Tilapia Farming Research Articles

Rethinking Freshwater Cage Aquaculture: A Case in Ghana

Lakes around the world, including Ghana’s Lake Volta, are facing insidious threats from pollutants due to high dependency on aquatic ecosystems. Cage aquaculture is expanding across Africa because of its potential to address food insecurity, provide livelihoods, and boost local economies. However, the uncontrolled expansion of cage aquaculture can have significant negative impacts on water resources, including environmental footprints that threaten biodiversity. Given the intensification of cage aquaculture for tilapia farming on Lake Volta, we advocate for a transition to inland-integrated aquaculture systems that promote circularity. Strengthening stakeholder collaboration is essential for enhancing competence in mapping inland aquaculture areas, identifying eco-friendly alternatives and reinforcing aquaculture regulations, with particular emphasis on cage culture on Lake Volta. These strategies can reduce the pressures imposed by tilapia cage farms on the lake while promoting best management practices. Additionally, capacity building must be an ongoing process to address knowledge gaps, including the development of effective preparedness plans executed during emergencies. The ongoing pollution from illegal mining in the Black Volta River, a tributary of Lake Volta, along with endemic diseases in the lake, further compounds fish health and welfare issues. This underscores the urgent need to implement inland transition strategies to protect the lake, mitigate disease spread, and ensure safe fish food production.

Environmental and human health risk of potentially toxic metals in freshwater and brackish water Nile tilapia (Oreochromis niloticus) aquaculture.

Tilapia aquaculture is rapidly expanding worldwide, particularly in Bangladesh. However, metal pollution in aquaculture presents significant environmental and human health risks. This study aimed to evaluate the concentrations of 13 potentially toxic metals (As, Be, Cd, Co, Cr, Cu, Hg, Ni, Pb, V, Mn, Se, and Zn) in Nile tilapia (Oreochromis niloticus), surface water, and sediment from freshwater and brackish water aquaculture ponds. The study also assessed the associated environmental and human health risks. Samples of tilapia, water, and sediment were collected between October and November 2021 and analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The estimated daily intake (EDI) of As, Cr, Pb, Se, and Zn in tilapia muscle of both freshwater and brackish water, as well as Cd and Ni in brackish water, exceeded recommended EDI values. The Target Hazard Quotient (THQ) was less than 1 for most metals, except for As in brackish water tilapia and Cr in both freshwater and brackish water tilapia, indicating potential health risks. The Target Cancer Risk (TR) values for As in both freshwater and brackish water tilapia, and for Cr and Ni in freshwater tilapia, exceeded acceptable ranges. While the concentrations of metals in surface water of both freshwater and brackish water tilapia farms varied, all mean concentrations were below WHO recommended limits. The contamination factor (Cf) values were less than 1 for all metals in both types of aquaculture ponds, except for Zn in freshwater sediment and Se in brackish water sediment. Additionally, the calculated risk indices including the Pollution Load Index (PLI), Geoaccumulation Index (Igeo), Ecological Risk Factor (Er), and Potential Ecological Risk Factor (PER) for sediment were below the risk thresholds values (PLI < 1, Igeo < 0, Er < 40, and PER < 150). The significant positive correlations were found between tilapia muscle and the sediment of the respective ponds for arsenic (As) (ρ= 0.8, p<0.002) and Cr (ρ= 0.7, p<0.02). Although the levels of studied metals in water and sediment from freshwater and brackish water aquaculture ponds were generally within recommended guidelines, this study underscores the need for continuous monitoring and preventative measures, particularly to address elevated levels of As and Cr in tilapia muscle, which may pose potential risks to human health.

Water Quality Monitoring and Control System for Tilapia Cultivation Based on Internet of Things

This research analyzes the quality of water for tilapia habitat which is a type of brackish water fish that is currently widely cultivated by pond farmers. This fish is the choice because of its flexibility regarding habitat. However, despite having flexibility in terms of habitat, each harvest of tilapia that lives in a different habitat will produce tilapia with different quantity and quality. Currently, many tilapia farmers still carry out the cultivation process using traditional methods using ponds. Kuala Kerto Village, Lapang District, North Aceh is one of the locations where many tilapia fish farmers use ponds as a habitat for this fish. Not infrequently, changes in natural conditions such as rain and floods have an impact on tilapia fish ponds in this village. Thus, crop yields are very varied, often even resulting in losses. One of the reasons for this is that there is still minimal use of technology in tilapia cultivation in this village. The design of a water quality monitoring and control system for IoT-based tilapia cultivation in this research was carried out to help the problems of tilapia pond farmers. Through this research, a tool was produced in the form of a prototype IoT device that can be used to monitor and control water quality in tilapia fish ponds. This device utilizes several sensors such as turbidity sensors, ammonia sensors, salinity sensors, pH sensors, and several other sensors as data takers which will later be transmitted and displayed via a web application. Research and development of this device uses the RD method, namely research and development.

Exploring the prospects, challenges and need assessment of live fish marketing from aquaculture farms in Kerala

The current study investigated the potential and challenges of live fish marketing in the aquaculture farms of Kerala, India. Surveys were conducted among farmers from six major aquaculture producing districts of Kerala to gather information regarding aquaculture practices, harvesting methods and marketing strategies followed. Freshwater aquaculture systems, particularly tilapia farming was dominant among the farmers. The respondents primarily sold their products to domestic market through dealers. The study revealed that approximately 20% of the farmers adopted live fish transportation methods, preferring tank systems and open-type transportation. The study emphasised the importance of addressing challenges related to culture, harvest as well as post-harvest operations and providing knowhow on effective marketing and distribution channels to promote the adoption of live fish marketing. Keywords: Aquaculture, Kerala, Live fish transportation, Marketing, Need assessment, Price realisation

SUSTAINABLE AQUACULTURE; ORGANIC INNOVATIONS FOR DISEASE PREVENTION AND HEALTH MANAGEMENT IN NILE TILAPIA (OREOCHROMIS NILOTICUS)

Sustainable aquaculture has become imperative in guaranteeing the enduring prosperity of aquatic farming, specifically for the Nile tilapia (Oreochromis niloticus), one of the most extensively farmed fish species. This study examines organic developments in Nile tilapia farming focused on eco-friendly practices that reduce the use of artificial chemicals and antibiotics to avoid sickness and maintain health. Integrating natural probiotics, probiotics, and immunostimulants into fish meals is one of the most critical tactics for strengthening the immune system and boosting the resistance of Nile tilapia against parasitic, bacterial, and viral infections. By maintaining the fish's natural defenses and promoting intestinal health, these natural additions lessen the need for conventional antibiotics. Moreover, the employment of beneficial microorganisms and biofiltration systems are two sustainable water management strategies that are essential for limiting the spread of illness in aquaculture settings. By emphasizing water quality through natural filtration processes, organic pond systems create a more balanced environment, lowering stress levels and disease susceptibility. By minimizing nutrient run-off, organic feed formulations using plant-based components, essential oils, and herbal extracts improve fish health and reduce the environmental effects of aquaculture techniques. This analysis also assesses these organic systems' economic viability, emphasizing how cost-effective and scalable they are compared to conventional aquaculture techniques. The aquaculture sector may minimize ecological impact while increasing fish health, producing better results, and adding to global food security through sustainable methods in Nile tilapia cultivation. To further advance sustainable aquaculture in the future, more studies are required to maximize these advances under various environmental circumstances and tilapia strains.

Characterization of Streptococcus agalactiae 1a isolated from farmed Nile tilapia (Oreochromis niloticus) in North America, Central America, and Southeast Asia

Streptococcosis caused by Streptococcus agalactiae 1a in Nile tilapia (Oreochromis niloticus) is a severe disease challenge for the global supply of tilapia. Currently, the extensive use of antibiotics is the primary curative tool used to minimize the impact of the disease. Vaccination is a prophylactic measure that has been shown to reduce antibiotic use in the aquaculture sector substantially. However, no commercially licensed vaccine against Streptococcus agalactiae 1a is currently available.This study aimed to investigate, through molecular and immunological methods, if Streptococcus agalactiae 1a isolates collected from North America (NAM), Central America (CAM), and Southeast Asia (SEA) were similarly suitable for the development of a potentially effective vaccine to serve the global tilapia farming industry. Our comparative data showed that the Streptococcus agalactiae 1a isolates from NAM, CAM and SEA had similar biochemical profiles, and genetic multi-locus sequence typing (MLST) analysis showed that the NAM and CAM isolates belonged to sequence type 7 (ST-7) and clonal complex 1, while isolates from SEA grouped into three sequence types (ST-1650, ST-500, and ST-7) and two distinct clonal complexes (CC1 and CC12). Isolates from NAM, CAM, and SEA displayed similar antigenic profiles determined by western blotting with polyclonal rabbit antisera, which was supported by in vivo cross-protection studies, showing that fish immunized with vaccines based on SEA and CAM isolates with different genetic MLST profiles were highly protected against cross-challenge using the same bacterial strains for challenge. Overall, the data obtained from our investigations provide strong indications that Streptococcus agalactiae 1a distributed in NAM, CAM, and SEA are serologically uniform pathogens, and vaccines based on isolates of Streptococcus agalactiae 1a from these regions may be suited for vaccination of tilapia worldwide.

Impact of salinity on Streptococcus agalactiae and health parameters of Oreochromis niloticus during streptococcosis outbreaks

S. agalactiae infection is one of the most important bacterial diseases imparting mass mortality in the aquaculture sector, worldwide. It is responsible for posing both economic burdens and risks of cross-infectivity and zoonotic transmission. In this aspect, this study examined the virulence gene profiles, molecular serotyping and pathogenicity of S. agalactiae strains isolated from tilapia farms in Kerala, India in 2022. Following sample collection and processing, three S. agalactiae strains (KSA/01, KSA/02, and KSA/03) were isolated and confirmed the bacterial identity using 16S rRNA sequencing. In pathogenicity test, the LD50 of the S. agalactiae was found to be 1 × 106 CFU/ml. An increase in the salinity was found to affect the pathogenicity of S. agalactiae as well as the hematological and serological profile of tilapia. Thus the presence of S. agalactiae, a highly virulent and zoonotic pathogen in tilapia farms, underscores the imperative of continuous monitoring in aquaculture facilities.

Efisiensi Kerapatan Tananaman Pakcoy (Brassica Rapa) terhadap Kualitas Air untuk Mendukung Kelangsungan Hidup Ikan Nila

Asnan Ridoanrisna. Efficiency Of Pakcoy Plants (Brassica Rapa) In Maintaining Water Quality To Support The Survival Rate Of Tilapia. Under Guidance By Robin And Novita Mz. Tilapia is a freshwater fish commodity with high economic value. According to data from the Central Bureau of Statistics (BPS), tilapia exports reached 12.29 thousand tons with a value of USD 78.44 million. Tilapia farming faces the risk of mortality which can lead to economic losses, one of which is caused by organic pollution. To address this issue, this research employs phytoremediation methods with varying plant densities to improve water quality and tilapia survival. The study was conducted with four treatments: A75 (plant density 75% of the aquarium surface area), A50 (50%), A25 (25%), and A0 (no plants), using an aquarium size of 60 x 30 x 50 cm³. Each treatment received chicken manure at 1.8 grams per aquarium and 40 tilapia fish per aquarium. Observations were made over 15 days in March 2023, measuring physical and chemical water parameters including DO, pH, TDS, temperature, and ammonia, as well as calculating the survival rate of tilapia. Using a Completely Randomized Design (CRD), the study found that treatment A75 achieved the highest survival rate at 62.5%. This result indicates that higher plant density in the phytoremediation method is more effective in maintaining water quality and supporting tilapia survival.

Impact of climatic factors on water quality parameters in tilapia broodfish ponds and predictive modeling of pond water temperature with ARIMAX

Climate change represents a considerable threat to aquatic ecosystems, potentially affecting various water quality parameters.The study aims to assess the impacts climatic factors on the water quality parameters in tilapia broodfish pond and forecasting of water temperature in a tilapia broodfish pond using the ARIMAX model. Daily longitudinal time series data on water quality parameters were collected from the pond, while monthly climatic data were obtained from the Bangladesh Meteorological Department. Water temperature exhibited seasonal variation, peaking at 31.23 °C in October and dropping to 20.8 °C in December. pH levels ranged from 7.36 to 10.32, with the lowest recorded in December and the highest in August. Dissolved oxygen levels varied from 7.09 mg/L to 10.65 mg/L, with the lowest in September and the highest in January. Ammonia levels were highest in February at 0.33 mg/L. Water transparency ranged from 15.37 to 28 inches, with the highest in January and the lowest in June. Climatic factors significantly influenced these variations, as specified by Canonical correlation analysis (CCA). The best-fitting model, ARIMAX (1, 0, 1), indicated a fluctuating trend influenced by important exogenous factors like air temperature and solar intensity. By the end January 2025, the water temperature is expected to rise to 27.93 °C. This is a noticeable increase started from November to January. These higher temperatures may improve tilapia broodfish growth and development earlier. But the temperatures are predicted to drop started from February to March, which could negatively affect tilapia growth and development. A clear seasonal fluctuating pattern is exhibited in the future. These findings provide important insights for researchers, policymakers, academics, and those involved in tilapia farming. By considering air temperature and solar intensity in planning, stakeholders can better anticipate future pond conditions. Developing adaptive management strategies to reduce negative impacts and make the most of favorable conditions will be essential for sustainable tilapia production in the context of climate change.

Managing the microbiological safety of tilapia from farm to consumer.

Tilapia stands out as one of the most extensively farmed and consumed fish species globally, valued for its ease of preparation and relative affordability. Although tilapia is a valuable protein source, it can also function as a vector for foodborne pathogens. This literature review reveals that tilapia could carry a variety of contamination with various foodborne pathogens, including Plesiomonas shigelloides, diarrheagenic Escherichia coli, Vibrio parahaemolyticus, Salmonella Weltevreden, Salmonella enterica, Shigella, Staphylococcus aureus, Campylobacter jejuni, Clostridium botulinum, and Listeria monocytogenes. Although guidelines from entities, such as the Global Seafood Alliance, Aquaculture Stewardship Council, and International Organization for Standardization, have been established to ensure the microbiological safety of tilapia, the unique challenges posed by pathogens in tilapia farming call for a more nuanced and targeted approach. Recognizing that contaminants could emerge at various stages of the tilapia supply chain, there is a crucial need for enhanced detection and monitoring of pathogens associated with this fish and its culturing environment. Additionally, it is essential to acknowledge the potential impact of climate change on the safety of tilapia, which may elevate the prevalence and contamination levels of pathogens in this fish. Proactive measures are essential to understand and mitigate the effects of climate change on tilapia production, ensuring the sustainability and safety of this seafood product for both present and future generations.

Potency of cassava leaf as protein source for Nile tilapia (Oreochromis niloticus)

Cassava (Manihot esculenta, Crantz) leaves are cheap and readily available resource that can be used as a feed ingredient for Nile tilapia although they have different constituents that affect their nutritional values. The aim of the study was to examine the effects of processing methods on nutrient content of cassava leaves, digestibility, and growth performance of Nile tilapia. Eight processing methods, namely air-drying, soaking and boiling, baker’s yeast (Saccharomyces cerevisiae), rumen-fluid, molasses, yeast-rumen-fluid, yeast-molasses and molasses-rumen-fluid fermentations, were applied. One control and eight processed cassava leaf-based diets were made. The cassava leaf protein replaced 30% of crude protein (CP) from soybean cake in the control diet. The results showed that CP content in dry matter (DM) varied from 21.7 ± 0.25% (Molasses fermentation) to 30.3 ± 0.25% (Yeast-rumen-fluid fermentation). Rumen-fluid fermentation showed higher (p < 0.05) level of gross energy (21.9 ± 0.02 MJ/kg, DM) and ether extract (12.0 ± 0.21%) compared with other treatments. The apparent digestibility coefficient of CP was generally higher in the control diet (89.9 ± 0.61% in the hindgut), followed by rumen-fluid fermented diet (87.2 ± 0.61%), rumen-fluid-molasses fermented diet (86.1 ± 0.61%) and yeast-molasses fermented diet (85.3 ± 0.61%). Besides the control diet, the latter three diets also revealed the best growth rate, feed conversion ratio, protein efficiency ratio and production profitability. In conclusion, rumen-fluid, yeast-molasses, and rumen-fluid-molasses fermentation methods improved the nutritional value of cassava leaves. Diets with 30% protein from soybean cake replaced by rumen-fluid, rumen-fluid-molasses and yeast-molasses fermented cassava leaves had overall acceptable growth performance with better production outcomes for Nile tilapia farming.

Evaluating economic viability and environmental externalities of integrated tilapia-sugarcane farming in Maharashtra

In recent years, farmers in Maharashtra have engaged in aquaculture-sugarcane farming, with those from the Ujjani reservoir area practicing integrated sugarcane farming using tilapia farm discharge water. This study aims to systematically compare the economic viability and environmental externalities between sugarcane-only farms (SF) and tilapia-sugarcane farms (TSF) within the commanding area of the Ujjani reservoir. Primary data was collected from the 160 farmers (80 SF, 80 TSF), and Secondary data were collected from published literature, the Department of Fisheries, and fisheries cooperative societies. Data analysis used descriptive statistics to characterize demographic profile, farm performance (cost-benefit analysis, production function), and farmers' perceptions. Principal component analysis (PCA), cluster analysis, and two-way MANOVA were employed for environmental assessments. Results indicate that TSF yields higher profits across all cost scenarios, with a Benefit-Cost ratio of 1.69, surpassing SF's ratio of 1.55. The Cobb-Douglas production function analysis reveals increasing returns to scale for both SF and TSF, with the sum of coefficients exceeding one. The results of the Principal Component Analysis (PCA) indicate that 31 variables rated by sugarcane growers were extracted into ten components, which explains 65 % of the total variance for SF and 62 % for TSF. K-means cluster analysis grouped these components into four clusters, termed externalities of irrigation. A Two-way MANOVA indicated significant differences (p < 0.05) between SF and TSF farmers' perceptions of these externalities, with further distinctions among four farmer categories and significant interaction effects. Policy recommendations include financial incentives and environmental regulations to support TSF adoption, sustainable land-use policies, and institutional interventions for management practices and market research. These measures address challenges and promote the transition to sustainable TSF practices.

Nile Tilapia Farming and Diversity in Sub-saharan Africa: A Review

Nile Tilapia Farming and Diversity in Sub-saharan Africa: A Review

Masculinization of Tilapia (Oreochromis Niloticus) by Oral Method Using Senggani Fruit Extract (Melastoma Malabathricum L.)

Introduction: Tilapia have different growth rates in male and female fish where the growth of male fish is faster than female. Therefore, in tilapia farming activities, the production of tilapia weighing &gt;100g/head is difficult to achieve due to uncontrolled spawning. Method: This study was designed using a completely randomized design (CRD) with 5 treatments and 4 replicates, namely treatment A (control), B (Senggani fruit extract 0.75 g/kg feed), C (extract 1.5 g/kg feed), D (extract 2.25 g/kg feed), E (extract 3 g/kg feed). The organisms used in the study were 7-day-old tilapia larvae. Tilapia larvae were given feed that had been added with Senggani fruit extract according to the treatment dose. Tilapia were reared for 62 days, and given artificial feed containing 41% protein, each feeding was given with a frequency of 3 times a day (morning, afternoon, evening). Results and Discussion: The results showed that the highest percentage of male sex was found in treatments A, B, C, D and E, which amounted to 50; 56.25; 57.5; 58.75; and 60%, respectively. Daily growth rate, survival and feed conversion ratio obtained during the study in each treatment amounted to 7.49, 7.45; 7.44; 7.46; and 7.40. for survival 73.75; 72.5; 72.5; 70; and 68.75 then the results of feed conversion ratio respectively 1.86; 1.88; 1.89; 1.86; and 1.91. The analysis showed that the highest percentage of male sex was found in the treatment of 3 g/kg feed which amounted to 60% (P&gt;0.05). Daily growth rate, survival rate and feed conversion ratio did not significantly affect the treatment given (p&gt;0.05). Conclusion: The results of water quality measurements obtained are still within the optimum limits for tilapia rearing. Conclusion: Feeding using Senggani fruit extract to masculinize tilapia did not have a significant effect (p&gt;0.05) on the percentage of male tilapia, daily growth rate and feed conversion ratio.

Strep Easy Kit; a bio-enrichment dual ICG-strip test for simultaneous detection of Streptococcus agalactiae serotypes Ia and III in fish samples.

The Strep Easy Kit, a bio-enrichment dual ICG-strip test, is a diagnostic tool designed for the detection of Streptococcus agalactiae, an important pathogenic bacterium in tilapia farming. The kit can simultaneously identify two different serotypes of S. agalactiae, serotype Ia and serotype III. This capability is crucial for the collection of valuable epidemiological data and facilitates strategic planning for effective vaccine development and deployment. The Strep Easy Kit consists of two main steps: pathogen enrichment and pathogen detection. The enrichment step increases the concentration of bacteria so that the bacterial load is raised to the level reliably detectable by the subsequent ICG strip test. This is achieved by incubating the fish samples in a suitable liquid medium under specified temperature and time conditions. The second step involves the use of the dual-ICG strip test. This strip test consists of two monoclonal antibodies and one polyclonal antibody that are specific to S. agalactiae and can distinguish between S. agalactiae serotype Ia and S. agalactiae serotype III. This dual capability enables the ICG strip test to simultaneously detect both serotypes of S. agalactiae in a single test kit. The detection limit of the test kit, which consists of a dual ICG-Strip test combined with an enrichment step, is 100 CFU/mL. The kit can be used to detect S. agalactiae in both live and dead fish samples, making it versatile for various testing scenarios. The test results obtained using the Strep Easy Kit have shown a 94.4% correlation with the standard method (Thai Agricultural Standard; TAS 10453-2010), with 90.2% sensitivity and 100% specificity. Significant advantages of the Strep Easy Kit lie in its simplicity and portability, allowing farmers to perform the test by themselves and on-site. This makes it a practical and accessible tool for the tilapia farming industry.

ANALYSIS OF THE TILAPIA PARTNERSHIP PATTERN BETWEEN UPTD BIAT KUTASARI AND THE ASTANA MINA MANDIRI FISHERIES ASSOCIATION AND ITS INFLUENCE ON INCREASING THE INCOME OF FISH FARMER IN PURBALINGGA REGENCY

This research aims to determine the pattern of tilapia partnerships between UPTD BIAT Kutasari and the Astana Mina Mandiri Fisheries Association and its influence on increasing the income of tilapia farmers in Purbalingga Regeancy. Using a mixed qualitative and quantitative approach (mix method) with purposive sampling. In this research there were 15 respondents, namely tilapia farmers who joined the partnership. The data analysis used is descriptive analysis and paired sample test. The research results showed that the partnership pattern implemented was a general trade partnership pattern, there was an increase in tilapia farmer’s income from IDR. 7,106,533,33 to IDR. 9,655,000, increasing revenue by 36% from before the partnership. The result of the difference test on farmers’ income have a significance level of 0.000 and the t count is 5.140. It can be cloncluded that there is a significant difference between farmers’ income before and after the partnership, so that the partnersip has an impact on the income of tilapia farmers.

Reversing the detrimental effects of high stocking density in Oreochromis niloticus juveniles using coenzyme Q10 and l-carnitine dietary supplementation

A 14-week trial was undertaken to examine the effects of coenzyme Q10 (CQ10) and l-carnitine (LC) dietary supplementation, either individually or in combination, on the feed intake, growth, blood biochemistry, immunity, economic viability, and body composition of Nile tilapia fingerlings reared at a high stocking density. The study involved eight groups of 450 tilapia juveniles, with an average weight of 6.083 ± 0.09 g, assigned to different treatments. Two groups were fed a basal diet and stocked at densities of 30 and 60 fish per m3, respectively. The remaining groups were reared at a high stocking density of 60 fish/ m3 and fed diets fortified with LC at 150 mg (G3), LC at 300 mg (G4), CQ10 at 20 mg (G5), CQ10 at 40 mg (G6), LC at 150 mg + CQ10 at 20 mg (G7), or LC at 300 mg + CQ10 at 40 mg (G8) per kg of diet. The findings revealed that high stocking density had an adverse impact on tilapia growth performance. Nevertheless, the inclusion of LC and CQ10 in the diet, whether separately or in combination, significantly improved growth parameters and enhanced survival rates. The G6, G7, and G8 groups showed the most significant improvements in growth and survival. High stocking density resulted in decreased moisture and crude protein content, while LC and CQ10 supplementation increased these components and reduced crude fat and ash content. High stocking density negatively impacted blood metabolites, leading to elevated levels of aspartate aminotransferase, alanine aminotransferase, creatinine, and urea-N, as well as decreased total protein and albumin. However, supplementation with LC and CQ10 effectively alleviated these effects, improving the levels of these parameters. All supplemented groups showed enhanced lysozyme activity and IgM concentration, with the greatest improvements observed in the G6, G7, and G8 groups. Economic analysis indicated that LC and CQ10 supplementation improved final and relative margin, except in the G4 group. In conclusion, the combined supplementation of LC and CQ10 shows promise in enhancing productivity and profitability in tilapia farming under high stocking density conditions, particularly in concrete tanks.

KHÁNG KHÁNG SINH CỦA Streptococcus agalactiae GÂY BỆNH TRÊN CÁ RÔ PHI (Oreochromis sp.) Ở MIỀN BẮC VIỆT NAM

Antimicrobial resistance (AMR) is a threat to animal and human health globally. Antimicrobials are used in aquaculture to control different bacterial diseases. However, inappropriate use of antimicrobials can accelerate the emergence of AMR. This study was conducted to determine antimicrobial resistance in Streptococcus agalactiae, which affects and causes diseases with high mortality in tilapia. A total of 26 S. agalactiae isolates were streaked from kidney/brain/liver samples of diseased farmed tilapia from 2017 to 2021 at Hai Duong, Bac Ninh, Hoa Binh, Yen Bai provinces. The sensitivity of the isolates to 7 antimicrobials was established by disc diffusion (Oxiod). The results showed that levels of resistance vary from S. agalactiae to DOX (34.4%), RIF (64.1%), TET (45.0%), ERY (64.8%), TMPSMX (70%), FLO (35.3%), and AMP (75%). The resistance rate to DOX was significantly different (p&lt;0.05) compared to ERY. S. agalactiae has the highest resistance to 2 types of antibiotics at 19.2%, followed by resistance to 3 types (15.4%), and resistance to 6 and 7 types of antibiotics at a rate of 11.5%. The resistance in 1 type, 4 types, and 5 types of antibiotics was observed lowest at 7.7%. Vietnamese tilapia farmers need guidelines for effective antimicrobial treatment and wwider take up of vaccine or sustainable farming technology to prevent infections caused by S. agalactiae and reduce emergence of AMR

Duration of Protection and Humoral Immune Response in Nile Tilapia (Oreochromis niloticus L.) Vaccinated against Streptococcus agalactiae.

Streptococcosis caused by Streptococcus agalactiae (S. agalactiae) is a major bacterial disease affecting the production of Nile tilapia (Oreochromis niloticus L.), causing significant economic losses due to mortality in the growing phase. Vaccination is the most effective method for preventing streptococcosis on Nile tilapia farms. In Brazil, the major tilapia-producing regions have long production cycles (6-10 months) and harvest tilapias weighing over 900 g for fillet production. Thus, data on the duration of the humoral immune response and protection in farmed tilapia have not been reported or are poorly described. Furthermore, the efficiency of serological testing for the long-term monitoring of immune responses induced by vaccination against S. agalactiae has never been addressed. This study evaluated the duration of protection and humoral immune response induced in Nile tilapia vaccinated against S. agalactiae until 300 days post-vaccination (dpv). The immunization trial was composed of two groups: vaccinated (Vac), vaccinated intraperitoneally with a commercial vaccine, and unvaccinated (NonVac) group, injected fish with sterile saline solution. At 15, 30, 150, 180, 210, and 300 dpv, blood sampling was conducted to detect anti-S. agalactiae IgM antibodies using indirect Enzyme-Linked Immunosorbent Assay (ELISA), and the fish were challenged with pathogenic S. agalactiae to determine the duration of vaccine protection through relative percentage survival (RPS). Spearman's rank correlation was performed between the ELISA optical density (OD) of vaccinated tilapia and the duration of vaccine protection (RPS). The mean cumulative mortality in NonVac and Vac groups ranged from 65 to 90% and less than 35%, respectively. The average RPS was 71, 93, 94, 70, 86, and 67% at 15, 30, 150, 180, 210, and 300 dpv, respectively. RPS revealed that the vaccine provided protection from 15 to 300 dpv. The specific anti-S. agalactiae IgM antibody levels were significantly higher in the Vac group than that non-Vac group up to 180 dpv. The vaccinated fish exhibited significant protection for up to 10 months after vaccination. There was a positive correlation between the antibody response and RPS. This study revealed that a single dose of commercial vaccine administered to Nile tilapia can confer long-term protection against S. agalactiae and that indirect ELISA can monitor the duration of the humoral immune response for up to six months following vaccination. Finally, vaccine protection over six months can be associated with other components of the fish immune system beyond the humoral immune response by IgM antibodies.

Determinants of Production and Technical Efficiency of Tilapia Farming in the Philippines

The Philippines' economy depends heavily on the profitability of the tilapia aquaculture industry. The country's tilapia aquaculture still has a significant amount of untapped biophysical growth potential; therefore, more rapid expansion is needed to keep up with the increasing demand for fish. The study examined the variables affecting the technical efficiency of tilapia production in the Philippines. The face-to-face interview method was used to survey randomly selected tilapia farms. The efficiency of the Philippines' tilapia aquaculture was estimated in this study. Overall, the findings of the technical efficiency analysis indicated that all fish producers within the examined regions were functioning below the production frontier. Therefore, to boost productivity and efficiency, it is necessary to thoroughly study the origins of inefficiencies in socioeconomic variables and farm features. The mean technical efficiency, as determined by the maximum likelihood estimation of the stochastic production frontier, is 0.44. The model's outcome showed that area and stocking rate significantly impact tilapia output in a few selected Philippine locales. It was discovered that factors such as the utilization of aeration, adoption of advanced culture method, and access to government support are significant predictors of technical efficiency in tilapia farming. The policy implication is that there are still more opportunities to raise the current level of technical efficiency of tilapia production in the Philippines.