Shrimp Farming Research Articles

Monitoring and prediction of Aeromonas veronii dynamics via absolute quantification microbiome sequencing facilitated the development of a risk assessment tool in a shrimp farm

The outbreak of infectious bacterial diseases in aquaculture is a major concern in the industry. Among those pathogens, Aeromonas species are one of the most important bacterial pathogens of cultured animals. From May to June of 2022, an unexplained Aeromonas veronii outbreak was observed in a shrimp farm with high morbidity and mortality. To develop a risk assessment tool, the dynamics of the microbiome were monitored via absolute quantification of 16S rRNA amplicon sequencing for 18 consecutive days in a recirculating aquaculture system (RAS) for rearing water and the gut of whiteleg shrimp (Litopenaeus vannamei). A growth model was also developed for predicting the growth of Aeromonas in the shrimp gut and rearing water. The results showed that A. veronii is a dominant bacterial strain isolated from sick L. vannamei. The comparison of the bacterial community in the shrimp gut and rearing water over time showed remarkable shifts in A. veronii and probiotic Bacillus in the rearing water, with a significant decline in probiotic Bacillus. The rapid increase in A. veronii in rearing water subsequently altered A. veronii populations in the shrimp gut, with over 80% of A. veronii found on day 18. Linear regression analysis revealed a strong positive relationship between the abundance of A. veronii in the shrimp gut and the rearing water. The growth kinetic model agreed well with the observed values. Collectively, the temporal dynamics of the bacterial community in the rearing water offer valuable information for the fate of administered probiotics and pathogens. Growth kinetic models provide useful information to reduce the abundance of pathogens, which can be used as an early warning tool. These observations offer crucial insights into the dynamics of the bacterial community in shrimp and their environment, which can significantly impact shrimp health and productivity.

Novel sandwich immunoassay detects a shrimp AHPND-causing binary PirABVp toxin produced by Vibrio parahaemolyticus.

The binary PirA/PirB toxin expressed by Vibrio parahaemolyticus (PirABVp) is a virulent complex that causes acute hepatopancreatic necrosis disease (AHPND) in shrimps, affecting the global shrimp farming industry. AHPND is currently diagnosed by detecting pirA and pirB genes by PCR; however, several V. parahaemolyticus strains do not produce the two toxins as proteins. Thus, an immunoassay using antibodies may be the most effective tool for detecting toxin molecules. In this study, we report a sandwich ELISA-based immunoassay for the detection of PirABVp. We utilized a single-chain variable fragment (scFv) antibody library to select scFvs against the PirA or PirB subunits. Phage display panning rounds were conducted to screen and identify scFv antibodies directed against each recombinant toxin subunit. Selected scFvs were converted into IgGs to develop a sandwich immunoassay to detect recombinant and bacterial PirABVp. Antibodies produced as IgG forms showed sub-nanomolar to nanomolar affinities (KD), and a pair of anti-PirA antibody as a capture and anti-PirB antibody as a detector showed a limit of detection of 201.7 ng/mL for recombinant PirABVp. The developed immunoassay detected PirABVp in the protein lysates of AHPND-causing V. parahaemolyticus (VpAHPND) and showed a significant detectability in moribund or dead shrimp infected with a VpAHPND virulent strain compared to that in non-infected shrimp. These results indicate that the developed immunoassay is a reliable method for diagnosing AHPND by detecting PirABVp at the protein level and could be further utilized to accurately determine the virulence of extant or newly identified VpAHPND in the global shrimp culture industry.

Exploring the Antimicrobial Potential of Phyllanthus emblica L. (Amla) using Molecular Docking Studies against Shrimp Pathogens

Vibriosis is a major problem in shrimp farm. Farmers indiscriminately use hormones, antibiotics, disinfectants and other chemicals in fish feed and culture water to protect their crops. E. coli and Aeromonas sp were highly predominant isolates. Herbs act as agents in aquaculture to control or reduce pathogen infections. The results of phytochemicals screening of fruit extract of Phyllanthus emblica showed the presence of various phytchemicals. Phyllanthus emblica extract shows anti-bacterial properties against biofilm producing shrimp pathogens. Among the 10 bacterial genera, E. coli and P.aeruginosa were highly suppressed. The extracts exhibited the bacteria growth inhibitory activity in a dose-dependent manner. The compound sitosterol has potent antibiofilm activity was showed by molecular docking, which revealed a significant binding energy and interaction (-8.4 Kcal/mol) between it and key biofilm-forming protein. Diving analysis was done using the chemical compounds found in GCMS analysis.

Nanopore MinION Sequencing Generates a White Spot Syndrome Virus Genome from a Pooled Cloacal Swab Sample of Domestic Chickens in South Africa.

White spot syndrome virus is a highly contagious pathogen affecting shrimp farming worldwide. The host range of this virus is primarily limited to crustaceans, such as shrimps, crabs, prawns, crayfish, and lobsters; however, several species of non-crustaceans, including aquatic insects, piscivorous birds, and molluscs may serve as the vectors for ecological dissemination. The present study was aimed at studying the faecal virome of domestic chickens (Gallus gallus domesticus) in Makhanda, Eastern Cape, South Africa. The cloacal swab specimens (n = 35) were collected from domestic chickens in December 2022. The cloacal swab specimens were pooled-each pool containing five cloacal swabs-for metagenomic analysis using a sequence-independent single-primer amplification protocol, followed by Nanopore MinION sequencing. While the metagenomic sequencing generated several contigs aligning with reference genomes of animal viruses, one striking observation was the presence of a White spot syndrome virus genome in one pool of cloacal swab specimens. The generated White spot syndrome virus genome was 273,795 bp in size with 88.5% genome coverage and shared 99.94% nucleotide sequence identity with a reference genome reported in China during 2018 (GenBank accession: NC_003225.3). The Neighbour-Joining tree grouped South African White spot syndrome virus genome with other White spot syndrome virus genomes reported from South East Asia. To our knowledge, this is the first report of a White spot syndrome virus genome generated from domestic chickens. The significance of White spot syndrome virus infection in domestic chickens is yet to be determined.

Smart Shrimp Farming Using Internet of Things (IoT) and Fuzzy Logic

In the case of ponds with Litopenaeus Vannamei shrimp, water quality parameters play a significant role in shrimp growth. Leveraging technology enhances water quality to optimize growth and survivability in the shrimp farming industry. The research aimed to empower local farmers with smart shrimp farming technologies, including Information Technology (IT), such as the Internet of Things (IoT), and Fuzzy Logic. The research also involved a comparison between Litopenaeus Vannamei shrimp in two different aquariums: one serving as a control group and the other implementing IoT and Fuzzy Logic for a period of 30 days. The initial Litopenaeus Vannamei shrimp stocking was 135 shrimps for control aquariums and 132 for experimental aquariums. Then, the research used Arduino ESP 8266, Raspberry Pi 3, and SciKit-Fuzzy library to record and process the data. Through the application of IoT and Fuzzy Logic, the research successfully increases survivability by 6%, specific growth rate by 28%, and length by 8% in 30 days compared to conventional methods. The results highlight the potential use of technology in Litopenaeus Vannamei shrimp farming. The proposed system’s hardware and software architecture can be easily scaled to accommodate the needs of Litopenaeus Vannamei shrimp farmers with multiple ponds, offering flexibility and adaptability.

Potentially toxic element bioaccumulation in consumed indoor shrimp farming associated with diet, water and sediment levels

Shrimp production is an important industry for many countries and shrimp consumption is increasing worldwide. Shrimps are a highly nutritional food, but can pose a risk for human health if subject to high levels of environmental contaminants. This work studies the presence of As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn in shrimps from Ecuador and compares them to such contents noted in other shrimp-production areas in the world to evaluate the possible risks associated with these elements for consumer health, and to relate them to potentially toxic element (PTE) contents in water, sediments and diets, and also to animal biometric parameters. The PTE levels (mg kg−1 DM) obtained are as follows: in the head—As (3.52–6.11), Cd (0.02–0.10), Co (0.14–0.49) Cr (0.23–4.89), Cu (99.9––233.0), Ni (0.52–1.86), Pb (0.24–1.09), Zn (51.8–100.5) and Hg (μg kg−1 DM) (10.00–66.81); in the tail—(0.91–3.21), Cd (0.01–0.02), Co (0.01–0.43) Cr (0.01–6.52), Cu (20.0–72.44), Ni (0.15–2.03), Pb (0.01–0.69), Zn (31.2–66.1) and Hg (μg kg−1 DM) (10.00–67.18). The concentration of all the PTEs is generally lower than the limits set for seafood by European regulations, except for As in the cephalothorax (4.63 mg kg−1). Different behaviours for PTE accumulation in shrimps were found, which preferentially tend to accumulate in the cephalothorax, except for Hg (40.13 μg kg−1 DM), which accumulates in muscle (body) and is associated with contents of proteins, lipids and total shrimp weight. Nonetheless, the target hazard quotient (THQ) values for PTEs indicate that the consumption of shrimp muscles from Ecuador does not pose a human health risk because the values of these indices are below 1 in all cases.

Nucleic acid amplification‐based methods for diagnosis of shrimp viral diseases

AbstractViral diseases are one of the constraints affecting the sustainability of the shrimp farming industry worldwide. The common causes of viral infections include white spot syndrome virus, infectious hypodermal and haematopoietic necrosis virus, hepatopancreatic parvovirus, Penaeus monodon nudivirus, decapod iridescent virus 1, Taura syndrome virus, yellow head virus, infectious myonecrosis virus and Macrobrachium rosenbergii nodavirus. Accurate diagnostic methods are necessary for preventing the spread of these transboundary diseases. Many molecular diagnostic methods for shrimp viral diseases have been developed and are currently in use, including conventional polymerase chain reaction (PCR), nested PCR, loop‐mediated isothermal amplification PCR, recombinase polymerase assay and real‐time PCR. Although the World Organization for Animal Health (founded as OIE) recommends several PCR methods for shrimp disease diagnosis, there has been a lack of efforts to comparatively evaluate the performance of the available methods, resulting in a significant knowledge gap. Therefore, in this review, we compare various PCR assays and commercial PCR‐based diagnostic kits that have been developed and/or published previously, and discuss pros and cons of each of these methods. Our objective of this review is to offer enhanced clarity and a comprehensive overview of molecular diagnostic methods for shrimp viral diseases. This endeavour would serve as an important resource for researchers engaged in relevant studies and professionals within the shrimp‐farming industry, providing valuable guidance and insights.

Improving the Treatment of Saline Wastewater from Shrimp Farms Using Hybrid Constructed Wetlands Models toward Sustainable Development

This study investigated a feasible model for treating actual shrimp farm wastewater at a pilot scale that could be applied to farms in the Mekong Delta area. The research was carried out using a hybrid constructed wetlands (HCWs) model, which included a floating constructed wetland (FCW, total area of 1,500 m2) and a horizontal sub-surface constructed wetland (HSCW, total area of 400 m2). The HCWs were cultivated with native plants including: Scirpus littoralis Schrab, Cyperus alternifolius, and Paspalum vaginatum. These plants are all adapted to the high salinity levels of shrimp farm wastewater. The system was operated for 30 days to treat shrimp farm effluent. Results indicated that the model effectively removed organic matter and nitrogen compounds from the wastewater. The treated wastewater had low concentrations of COD (10.0-15.4 mg/L), BOD5 (7.1-12.5 mg/L), NH4+-N (0.04-1.11 mg/L), and TN (0.17-1.83 mg/L), which met the reliable conditions for reuse or safety requirements for discharge to aquatic systems. The findings of this study have significant implications for the sustainable management of shrimp farm wastewater in the Mekong Delta area. The HCWs model is a feasible and effective way to treat this type of wastewater, and it could be adapted to other regions facing similar challenges.

Development of a duplex PCR for the simultaneous detection of EHP and IHHNV and analysis of the correlation between these two pathogens

Infectious hypodermal and hematopoietic necrosis virus (IHHNV) is one of the linearly single-stranded DNA viruses. Ecytonucleospora hepatopenaei (EHP) is an intracellular parasitic microsporidian. IHHNV and EHP are pathogens that have been widely prevalent in shrimp farming. Both of them are associated with growth retardation of the penaeid shrimp, which causes serious economic losses to shrimp farming. Shrimp can be co-infected with IHHNV and EHP. In this study, a rapid duplex polymerase chain reaction (PCR) was developed and optimized for the simultaneous detection of EHP and IHHNV. The detection limit of the duplex PCR could reach 1.5 × 102 copies for EHP and IHHNV. A total of 578 Litopenaeus vannamei samples were detected by the established duplex PCR detection method. The results suggested that 398 samples were infected with EHP, 362 samples were infected with IHHNV, and 265 samples were co-infected with EHP and IHHNV. The case-control analysis of the detected shrimp samples showed a certain synergistic effect between EHP and IHHNV.

A Mini-Review on Plant-Derived Phenolic Compounds with Particular Emphasis on Their Possible Applications and Beneficial Uses in Aquaculture

Abstract The use of most antibiotics has been restricted and banned in finfish and shrimp farms due to several reasons comprising their long-lasting persistence in aquatic environments, relatively high prices, and their ability to promote the existence of antibiotic-resistant bacteria. Hence, finding economical, natural, and environmentally safe alternatives is of great importance. The use of polyphenols, polyphenol-rich plants, and plant-derived phenolic compounds for promoting aquatic animal health and welfare could be from the effective strategies for developing aquafeed and maintaining the sustainability of the aquaculture industry. Several plants are gorgeous in various bioactive functional ingredients known as phytochemicals and polyphenols. Phenolic compounds could be successfully used as natural immunostimulants in order to raise the immunity of finfish and shrimp species against several bacterial, viral, and parasitic infections and thus may replace the use of antimicrobial agents. Besides their potential roles for improvement of the growth performance, intestinal health, and enhancing the antioxidant capacity of the treated animals. Even though the trend of using plant-derived phenolic compounds is a new and leading era for the improvement of the functionality of aquafeed and the development of the aquaculture industry, there are fundamental needs and necessities to describe a clear understanding of their modes of action and potential roles in the improvement of the production rates, antioxidant activity, immune status, and disease resistance of farmed fish and shrimp.

Characteristics and diversity of Vibrio parahaemolyticus causing acute hepatopancreatic necrosis disease in Vietnam

Acute hepatopancreatic necrosis disease (AHPND) is a contagious disease in shrimp with extremely high mortality rate, causing an estimated $23.6 billion loss to the global shrimp industry during 2009–2016. A binary toxin, PirAB, is the causative agent, which is encoded by the pirABvp genes on a virulent plasmid typically found in Vibrio parahaemolyticus. Here, seventeen strains of V. parahaemolyticus were isolated from the Mekong Delta of Vietnam, of which 15 harboured identical pirABvp genes. The remaining two strains, which were PCR-negative for pirAB, and nine positive strains were selected for whole genome sequencing. Multi-locus sequence typing revealed five sequence types (STs), including one novel, that were associated with sites of isolation. A maximum likelihood tree of core genomes revealed that our strains formed three clusters and were closely related to strains from Thailand, South Korea, China, and Philippines. All sequenced strains carried β-lactam (including blaOXA-10 and blaNDM-1) and tetracycline resistance genes, with a range of 3–13 resistance genes. The pirAB-positive strains shared large regions of homology with the prototypical AHPND virulent plasmid. In summary, this work revealed the characteristics of AHPND-causing strains in the Mekong Delta of Vietnam and suggested possible transmission routes among Vietnam and other shrimp farming countries.

Water Conflict Between Fishermen And The Shrimp Farm Industry (Case Study Of Nglebeng Village, Panggul District, Trenggalek Regency)

This research aims to determine the conflict between fishermen and shrimp farming entrepreneurs in Nglebeng Village, Trenggalek Regency and the conflict resolution used. This qualitative research uses a case study approach carried out in Nglebeng Village. Using purposive sampling, the author collected data through observation and in-depth interviews with informants with specific criteria. In terms of validity testing, the author uses the triangulation technique, which is done by collecting similar data and comparing the data to obtain a picture of the information. Data analysis was carried out using interactive analysis techniques. The research results concluded that differences in interests between groups of fishermen and shrimp farming entrepreneurs caused the conflict between fishermen in the waters of Konang Nglebeng Beach. In this case, it is related to environmental pollution. Conflicts are caused by differences in interests held by each group, where shrimp farmers want to develop their business and fishermen want the sea not to be polluted by waste because it can disrupt the ecosystem of marine creatures. Conflict resolution in dealing with the problem of shrimp farms and fishermen is solved using Dahrendorf theory, namely Conciliation, Mediation, and Arbitration.

Prevention of white impurities in vaname shrimp (Litopenaeus vannamei) using noni fruit extract (Morinda citrifolia) in semi-intensive shrimp cultivation system

White vanamae shrimp is one of the superior commodities in aquaculture. Currently, the productivity of white vanamae shrimp has not yet reached its production target. So, it is necessary to increase the amount of production on a gradual scale carried out by the community. In shrimp farming activities, disease problems are often encountered. Namely is a white stool, white feces, or White Feces Disease (WFD). The clinical symptoms that arise when shrimp are attacked by White Feces Disease (WFD) are that the shrimp's appetite decreases, the shrimp's intestines change color to white and even look empty due to lack of food intake, white feces floating on the surface of the water, and the shrimp's growth becomes abnormal. This WFD disease can be caused by poor cultivation practices, unhealthy seeds, and poor water quality, causing the emergence of disease microorganisms such as Vibrio sp bacteria. One way to treat this disease is to provide alternative medicine, noni fruit extract. This research consisted of 3 noni extract treatments and consisted of 3 replications, namely Treatment A: 10 mL/L; Treatment B: 15 mL/L; Treatment C: 20 mL/L. The noni dose is given at the specified dose once daily for one month. The survival rate of shrimp increased to 86.7%.

The Role of Shrimp Breeding Innovation in Improving Aquaculture Productivity and Fisheries Business Sustainability in Sumbawa, West Nusa Tenggara

The aquaculture sector has come to be recognized as a key engine of both economic growth and seafood production worldwide. Shrimp farming in particular, and aquaculture in general, are major contributors to local livelihoods and food security in Sumbawa, West Nusa Tenggara, Indonesia. However, as this industry expands, it will have to contend with issues pertaining to productivity, sustainability of the environment, and the long-term viability of the fishing industry. Innovations in shrimp breeding have been implemented in the area to solve these problems. The various effects of these advances on aquaculture productivity and the long-term viability of Sumbawa's fishing enterprises are examined in this qualitative investigation. The results show how innovation, productivity, sustainability, and the particular socio-environmental setting of the area interact in a complicated way. Shrimp growth and disease resistance have increased thanks to selective breeding techniques, but genetic manipulation is still up for discussion. Sustainable feed methods are a viable way to lessen the impact on the environment. Effective disease management, together with market access and adherence to international quality standards, are critical components of a sustainable fisheries enterprise. This study promotes sustainable aquaculture methods and the long-term success of Sumbawa's fishing enterprises by offering useful insights and suggestions.

Design of Tandem Epitope Vaccine Against White Spot Syndrome Virus

White spot syndrome virus (WSSV) has long been a major threat on shrimp industry, but there is always a lack of effective prevention and control methods. Vaccines are widely regarded as the safest and most effective methods for preventing WSSV, and some main envelope proteins have showed this potential. In order to combine the antigenicity of these proteins together for better vaccine performance, in this study a strategy commonly used in vertebrates was tried in shrimp. The dominant epitopes of five envelope proteins VP19, VP24, VP26, VP28 and VP41A were predicted and combined for tandem epitope vaccine design by bioinformatics methods, the designed vaccine gene was chemically synthesized and expressed in Escherichia coli, then the recombinant peptide was purified for function evaluation in shrimp. The results showed that the designed peptide had good flexibility, hydrophily and antigenicity with all the epitope regions accessible; the synthesized gene was linked with the tag sequence and successfully expressed in BL21(DE3), and the purified fusion peptide showed a positive effect in WSSV prevention. This research provided a promising method to design vaccines against WSSV, and further work in genetic engineering should be done so as to make it operable for application in shrimp farm.

Use of shrimp farming waste in the production of biomaterials for sustainable agriculture and mitigation of environmental damage

AbstractBackgroundDue to the environmental degradation caused by shrimp farming in Brazilian mangrove ecosystems, it is of great importance to develop techniques capable of inserting waste into the production chain, strengthening the premise of sustainable shrimp farming development due to its economic and social impact. In this work, solid residues from shrimp farming were used as a slow‐release fertilizer (SRF) in formulations that also contain chitosan, montmorillonite, and urea.ResultsFertilizer granules produced without (FERT A) and with additional layers (FERT B) were characterized by elemental analysis (Carbon, Hydrogen, Nitrogen), obtaining values of 14.4%–18.4% for carbon, 5.6%–6.9% for hydrogen, and 12.3%–19.3% for nitrogen. The fertilizers had low C/N ratios of around 1.0–1.50, compared to a value of 0.87 for urea, the nitrogen fertilizer most widely used in Brazilian agriculture. Release tests in water showed the same release pattern in the first 5 min for FERT A and FERT B, with <10% urea release. After 30 min, the release from the fertilizers progressively increased, reaching >60% after 1 day and a maximum of 95%–97% after 15 days. In the first 3 days of incubation in the soil, the releases of nitrogen from FERT A, FERT B, and conventional urea presented different patterns, with values of 32%, 10%, and 90%, respectively. After incubation for 25 days, FERT A and FERT B presented nitrogen releases lower than 78%, confirming the slow release of the nutrient from these fertilizers. Degradation experiments showed that the fertilizers were biodegradable in the soil, with degradation exceeding 60% after 30 days, indicating that they could be applied to the soil without leaving residues.ConclusionsThe fertilizer granules produced are SRFs that have the potential to increase the efficiency of nitrogen fertilization, reducing the frequency of applications and minimizing nitrogen losses in the soil. In addition, they enable the reuse of shrimp farming waste, producing a new material of agricultural interest.

The effects of ammonium loading rates and salinity on ammonium treatment of wastewater from super-intensive shrimp farming

Treatment of wastewater from super-intensive shrimp farming (SISF) for discharge or recirculation purposes is currently attracting the attention of managers and researchers. The fixed bed biofilm reactor (FBBR) has been successfully used for biological treatment of drinking water as well as for wastewater treatment in aquaculture farm. Ammonium and salinity are important factors affecting the efficiency of pollutants treatment. This paper presents the results of research on ammonium treatment in super-intensive shrimp wastewater by aerobic microbiological process using FBBRs. The results showed that at ammonium loading rates of 0.014; 0.028; 0.049 and 0.070 kg/m3/d, at salinity of 10‰, the ammonium removal efficiencies were 98 - 99; 97.7 - 98.8; 96.8 – 98.7 and 95.7 – 98.0 percent respectively (ammonium concentrations in effluent were 0.05 – 0.1; 0.12 – 0.23; 0.23 – 0.56 and 0.51 – 1.07 mgN/l, respectively), at salinity of 15‰, the ammonium removal efficiencies were 95.8-96.0, 94.5-92.0, 93.1-92.3 and 66.8-68.8 percent respectively (ammonium in effluent were 0.20 – 0.21; 0.55 – 0.8; 1.20 – 1.35 and 7.8 – 8.3 mgN/l, respectively), at salinity of 20‰, the ammonium removal efficiencies were 92.0-96.0, 87.0-89.0, 69.1-70.9 and 59.6-66.0 percent respectively (ammonium in effluent were 0.2 – 0.4; 1.1 – 1.3; 5.1 – 5.4 and 8.5 – 10.1 mgN/l, respectively). This result showed that the influence of ammonium loading and salinity on ammonium treatment efficiency was very significant.

Counting and measuring the size and stomach fullness levels for an intelligent shrimp farming system

The penaeid shrimp farming industry is experiencing rapid growth. To reduce costs and labour, automation techniques such as counting and size estimation are increasingly being adopted. Feeding based on the degree of stomach fullness can significantly reduce food waste and water contamination. Therefore, we propose an intelligent shrimp farming system that includes shrimp detection, measurement of approximated shrimp length, shrimp quantity, and two methods for determining the degree of digestive tract fullness. We introduce AR-YOLOv5 (Angular Rotation YOLOv5) in the system to enhance both shrimp growth and the environmental sustainability of shrimp farming. Our experiments were conducted in a real shrimp farming environment. The length and quantity are estimated based on the bounding box, and the level of stomach fullness is approximated using the ratio of the shrimp´s digestive tract to its body size. In terms of detection performance, our proposed method achieves a precision rate of 97.70%, a recall rate of 91.42%, a mean average precision of 94.46%, and an F1-score of 95.42% using AR-YOLOv5. Furthermore, our stomach fullness determined method achieves an accuracy of 88.8%, a precision rate of 91.7%, a recall rate of 90.9%, and an F1-score of 91.3% in real shrimp farming environments.

DOES FARMERS' EDUCATION AFFECT THE PROFITABILITY OF SHRIMP FARMING? EVIDENCE FROM THE COASTAL REGION OF BANGLADESH

This study explores the impact of farmers' level of education on the profitability of shrimp farming. The authors have collected data from a sample of 200 shrimp farmers in three districts in the southwest region of Bangladesh, namely Khulna, Bagerhat, and Satkhira, using a proportionate random sampling technique. The shrimp farmers' education and productivity status are investigated through descriptive statistics. The authors estimated a Cobb-Douglas Production Function (CDPF) to examine the effect of farmers' level of education on the profitability of shrimp farming. Using a Tobit regression model, this study tried to investigate the association between the educational attainment of farmers and their degree of knowledge in farm management. The study finds that the average level of shrimp production in southwestern Bangladesh is 425 kg per hectare, resulting from the absence of modern farming methods and a deficiency in adequate farming knowledge. The activity budget equation illustrates that farmers with higher education levels exhibit greater profitability compared to their less educated counterparts. The analysis of efficiency factors of production (EFP) indicates that farmers with higher education levels exhibit greater efficiency than their counterparts with lower education levels. The break-even point (BEP) analysis reveals that the average production volume, price, and the gher size in the study area outstrip the BEP threshold, suggesting that shrimp farming in this region is economically feasible. The analysis of field-level data reveals a strong association between farmers' level of education and their profitability, suggesting that higher levels of education among farmers have a substantial positive impact on their financial gains. It is evident from the study findings that knowledge of farm management plays a significant role in shrimp productivity. Therefore, the degree of farm management knowledge is affected by the education of the farmers. Consequently, this research suggests augmenting the accessibility of contemporary technology-driven farming methods and effectively utilizing information via a training initiative targeting shrimp farmers. Additionally, this study recommends offering incentives or credit opportunities to newly participating educated farmers.

The adverse impacts of ammonia stress on the homeostasis of intestinal health in Pacific white shrimp (Litopenaeus vannamei)

Ammonia is a prevalent pollutant in aquaculture systems that poses a risk to shrimp health. The shrimp's intestine plays a crucial role in immunity and metabolism. Therefore, we exposed Litopenaeus vannamei to 2 mg/L ammonia-N stress for a duration of 7 days, and explored the alterations in intestinal tissue morphology, physiological status, microbial community, and metabolic function. The findings revealed that ammonia stress led to a decrease in shrimp survival rates and inflicted damage to the intestinal mucosa, resulting in epithelial exfoliation. The mRNA relative expression levels of oxidative stress genes (Nrf2 and SOD) were elevated, while the level of GPx was decreased. Additionally, there was an increase in the levels of endoplasmic reticulum stress genes (Bip, IRE1 and XBP1), inflammatory cytokines (NF-κB and JNK), and apoptosis mediators (CytC and Casp-3) were increased. Ammonia stress also caused a decline in intestinal microbial diversity and significant variations in the bacterial community composition, including Bacteroides, Enterococcus, Faecalibacterium, Nautella, Pseudoalteromonas, Tenacibaculum, and Weissella. Furthermore, ammonia stress disrupted the intestinal metabolic function, particularly affecting pyrimidine, purine, amino acid, and alkaloid metabolism. These results revealed that 2 mg/L ammonia-N stress damaged the intestinal health of the shrimp by damaging mucosal integrity, affecting physiological homeostasis, causing microbial community and metabolic variation, which are related to the decreased survival of the shrimp and should be paid attention to in shrimp farming.