Juvenile Macrobrachium Rosenbergii Research Articles

Short-term dietary supplementation of β-glucan and chitosan modulates the immune response in freshwater prawn, Macrobrachium rosenbergii (De Man, 1879)

Aim: The present study evaluates the immunomodulatory potentials of β-glucan and chitosan administered orally for 15 days to the freshwater prawn, Macrobrachium rosenbergii juveniles. Methodology: Two diets were formulated supplementing 1.5 g kg-1 and 20 g kg-1 of β-glucan (diet G) and chitosan (diet C), respectively, with a control diet (diet B). The prawns were fed twice daily at 5% biomass. At the end of the feeding trials, mRNA expression profiles of immune-related genes lipopolysaccharide- and β-1,3-glucan binding protein (LGBP) and chitinase 3 were analyzed in qPCR. Corresponding LGBP protein and chitinases/CBP (chitinase 1, chitinase 1C and obstructor E, a chitin-binding protein) protein levels were also estimated by ELISA. Results: Supplementation of the immunostimulants (diets G and C) significantly enhanced the mRNA expression of both LGBP and chitinase 3 in the hepatopancreas. The protein expression of LGBP and chitinases/CBP was also significantly increased in the serum and hepatopancreas samples of both treatment groups. Interpretation: The short-term supplementation of β-glucan and chitosan in diets demonstrated beneficial effects in M. rosenbergii by enhancing the expression of important immune molecules like LGBP and chitinases, indicating their potential applications during the period of biotic stress. Key words: β-glucan, Chitinase, Hepatopancreas, Immunostimulants, LGBP, Macrobrachium rosenbergii

Apparent Digestibility Coefficients of Nutrients and Energy from Animal-Origin Proteins for Macrobrachium rosenbergii Juveniles

Apparent Digestibility Coefficients of Nutrients and Energy from Animal-Origin Proteins for Macrobrachium rosenbergii Juveniles

Effects of Different Inclusion Rates of Pre-Treated Rubber Seed Meal (RSM) on Physicochemical Properties of Juvenile Macrobrachium rosenbergii Feed

The present study investigated the potential of rubber seed as an alternative ingredient partial inclusion with improved nutritional value and inexpensive freshwater prawn feed. Rubber seeds are proven to have a nutritional composition such as protein suitable in animal feed. In this study, Rubber Seed Meals (RSM) were formulated using different inclusion rates of 10%, 20%, 30% and 40% Sodium Bicarbonate Treated Rubber seed (SBRS) as a partial replacement to fish meal in prawn diets, while feed without SBRS as control. The study’s objectives were to evaluate the chemical composition and sensory acceptability of the newly formulated RSM through proximate analysis, physical properties analysis and Textural Profile Analysis (TPA). Each of the analyses was performed in triplicates. The preliminary proximate analysis revealed that raw rubber seed powder contained a higher amount of crude protein (19.63%), crude fat (40.00%), crude fibre (7.20%) and metabolisable energy (4961 Kcal/kg) as compared to the SBRS powder. Among all treatments, a diet with 40% inclusion of SBRS showed the highest value of crude fat of 40.80% while with 0% SBRS has the lowest value of 27.22%. In conclusion, RSM with 20% inclusion of SBRS was found to be the most suitable diet that satisfies the nutritional needs of juvenile M. rosenbergii; due to its acceptable content of crude protein (32.70%), crude fat (31.88%), crude fibre (5.33%) and ash content (4.50%). In addition, diet with 20% inclusion of SBRS as the potential alternative prawn feed by having suitable physical properties with bulk density (0.57 g/mL) and sinking velocity (0.09 s/cm). In addition, values for hardness of the pellet were 1073 g and for cohesiveness and springiness were 1.15 and 8.46, respectively.

Impact of Titanium Dioxide-Graphene Oxide (TiO2-GO) Composite Nanoparticle on the Juveniles of the Giant River Prawn, Macrobrachium rosenbergii: Physio-Biochemistry and Transcriptional Response

Nanomaterials are used in many fields, resulting in inevitably releasing into the aquatic environment. The presence of nanomaterials, including TiO2-GO in the aquatic environment, can be toxic to aquatic organisms. However, few studies have focused on the effects of TiO2-GO composite nanoparticle on crustaceans. In the present study, the giant river prawn Macrobrachium rosenbergii juveniles were exposed to two concentrations of TiO2-GO composite nanoparticle (0.1 and 0.5mg/L). The effects of TiO2-GO composite exposure on activities of digestive and antioxidant-related enzymes and expressions of growth and immune-related genes at the transcriptome were studied. The results showed that the survival rate and growth performance were not negatively affected by TiO2-GO composite at the two exposure levels. Nevertheless, exposure to TiO2-GO composite causes an effect on the activities of digestive and antioxidant enzymes in the juvenile prawns. The enzyme activities of CAT, SOD, GSH-Px, AMS, TPS, and LPS in the 0.1mg/L TiO2-GO composite experimental group were markedly reduced than those in the control group. Additionally, the expression level of genes involved in growth and immunity was significantly affected by TiO2-GO composite. After exposure to the 0.1mg/L TiO2-GO composite, the mRNA expression level of MSTN was significantly increased, but the level of EcR, Raptor, and CaBP was significantly decreased. However, the mRNA levels of the CTL, TLR, JAK, and STAT were significantly increased after exposure to the 0.5mg/L concentration of TiO2-GO composite. Furthermore, to understand the molecular mechanism of M. rosenbergii under TiO2-GO composite exposure, RNA-Seq was employed to analyze the changes of the muscle and hepatopancreas transcriptome. Compared with the control group, we identified 5166 and 4784 differentially expressed genes (DEGs) in the muscle and hepatopancreas, respectively (p < 0.05). Based on gene ontology and KEGG analysis, significant differences were observed in the DEGs involved in activity and binding, metabolism, immune response, and environmental information processing. These results showed that exposure to TiO2-GO composite nanoparticle led to the changes of enzyme activity and gene expression, suggesting that TiO2-GO composite existing in aquatic environments would disrupt the physiology of M. rosenbergii. This study will serve as a foundation for subsequent research into the evaluation of nanomaterial toxicity on crustacean species.

Effects of titanium dioxide (TiO2)/activated carbon (AC) nanoparticle on the growth and immunity of the giant freshwater prawn, Macrobrachium rosenbergii: potential toxicological risks to the aquatic crustaceans.

Due to their unique physicochemical characteristics, nanomaterials exhibit many excellent properties and functions, leading to their applications in numerous fields. The large-scale production and widespread application of nanomaterials have inevitably resulted in their release into the environment, especially the water environment. Several studies have confirmed that exposure to nanomaterials can be toxic to aquatic organisms. However, few studies have focused on the effects of nanomaterial exposure on growth and immunity in crustaceans. In the present study, juvenile Macrobrachium rosenbergii were exposed to different concentrations of titanium dioxide (TiO2)/activated carbon (AC) composite nanomaterial (0.1 and 0.5mg/L) for 45days. The effects of nanoparticle exposure on digestion and antioxidant-related enzyme activities, as well as the expression of growth and immunity-related genes and signaling pathway, were evaluated. Our results show that in response to low concentration of TiO2/AC nanoparticle (0.1mg/L), most of the enzyme activities related to digestion and antioxidation (TPS, LPS, AMS, SOD, and CAT) were diminished. On the contrary, the GSH-Px activity increased under the 0.1mg/L group of TiO2/AC nanoparticle concentration. Additionally, the level of digestive and antioxidant enzyme activities we detected was increased when exposed to 0.5mg/L TiO2/AC nanoparticle. By comparison to the expression level of growth-related genes in the control group, MSTN, CaBP, E75, Raptor, EcR, and EGF were significantly inhibited at 0.1 and 0.5mg/L concentrations of TiO2/AC nanoparticle, whereas the expression level of genes (TLR, JAK, STAT, PPAF, ACP, and AKP) related to immunity was increased when exposed to different concentrations of TiO2/AC nanoparticle. Compared with the control group (0mg/L concentration), 5166 DEGs were identified in the TiO2/AC nanoparticle group, and a large number of DEGs were involved in molting, energy metabolism, stress tolerance, and germ cell development. Moreover, KEGG analysis revealed that many DEGs were assigned into signaling pathways related to metabolic growth and immune stress. These results showed that exposure to TiO2/AC nanoparticle will result in the changes of enzyme activity and routine mRNA expression, suggesting that TiO2/AC nanoparticle which existed in aquatic environment might affect the physiology of M. rosenbergii. This study will provide significant information for the evaluation of nanomaterial toxicity on aquatic crustaceans.

Probiotics in the rearing of freshwater prawn Macrobrachium rosenbergii (de Man, 1879) in a biofloc system

The present work evaluated the daily addition of probiotics (Bacillus subtilis and Bacillus licheniformis), during the rearing of Macrobrachium rosenbergii juveniles in a biofloc system for 40 days. Juveniles (0.12 ± 0.32 g) were stocked in 16 experimental units with bottom area of 0.20 m2, 50 L of useful volume, and an equivalent density of 150 prawns m−2. Four treatments were evaluated: Control (without addition of probiotics), TP1 (1.08 × 105 CFU g−1), TP2 (2.17 × 105 CFU g−1) and TP3 (3.25 × 105 CFU g−1). The treatments were randomly assigned to the experimental units with four replicates each. For quantitative evaluation of probiotic bacteria in the rearing water and in the hepatopancreas of prawns, microbiological analyses were carried out at days 0, 20 and 40. The results indicated a predominance of B. subtilis in the hepatopancreas and B. licheniformis in the water. The bacteria were differentiated by colony morphology and confirmed by Polymerase Chain Reaction (PCR) using species-specific primers. This study demonstrated that concentrations as low as 1.08 × 105 CFU g−1 (TP1) contribute to significantly higher survival (p = 0.014) of M. rosenbergii in Biofloc Technology System (BFT).

Dietary supplementation of host‐associated lactic acid bacteria modulates growth, metabolic activities, and immune‐related gene expression in giant freshwater prawn, Macrobrachium rosenbergii

AbstractThe present study was carried out to evaluate the dietary effects of host‐associated lactic acid bacteria on growth performance, metabolic enzyme activities, and immune response of Macrobrachium rosenbergii juveniles. To formulate the test diets, a control (Con) diet was supplemented with a commercial probiotic and three host‐derived bacteria Enterococcus faecalis (EC), Lactococcus lactis I (LC‐I), and L. lactis II (LC‐II), which were previously isolated from the gastrointestinal tract of adult individuals of M. rosenbergii. Juvenile M. rosenbergii (0.65 ± 0.008 g) were randomly stocked at 20 individuals/100 L of fiberglass tanks with three replications for each test diet. After 50 days, juveniles fed the diets LC‐I and LC‐II showed significantly higher (p &lt; .05) weight gain, specific growth rate, and the lowest feed conversion ratio. The analyses of glutamic oxaloacetate transaminase and glutamic pyruvate transaminase in muscle and hepatopancreas revealed significantly (p &lt; .05) reduced values in LC‐I fed juveniles. The total hemocyte count and phenoloxidase activity were significantly increased (p &lt; .05) in LC‐I and LC‐II fed juveniles. The relative mRNA expression patterns of immune‐related α2‐M, LGBP, ProPO, Cu, Zn‐SOD, TG, PE, AKP, and ACP genes were significantly (p &lt; .05) upregulated in juveniles fed with LC‐I followed by the diet LC‐II. Finally, the study suggests that the growth performance and immune response of M. rosenbergii can be improved through supplementation of host‐associated L. lactis bacteria for its higher production.

Essential oil of Lippia alba in the diet of Macrobrachium rosenbergii : Effects on antioxidant enzymes and growth parameters

The juveniles of Macrobrachium rosenbergii (0.060 ± 0.004 g and 2.018 ± 0.071 cm) were fed during 60 days with diets containing different doses of Lippia alba essential oil (EOLA) (0.0—control, 1.0, or 2.0 ml EOLA/kg diet; in triplicate, with 20 prawns/replicate). After the experimental period, were verified the survival, growth parameters and the antioxidant enzymes, lipid peroxidation and Na/K‐ATPase activities in hepatopancreas and gills, respectively, of the animals. There were no significant differences on survival, growth parameters and gill Na/K‐ATPase activity. However, glutathione peroxidase and glutathione‐S‐transferase activities were lower in hepatopancreas of prawns fed with 1.0 ml EOLA/kg diet compared to the control. Moreover, the activity of the enzyme superoxide dismutase was higher in hepatopancreas of prawns that received 2.0 ml EOLA/kg diet compared to those fed with 1.0 ml EOLA/kg diet. Although the addition of both EOLA doses has not improved the survival and growth parameters of M. rosenbergii, these doses contributed to decrease lipid peroxidation. Additionally, the dose of 2.0 ml EOLA/kg diet contributed for increasing the antioxidant enzymes activities in the hepatopancreas, improving antioxidant status, and therefore, it can be recommended as diet supplementation for M. rosenbergii.

Effect of different stock types and dietary protein levels on key enzyme activities of glycolysis‐gluconeogenesis, the pentose phosphate pathway and amino acid metabolism inMacrobrachiumrosenbergii

A feeding trial was conducted to study the effect of dietary protein (DP) levels on the enzyme activities of different stocks of Macrobrachium rosenbergii juveniles, fed two diets prawn type diets either at optimum (ODP, 32%) or sub-optimum (SDP, 27%) dietary protein. The activity of key enzymes: glycolysis, gluconeogenesis, amino acid catabolism, pentose phosphate pathway, and energy metabolism was examined on different stocks of M. rosenbergii juveniles in various tissues (muscle, hepatopancreas, and gill). Wild juveniles of M. rosenbergii were collected from the west coast of India, Gujarat (G), Maharashtra (M) and from the east coast of India, Andhra Pradesh (A), and raised in culture ponds of 200 m2 at 1 juvenile m-2. The experiment was conducted for a period of 60 days. A Visible Implant Elastomer (VIE) Tag was injected into different prawn juveniles’ stocks A, (3.06–3.10 g), M, (0.80–1.01 g) and G (0.90–1.06 g) for the individual identification of each class. All the animals were acclimatized for 7 days before being released into the pond. Each of the two diets, the first with 27% SDP, termed the sub-optimum level (S), and the second 32% DP, termed the optimum level (O), was fed in triplicate ponds. The weight gain of stocked prawn was significantly higher for G stock (3.03 ± 0.18 g) compared to M stock (2.53 ± 0.25 g) and A stock (1.33 ± 0.10 g). In addition weight gain in ODP was significantly higher (3.05 ± 0.22 g) compared to SDP (2.11 ± 0.17 g). Furthermore, both protein level and stock type had a significant (p ≤ 0.05) effect on the survival rate, specific growth rate, and feed conversion ratio of the prawn. A significant interaction was recorded between metabolic enzyme activities and the variation of dietary protein levels and differences in M. rosenbergii stocks, in which stock “G” and “M” exhibited healthier enzyme physiological status than stock “A”. The findings presented here may conclude that the enzymes quickly respond to dietary protein manipulations of cultured shrimp. The results can be useful in identifying the optimum stock (genotypes) in a given culture condition and subsequently higher production may be achieved.

Effect of Optimum and Suboptimum Dietary Protein on Hemolymph Physiology, Oxidative Physiology, Plasma Fatty Acids, and Histoarchitectural Modulations in Farmed Giant Freshwater Prawns Macrobrachium rosenbergii

AbstractWe examined the effect of optimum (32%) and suboptimum (27%) levels of dietary protein on the hemolymph and oxidative physiology of giant freshwater prawn Macrobrachium rosenbergii juveniles. Wild juveniles of different stocks were collected from the west coast (Gujarat [G‐stock] and Maharashtra [M‐stock]) and east coast (Andhra Pradesh [A‐stock]) of India. Prawns were raised in 200‐m2 culture ponds, with individual animals tracked by using stock‐specific, colored elastomer tags. Hemolymph glucose, plasma total protein, albumin‐to‐globulin (A:G) ratio, plasma calcium, and activity of five key metabolic enzymes in plasma (plasma cholinesterase, aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase, and amylase) were examined to compare the hemolymph physiology due to dietary protein variations fed to the different stocks. Plasma fatty acid profile was also monitored. Effect of feeding on oxidative physiology of prawns was analyzed by measuring the catalase and acetylcholinesterase activity in peripheral and brain tissues, respectively. Oxygen‐dependent intrinsic defense ability was also measured by nitro blue tetrazolium‐based respiratory burst activity. Physiology of prawns was correlated with the histological examinations of hepatopancreas and gills. Our results suggest that the hemolymph and oxidative physiology of giant freshwater prawns remained unaffected by the optimum and suboptimum dietary protein levels fed. Furthermore, stock‐based differences in the response were evident: the G‐stock and M‐stock prawns exhibited healthier plasma and oxidative physiology than A‐stock prawns. Our study provides a useful tool to select “good responder” stocks (genotypes) to obtain higher production levels in a given culture management scheme.

Histopathological changes in giant freshwater prawnMacrobrachium rosenbergii(de Man 1879) fed with probioticBacillus licheniformisupon challenge withVibrio alginolyticus

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.

Effect of dietary supplementation of Agrimos® on growth performance, feed utilization and immunological parameters of Macrobrachium rosenbergii juveniles

The present study was conducted to investigate the impact of adding commercial feed additives Agrimos® (combined yeast, Saccharomyces cerevisiae mannan oligosaccharides, and β-glucan) in the diet of Macrobrachium rosenbergii during the juvenile stage on growth performance, feed utilization, and immunological parameters. Four hundred and fifty juveniles of average weight 2.2 ± 0.02 g were divided into five experimental groups with three replicates each. The experiment was conducted for 56 days. Five isocaloric and isonitrogenous diets were formulated to be contain 350 g kg−1 crude protein and 19.4 MJ GE; four diets contain different levels of Agrimos® (1.5, 2, 2.5, and 3 g kg−1) in addition to control diet without Agrimos®. Final body weight, weight gain, and specific growth rate of Agrimos® fed groups were significantly higher (p 0.05). In addition, the feed conversion ratio and protein efficiency ratio in treatments supplemented by Agrimos® were significantly better (p 0.05) were observed among different treatments. Increased immune response was observed in experimental groups with the 2.5 g kg−1 Agrimos® concentration yielding the significantly higher (p < 0.05) total hemocyte count and phenoloxidase. In conclusion, the additions of Agrimos® in the diet 3 at a concentration of 2.5 g kg−1 improved and enhanced the growth performance and feed utilization of M. rosenbergii juveniles.

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.

Temperatura preferida y óptima para el crecimiento de postlarvas y juveniles de Macrobrachium rosenbergii (Crustacea: Palaemonidae)

Postlarvae and juveniles of Macrobrachium rosenbergii were acclimated at six temperatures and used to test their preferred and optimum growth temperature. For both stages, final temperature preferendum using acute preferenda and ·optimum growth were in the range of 29 to 31°C. One site-selection requirement for cornmercial cultures ought to be that yearly water temperature variations do not exceed that range.

Effect of salinity on survival and growth of giant freshwater prawn Macrobrachium rosenbergii (de Man)

Two independent experiments were performed to determine the effects of salinity on survival and growth of juvenile Macrobrachium rosenbergii, first one was to determine the median lethal salinity (MLS-5096h) and second one was to assess the survival and growth at different sub-lethal salinities under field condition. In MLS-5096h study 0, 5, 10, 15, 20, 25 and 30ppt salinities were used to initially find out the salinity tolerance range. Accordingly, a definitive salinity tolerance test was done in next phase to find out exact median lethal salinity by directly transferring the test species to 21, 22, 23, 24, 25, 26 and 27ppt salinity for 96h. The median lethal salinity of M. rosenbergii was estimated at 24.6ppt. In the second experiment, survival and growth performances of the prawn were recorded at different sub-lethal salinities viz., 5, 10, 15 and 20ppt along with 0ppt as control during 60 days culture period. The prawn exhibited lowest final average weight at 20ppt salinity and significantly highest at 10ppt salinity. Highest SGR and weight gain were obtained at 10 ppt followed by 5ppt, 15ppt and 0ppt salinity but differences among treatment were not significant (P>0.05). Survival rate of prawn varied between 91% (at 0ppt) and 78% (at 20ppt). The prawn grew and survived satisfactorily at 0–15ppt salinities, implying that the species can be cultured commercially at wide salinity range. M. rosenbergii can be considered as an ideal species to promote, in view of current and future climate variables as more and more coastal areas of India are going to be vulnerable to saline water inundation.

Suitability of Green Macroalgae Enteromorpha intestinalis as a Feed Form Macrobrachium rosenbergii

Future use of animal protein sources in prawn feeds is expected to be considerably reduced as a consequence of increasing economical, environmental and safety issues. Of main concern has been the use of expensive marine protein sources, such as fish meal which often results in fouling of water quality and disease outbreak in cultured species. To determine prawn capacity to use practical feeds with plant proteins as replacement ingredients to animal protein sources, 8-months growth trial was conducted in two sets of ponds using juvenile (0.02 gm) Macrobrachium rosenbergii. Among the two sets, one set (comprising of three ponds) is experimental pond included formulated feed prepared with 30% Entermorpha intestinalis dust along with other general ingredients and another set (comprising of another three ponds) is control pond with commercial feed. Mean final weight, percent weight gain, final net yield, feed conversion ratio and survival were evaluated. Higher condition index values, survival rate and gain in prawn weight were observed in experimental pond compared to control pond. Low FCR values were observed in the experimental pond than the control pond. Evaluation of production parameters at the end of the study demonstrated significant differences (P ≥ 0.05) among two ponds. The variation may be attributed to specially formulated plant based feed that not only boosted up the growth of prawns, but also upgraded the ambient aquatic health. These results indicate that fish meal can be replaced with algal protein sources in diets without affecting prawn growth and production.

Social status and individual behavioral differences in juvenile Macrobrachium rosenbergii

Adult Macrobrachium rosenbergii males appear in three distinct morphotypes associated with dominance hierarchy. Juveniles can also differ but only in body size. We examined whether juveniles present a size-related dominance hierarchy and whether it could be related to individual behavioral profile. Behaviors were recorded in groups of four prawns for 30 days in the laboratory, four times during light and dark phases of the 24 h cycle. Dominance ranks were analyzed using David’s score method. Observed behaviors differed between light phases. In most groups, two individuals obtained a positive score and the other two a negative score; they were therefore considered dominants and subordinates, respectively. There was no correlation between dominance and general behavioral activities. Dominants had greater weight gain and faster access to food. The precocious relation between growth and dominance suggests dominant juveniles are more likely to become blue claw adult males, the morphotype with greater reproductive success.

Effect of dietary β-glucan on immune response and disease resistance against Aeromonas hydrophila in giant freshwater prawn, Macrobrachium rosenbergii (de Man. 1879)

Macrobrachium rosenbergii juveniles (0.34 ± 0.01 g) were fed with β-glucan-incorporated diets at levels 0.0, 1.0, 2.0 and 3.0 g kg−1 diet. After 60 days of feeding trial, immune response and resistance to Aeromonas hydrophila were studied. Immune parameters, namely prophenol oxidase, super anion production, total hemolymph protein and total hemocyte count, were found significantly different (p < 0.05) in 1.0 g kg−1 β-glucan-incorporated diet. The relative percentage survival was observed significantly higher (p < 0.05) in 1.0 g kg−1 β-glucan inclusion level, after challenged against A. hydrophila. These results indicated that dietary level of β-glucan at 1.0 g kg−1 could enhance immune responses and resistance to A. hydrophila in M. rosenbergii.

Use of artificial substrate in pond culture of freshwater prawn (Macrobrachium rosenbergii): a new approach regarding growth performance and economic return

An experiment was conducted for six months to evaluate the effects of artificial substrates on the survival, growth and production of Macrobrachium rosenbergii juveniles. The T1 contained locally available bamboo-made substrate both vertical and horizontal and T2 received no substrate. Juvenile prawns (0.40±0.13 g) were stocked at the rate of 19,760 prawns ha-1. The water quality parameters range such as temperature, pH and DO were 22.06-33.45°C, 7.70-8.40 and 4.75-6.15 mgl-1 respectively which was no significant difference (P&lt;0.05) between two treatments. The final weight was 56.48±6.56 g and 45.03±2.11 g in T1 and T2 respectively. The survival rate of T1 was 63.12% which was significantly higher (P&gt;0.05) than T2 (56.87%). The specific growth rate, food conversion ratio and protein efficiency ratio were 1.19 % and 1.14 %, 3.15 and 4.39, 0.98 and 0.71 in T1 and T2 respectively which were not significantly different (P&lt;0.05) between treatments. The total production and net profit in T1 was 1408 kgha-1 and BDT 117,325 ha-1 which was significantly higher (P&gt;0.05) than T2. Thus growth and survival of prawn juveniles improved in presence of artificial substrate which could be economically viable technique for the freshwater prawn culture.

Use of artificial substrate in pond culture of freshwater prawn (Macrobrachium rosenbergii): a new approach regarding growth performance and economic return

An experiment was conducted for six months to evaluate the effects of artificial substrates on the survival, growth and production of Macrobrachium rosenbergii juveniles. The treatment T1 contained locally available bamboo-made substrate both vertical and horizontal and treatment T2 received no substrate. Juvenile prawns (0.40±0.13 g) were stocked at the rate of 19,760 prawns ha-1. The water quality parameters range such as temperature, pH and DO were 22.06-33.45°C, 7.70-8.40 and 4.75-6.15 mgl-1 respectively which was no significant difference (P&lt;0.05) between two treatments. The final weight was 56.48±6.56 g and 45.03±2.11 g in T1 and T2 respectively. The survival rate of T1 was 63.12% which was significantly higher (P&gt;0.05) than T2 (56.87%). The specific growth rate, food conversion ratio and protein efficiency ratio were 1.19 % and 1.14 %, 3.15 and 4.39, 0.98 and 0.71 in T1 and T2 respectively which were not significantly different (P&lt;0.05) between treatments. The total production and net profit in T1 was 1408 kgha-1 and BDT 117,325 ha-1 which was significantly higher (P&gt;0.05) than T2. Thus growth and survival of prawn juveniles improved in presence of artificial substrate which could be economically viable technique for the freshwater prawn culture.