of Koraput district, Odisha, India. Two treatments namely T1 and T2 having four replications each were supplied with commercial feed and formulated feed. Feeds were applied as per the body weight of prawns at 20% for the 1st month, 15% for the 2nd month, 10% for the 3rd and the 4th month, 5% for the 5th month and 2% till the end of the experiment. The water temperature, pH, dissolved oxygen, transparency, nitrate, phosphate, silicate, Chl a in the culture tanks and ponds were monitored fortnightly. ANOVA results between all the water parameters for both culture tanks and ponds showed significant variation (P < 0.05). The survival rate (77.0% ± 0.89%), daily growth rate (0.233 ± 0.05) g/day, specific growth rate (4.657% ± 1.04%) per day and condition index (2.638 ± 0.05) were found to be highest in prawns fed formulated feed. The feed conversion ratio varied from (2.03 ± 0.05) to (2.68 ± 0.04). Benefit cost ratio of field culture were 1.46 with yield of 702 kg/ha in conventional feed and 1.75 with yield of 950 kg/ha in formulated feed respectively. The study proved grass extracts to be efficient micronutrients for prawn feed which can be easily adopted in prawn production.

Effects of Ambient Microbiota on the Gut Microbiota of Macrobrachium rosenbergii

The gut microbiota (GM) compositions of aquatic animals are influenced by microorganisms in ambient water and sediment. However, the extent to which environmental microorganisms can affect shrimp GM composition is unknown. We analyzed the impact of water and sediment microorganisms on the GM of Macrobrachium rosenbergii at different growth stages. We collected water, sediment, and M. rosenbergii gut samples at the early, middle, and late stages of an M. rosenbergii culture and analyzed the microbiota composition. The shrimps’ body weight differed significantly between sampling stages. The shrimp GM composition differed significantly from that of the ambient water and sediment, and these differences were remarkably stronger than those between the shrimp GM at different sampling times and in different ponds. The proportion of sediment bacteria in the shrimp GM was approximately three times higher than that of water bacteria, which changed among ponds and over sampling time. These results provide important reference information for a deeper understanding of the impact of environmental microorganisms on the composition of shrimp GM. Moreover, the results also provide reference information for increasing the production of shrimp culture as well as ensuring a good health status of the culture.

GROWTH COMPARISON OF MONO AND MIXED-SEX GIANT FRESHWATER PRAWN (MACROBRACHIUM ROSENBERGII, DE MAN) AND STOCKING OPTIMIZATION OF MALE MONOSEX FARMING

Most often male freshwater Prawn (Macrobrachium rosenbergii) exhibits higher growth compared to the female counterpart. The current study has been conducted to evaluate the production performance and the survival rate of mono-sex male freshwater prawn culture compared to mono-sex female and mixed-sex culture. Conjointly the study also appraises the production competence of mono-sex male M. rosenbergii at different stocking densities. The experiment was conducted in two different phases. The first experiment comprised of three treatments, viz. mono sex male (T1), mono sex Female (T2) and both male &amp; female (T3) with the same stocking density (3 in d/m2) and maintaining the sex ratio 100% male and female for T1 and T2, and 50:50 ratio for T3. The second experiment was conducted with all-male prawn (100% male) with three different stockings densities (i.e. 1, 2 and 3 in d/m2 successively as D1, D2 and D3). The results showed that in the first experiment, mono-sex males performed better growth, survival and production than mono-sex females and mixed-sex populations. In the second experiment, the highest individual growth was found to be 57.81±0.12 g in D1, 52.22±0.14 g in D2 and 40.97±0.1g in D3. Similarly, D1 showed the highest survival compared to D2 and D3. In contrast, the highest production (888.05±9.05 kg/ha) was found in D2, followed by D3 (826±42.07 kg/ha) and D1 (496.18±34.86 kg/ha). Hence, this research suggests practicing mono-sex male M. rosenbergii culture at stocking of 2/m2 for accomplishing maximum profits.

Role of mesophilic fungal biomass and diversity in the pond soil for the productivity of freshwater prawn Macrobrachium rosenbergii

The study was carried out to screen the mesophilic fungal population in the pond soil of Macrobrachium rosenbergii culture in India. Soil samples were collected from April to September in two independent ponds (A and B) and fungal diversity was identified and enumerated throughout by serial dilution and colonies were subcultured using Potato Dextrose Agar (PDA) mycological methods. Physicochemical parameters were determined during the culture period and prawn productivity was measured. Twelve species of fungus were studied in the ponds and six isolates were common to ponds A and B. Nevertheless, the array of fungal species was higher in pond B whereas the number of colonies forming units was higher in pond A. The genus Aspergillus was dominant but other filamentous and yeast fungal species were also found in both ponds. Mesophilic fungal populations were most highly correlated with temperature, followed by dissolved oxygen concentration in the freshwater. Taken together, our data support that a high density of a few fungi species could be more significant for biotransformation and prawn productivity than fungal diversity itself. Thus, the effective knowledge and management of the fungal community in the pond soil could improve the productivity of M. rosenbergii culture.

Application of herbal plants in giant freshwater prawn: A review on its opportunities and limitation

Macrobrachium rosenbergii can be found in northwest India’s freshwater to Southeast Asia, Papua New Guinea, and Northern Australia. Nowadays, it becomes the most commercially crucial freshwater crustacean species cultured in many countries in the Asia region and beyond its natural distribution. On the other hand, feed additives are one of the feed ingredients that significantly improve the immune system, enhance the ingestion of feed, stress resistance, and reproduction. There are also many challenges in feed additives, i.e., high price, water-soluble, food safety, environmental issue, and the ban of nutritive antibiotics. Intensified research is devoted to exploiting natural products such as herbs in developing herbal feed additives to enhance cultured aquatic species’ performance. Herbs are cheap, safe, effective, easily prepared, biodegradable resources, and a high potential for mass production. Herbs contain many beneficial ingredients that can help as a growth promoter and immunostimulants for animals. However, herbal plants’ application to the animal must be in the right dosage to prevent toxicity. This review discusses the findings from different studies related to the in-vitro and in-vivo applications of herbs as a growth promoter, antimicrobial, and immunostimulant agent besides its opportunity and limitations in applying herbs focusing on M. rosenbergii culture.

Role of giant freshwater prawn (Macrobrachium rosenbergii) in livelihoods of the rural fishers of Northern Province of Sri Lanka

The overall objective of this study was to assess to what extent Macrobrachium rosenbergii culture in reservoir is sustainable and whether it has the potential to provide a livelihood option for reservoir fishers. Fisheries and socio-economic data collection were conducted from 2016 January to 2018 December in five perennial reservoirs in the Northern Province of Sri Lanka. Results revealed that culture-based fisheries and the introduction of M. rosenbergii in the five selected reservoirs have achieved considerable success and resulted in significant increases in fish production, income of fishers, availability of fresh fish for the rural communities and livelihood opportunities for fishing families. Socio-economic factors such as, age, fisheries experience, fish catch of the previous day, market value, household status and livelihood diversification influenced reservoir fishing. Low rainfall, strong wind, high temperature, over-growth of aquatic plants and algal blooms wildlife attacks and theft of fishing gear were identified as key stressors.

Effect of different C/N ratios on volume and potential microbial composition of flocs in freshwater prawn Macrobrachium rosenbergii culture system

The present study was conducted to evaluate the effects of C/N ratio on the volume of floc formation as well as on the load of several potential microbes of the fresh water prawn (Macrobrachium rosenbergii) culture tanks. The experiment was designed with three different C/N ratios viz. 10:1, 15:1, and 20:1 as T1, T2 and T3 were applied with a control (C) at laboratory condition. It was observed that C/N ratio 15:1 (12.22 ± 1.08 ml/L) and 20:1 (15.33 ± 1.37 ml/L) gave higher floc development compared to control C (5.22 ± 0.62 ml/L) and T1 (7.22 ± .46 ml/L) (P

Transcriptome analysis and immune-related genes expression reveals the immune responses of Macrobrachium rosenbergii infected by Enterobacter cloacae

Macrobrachium rosenbergii is an important cultural species in China and other Southeast Asian countries. However, Enterobacter cloacae infection has caused a great economic loss in M. rosenbergii culture industry. The immune responses of M. rosenbergii to the E. cloacae infection is not fully characterized. To investigate the immune response of M. rosenbergii against E. cloacae, we performed transcriptome analysis of the M. rosenbergii hepatopancreas with and without E. cloacae infection using RNA-seq. After assembly and annotation, 29,731 high quality unigenes were obtained from RNA-seq data. Differential expression analysis revealed the existence of 2498 significantly differently expressed genes (DEGs) at 12 h post infection, with 1365 up-regulated and 1133 down-regulated genes. Among these DEGs, some well-known immune-related genes were up-regulated significantly, including C-type lectin 1, lectin 3, anti-lipopolysaccharide factor 2, Cu/Zn superoxide dismutase and heat shock protein 70. GO analysis demonstrated 24 biological process subcategories, 14 cellular component subcategories, and 12 molecular function subcategories that were enriched among these DEGs, and some DEGs were clustered into immune related subcategories such as immune system process, response to stimulus, biological adhesion, and antioxidant activity. These DEGs were enriched into 216 KEGG pathways including a core set of immune correlated pathways notably in phagosome and lysosome. In addition, 5 up-regulated and 5 down-regulated immune-related DEGs were selected for further validation by quantitative real-time PCR and the results showed consistence with the RNA-seq data. Additionally, the expression level of six selected immune-related genes (ALF2, CLEC1, LEC3, hemocyanin1, HSP70 and SOD) based on the transcriptomic data were monitored at different point of time in hepatopancreas, gill, hemolymph and intestine. Results revealed these immune-related genes were significantly up-regulated in different tissues from 6 to 24 h after E. cloacae infection. Overall, these results provided valuable information for further studying the immune response of M. rosenbergii against E. cloacae infection.

Effects of dietary Pediococcus acidilactici GY2 single or combined with Saccharomyces cerevisiae or/and β-glucan on the growth, innate immunity response and disease resistance of Macrobrachium rosenbergii

One Pediococcus acidilactici strain, named PA-GY2 was isolated from the gut of cultured Macrobrachium rosenbergii. In order to better examine the potential scope and applicability of this strain in M. rosenbergii culture, based on the control diet, four experimental diets containing single or combined immunostimulants were produced by supplementing with yeast (Saccharomyces cerevisiae, SC) or/and β-glucan (G), then fed to the prawns (6.70 g ± 0.74) in five groups, which were named as group C (control group), P (PA-GY2), PS (PA-GY2 + SC, 1:1), PG (PA-GY2 + G) and PGS (PA-GY2 + SC + G), respectively. After a 60-day feeding trial, growth performance, feed utilization, immune response and disease resistance of prawns were evaluated in the present study. Results indicated that (1) The growth performance of the prawns in group PS and PGS were significantly improved. The prawns in group PGS presented the lowest feed coefficiency (FC), while prawns in group C presented the highest FC. (2) The protease activity was significantly improved by dietary immunostimulants supplementation, meanwhile, prawns in the group PS presented the highest lipase activity. (3) The highest total hemocyte count and respiratory burst activity were found in the group P and PG, respectively. The phagocytic index of the prawns in the group C was significantly lower than those in group P and PGS. (4) Dietary PA-GY2 single or combined with SC or/and β-glucan increased the immune related genes expression, including some antibacterial and antioxidant enzymes, while decreased the tumor necrosis factor-α gene expression, which led to the decreased cumulative mortality rate of prawns during the Aeromonas hydrophila challenge test. Based on the results of growth performance, digestive enzymes activity and immune response of M. rosenbergii, PA-GY2 supplementation, single or combined with SC or/and β-glucan could be suggested as promising immunostimulants in prawns farming.

Effect of time-restricted feeding and refeeding regimes on compensatory growth, body composition, and feed utilization in prawn (Macrobrachium rosenbergii) culture system

ABSTRACT A 14-week feeding experiment was conducted to determine the effect of a time-restricted feeding and refeeding regime on compensatory growth, body composition, and feed utilization in improved traditional prawn (Macrobrachium rosenbergii) culture systems. Three groups of prawn were used in which the control group (C) received feed regularly at ad libitum and the other two groups, Treatment 1 (T1) and Treatment 2 (T2), consumed feed 4 and 5 days per week respectively throughout the first 9 weeks. After feeding restriction, satiation of feed was given in the last 5 weeks. At the end of the experiment, the final weight of prawn in C, T1, and T2 were found to be 17.23 ± 6.56g, 16.04 ± 6.18g, and 15.64 ± 6.34 g respectively, which was insignificant. FCR decreased with increased restriction of feeding, while PER and NPU increased. Moisture content increased significantly, while protein and lipid content decreased significantly with increasing restriction time of feeding. After the satiation period, only the T2 group was able to replenish the lipid content. Water quality parameters didn’t vary significantly among the experimental groups and remained within optimum level. Therefore, time restriction could be applied in Macrobrachium rosenbergii culture without detrimental effects on growth, feed efficiency, and nutrient utilization.

Effects of electrolyte enhanced water on culturing giant freshwater prawn Macrobrachium rosenbergii

In this work, electrolyte enhanced water (EW) was used to determine the effect of EW in culturing freshwater prawns. The giant freshwater prawn juvenile, Macrobrachium rosenbergii, was exposed to different concentrations of EW in experiment 1. The EW was added into the water and labeled as treatment A1 which consists of 1% anolyte and 0.5% catholyte. In the respective treatments, the proportion of anolytes and catolytes are as follows: treatment B1 (1% anolyte and 1% catholyte), treatment C1 (2% anolyte and 0.5% catholyte), treatment D1 (2% anolyte and 1% catholyte), and control (without EW). All these treatments were run in three replicates for each treatment including the control. In the first experiment, the growth of the M. rosenbergii under treatment A1 showed an increased in growth as compared to the control after 56 days of exposure with a significant difference of p < 0.05. The survival rate of prawns is higher in treatments A1 (73%), B1 (70%), and control (63%) as compared to treatments C1 (53%) and D1 (50%). In the second experiment, the treatment using EW concentration of 1% anolyte and 0.5% catholyte was used as the most suitable concentration for the prawn culturing tested with recirculating aquaculture system (RAS). The treatments used in the second experiment was labeled as A2 (EW), B2 (EW and RAS), C2 (RAS), and control. Treatment B2 showed a higher growth and survival rate and was significantly different to the other treatments. The colony-forming unit (CFU) showed a lower count of bacteria in all experiments that used EW as compared to the control. The concentration of 1% of anolyte and 0.5% of catholyte has shown to improve the growth and survival rate of the M. rosenbergii culture when combined with the RAS. This study showed a potential use of electrolyte enhanced water in culturing giant freshwater prawn.

Social, economic and production characteristics of freshwater prawn, Macrobrachium rosenbergii (De Man, 1879) culture in West Bengal, India

Farming of giant freshwater prawn Macrobrachium rosenbergii, popularly known as ‘scampi,’ has recently been expanding in India. The present study was conducted using questionnaire survey, Participatory Rural Appraisal (PRA), key informant interviews, and focus group discussion and to assess the present state of production of giant river prawn (M. rosenbergii) in South 24 Parganas District of West Bengal, India. The socio-economic and technical survey on 80 prawn farmers was conducted during May, 2014–April, 2015. Prawn culture in ponds is slowly departing from the traditional endogenously managed system to a more extensive and commercial venture in the study areas. However, use of technology and scientific knowledge has not been adopted widely. In spite of operating within a semi-traditional system, this enterprise has shown moderate productivity and higher income in the study areas. Major constraints in the large-scale culture of prawn were adequate supply of seed at required quantities across locations, disease management, and social evils such as theft and poisoning of pond. Yield of prawn culture was affected by pond condition, family labor engagement in prawn culture, and resource endowment of the farm family. Linkage with formal financial institutions, subsidized input support from fishery department and investment in human resource development of farmers might be some point of intervention to boost prawn culture in the coastal zone of West Bengal, India.

Effects of C/N ratio control combined with probiotics on the immune response, disease resistance, intestinal microbiota and morphology of giant freshwater prawn (Macrobrachium rosenbergii)

A 90-day growth trial was performed to evaluate the effects of biofloc technology in combination with probiotics based on a rearing system on the growth and immunity of giant freshwater prawn (Macrobrachium rosenbergii). Two experimental groups (B-10 and B-20, with the addition of carbohydrates and without water change) and one control group (with water change and without the addition of carbohydrates) were designed. At the beginning of this study, the C/N ratios were adjusted to 10:1 and 20:1 through the addition of molasses to promote the formation of bioflocs in the two experimental groups. Each group comprised triplicate tanks, and each tank was stocked with 225 prawns (0.26±0.02g). On the fourth day post-stocking, Bacillus subtilis and Lactobacillus were dosed into all tanks. The results indicated that no significant difference existed in the survival rate and growth performance among the three groups (P>0.05). However, biofloc technology combined with the addition of probiotics could improve the humoral and hepatopancreatic immunity of the prawns by increasing the total hemocyte count, phagocytic activity, respiratory burst activity, and serum activity of superoxide dismutase (SOD) and lysozyme (LZM) (P<0.05). The activities of total nitric oxide synthase, SOD and LZM in the hepatopancreas were also improved in the two biofloc groups (P<0.05). After being challenged with Aeromonas hydrophila, the prawns in the control group had significantly higher cumulative mortality than did those in the B-10 and B-20 groups within 7days (P<0.05). Moreover, a relatively high proportion of Bacillus subtilis and Lactococcus was detected in the rearing water and intestines of the prawn reared in the biofloc systems (P<0.05). Meanwhile, biofloc technology combined with the addition of probiotics produced a higher fold height (HF) of the distal intestine than in the control group (P<0.05). The study suggested that rearing prawns using in situ biofloc technology combined with the addition of probiotics could enhance nonspecific immune responses and disease resistance under zero-water-exchange systems, sustain the homeostasis of intestinal microbiota and improve the absorption area of the intestine by increasing intestinal HF, which ensures the sustainability of M. rosenbergii culture. Statement of RelevanceGiant freshwater prawn, Macrobrachium rosenbergii reared using in situ biofloc technology in combination with probiotics could enhance non-specific immune responses, disease resistance under zero water exchange system, sustain the intestinal microbiota homeostasis and improve the absorption area of the intestine by increasing intestinal fold height, which ensured the sustainability of M. rosenbergii culture.

Development of Probiotics Based Culture System of Macrobrachium rosenbergii Using Different Stocking Densities

Owing to the problem of antibiotic resistance and subsequent reluctance of using antibiotics, probiotics use in aquaculture is becoming popular day by day. One experimental design with 150 days culture period of Macrobrachium rosenbergii was conducted with 3 treatments maintaining stocking density of 02/m2, 03/m2 and 04/m2 in T1, T2 and T3 respectively. Each of the treatments was with 3 replicates where each replicate was segmented into two parts to separate probiotics and non-probiotics based culture system. The higher body weight of 63.7 g was recorded in lower SD of T1 in comparison to lower body weight of 55.7 g and 43.0 g in higher SD of T2 and T3 respectively for probiotics application segments. The average body weight of 55.7 g, 46.7 g and 37 g respectively were found for the same treatments in non-probiotics segments. The average survival rate of 69.3%, 62.7% and 58.3% were recorded in probiotics and 68.3%, 63% and 57.7% respectively in non-probiotics treatments. Average daily growth rate and gross production were found better in probiotics than that of non-probiotics segments in all the treatments. Average daily growth rate of T1 was found 0.41 g and 0.36 g respectively for probiotics and non-probiotics segments. Similarly, for T2 and T3 average daily growth rate were found 0.35 g and 0.27 g for probiotics and 0.30 g, 0.23 g for non-probiotics segments respectively. Gross average production showed better result of 103 g/m2/crop in T2 probiotics treated segment than that of other two results of 87.23 g/m2 and 98.10 g/m2 in T1 and T3 treatments respectively where as 74.62 g, 87.23 g and 84.26 g/m2/crop was recorded in T1, T2 and T3 respectively in nonprobiotics treatments. Abiotic parameters in all segments of 3 treatments were within the optimum ranges for M. rosenbergii culture during the study period.

Identification of the Potential Reservoirs for Giant Fresh Water Prawn (Macrobrachium Rosenbergii) Culture in Moneragala District A GIS Approach

Identification of the Potential Reservoirs for Giant Fresh Water Prawn (Macrobrachium Rosenbergii) Culture in Moneragala District A GIS Approach

Strain performance of tilapia in freshwater prawn polyculture

Production performance of two tilapia (Oreochromis niloticus) strain viz. Chitralada and GIFT (Genetically Improved Farmed Tilapia) in fish-prawn polyculture system was compared, and possible effect of tilapia inclusion in freshwater prawn (Macrobrachium rosenbergii) culture was evaluated in 120 days of grow-out phase. There were three treatments, i.e. only freshwater prawn as control (T1), prawn + Chitralada (T2), and prawn + GIFT (T3) with three replications of each. Stocking densities for prawn juvenile was 30,000 ha-1 in all the treatments and for both tilapia strains were 10,000 ha-1. Floating feed containing 28% protein for tilapia and pelleted sinking feed for prawn were provided twice daily at a rate of 10-5% bw adjusted after each month of sampling. Water transparency was significantly lower (P&lt;0.05) in treatment T1 with significantly higher chlorophyll-? content that increased with progression of time. Along with, plankton abundance was significantly higher (P&lt;0.05) in T1 indicating prawn-tilapia mixed culture is better than traditional single species culture of prawn in terms of water quality management. Average individual weight, final weight, survival and production of prawn did not differ significantly (P&gt;0.05) among the treatments. In case of tilapia, average individual weight was significantly higher in Chitralada (254.22 g) than that of GIFT (201.52 g). However, survival of GIFT was significantly higher (92.50%) than that of Chitralada (65.83%). Gross and net production of tilapia did not vary significantly. It was concluded that prawn-tilapia mixed culture is advantageous over traditional mono culture regarding production augmentation, and tilapia inclusion improving water quality.J. Bangladesh Agril. Univ. 14(1): 127-134, June 2016

Growth performance, digestive enzyme activity and immune response of Macrobrachium rosenbergii fed with probiotic Clostridium butyricum incorporated diets

To determine antagonistic effect of Clostridium butyricum against Vibrio harveyi and its probiotic effect on growth performance, digestibility and immune response of fresh water prawn, Macrobrachium rosenbergii juveniles were examined following feeding with C. butyricum incorporated feed for 60days. Significant reduction of V. harveyi growth was found at 8 hr and onward in in-vitro and at 10days and onward in in-vivo challenge test. After rearing prawn with the bacteria in feed treatment for 60days, body weight and growth rate of prawns was significantly higher (p<0.05) than in control. Digestive protease and amylase activities in the gastrointestinal tract were also significantly (p<0.05) higher than in controls. Immune response was a little high in treatment group, although it was not significant (p>0.05) compared to control group. This study revealed that probiotic, C. butyricum incorporated diets were found to be beneficial for M. rosenbergii culture in terms of hindering the growth of pathogenic bacteria and increasing the growth, protease and amylase activities of prawn. Results from this study will be helpful to improve fresh water prawn farming.

Growth and Economic Performances of Macrobrachium rosenbergii (De Man, 1879) Culture in South-West Coastal Region of Bangladesh

The growth performance of Macrobrachium rosenbergii (Deman,1879) under different stocking densities was conducted under three treatments each with three replications namely T1: 10m-2 T2: 12m-2; T3: 14m-2 for a period of six months from April to September, 2012 in 9 experimental ponds in Terokhada Upazilla under Khulna district. Supplementary feeds (mustard oil cake (20%), wheat bran (20%), rice bran (20%), fish meal (25%) and maize bran(15%) were used for all stocked individual. Water quality parameters and growth performances were monitored monthly. The mean values of water temperature, transparency, dissolve O2, pH and salinity were varied from 28.88 ± 0.161±oC(T2) to 31.32 ± 0.97±oC (T1), 29.73 ± 0.34cm(T1) to 32.70 ± 0.28cm(T2), 5.33 ± 0.184mg-1(T3) to 6.17 ± 0.13 mg-1 (T1), 6.52 ± 0.205(T2)to 6.79 ± 0.18(T1) and 13.75 ± 0.16(T2) to 15.22 ± 0.20(T1). The weight gain of Macrobrachium rosenbergii were 59.79± 0.15 g(T1), 50.86±0.14g(T2),48.78±0.12g(T3).The survival rate (%) of M. rosenbergii were 75.02±0.577 (T1), 66.66±0.88 (T2), 61.01±0.577(T3) respectively. Yields (Kg ha-1 6 month-1) Macrobrachium rosenbergii were 2302.04kg (T1), 1768.52 kg (T2), 1393.808 kg (T3) respectively. Total cost 656000 ± 17480 Tk ha-1 (T1), 596120 ± 4520 Tk ha-1 (T2) and 549100 ± 9440 Tk ha-1 (T3) respectively and total return of different treatments T1, T2 and T3 were 1492400 ± 12800 Tk ha-1, 1078200 ± 11930 Tk ha-1 and 806480 ± 9190 Tk ha-1 respectively. Net benefit were 801900 ± 7340 Tk ha-1, 49400± 5930 Tk/ha and 288600 ± 13240 Tk ha-1 in T1, T2, T3 treatments respectively. From these findings, it could be concluded that highest yield was achieved from T1 and lowest in T3 which was significantly (P&lt;0.05) different among the treatments where stocking density were less than other treatments.J. Environ. Sci. &amp; Natural Resources, 9(1): 53-57 2016

Chytrid Batrachochytrium dendrobatidis fungal infection in freshwater prawn, Macrobrachium rosenbergii (de Man) - A new report

For the first time the occurrence of a chytrid, Batrachochytrium dendrobatidis (Bd) fungus infection in the fresh water prawn, Macrobrachium rosenbergii in grow out farms is reported. An extensive survey carried out between 2007 and 2011 in 15 farms (F) indicates that B. dendrobatidis is responsible for major pandemics in M. rosenbergii culture ponds as evidenced by the unique characteristics of the presence of fungal hyphae in claws and other features in the infected prawn. The pathogenicity of the fungus, LD50, histopathology, hematology and immunological response of the infected prawn is reported; the clinical symptoms include dull body color, abnormal protrusion associated with a grayish white color, wooly appearance with radiating grayish white fungal filaments on claw. Histopathology studies revealed that the infection resulted in faded eye color, occurrence of dark spots and melanization on the cephalothorax and muscles, translucent musculature, cuticular erosion, tissue atrophy with proliferated and infiltrated cells causing distension and gross enlargement of gill lamellae. An optimum dose of 105 zoospores/prawn (LD50) resulted in 50% mortality from 4 to 6days. At high dose of 108 zoospores/prawn, the infection caused total mortality from 2 to 4days. After 2nd week the total hemocyte counts (THCs) significantly decreased while the phenoloxidase (PO) level, relative superoxide anion production level, and superoxide dismutase (SOD) activity registered a significant increase (p<0.05) when compared to control. The cumulative mortality was 90% when challenged with Bd for 30days. The prevalence of infection was high in cooler or winter season (October, November, and December) and low in hot or summer season (March, April, May, and June) indicating a seasonal influence wielding a significant effect on mortality, hematology, and immunology profiles. Statement of relevanceIn India about 1000ha of shrimp/prawn ponds were affected by the disease, resulting in an annual loss of Rs. 10 million (US$0.23 million) during 1994–95 and Rs. 25 million (US$0.58 million) during 1995–96 (Ayyappan, 2000). Intensive prawn farming favors the rapid deterioration of environmental conditions which increase the incidence of diseases and failure of culture. Therefore augmenting the immune resistance and anti-environmental stress of prawns are of primary concern. Chytridiomycosis is an infectious disease caused by the chytrid, Batrachochytrium dendrobatidis; it is a non-hyphal zoospore fungus belonging to Chytridiomycota (Canter-Lund and Lund, 1995) or Blastocladiomycota (James et al., 2006) phylum. Chytrids are a diverse group of microscopic fungi (Barr, 1980; Barr, 2001; Kendrick, 1992) that disperse in an aqueous environment by motile zoospores with a single posterior whiplash flagellum (Sparrow, 1960). Chytrids have been well documented in amphibians (Longcore et al., 1999; Berger et al., 1999). A number of fungal pathogens were isolated and identified from prawns and shrimps (Krishnika and Ramasamy, 2014; Karthikeyan and Gopalakrishnan, 2014; Hatai, 2012; Cruz da Silva et al., 2011; Ramaiah, 2006). Recently, fungal pathogen like Aspergillus awamori has been isolated from marine shrimp, Liptopenaeus vannamei (Karthikeyan et al., 2015) and Gilbertella persicaria from Penaeus monodon. To our knowledge there is no report of the Batrachochytrium dendrobatidis infection in fish, prawn, and shrimp.

Giant Freshwater Prawn Macrobrachium rosenbergii Farming: A Review on its Current Status and Prospective in Malaysia

In Malaysia, the giant freshwater prawn Macrobrachium rosenbergii is becoming an increasingly important targeted species, as its culture, is considered to have the potential to raise income among impoverished farmers. Although, total freshwater aquaculture production decreased in the year 2013 compared to previous year, the aquaculture production of M. rosenbergii increased from 318 tonnes in 2012 to 457 tonnes in 2013. Recently, the production of giant freshwater fries increased from the three government and 21 private hatcheries in 2012 to the four government and 19 private hatcheries in 2013. The number and production of feed mills increased in 2013 compared to the four years ago. Until recently, lack of a stable nursery of PL and feed had been an important obstacle to the further expansion and development of M. rosenbergii culture. This paper reviews the current status of freshwater prawn culture in Malaysia and background history, and future prospects of freshwater prawn farming. It was concluded that freshwater prawn farming in Malaysia has a favorable scenario for expansion due to increasing demand and to prospects of an improved organization of the productive chain.