Aquaculture, particularly shrimp production, is experiencing significant global growth, with an estimated increase of 5.7% per year. By 2020, shrimp production is expected to rise by 18%, reaching a total of 3.5 million metric tons. However, the shrimp industry faces challenges related to international market prices and production costs (GSMC 2018), which can hinder its growth and productivity on a global scale. In Bangladesh, shrimp aquaculture plays a crucial role in the economy, contributing 5% to the national GDP. It is a significant source of livelihood (DoF 2013) for approximately 8.5 million people, particularly those residing in coastal areas. The industry is vital for the economic well-being of these communities. However, the rapid growth and expansion of the shrimp industry are hampered by the presence of various pathogenic bacteria and viruses. These pathogens cause significant losses in yield and result in substantial economic damages every year (Paul et al., 2012). Addressing the occurrence of these diseases is crucial for the sustainable development and success of the shrimp aquaculture industry. Efforts such as the utilization of bacteriophages and non-pathogenic Vibrio, as mentioned earlier, are aimed at preventing and controlling these microbial diseases. Such approaches can help mitigate the economic losses and support the growth of the industry by reducing the dependence on antibiotics and addressing antibiotic resistance concerns. Continued research and development in the field of disease prevention and control are essential to ensure the long-term sustainability and productivity of the shrimp aquaculture industry, both in Bangladesh and globally.
Epidemic outbreaks caused by bacteria and viruses have had significant economic impacts, particularly in Asia. Diseases such as Acute Hepatopancreatic Necrosis Disease (AHPND), also known as Early Mortality Syndrome (EMS), Taura Syndrome Virus (TSV), Infectious Hypodermal and Hematopoietic Virus (IHHNV), White Spot Syndrome Virus (WSSV), Hepatopancreatic Parvovirus (HPV), Yellowhead Virus (YHV), and Monodonbaculovirus (MBV) have resulted in substantial economic losses (Flegel 2012; Hong et al., 2016). Vibrio species, a type of bacteria, are widely found in marine environments (Thompson et al., 2004). Among the Vibrio species, V. anguillarum, V. harveyi, and V. parahaemolyticus are known to be pathogenic to shrimp (Lightner and McVey 1993). The presence of these pathogenic bacteria and viruses poses a significant challenge to the shrimp aquaculture industry. Outbreaks of these diseases can lead to high mortality rates and economic losses. Efforts to prevent and control these diseases, such as the use of bacteriophages and non-pathogenic Vibrio, as mentioned earlier, are crucial for the sustainability and growth of the industry. Continued research and development in disease prevention, along with effective management practices, are essential in mitigating the impact of these pathogens on shrimp aquaculture. By addressing these challenges, the industry can enhance its productivity, profitability, and overall sustainability.
The use of antibiotics in shrimp aquaculture can pose potential threats to both human health and the environment. Residual antibiotics in the food system can be a concern, as they may enter the human food chain and contribute to the development of antibiotic resistance (Selvin and Lipton 2003, 2004). The use of antibiotics in aquaculture is widespread, with 36 different antibiotics being used in seven major aquaculture-producing countries (Rico et al., 2012). In hatcheries, antibiotics are often used to control diseases. However, this practice can sometimes lead to the failure to maintain the balance of luminous bacteria. The growth of antibiotic-resistant Vibrio harveyi has been observed in larval tanks, leading to severe mortality in Penaeus monodon larvae (Lavilla-Pitogo et al., 1990; Karunasagar et al., 1994). The emergence of antibiotic-resistant strains is a significant concern in shrimp aquaculture. Antibiotic resistance can render antibiotics ineffective in treating bacterial infections and can have serious implications for both animal and human health. It is crucial to find alternative approaches to disease prevention and control, such as the use of bacteriophages and non-pathogenic Vibrio, to reduce the reliance on antibiotics and mitigate the risk of antibiotic resistance development. Efforts should be focused on promoting sustainable and responsible aquaculture practices that prioritize the health and welfare of shrimp, minimize the use of antibiotics, and ensure the safety of the final food products. Continued research and the adoption of alternative disease management strategies are essential for the long-term sustainability of the shrimp aquaculture industry.
Indeed, research on the efficacy of bacteriophages and non-pathogenic Vibrio in protecting Penaeus monodon (black tiger shrimp) against Vibrio parahaemolyticus is limited. However, there have been studies that have explored the potential of these treatments in shrimp aquaculture. Phage therapy is considered a promising approach for the treatment of Vibriosis in aquaculture. Bacteriophages are viruses that specifically infect bacteria, multiply within their host cells, and ultimately destroy them. They can naturally target, infect, and kill specific bacterial species or groups, including unrelated bacteria. This makes them highly effective in controlling the population density of their target bacteria. Bacteriophages are abundant in the aquaculture environment, particularly in seawater. The total number of viruses in seawater often exceeds the concentration of bacterial cells by a factor of 10 (Thiel 2004). This abundance of bacteriophages in the environment presents an opportunity to harness their potential for controlling bacterial pathogens in shrimp aquaculture. While more research is needed to fully understand the effectiveness of bacteriophage therapy and non-pathogenic Vibrio in protecting shrimp against Vibrio parahaemolyticus, their potential as alternative disease management strategies is promising. Continued studies in this area can provide valuable insights into the development of sustainable and effective methods for preventing and controlling bacterial diseases in shrimp aquaculture.
Phages have been proposed as an alternative method for controlling bacterial infections in shrimp aquaculture due to their effective bacteriolytic activity and advantages over conventional antibiotics. They are natural and relatively inexpensive compared to antibiotics (Gutiérrez et al., 2010). Studies have shown that specific lytic bacteriophages, such as vB_VpS_BA3 and vB_VpS_CA8, isolated from sewage, can effectively kill multidrug-resistant V. parahaemolyticus, suggesting their potential as biological control agents (Yang et al., 2020). Another study found that the bacteriophage pVp-1 exhibited effective bacteriolytic activity against multiple-antibiotic-resistant V. parahaemolyticus strains (Jun et al., 2014). In laboratory settings, the use of bacteriophages has resulted in shrimp survival rates higher than 80% after treatment, compared to control groups with only 25% survival (Vinod et al., 2006). Food prepared with infused phages has shown promising results in experimental infections, with a positive correlation between phage activity and protection against infection (Park et al., 2000; Park and Nakai 2003). Studies have also reported no evidence of phage-resistant organisms or compounds released by the immune system that could neutralize the phage's effects in both healthy and infected fish (Oliveira et al., 2012; Rao and Lalitha 2015). Overall, the application of bacteriophages has been shown to lead to low infection rates and fish mortality (Park and Nakai 2003). While several studies have investigated the potential of bacteriophages to control V. parahaemolyticus infections in shrimp, the efficacy of bacteriophages may vary depending on the specific phage strain and the target V. parahaemolyticus strain. Further research is needed to explore their effectiveness in field conditions and to develop strategies for their successful implementation in shrimp aquaculture.
Non-pathogenic Vibrio strains, including Vibrio alginolyticus and Vibrio harveyi, have been investigated for their potential as probiotics in shrimp aquaculture. These beneficial bacteria have shown the ability to compete with and suppress the growth of pathogenic V. parahaemolyticus strains (Zokaeifar et al., 2012). Probiotics work by colonizing the gut and other surfaces of the shrimp, thereby creating a protective barrier against pathogens. In the case of non-pathogenic Vibrio strains, they can outcompete and inhibit the growth of V. parahaemolyticus, reducing the risk of infections in shrimp. Furthermore, non-pathogenic Vibrio strains have been found to enhance the immune response of Penaeus monodon, also known as black tiger shrimp. They can stimulate the production of immune-related molecules and enhance the activity of immune cells, making the shrimp more resistant to V. parahaemolyticus infections. The use of non-pathogenic Vibrio strains as probiotics offers a potential sustainable approach to disease prevention in shrimp aquaculture. By promoting a healthy microbial balance and enhancing the shrimp's immune system, these probiotics can help reduce the reliance on antibiotics and mitigate the risk of antibiotic resistance development.
The investigation of a combination approach using both bacteriophages and non-pathogenic Vibrio to control V. parahaemolyticus infections in shrimp is a valuable area of research. This approach has the potential to yield promising results in terms of reducing the prevalence and severity of V. parahaemolyticus infections in P. monodon post-larvae when administered through immersion methods. It is crucial to consider that the efficacy of these treatments can be influenced by various factors, including the specific strains of bacteriophages and non-pathogenic Vibrio used. Therefore, it is important to carefully select and evaluate the effectiveness of these strains in targeting and controlling V. parahaemolyticus infections. The research should assess mortality rates, the presence of infection or disease outbreaks, and the timing and dosage of application in shrimp aquaculture systems, particularly in the nursery pond environment. Additionally, environmental conditions, such as water quality, temperature, and salinity, should be taken into account, as they can influence the success of the treatment approach. By investigating the combined use of bacteriophages and non-pathogenic Vibrio, this research can contribute to the development of effective and sustainable strategies for the prevention and control of V. parahaemolyticus infections in shrimp aquaculture.
Indeed, the rapid growth of shrimp aquaculture has brought significant economic benefits and livelihood opportunities to coastal areas of Bangladesh. However, the industry also faces various challenges that can impact its sustainability and profitability. Fluctuating international market prices and production costs are significant concerns for shrimp farmers. Market prices can be influenced by factors such as global supply and demand dynamics, trade policies, and consumer preferences. Fluctuations in prices can directly affect the profitability of shrimp farms, making it essential for farmers to carefully manage their production costs and explore strategies to mitigate price volatility. Another major challenge in shrimp aquaculture is the presence of pathogenic bacteria and viruses. These pathogens can cause diseases in shrimp, leading to significant yield losses and economic damages. Common pathogens include Vibrio species, such as V. parahaemolyticus, and viruses like the White Spot Syndrome Virus (WSSV) and the Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV). Outbreaks of these diseases can result in high mortality rates and reduced shrimp growth, impacting farm productivity and profitability. Efforts to control diseases in shrimp aquaculture are crucial for sustaining and expanding the industry. Disease management strategies include implementing biosecurity measures, improving water quality management, and adopting disease-resistant shrimp breeds. Additionally, research is being conducted on alternative disease control methods, such as the use of bacteriophages and non-pathogenic Vibrio strains, as discussed earlier. These approaches offer the potential to target specific pathogens, reduce the reliance on antibiotics, and improve shrimp health and productivity. By addressing these challenges through effective disease management strategies, the shrimp aquaculture industry in Bangladesh can aim to minimize economic losses, enhance sustainability, and continue to contribute to the local economy and livelihoods.
Efforts to control diseases in shrimp aquaculture are indeed crucial for sustaining and expanding the industry. The occurrence of pathogenic bacteria and viruses can lead to significant financial losses through high mortality rates and reduced shrimp growth. Therefore, it is essential to implement effective disease management strategies to mitigate the impact of these pathogens. One approach being explored is the use of bacteriophages and non-pathogenic Vibrio. Bacteriophages are viruses that specifically target and infect bacteria, including pathogenic strains. By using bacteriophages, farmers can achieve targeted control of specific pathogens, reducing the need for broad-spectrum antibiotics. This approach not only helps to combat the spread of antibiotic resistance but also minimizes the potential negative impacts of antibiotics on shrimp health and the environment. Non-pathogenic Vibrio strains can also be utilized as a disease management strategy. These non-pathogenic strains can outcompete and prevent the colonization of pathogenic bacteria, thereby reducing the risk of disease outbreaks. By introducing beneficial bacteria into the shrimp aquaculture system, farmers can improve shrimp health and productivity. Implementing these strategies offers several potential benefits. Firstly, the targeted control of specific pathogens helps to minimize the impact of diseases on shrimp populations, reducing mortality rates and improving overall growth. Secondly, by reducing the reliance on antibiotics, the industry can contribute to the global effort to combat antibiotic resistance, which is a growing concern in aquaculture and human health. Lastly, improved shrimp health and productivity contribute to the sustainability of the industry, ensuring its long-term growth and economic viability.
By adopting and implementing effective disease management strategies, such as the use of bacteriophages and non-pathogenic Vibrio, the shrimp aquaculture industry can minimize economic losses and achieve sustainable growth. This not only benefits the industry itself but also supports the livelihoods of those involved in shrimp farming and contributes to the economic development of coastal areas.