Marine Shrimp Research Articles

A new strategy to study pond soil chemistry in intensive and extensive cultures of Litopenaeus vannamei: A case study in Brazil

Improvements in the sampling of pond soil and bioremediation techniques can increase the efficiency of soil treatments by emphasizing zones of greater nutrient deposition. This work evaluated the relative deposition of nutrients and their statistical correlation in pond soils in intensive and extensive Litopenaeus vannamei farming. Soil samples were collected (n: 150) in six ponds at two marine shrimp farms (one intensive and one extensive) after being drained and harvesting the shrimp. The ponds were divided into 5 zones - Water Inlet (WI), Water Outlet (WO), Plateau (P), Ditch (D) and Feeder (F), of which five samples were collected in each zone. Soil texture, Total Carbon (TC), Total Organic Carbon (TOC), Total Nitrogen (TN), C/N ratio, Total Phosphorus (TP), Available Phosphorus (AP), aluminum (Al), calcium (Ca), magnesium (Mg), potassium (K) and pH (H2O) were analyzed. All variables were submitted to the Kolmogorov-Smirnov and Levene test to verify normality and homoscedasticity, respectively. Variables that met the requirements were compared by one-way ANOVA analysis of variance, and Tukey test or Student's t-test. The correlation of nutrient concentration was performed using linear regression. Soil from intensive and extensive cultivation ponds were classified as sandy loam and sandy, respectively. The deficiency of carbon and potassium, and excess of phosphorus in the pond soil of both farms was verified. The soil from the ponds of the intensive cultivation farm showed high relative deposition for TC, TOC, TN and AP near the Feeder (F) and the Water Outlet (WO), which infers that these zones (16.32% of the total pond area) may need higher treatment frequencies or different treatment from the other zones studied (WI, P and D). In the soil of the extensive cultivation ponds, the highest values for TC, TOC, TN and AP were found in the Water Inlet (WI), Ditches (D) and Feeder (F) (2.68% of the total pond area). This also indicates the need for higher treatment frequencies or different treatment from the other zones studied (WO and P). In addition, results suggest that phosphorus is the nutrient with the greatest potential for accumulation in the soil, either organically or inorganically, due to its high adsorption potential, occurring mainly in areas of organic matter decomposition regardless of the cultivation system, while nitrogen was mainly organic due to its low adsorption potential. Therefore, based on this study it is recommended that as part of their soil management strategy, shrimp farmers treat the pond areas in a differentiated manner giving special attention to areas of organic matter decomposition with the goal of avoiding waste and increasing production efficiency, potentially saving up to 97% in probiotic products.

Analysis of feed composition and growth parameters of Penaeus monodon supplemented with two probiotic species and formulated diet

A feed trial was conducted in Penaeus monodon to evaluate the efficacy of two probiotic strains Bacillus coagulans and Bacillus firmus. The marine shrimp, P. monodon was fed with probiotics in live, lyophilized forms, and also formulated feeds incorporated individually with spirulina and yeast. Results manifested that the two probiotic - live or lyophilized, independently or in combination could bring about highest gross energy 3585.3 kcal/kg in the shrimps. Growth parameters such as weight gain % (163.84%), length gain % (95.91%), DWG (12.6 mg), SGR (2.76), FCR (3.60 g), feed intake (2.53 g) and survival (26.6–66.6%) significantly increased with the combined probiotic diet. SEM observations showed the presence of peritrichous pili-like attachment by the probiotic bacteria clinging to the stomach lining. It could be inferred that administration of two probiotic strains in all the three forms, viz., live, lyophilized or in combined form impart beneficial effects on the growth, survival, and for their establishment in the gut microbiota of P. monodon.

Microbially Derived Co-Products from Zero-Discharge Aquaculture

Background: Global seafood production has doubled over the last two decades with aquaculture now contributing nearly 50% of supply. Pressure to reduce or eliminate water and waste discharge from aquaculture increases with each passing year. In response to this pressure, producers have adopted increasingly sophisticated technology, expanding fish and shellfish production from 2,000 kg/ha to over 40,000 kg/ha. While water discharge has been drastically reduced, waste solids production from intensive aquaculture continues to pose a management challenge. One potential solution is to co-culture filterfeeding aquatic organisms with higher-value aquaculture species as a technique to harvest and covert excess bacterial and algal biomass into useful co-products and biofuels. Methods: Over a period of twenty years, the author and co-workers have designed and operated catfish and marine shrimp production systems employing co-culture of tilapia (Oreochromis niloticus) and brine shrimp (Artemia) to remove, concentrate, and convert microbial solids into animal biomass and biofertilizer. Past system operations are reviewed, and additional methods and data are presented and discussed. In the case of tilapia, a technique entitled “tilapia enhanced sedimentation” is evaluated for use in converting algae into concentrated fertilizer and fish flesh. Alternatively, brine shrimp are used to harvest and convert microbial solids into a potential fish-meal replacement. Results: Tilapia co-culture was shown to be cost-effective in controlling aquaculture system algal species and density, selectively removing cyanobacteria from culture water promoting green algal dominance, reducing off-flavor in cultured fish species. Tilapia co-culture at biomass levels from 20-25% of targeted fish carrying capacity was required to reduce algal and bacterial levels, significantly reducing oxygen demand and aeration requirements, Tilapia enhanced sedimentation was demonstrated to be effective in removing suspended algal and bacterial solids, concentrating excreted biomass into rapidly settling fecal pellets. Brine shrimp culture has been demonstrated at densities of 2,000-4,000 animals/ liter, corresponding to 4 gm/liter of dry weight animal biomass concentration. Brine shrimp are capable of conversation efficiencies as high as 50% of microbial dry weigh to brine dry shrimp weight, as opposed to <3% conversion with tilapia. However, successful Artemia culture necessitates unique culture system design and management, requiring two-stage, multiple-batch cultures of uniformly sized cohorts to yield maximum growth and conversion efficiency. Unique pH and ammonia toxicity response of brine shrimp necessitates management protocols very different from typical aquatic animal culture. Tilapia harvested algal sludge is limited to fertilizer application, yielding a value of $0.10/kg at 98% dry weight. On the other hand, brine shrimp biomass can be used as a potential fish-meal replacement at a value of $ 1.50/kg dry weight. Conclusion: Utilization of co-culture of filter-feeder organisms such as tilapia and brine shrimp to harvest, concentrate, and convert algal and bacterial solids into concentrated sludge or animal biomass offers potential to provide value-added products from integrated aquaculture operations as a more environmentally friendly practice.

Dried acetes as growth promoter for guppy (Poecilia reticulata) nutrition

Acetes is a marine shrimp that is still an under-studied source as feed ingredient for tropical ornamental fish. Ornamental fish is regarded as pet fish due to its mystic attractiveness for pet fish enthusiasts and requires good protein source to attain good growth and skin colour enhancement. The prevailing feed industry due to continuos pandemic has resulted many enthusiasts to look for alternative growth promoter as feed for guppy. The aims of this study were to determine the nutritional composition in dried Acetes and to investigate the effects of dietary dried Acetes meal on growth performance of Guppy (Poecilia reticulate). Five dietary isocaloric feeds namely Tcontrol (commercial feed only), T0 (100% commercial feed and 0% of dried Acetes.), T1 (75% commercial diet and 25% of dried Acetes spp.), T2 (50% commercial diet and 50% of dried Acetes), T3 (25% commercial diet and 75% of dried Acetes) and T4 (0% commercial diet and 100% of dried Acetes) were formulated as feed for juveniles of Guppy (Poecilia reticulata) reared in triplicates for 30 days. Growth indices like Body Weight Gain, Feed Conversion Rate, Feed Intake and Survival Rate were observed in every 10 days. Results indicated that T4 with 100% dried Acetes attained a significantly high BWG of 222.6% with low feed intake and FCR of less than 3.5. It can be concluded that inclusion of 50 to 100% dried Acetes in feed has contributed to optimal growth performance of guppy. It is also recommended that further studies on dietary Acetes could be done to examine other properties that could be further developed as superfeed for ornamental fish and thereby enhance growth and productivity of the ornamental fish industry as well as economic efficiency.

Temporal and spatial variations in metals and arsenic contamination in water, sediment and biota of freshwater, marine and coastal environments after the Fundão dam failure

Temporal and spatial variabilities in concentrations of metals (Cd, Cr, Cu, Fe, Hg, Mn, Pb and Zn) and metalloid (As) associated with the Fundão dam tailings were evaluated in water, sediment and biota from freshwater (tributary, river, lakes and lagoons), marine and coastal (mangroves and beaches) ecosystems affected by the Mariana dam disaster (southeastern Brazil). In freshwater shrimps and fishes, temporal increases in the concentrations of most elements analyzed were observed. This finding was clearly associated with temporal increases in the concentrations of As and metals observed in both water and sediment. In turn, freshwater plankton showed only a temporal increase in Hg concentration, which was also associated with an increased concentration of this metal in the abiotic matrices. In marine fishes, temporal increases were only observed for Cu, Fe and Pb concentrations. Also, temporal increase was observed for Fe concentration in marine plankton (phytoplankton and zooplankton) and shrimps. Marine phytoplankton also showed a temporal increase in Hg concentration. All these findings were clearly associated with temporal increases in the concentrations of these metals in marine sediments. Mangrove crabs showed temporal increases in Hg and Cd, which were associated with temporal increases in water Hg and sediment Cd concentrations, respectively. In turn, beach crabs displayed temporal increases in Mn and Zn, which were associated with temporal increases in the concentrations of these metals in sediments, especially for Mn. In summary, all environmental matrices evaluated in the present study were shown to be contaminated with metals and metalloid associated with the Fundão dam tailings. Additionally, findings reported in the present study relative to the spatial variabilities observed in the whole aquatic area affected by the Fundão dam failure clearly reinforce the need of incorporating biological diversity in monitoring programs aiming to assess environmental health of aquatic systems, considering that patterns of metals and metalloid contamination levels may vary among taxa.

DNA Binding Activity of Marine Shrimp LvProfilin

Shrimp farming is an important business in Thailand and worldwide. The study of molecular biology and biochemical pathway of the key molecules controlling muscle growth is an essential to improve shrimp livestock. Profilin is a pivotal protein in muscle formation, especially actin protein. Its nuclear function has been reported in many species for gene regulation. Here in this work, we characterized the function of LvProfilin, a marine shrimp profilin from Litopenaeus vannamei, both in silico and in vitro. The phylogenetic tree of LvProfilin among organisms and its 3D protein structure showed that LvProfilin was highly conserved among shrimp and arthropods. The homology modeling of its 3D structure revealed 3 alpha-helices and 6 beta-strands similar to most eukaryotic profilins. To interpret its possible function, the gene expression of LvProfilin in various tissues was performed. We found that this gene was expressed in various tissues. This result may imply that LvProfilin could share a common function in all tissues. Nuclear activity has been a promising function of LvProfilin. We performed a DNA/RNA binding prediction analysis using DRNApred. The result indicated that Lysine-90 and Threonine-91 were the putative DNA-binding sites with the probability of 63.12% and 54.16%, respectively. Its binding activity was confirmed in vitro which bound stronger to single strand DNA than double strand DNA. To our best knowledge, this is the first report of DNA binding activity of profilin in invertebrates.

DNA Barcoding of Penaeidae (Decapoda; Crustacea): Non-Distance-Based Species Delimitation of the Most Economically Important Shrimp Family

The Penaeidae family includes some of the most economic and ecological important marine shrimp, comprising hundreds of species. Despite this importance and diversity, the taxonomic classification for penaeid shrimp has constantly been revised, and issues related to the species identification are common. In this study, we implemented DNA barcoding analyses in addition to single-gene species delimitation analyses in order to identify molecular operational taxonomy units (MOTUs) and to generate robust molecular information for penaeid shrimp based on the cytochrome oxidase subunit I (COI) mitochondrial gene. Our final data set includes COI sequences from 112 taxa distributed in 23 genera of penaeids. We employed the general mixed Yule coalescent (GMYC) model, the Poisson tree processes (PTP), and the Bayesian PTP model (bPTP) for MOTUs delimitation. Intraspecific and interspecific genetic distances were also calculated. Our findings evidenced a high level of hidden diversity, showing 143 MOTUs, with 27 nominal species not agreeing with the genetic delimitation obtained here. These data represent potential new species or highly structured populations, showing the importance of including a non-distance-based species delimitation approach in biodiversity studies. The results raised by this study shed light on the Penaeidae biodiversity, addressing important issues about taxonomy and mislabeling in databases and contributing to a better comprehension of the group, which can certainly help management policies for shrimp fishery activity in addition to conservation programs.

Microbial diversity of marine shrimp pond sediment and its variability due to the effect of immobilized media in biohydrogen and biohythane production

Immobilization of microorganism on material is one of the effective methods to improve the production of bio-products including biofuel such as biohydrogen and biohythane (H2 + CH4). In this work, the effect of immobilizing media was studied including clay/activated carbon (CAC), clay/zeolite (CZ) and clay/mixed activated carbon and zeolite (CACZ) on microbial attachment and biogas production including biohydrogen and biohythane using shrimp pond sediment as organic resource and microbial consortium. The result showed that CAC was the most appropriate material for microbial attachment among the other materials. CAC digesters demonstrated higher H2 concentration than control reactors. Interestingly, the control reactors of using only shrimp pond sediment without CAC showed the ability of biohythane production. From 454-pyrosequencing results, it found that Alcaligenaceae family, Tissierella Soehngenia sp. and Planomicrobium sp. were the predominant species in shrimp pond sediment. Meanwhile, the study of microbial species on CAC after digestion process by Illumina MiSeq platform represented Clostridium cellobioparum, Tolumonas auensis and Microbacter margulisiae for bacteria and Methanobacterium aggregans for archaea as predominant species. It was shown that the immobilized media (CAC) favored some types of microbes mainly hydrogen producing microbes and hydrogenotrophic methanogen. This research suggests the CAC as an alternative immobilizing media for bioenergy production especially biohydrogen and biohythane.

Review: A bibliometric survey of live feed for marine finfish and shrimp larval production

Aquaculture research contributes to development of the industry, and practitioners depend on effective and understandable information about research findings. A bottleneck for increased diversification and efficient farming of larvae of marine finfish is lack of sufficient quantities of high quality live feed, that is, copepods. Number of scientific articles and conference contributions' mentioning live feed organisms is considered reflecting research activity and is used here as a proxy indicating awareness of importance amongst aquaculture researchers and producers. The percentage of live feed of total aquaculture articles has steadily declined over the past decades, reaching ≤5%, ranking Artemia first followed by rotifers and then copepods in total frequency in WoS and in conference abstracts except for LARVI. Exponential increase of number of live feed WoS articles is in contrast with a stagnant numerical frequency of WAS and EAS conference abstracts mentioning live feed over time. Since aquaculture practitioners likely not get similar information as researchers there is a risk that exposure to new research will face a time-lag or even not reach these stakeholders and implementation of new discoveries will not happen properly. We imagine it lead to less innovation and diversification in marine finfish and shrimp production and propose a dissemination mitigation strategy.

Effect of the transference of animals to different culture systems on growth performance and response to infection by white spot syndrome virus in the marine shrimp Litopenaeus vannamei (Boone, 1931) in the nursery phase

The aim of the present study was to evaluate the influence of a change in the culture system on the growth performance and immunological resistance to WSSV in Litopenaeus vannamei during the nursery phase. Two systems were evaluated (Biofloc [BFT] and clear water recirculation [CWR]) in three steps: (1) postlarvae (PL10, 3.4 ± 0.01 mg) were maintained for 10 days in each system; (2) investigation of four treatments (BFT-BFT, BFT-CWR, CWR-BFT and CWR-CWR) with the redistribution of PL20 at the end of the first step (30 days); and (3) viral challenge (8 days). Regarding L. vannamei growth performance, the BFT system proved to be more efficient (p ≤ 0.05) in both steps (0.090 and 0.334 kg m−3 in steps 1 and 2 respectively) compared to CWR (0.029 and 0.268 kg m−3 in steps 1 and 2 respectively). The Vibrio sp. was higher (p ≤ 0.05) in the treatments from or maintained in BFT (4.17–9.17 × 106 CFUs g−1) compared to CWR (0–1.33 × 106 CFUs g−1). Hypertrophic nuclei with basophilic inclusion bodies were found in the gills, lymphoid organ and stomach of the animals experimentally infected with WSSV in all four treatments. The results indicate that the BFT system achieved better growth indices, especially in the first phase of life. However, regardless of the culture system, higher mortality was found in treatments involving the transfer of animals between systems when subjected to a viral load of 4.3 × 107 copies of WSSV/µl of DNA.

Comparison of different solvents for extraction of oils from by‐products of shrimps Penaeus vannamei and Procambarus clarkia

The effects of different extraction solvents on the extraction yield and chemical composition of oils from by-products of marine shrimp Penaeus vannamei (Pv) and freshwater shrimp Procambarus clarkia (Pc) were investigated. Our results indicated that the ethanol and n-hexane mixture (4:1, v/v) was suitable solvent for simultaneous extraction of phospholipid and nonpolar lipids. By contrast, the ethanol and n-hexane mixture (4:1, v/v) and single ethanol were suitable solvents for the extraction of polyunsaturated fatty acids-rich (36.10%–42.78% of total fatty acids for Pv and 23.57%–25.58% of total fatty acids for Pc) and phosphatidylcholine-rich (66.22–67.09 mol% of total phospholipids for Pv and 55.01–58.68 mol% of total phospholipids for Pc) oils, but acetone was suitable solvent for the extraction of astaxanthin-rich oil (436.19 μg/g oil for Pv and 799.27 μg/g oil for Pc). The findings will provide relevant information that can be used to improve the production of nutritional oils from shrimp by-products. Practical applications This study provides a theoretical basis for creating proper extraction processing to recover nutritional oils from shrimp by-products. For example, the ethanol and n-hexane mixture (4:1, v/v) was a suitable solvent for simultaneous extraction of phospholipid and non-polar lipids. By contrast, both of the ethanol and n-hexane mixture (4:1, v/v) and single ethanol were suitable solvents for the extraction of polyunsaturated fatty acids (PUFA)-rich and phosphatidylcholine-rich oils, but acetone was a suitable solvent for the extraction of astaxanthin-rich oil. Therefore, the oils extracted from shrimp by-products are rich in phospholipid, PUFA, and astaxanthin, which may be used as new functional food ingredients.

Cryopreservation of Germ Cells of Banana Shrimp (Fenneropenaeus merguiensis) and Black Tiger Shrimp (Penaeus monodon).

Germ cell cryopreservation has been used to preserve many fish species. However, this method has not been established for crustaceans; thus, we attempted to do this herein. The efficiency of slow freezing was compared to vitrification methods for germ cell cryopreservation in two types of marine shrimp, Fenneropenaeus merguiensis and Penaeus monodon. In situ hybridization with a vasa probe was used to identify germ cells. The effects of three cryoprotectants, dimethyl sulfoxide (DMSO), glycerol (GLY), and magnesium chloride (MgCl2), on germ cell viability and recovery rate were compared at three concentrations (5%, 10%, and 15%). The effects of thawing temperature, including 10 and 27°C, were also investigated. We discovered that 10% DMSO with the vitrification is suitable for preserving the germ cells of F. merguiensis for a long time, whereas 10% GLY with vitrification is suitable for P. monodon. Moreover, the most suitable thawing temperature was 10°C for both species. This is the first report of germ cell cryopreservation in crustaceans. Thus, we provide evidence that crustacean germ cells can be preserved long-term in liquid nitrogen; this is the first step in the sustainable preservation of crustaceans, especially shrimp.

Pacific white shrimp, red drum, and tilapia integrated in a biofloc system: Use of tilapia as a consumer of total suspended solids

AbstractThe objective of this study was to evaluate tilapia, Oreochromis niloticus, for the biological control of suspended solids in an integrated biofloc technology (BFT) system rearing red drum, Sciaenops ocellatus, and Pacific white shrimp, Litopenaeus vannamei. Four integrated systems were structured with recirculating water in closed circuits composed of separate tanks for each species. The experiment compared the use of tilapia to control suspended solids (biological treatment [BT]) to control systems without tilapia. The initial mean weights and stocking densities were: 2 g and 250 ind/m3 for shrimp; 71 g and 1.04 kg/m3 for red drum; and 85 g and 5.12 kg/m3 for tilapia. Temperature, dissolved oxygen (DO), pH, alkalinity, salinity, total suspended solids, total ammonia nitrogen (TA‐N), and nitrite were measured. Temperature, DO, pH, alkalinity, and TA‐N were maintained within guidelines recommended for shrimp, red drum, and tilapia. Nitrite concentrations remained within guidelines for red drum and tilapia. No significant difference in growth performance between the control and BT was observed, but the apparent consumption of solids in systems with tilapia resulted in decreased particulate matter in the effluent compared to the control. The study showed that the tilapia could control the suspended solids when integrated with red drum and marine shrimp culture with BFT in an integrated multitrophic system.

Transcriptome analysis of five ovarian stages reveals gonad maturation in female Macrobrachium nipponense

BackgroundMacrobrachium nipponense is an economically important species of freshwater shrimp in China. Unlike other marine shrimps, the ovaries in adult female M. nipponense can mature rapidly and periodically during the reproductive period, but the resulting high stocking densities and environmental deterioration can negatively impact the harvest yield and economic benefits. To better understand ovary development in female M. nipponense, we performed systematic transcriptome sequencing of five different stages of ovarian maturation.ResultsWe obtained 255,966 Gb of high quality transcriptome data from 15 samples. Of the 105,082 unigenes that were selected, 30,878 were successfully annotated. From these unigenes, we identified 17 differentially expressed genes and identified three distinct gene expression patterns related to different biological processes. We found that cathepins, legumains, and cystatin were enriched in the lysosome pathway, and they are related to vitellogenin hydrolysis. Additionally, we found that myosin heavy chain 67 participated in oocyte excretion.ConclusionsWe provide the first detailed transcriptome data relating to the ovarian maturation cycle in M. nipponense. Our results provide important reference information about the genomics, molecular biology, physiology, and population genetics of M. nipponense and other crustaceans. It is conducive to further solve the problem of M. nipponense rapid ovarian maturation from the aspects of energy supply and cell division.

Treatment of gregarines sporozoites in shrimp with allicin an herbal preparation and control intermediate hosts with copper sulphate

Purpose: The purpose of study is to evaluate Allicin supplementation to tackle Gregarines Sporozoites infection in shrimp. Parasitic infections and associated diseases are a significant risk factor in aquaculture productivity, marine, and freshwater. Apart from bacterial and viral infections, aquatic animals are prone to protozoa infection. As the most common parasitic protozoa infection in marine shrimp, Gregarines reported a significantly high infection frequency, i.e., up to 90%. Penaeid shrimp are infected by at least three genera of gregarine (Protozoa, Apicomplexa). Method: Here, in this study, allicin an organo-sulfur compound used to treat gregarines infections in shrimps. Here, garlic paste containing allicin was incorporated in the feed for 10 days at 10, 20, 30, 40, and 50 gm/Kg concentration twice in a day. Microscopic analysis was carried out to evaluate effect of Allicin with copper sulphate supplemented in shrimp feed. Results: Study reports here, shrimps fed with garlic paste as the major source of allicin shown a significant reduction in gregarines. As a control, we used turmeric in shrimp feed given at 5, 10, 15 and 20 g/Kg in two times a day for 10 days. Here, we also incorporated a second dose of allicin along with copper sulphate at 0.1, 0.2, 0.3, 0.4 and 0.5 ppm concentrations to minimize secondary infection. Conclusion: We report here, administration of garlic paste to shrimp significantly reduces gregarines in shrimps.

Natural Infection of Covert Mortality Nodavirus in Small Yellow Croaker in Coastal Water

Covert mortality nodavirus (CMNV) is an alphanodavirus mainly infecting marine shrimp and co-inhabiting organisms in aquaculture ponds. To evaluate the possibility of CMNV prevalence in the wild fish species, epidemiological survey of CMNV infection in Larimichthys polyactis, the dominant species in the Yellow Sea and East China Sea, were conducted in the present study. We performed CMNV RT-LAMP assay in samples of L. polyactis collected in August 2018 and 2019 and found that CMNV prevalence was 18% and 7%, respectively. The nucleotide sequences of both RdRp and capsid protein genes of CMNV from L. polyactis were 99% similar to those of CMNV isolated from shrimp. CMNV-positive L. polyactis exhibited necrosis of cardiac muscle, oocytes loosely arranging, severe cytoplasmic vacuolation of hepatocytes, moderate pyknosis of brain pyramidal cells, degenerate renal tubular cells with ill-defined margins, and declined spleen cells in the histological examination. Moreover, CMNV-positive signals were further observed in pyramidal cells of the brain, the cortical area of the kidney, oocyte growth rings, and in necrotic tissues of cardiac muscle, liver, and spleen in the in situ hybridization assay. The results revealed that CMNV had colonized in the wild populations of L. polyactis and the ecological risk of CMNV spread and epidemic in wild fish in the coastal water was non-negligible.

γ-Irradiated Chitosan From Carcinoscorpius rotundicauda (Latreille, 1802) Improves the Shelf Life of Refrigerated Aquatic Products

The γ-irradiated horseshoe crab chitosan was used as food coating to extend the shelf life of marine shrimp and fish. Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), and X-ray diffraction (XRD) were used to characterize the γ-irradiated chitosan. After employing control (untreated seafood samples/no preservatives), chemical preservation (treated with 2% glacial acetic acid) and 2% chitosan (0, 10, and 20 kGy γ-irradiation) for the assessment assay, the shrimp (Penaeus merguiensis), pomfret (Pampus argenteus), and hilsa fish (Tenualosa ilisha) samples were examined for pH, thiobarbituric acid reactive substance (TBARS), total viable counts (TVC), and sensory evaluation changes while under 15-day refrigeration at 4°C. The results of FT-IR, XRD, and FE-SEM analysis revealed that irradiated chitosan possessed a crystalline structure with smooth texture on its surface. Analysis of pH, TBARS, TVC, and sensory evaluation demarcated irradiated chitosan with the ability to delay microbial growth and this prolonged the shelf life of refrigerated shrimp and fish. With novelty on γ-irradiated horseshoe crab chitosan use as natural preserving agent, fisheries industries and food packaging practitioners would benefit from its microbial-inert abilities particularly for long distant cold storage transport of packaged marine meats.

The effect of different stocking densities of marine shrimp larvae Litopeneaus vannamei on growth performance and survival rate using biofloc technology

There is a need to develop diets for shrimp cultured in Egypt in different rearing systems that will provide sufficient protein for shrimp production while minimizing the amount of nitrogen being introduced into the culture medium. Biofloc technology (BFT) is a new application in keeping up good water quality and growth performance of shrimp cultured. The present experiment was conducted to investigate the effect of three different stocking densities of Litopeneaus vannamei and the carbon source (sugarcane bagasse) with biofloc and commercial diet (38% CP) with a control system. The impact of the aforementioned variables was recorded with respect to water quality, microbial communities, biofloc composition, growth performance, feed utilization, and survival rates of shrimp. Shrimp were stocked with different densities (12, 14 and16 larvae/l) in 18 tanks with a water volume of 150 L for 90-days; triplicate groups of shrimp for both biofloc treatment and control. Shrimp were fed thrice daily at a ratio of 14% of body weight (initial weight of mean 0.002g) and re-adjusted gradually to 5% at the end of the experiment. The water quality parameters {temperature, salinity, PH, total ammonia nitrogen (TAN), nitrite (NO2), nitrate (NO3), phosphate (PO4), total suspended solids (TSS) and biofloc volume (BFV)} were suitable for culture of L. vannamei in biofloc and control treatments. TSS and BFV were significantly higher in biofloc treatments compared to control. Growth performance and survival rate were better in all biofloc treatments. The results suggest that 16 larvae/l BF treatment is the best stocking density according to the economic analysis. The addition of a carbon source into L. vannamei culture reduced the total ammonia-N compounds, increasing total heterotrophic microorganisms. Furthermore, the increase in total heterotrophic bacteria loaded an effect on the increase of the zooplankton community which, in return, improved the growth performance and survival rate of shrimp.

Biofloc removal by the oyster Crassostrea gasar as a candidate species to an Integrated Multi-Trophic Aquaculture (IMTA) system with the marine shrimp Litopenaeus vannamei

Currently, aquaculture seeks to implement production models that keep up with the global demands for sustainability and reduced environmental impacts. One of the options adopted is integrated multi-trophic aquaculture (IMTA), which cultivates species of different trophic levels, improving the use of nutrients and increasing the economic profitability of the system. On the other hand, the Biofloc Technology system (BFT) has also been highlighted as an important eco-friendly activity. In an attempt to reduce total suspended solids (TSS) and in accordance with the IMTA principles, the present work evaluated the action of the oyster Crassostrea gasar on the reduction of TSS and its influence on the microbial community present on the bioflocs. An experiment with two treatments (With and Without Oyster) was carried out in waters from an ongoing marine shrimp crop. The experiment lasted for 5 days, when water samples and oyster stomach content were collected for analysis of microorganisms. The water quality parameters did not show significant differences. The TSS and aggregates number also showed no differences between treatments, indicating that the presence of oysters did not influence the amount of total suspended solids. However, the predominance of flagellates in the stomach contents of the bivalves indicates a prey selectivity by C. gasar by this microorganism. Thus, it is likely that C. gasar is not an effective tool to reduce suspended solids in IMTA, but this organism can highly benefited from protozoan present in BFT system.

The impact of nitrifying probiotic to population growth of pathogenic bacteria, Vibrio sp., and toxic nitrogen gasses in marine shrimp culture media under laboratory condition

Intensification of shrimp farming has led to problems of water quality and development of pathogenic bacteria. The excess feed and fecal deposited in the bottom of the pond undergo ammonification and result in excess of ammonia formation in pond water and sediment. The purposes of this research was to investigate the impact nitrifying bacteria application on the controlling of pathogenic Vibrio sp. bacteria and toxic nitrogen gasses. Twelve (12) transparent glass bottles (effective volume of 3 L) were used in this research. Tested probiotic was purchased in free market and producer claims to contain Nitrosomonas sp., Nitrosococcus sp., Nitrobacter sp., Bacillus sp., Aerobacter sp., and Pseudomonas sp. The tested media was sea water containing Vibrio sp., TAN, NO2 and NO3 of 54.07 ± 2.93 mg/L; 6.33 ± 0.17 mg/L; 2.43 ± 0.04 mg/L; and 0.46 ± 0.01 mg/L respectively. The treatment of probiotic was 0 mg/L as a control; 0.1 mg/L; 0.2 mg/L; and 0.4 mg/L with 3 replications. In regard to concentration of Vibrio sp., NH3 and NO2 gasses, treatment doses of 0.1 mg/L (A) resulted a save level within 4 days after treatment, but to more secure in the practical work for shrimp farm, the doses of 0.2 mg/L (B) is suggested.