Field Of Aquaculture Research Articles

Managing Complexities in Giant Freshwater Prawn Breeding Facilities in Perak, Malaysia: A Case Study

Malaysia's aquaculture industry has seen significant growth in recent years, with the giant freshwater prawn (Macrobrachium rosenbergii) emerging as a key species of economic importance. This study examines the intricate challenges faced by hatchery owners’ breeding facilities in Manjung, Perak, Malaysia as they strive to maintain and improve the brood stock production of this valuable crustacean. The research focuses on multifaceted, operational aspects of managing giant freshwater prawn hatcheries. Through a combination of field studies guided by qualitative methodology, the identification of primary obstacles encountered at Manjung breeding facilities was evaluated via current management practices. The findings revealed that hatchery owners lack adequate managerial skills in handling operational matters such as budgeting, labor utilization, utilities, marketing, and networking. The most critical factor was cost-effective sourcing of healthy, brood stock supply from local fishermen. Furthermore, the research underscores the importance of genetic diversity in broodstock populations as hatcheries struggle with inbreeding depression, necessitating the development of more robust breeding programs. From the socio-economic standpoint, a holistic approach to addressing these issues, emphasizes the need for increased collaboration between research institutions, government agencies, and private sector stakeholders. The study provided a comprehensive overview of the complexities inherent in managing giant freshwater prawn breeding facilities in Malaysia. By identifying key challenges and potential solutions, it aims to contribute to the sustainable development of this vital sector of Malaysia's aquaculture industry. The findings have implications for policy-making, industry practices, and future research directions in the field of freshwater prawn aquaculture and food security agenda.????????????????

Advancing Aquaculture Sustainability: A Comprehensive Review of Biofloc Technology Trends, Innovative Research Approaches, and Future Prospects

ABSTRACTBiofloc technology (BFT), initially adapted for shrimp farming in the 1970s, represents a sophisticated ecosystem of microorganisms designed to enhance aquaculture productivity and sustainability. Despite its established history, research into BFT is surprisingly still at an early stage globally. This review conducted a bibliometric analysis of 612 articles from major aquaculture journals spanning 2008–2023 to systematically explore the development, trends, and focal points of BFT research. The analysis revealed that the bulk of significant contributions originates from Brazil and China, and highlighting areas of interest can be categorized into four hotspots, such as (1) efficient nitrogen transformation, (2) biofloc microbiology, (3) biofloc's immunostimulant properties, and (4) the evaluation of research methodologies. At the end, the microecology concept was introduced, and the cross‐discipline methods were promoted in the aquaculture field. Notably, much of the BFT research is still at an exploratory phase, with numerous functional bacteria unidentified and optimization strategies for BFT underdeveloped. These gaps present opportunities for enhancing aquaculture through improvements in wastewater management, product quality, safety, and yield. Furthermore, the review notes a growing trend in applying microbiome research and microecological analysis in aquaculture, with high‐throughput sequencing data increasingly used to understand microbial interactions and nitrogen transformation within bioflocs. This direction promises to unlock further insights into the complex microbial ecosystems of bioflocs and their applications in sustainable aquaculture.

Genotypic variation in the white spot syndrome virus detected from giant tiger shrimp (Penaeus monodon) in North Western and Eastern provinces of Sri Lanka

Shrimp farming in Sri Lanka accounting for 70 % of the exports in the field of aquaculture in Sri Lanka. However, it encounters substantial obstacles as a result of the white spot syndrome virus (WSSV) affecting the giant tiger shrimp (Penaeus monodon). This study focused on comprehending the current state of the disease and the genetic diversity present in the North Western and Eastern provinces in Sri Lanka. By extracting genomic DNA from the gills and pleopods of suspected infected shrimps and post-larvae, the study identified a high infection rate of at least 83 % (88/106), with varying incidence in sampled farms across regions. The analysis of the genome indicated distinct sizes of PCR products, suggesting the presence of variation in the tandem repeat units within the ORF94 region of the WSSV. Notably, the study discovered single nucleotide polymorphisms (SNPs) in Sri Lankan WSSV strains, which showed the change between T (Thymine) and G (Guanine) at the 48th site of the RU sequence, which is designated as K (keto) as indicated in the IUPAC code, indicating genetic diversity. Phylogenetic analysis suggested two distinct origins for Sri Lankan WSSVs, with possible links to North America and Mexico strains, highlighting a potential common source of outbreaks. This study emphasizes the intricate nature of WSSV infections in Sri Lanka and emphasizes the necessity for customized approaches to address this significant risk to the shrimp aquaculture industry.

Exploitation and Application of a New Genetic Sex Marker Based on Intron Insertion Variation of erc2 Gene in Oplegnathus punctatus.

Spotted knifejaw (Oplegnathus punctatus), one of the most valuable mariculture species, grows with significant sexual dimorphism, with males growing significantly faster than females. O. punctatus not only has excellent growth characteristics and high food value, but also shows high economic value in aquaculture, which has become a hotspot in the field of aquaculture. The current insufficiency of sex marker identification in O. punctatus restricts the process of its unisexual breeding. Rapid identification of sex will help to study the mechanisms of sex determination and accelerate the development of sex-controlled breeding. With the completion of the sequencing of the male and female genomes of O. punctatus, the efficient and precise development of genetic sex markers has been made possible. In this study, we used genome-wide information combined with molecular biology techniques from marker sequences to further establish a rapid method for DNA insertion variant detection in the intron of O. punctatus erc2 gene, which can be used to rapidly, accurately, and efficiently identify whether DNA insertion occurs in the intron of O. punctatus erc2 gene to be detected, and to identify the sex of O. punctatus to be detected. It could also be distinguished by agarose gel electrophoresis, which would shorten the time for accurate identification and improves the detection efficiency. Homozygous comparison of male and female individuals showed that the length of the DNA fragment of the erc2 gene was 239bp on chromosome X1 and 1173bp on chromosome Y. It can therefore be inferred that a 934bp insertion fragment exists on the Y chromosome. The PCR amplification results showed that two DNA fragments of 1173bp and 239bp could be amplified in male O. punctatus, and the 1173bp fragment was a marker fragment specific to the variant intron erc2 gene, while only a single DNA fragment of 239bp was amplified in female O. punctatus. It has important significance and application value in the study of neurotransmitter transmission and environmental adaptability of female and male fish based on erc2 gene, as well as the identification of male and female sex, the preparation of high male fry, and family breeding.

Development of a Portable Residual Chlorine Detection Device with a Combination of Microfluidic Chips and LS-BP Algorithm to Achieve Accurate Detection of Residual Chlorine in Water.

Chlorine is widely used for sterilization and disinfection of water, but the presence of excess residual chlorine in water poses a substantial threat to human health. At present, there is no portable device which can achieve accurate, rapid, low-cost, and convenient detection of residual chlorine in water. Therefore, it is necessary to develop a device that can perform accurate, rapid, low-cost, and convenient detection of residual chlorine in water. In this study, a portable residual chlorine detection device was developed. A microfluidic chip was studied to achieve efficient mixing of two-phase flow. This microfluidic chip was used for rapid mixing of reagents in the portable residual chlorine detection device, reducing the consumption of reagents, detection time, and device volume. A deep learning algorithm was proposed for predicting residual chlorine concentration in water, achieving precise detection. Firstly, the microfluidic chip structure for detecting mixed reagents was optimized, and the microfluidic chip was fabricated by a 3D-printing method. Secondly, a deep learning (LS-BP) algorithm was constructed and proposed for predicting residual chlorine concentration in water, which can realize dual-channel signal reading. Thirdly, the corresponding portable residual chlorine detection device was developed, and the detection device was compared with residual chlorine detection devices and methods in other studies. The comparison results indicate that the portable residual chlorine detection device has high detection accuracy, fast detection speed, low cost, and good convenience. The excellent performance of the portable residual chlorine detection device makes it suitable for detecting residual chlorine in drinking water, swimming pool water, aquaculture and other fields.

CLIP-FSSC: A transferable visual model for fish and shrimp species classification based on natural language supervision

Fish and shrimp species classification is a practical need in the field of aquaculture. Traditional classification method includes extracting modal features of the single image and training them on downstream datasets. However, this method has the disadvantage of requiring manual annotated image data and significant training time. To address these issues, this paper introduces a method named CLIP-FSSC (Contrastive Language–Image Pre-training for Fish and Shrimp Species Classification) for zero-shot prediction using a pre-trained model. The proposed method aims to classify fish and shrimp species in the field of aquaculture using a multimodal pre-trained model that utilizes semantic text description as an image supervision signal for transfer learning. In the downstream fish dataset, we use natural language labels for three types of fish - grass carp, common carp, and silver carp. We extract text category features using a transformer and compare the results obtained from three different CLIP-based backbones for the image modality - vision transformer, Resnet50, and Resnet101. We compare the performance of these models with previous methods that performed well. After performing zero-shot predictions on samples of the three types of fish, we achieve similar or even better classification accuracy than models trained on downstream fish datasets. Our experiment results show an accuracy of 98.77 %, and no new training process is required. This proves that using the semantic text modality as the label for the image modality can effectively classify fish species. To demonstrate the effectiveness of this method on other species in the field of aquaculture, we collected two sets of shrimp data - prawn and cambarus. Through zero-shot prediction, we achieve the highest classification accuracy of 92.00 % for these two types of shrimp datasets. Overall, our results demonstrate that using a multimodal pre-trained model with semantic text description as an image supervision signal for transfer learning can effectively classify fish and shrimp species with high accuracy, while reducing the need for manual annotation and training time.

Effects of Dietary Melatonin on Antioxidant Capacity, Immune Defense, and Intestinal Microbiota in Red Swamp Crayfish (Procambarus clarkii).

The aim of this study was to investigate the effects of melatonin (MT) feed supplementation on the antioxidant capacity, immune defense, and intestinal flora in Procambarus clarkii (P. clarkii). Six groups of P. clarkii were fed test feeds containing different levels of MT: 0mg/kg (control), 22.5, 41.2, 82.7, 165.1, and 329.2mg/kg for a duration of 2months. The specific growth rate, hepatosomatic index, and condition factor were recorded highest in the test group of shrimp fed an MT concentration of 165.1mg/kg. Compared to the control group, the rate of apoptosis was lower in hepatopancreas cells of P. clarkii supplemented with high concentrations of MT. Analyses of antioxidant capacity and immune-response-related enzymes in the hepatopancreas indicated that dietary supplementation of MT significantly augmented both the antioxidant system and immune responses. Dietary MT supplementation significantly increased the expression levels of antioxidant-immunity-related genes and decreased the expression levels of genes linked to apoptosis. Dietary MT was associated with an elevation in the abundance of the Firmicutes and a reduction in the abundance of the Proteobacteria in the intestines; besides, resulting in an increase in the abundance of beneficial bacteria, such as Lactobacilli. The broken-line model indicated that the suitable MT concentration was 154.09-157.09mg/kg. MT supplementation enhanced the growth performance of P. clarkii, exerting a positive influence on the intestinal microbiota, and bolstered both immune response and disease resistance. Thus, this study offered novel perspectives regarding the application of dietary MT supplementation within the aquaculture field.

Immune protection of grass carp by oral vaccination with recombinant Bacillus methylotrophicus expressing the heterologous tolC gene

In the field of aquaculture, the enhancement of animal health and disease prevention is progressively being tackled using alternatives to antibiotics, including vaccines and probiotics. This study was designed to evaluate the potential of a recombinant Bacillus methylotrophicus, engineered to express the outer membrane channel protein TolC of Aeromonas hydrophila AH3 and the green fluorescent protein GFP, as an oral vaccine. Initially, the genes encoding tolC and GFP were cloned into a prokaryotic expression system, and anti-TolC mouse antiserum was generated. Subsequently, the tolC gene was subcloned into a modified pMDGFP plasmid, which was transformed into B. methylotrophicus WM-1 for protein expression. The recombinant B. methylotrophicus BmT was then administered to grass carp via co-feeding, and its efficacy as an oral vaccine was assessed. Our findings demonstrated successful expression of the 55 kDa TolC and 28 kDa GFP proteins, and the preparation of polyclonal antibodies with high specificity. The BmT exhibited stable expression of the GFP-TolC fusion protein and excellent genetic stability. Following oral immunization, significant elevations were observed in serum-specific IgM levels and the activities of acid phosphatase (ACP), alkaline phosphatase (AKP), superoxide dismutase (SOD), and lysozyme (LZM) in grass carp. Concurrently, significant upregulation of immune-related genes, including IFN-I, IL-10, IL-1β, TNF-α, and IgT, was noted in the intestines, head kidney, and spleen of the grass carp. Colonization tests further revealed that the BmT persisted in the gut of immunized fish even after a fasting period of 7 days. Notably, oral administration of BmT enhanced the survival rate of grass carp following A. hydrophila infection. These results suggest that the oral BmT vaccine developed in this study holds promise for future applications in aquaculture.

Study of the influence of fish feeding on the example of carp (Cyprinus carpio L.) under conditions of chemical pollution of the aquatic environment

The study of the influence of chemicals in the aquatic environment on the nutrition of fish, which lead to gradual pollution of the aquatic environment and violation of living conditions, and the development of methods for improving the nutritional properties of fish, which is an important branch of science that combines fish biology, in-depth study of nutrition and rational management, has been established fish resources and environmental sustainability. In recent years, a significant amount of research has been conducted aimed at understanding the relationships between fish nutrition, their development and the quality of fish products, the influence of chemicals on these processes in today's conditions using the example of carp (Cyprinus carpio L.). Analyzing the data, it was found that the quality of fish nutrition depends on the quality and composition of water, which affects the growth, development and health of fish. Considering the requirements of nutrients such as proteins, fats, vitamins and minerals, good nutrition can improve the quality of fish production. Special attention is paid to the role of proteins in the metabolism of fish using the example of cyprinus carp (Cyprinus carpio L.), growth and development, as well as adaptation to the interesting study of the composition of tissue proteins of carp during cadmium and lead intoxication. This year's carp (Cyprinus carpio L.), which is a widespread object of pond culture in Ukraine, was used for the experiment. A detailed analysis indicates that taking into account the effect of toxic substances on fish nutrition is necessary to ensure their health and optimal fish production. The development of new feeding strategies and the use of special additives is becoming a key aspect not only for improving the quality of products, but also for ensuring compliance with safety standards and environmental sustainability in the field of aquaculture and fisheries. Such research identifies new ways to create sustainable and healthy fish populations, contributing to the coordinated development of the agro-industrial sector and the preservation of aquatic ecosystems.

Isolation, Purification, and Identification of Bacitracin-producing Bacillus licheniformis from Fresh Feces of Healthy Pigs.

Bacillus licheniformis and bacitracin have a huge application market and value in the fields of medicine, chemistry, aquaculture, agricultural, and sideline products. Therefore, the selection of B. licheniformis with high production of bacitracin is of great importance. In this experimental protocol, Bacillus with a high yield of bacitracin was isolated, purified, and identified from the fresh feces of healthy pigs. The inhibitory effect of secondary metabolite bacitracin on Micrococcus luteus was also tested. Thin-layer chromatography and high-performance liquid chromatography were used for the qualitative and quantitative detection of bacitracin. The physiological and biochemical characteristics of B. licheniformis were determined by relevant kits. The phylogenetic relationships of B. licheniformis were determined and constructed using gene sequence detection. This protocol describes and introduces the standard isolation, purification, and identification process of B. licheniformis from animal fresh feces from multiple perspectives, providing a method for the large-scale utilization of B. licheniformis and bacitracin in factories.

On-site colorimetric determination of pH in brackish water aquaculture

Purpose This study aims to describe on-site determination of pH in aquaculture using a portable colorimeter. Design/methodology/approach A basic and inexpensive portable colorimeter having light sources of different wavelength has been optimized for the determination of pH. A chromic reagent is optimized to develop colors depending on different pHs. Then, the color is measured using portable colorimeter in terms of resistance. Using the resistance to absorbance relationship, the resistance values are converted to absorbance. The performance of the developed colorimetric system is compared with commercially available colorimeter and pH meter. Eighty brackish water aquaculture samples were tested using the developed colorimetric system to check its adaptability in aquaculture farms. Findings A chromic reagent optimized in this study exhibited linear relationship with the pH changes of pH standards. Portable colorimeter having three different light sources is optimized using this chromic agent for determination of pH. Colorimeter possessing yellow light revealed more linear results than the others. The developed colorimetric system determines the pH of aquaculture water with an accuracy of ±0.14 in comparison with commercial colorimeter at the pH range of 6.0−9.0. Originality/value pH plays a pivotal role in aquaculture, impacting not only productivity but also profitability. The colorimetric system introduced in this research is promising for pH measurement in the field of brackish water aquaculture. The on-site pH assessment facilitated by this colorimetric system holds significant potential for adoption within the aquaculture sector, owing to its precision, portability, simplicity of use and user-friendly nature.

Early stress exposure on zebrafish development: effects on survival, malformations and molecular alterations

The effects of stress during early vertebrate development can be especially harmful. Avoiding stressors in fish larvae is essential to ensure the health of adult fish and their reproductive performance and overall production. We examined the consequences of direct exposure to successive acute stressors during early development, including their effects on miR-29a and its targets, survival, hatching and malformation rates, larval behaviour and cartilage and eye development. Our aim was to shed light on the pleiotropic effects of early-induced stress in this vertebrate model species. Our results showed that direct exposure to successive acute stressors during early development significantly upregulated miR-29a and downregulated essential collagen transcripts col2a1a, col6a2 and col11a1a, decreased survival and increased malformation rates (swim bladder, otoliths, cardiac oedema and ocular malformations), promoting higher rates of immobility in larvae. Our results revealed that stress in early stages can induce different eye tissular architecture and cranioencephalic cartilage development alterations. Our research contributes to the understanding of the impact of stressful conditions during the early stages of zebrafish development, serving as a valuable model for vertebrate research. This holds paramount significance in the fields of developmental biology and aquaculture and also highlights miR-29a as a potential molecular marker for assessing novel larval rearing programmes in teleost species.

A Duplex PCR Assay for Rapid Detection of Klebsiella pneumoniae and Chryseobacterium in Large Yellow Croaker Fish.

Both Klebsiella pneumoniae and Chryseobacterium cause an increasing number of diseases in fish, resulting in great economic losses in aquaculture. In addition, the disease infected with Klebsiella pneumoniae or Chryseobacterium exhibited the similar clinical symptoms in aquatic animals. However, there is no effective means for the simultaneous detection of co-infection and discrimination them for these two pathogens. Here, we developed a duplex polymerase chain reaction (PCR) method based on the outer membrane protein A (ompA) gene of Klebsiella pneumoniae and Chryseobacterium. The specificity and validity of the designed primers were confirmed experimentally using simplex PCR. The expected amplicons for Klebsiella pneumoniae and Chryseobacterium had a size of 663 and 1404 bp, respectively. The optimal condition for duplex PCR were determined to encompass a primer concentration of 0.5 μM and annealing temperature of 57°C. This method was analytical specific with no amplification being observed from the genomic DNA of Escherichia coli, Vibrio harveyi, Pseudomonas plecoglossicida, Aeromonas hydrophila and Acinetobacter johnsonii. The limit of detection was estimated to be 20 fg of genomic DNA for Chryseobacterium and 200 fg for Klebsiella pneumoniae, or 100 colony-forming units (CFU) of bacterial cells in both cases. The duplex PCR was capable of simultaneously amplifying target fragments from genomic DNA extracted from the bacteria and fish liver. For practical validation of the method, 20 diseased fish were collected from farms, among which 4 samples were PCR-positive for Klebsiella pneumoniae and Chryseobacterium. The duplex PCR method developed here is time-saving, specific, convenient, and may prove to be an invaluable tool for molecular detection and epidemiological investigation of Klebsiella pneumoniae and Chryseobacterium in the field of aquaculture.

Preparation of valine-curcumin conjugate and its in vitro antibacterial and antitumor activity and in vivo biological effects on American eels (Anguilla rostrata)

Curcumin (Cur) exhibits diverse natural pharmacological activities, despite its limited water solubility (hydrophobicity) and low bioavailability. In this investigation, a valine-curcumin conjugate (Val-Cur) was synthesized through amino acid side chain modification, and its solubility increased to 1.78 mg/mL. In vitro experimental findings demonstrated that the antibacterial activity of Val-Cur against Escherichia coli, Staphylococcus aureus, Aeromonas hydrophila, and Vibrio parahaemolyticus was significantly superior to that of Cur. The inhibition rate of Val-Cur against HepG2 (human hepatocellular carcinoma) cells was higher than that of Cur at low concentrations (below 25 μmol/L), although the IC50 value of Val-Cur did not differ significantly from that of Cur. In vivo biological effects of Val-Cur were assessed by adding it into the feed (150 mg/kg) of American eels (Anguilla rostrata). Val-Cur significantly improved the growth performance (↑weight gain rate, ↑specific growth rate, and ↓feed conversion rate) and activities of intestinal digestive enzymes (amylase and lipase) and antioxidant enzymes (superoxide dismutase) in American eels. Additionally, Val-Cur significantly improved serum biochemical indices (↑high-density lipoprotein cholesterol, ↓low-density lipoprotein cholesterol, ↓aspartate and alanine aminotransferases). Furthermore, Val-Cur increased intestinal microbial diversity, reduced the abundance of potentially pathogenic bacteria (Spiroplasma, Clostridium, and Pseudomonas), and elevated the abundance of beneficial digestion-promoting bacteria (Romboutsia, Phyllobacterium, Romboutsia sedimentorum, and Clostridium butyricum) conducive to glucose metabolism (P < 0.05). To the best of our knowledge, this study is the first to explore water-soluble curcumin in aquaculture, and the findings will lay the groundwork for the potential application of water-soluble curcumin in the field of aquaculture.

SOLUȚII TEHNICE PENTRU ESTIMAREA BIOMASEI CONFORM CONCEPTULUI DE ACVACULTURĂ 4.0

Aquaculture, as a dynamic field, undergoes continuous evolution requiring continuous improvements in efficiency and new research efforts. Estimating fish biomass is an essential practice in the field of precision aquaculture, obtaining periodic information on fish biomass has been identified as an urgent need, considering the objective of optimizing daily feeding, controlling fish density and finally determining the optimal timing of harvesting. Conventional weighing methods, which often rely on manual procedures, have inherent challenges. Manual weighing processes are labor-intensive, requiring substantial time and human resources. Furthermore, manual handling of fish during weighing procedures induces considerable stress on aquatic organisms, potentially compromising their health and welfare. Consequently, there is a pressing need in the aquaculture industry to explore alternative weighing techniques that alleviate stress levels while increasing operational efficiency. In response to these challenges, contemporary research efforts have increasingly focused on the development of noninvasive and automated weighing methodologies. These innovations aim to simplify the weighing process, minimize human intervention and reduce the level of stress experienced by the fish population. However, estimating fish biomass without human intervention presents significant challenges because fish are sensitive and move freely in an environment where visibility, lighting, and stability are difficult to control. The paper analyzes technological solutions for biomass estimation according to the concept of Aquaculture 4.0.

Advances in the application of stereo vision in aquaculture with emphasis on fish: A review

AbstractThe effective implementation of machine vision has played a crucial role in advancing intelligent aquaculture across various domains. Stereo vision, as a branch of machine vision, has become a mainstream technology in aquaculture. Its distinctive capability to conduct comprehensive underwater monitoring from multiple angles, unaffected by object occlusion has propelled it to the forefront of aquaculture applications. This article offers a comprehensive review of the diverse applications of stereo vision in aquaculture spanning from its inception to present. The exploration encompasses its role in crucial areas such as biomass estimation and behavioural analysis, which include fish counting, weight estimation, swimming behaviour, feeding behaviour and abnormal behaviour. Furthermore, the paper delves into the advantages of stereo vision over traditional 2D machine vision approaches, while also acknowledging limitations, and identifying future challenges that must be addressed to fully leverage its potential in aquaculture. The review emphasizes the prospect of advancement in deep learning stereo‐matching algorithms specifically designed for underwater environments to catalyse a breakthrough in stereo vision technology. In summary, this review aims to provide researchers and practitioners with a better understanding of the current development of stereo vision in aquaculture, optimizing stereo vision technology and better serving the aquaculture field.

Green Synthesized Chitosan Nanoparticles for Controlling Multidrug-Resistant mecA- and blaZ-Positive Staphylococcus aureus and aadA1-Positive Escherichia coli.

Antimicrobial resistance has recently been considered an emerging catastrophe globally. The public health and environmental threats were aggravated by the injudicious use of antibiotics in animal farming, aquaculture, and croup fields, etc. Consequently, failure of antibiotic therapies is common because of the emergence of multidrug-resistant (MDR) bacteria in the environment. Thus, the reduction in antibiotic spillage in the environment could be an important step for overcoming this situation. Bear in mind, this research was focused on the green synthesis of chitosan nanoparticles (ChiNPs) using Citrus lemon (Assam lemon) extract as a cross-linker and application in controlling MDR bacteria to reduce the antibiotic spillage in that sector. For evaluating antibacterial activity, Staphylococcus aureus and Escherichia coli were isolated from environmental specimens, and their multidrug-resistant pattern were identified both phenotypically by disk diffusion and genotypically by detecting methicillin- (mecA), penicillin- (blaZ), and streptomycin (aadA1)-resistance encoding genes. The inhibitory zone's diameter was employed as a parameter for determining the antibacterial effect against MDR bacteria revealing 30 ± 0.4 mm, 34 ± 0.2 mm, and 36 ± 0.8 mm zones of inhibition against methicillin- (mecA) and penicillin (blaZ)-resistant S. aureus, and streptomycin (aadA1)-resistant E. coli, respectively. The minimum inhibitory concentration at 0.31 mg/mL and minimum bactericidal concentration at 0.62 mg/mL of yielded ChiNPs were used as the broad-spectrum application against MDR bacteria. Finally, the biocompatibility of ChiNPs was confirmed by showing a negligible decrease in BHK-21 cell viability at doses less than 2 MIC, suggesting their potential for future application in antibiotic-free farming practices.

APPLICATION OF BIOTECHNOLOGY IN AQUACULTURE

Biotechnology plays a major role in fish production through various techniques such as selective breeding , genetic engineering to enhance the growth rate and disease resistance in aquaculture . Fish culture business is fastest-growing sector of agricultural fields. The consumer demand for fish products continues to rise at an alarming rate. At the same time, wild fish stocks are declining at a fast pace due to over-fishing – a major concern. Every year, aquaculture contributes more than 18 million tons of fish and shellfish to the world's food supply. The increased public demands for fish, coupled with the dwindling natural marine habitats, have led scientists to study ways in which biotechnology can help boost fish and shellfish production. application of biotechnology allows researchers to identify and combine traits in fish and shellfish to enhance the productivity and quality . This article delves into the various ways in which biotechnology is applied to aquaculture and what the future holds for fish farming. The field of aquaculture has been revolutionized by the introduction of biotechnology. With the help of advanced genetic research, scientists have been able to enhance the growth of fish production.

Feed production for sustainable aquaculture: A Bibliometric Network Analysis

In recent years, aquaculture has played a fundamental role in human nutrition and livestock for the ability to produce different animal and vegetable protein and lipid sources essential for human and animal health. However, the growing increase in aquaculture has led to a greater demand for ingredients composing feed for aquatic organisms, many of which are derived from wild fish making the aquatic feed production an unsustainable process. For this reason, the aquaculture sector has expanded experimentation to search for alternative ingredients to reduce environmental impact. This study explored the global scientific literature on sustainable aquaculture with particular reference to feeding using VOSviewer software, which allows for generating, visualizing, and exploring maps based on bibliometric network data. The results allowed a comprehensive overview of the scientific literature on sustainable aquaculture through network maps displaying the relationships among keywords, authors, countries, and journals. In detail, this paper highlighted that in the last years, particularly in recent decades, the research widely focused attention on different aspects of the sustainable aquaculture field. The first journal that researched sustainable aquaculture was the Aquaculture Journal, and the leading countries that pursued this type of research were the USA, UK, and China. Concerning the co-occurrence, the top keywords were aquaculture, sustainability, animals, nonhuman, and sustainable development, highlighting a growing interest in research on microalgae, diet, fishmeal, and climate change. The description of the current state of the art in sustainable aquaculture reported in this article highlighted that the combined use of social network analysis and bibliometrics allows exploring the development of research in specific fields of science and lays the foundations for delving into questions that have not yet been sufficiently investigated.

Strain-Specific Benefits of Bacillus on Growth, Intestinal Health, Immune Modulation, and Ammonia-Nitrogen Stress Resilience in Hybrid Grouper.

In the dynamic field of intensive aquaculture, the strategic application of probiotics has become increasingly crucial, particularly for enhancing resistance to environmental stressors such as ammonia-nitrogen. Over a 42-day period, this study investigated the effects of different probiotic strains-Bacillus subtilis (BS, 6-3-1, and HAINUP40)-on the health and resilience of hybrid groupers. Each strain, distinct in its origin, was assessed for its influence on growth performance, antioxidant capacity, immune gene expressions, and ammonia-nitrogen stress response in the hybrid grouper. The experimental design included a control group and three experimental groups, each supplemented with 1 × 108 CFU/g of the respective probiotic strains, respectively. Our results demonstrated notable differences in growth parameters, including final body weight (FBW) and feed conversion ratio (FCR). The 6-3-1 strain, originating from grouper, exhibited significant improvements in growth, oxidative capacity, and intestinal health. Conversely, the BS strain achieved the highest survival rates under ammonia-nitrogen stress, indicating its superior ability to regulate inflammatory responses despite its less pronounced growth-promoting effects. The HAINUP40 strain was distinguished for its growth enhancement and improvements in intestinal health, though it also showed significant activation of inflammatory genes and decreased resistance to ammonia-nitrogen stress after extended feeding. The uniqueness of this study lies in its detailed examination of the strain-specific effects of probiotics on fish in the context of ammonia-nitrogen stress, a significant challenge in contemporary aquaculture. The research revealed that host-derived probiotics, particularly the 6-3-1 strain, provided more comprehensive benefits for growth performance and stress resilience. In contrast, the BS and HAINUP40 strains exhibited varying efficiencies, with BS excelling in stress resistance and HAINUP40 promoting growth and gut health. In conclusion, this study underscores the complex roles of different probiotic strains in aquaculture, contributing to the understanding of probiotic applications and presenting new approaches to address the challenges of intensive farming.