TPD “translucent post-larvae” in whiteleg shrimp has become a “hot” phrase in the current period. The bacterium Vibrio parahaemolyticus has been identified as the main cause of TPD in shrimp and can cause great damage to the aquaculture industry. TPD in shrimp can cause high mortality in shrimp populations, leading to reduced productivity and profits for farmers. This disease can also cause shrimp to weaken, reduce growth and resistance to other diseases. Importantly, there is currently no effective medicine or treatment for TPD. To help you have an overview of TPD, Truong Hai Tien Company would like to present some challenges and solutions in preventing and treating TPD in shrimp.
ABOUT CHALLENGES:
1. No specific treatment method:
Currently, there is no specific medicine or treatment method to completely cure TPD. Most measures are only preventive or to minimize the impact of the disease.
2. Difficulty in diagnosis
– TPD can cause unclear symptoms in the early stages, leading to late diagnosis.– In the early stages, infected post-larvae shrimp only show a slightly blurry, transparent appearance, difficult to recognize with the naked eye.– When symptoms are obvious (shrimp are weak, lose reflexes, cannot swim normally), the disease has often progressed severely, leading to a high mortality rate.
Figure 1: Clinical signs of whiteleg shrimp infected with TPD
(a) Post-larvae affected by TPD
(b) Post-larvae infected with experimental infection
3. High mortality rate, affecting the survival rate of shrimp larvae
Sick post-larvae often die en masse in a short period of time. This reduces the quality and quantity of input shrimp larvae, affecting commercial farming productivity.
4. Impact of water environment
– Poor water quality (organic pollution, unstable pH, high NH3 concentration) increases the risk of disease outbreaks.
– Improperly cleaned nursery ponds or farming systems are also the cause of disease spread.
ABOUT SOLUTIONS:
1. Control the quality of shrimp larvae: Select shrimp larvae from reputable farms, ensure they are disease-free and have good resistance. Avoid importing shrimp larvae from unclear sources.
2. Water environment management:
Preparing the pond: the pond needs to be disinfected, balanced with minerals Ca, Mg, K according to shrimp standards. LIQUID SEAWEED concentrated algae extract will be the top choice to bring the pond water environment back to its natural state, providing necessary nutrients. Using 1 liter/500m3 of the pond and 1.5 – 2 liters/1000m3 of the pond directly 2-3 days before and 30 minutes before releasing the shrimp will help the shrimp adapt easily and not be shocked when the environment changes.
Maintain stable water quality, especially salinity, pH and dissolved oxygen concentration. Use a water filtration system, disinfect with ozone or UV before putting it into the nursery tank. Limit the growth of Vibrio spp. bacteria by using biological products. Bacillus probiotics will be the top choice thanks to its safety and many benefits. Our company would like to introduce TPD CONTROL, a super concentrated Bacillus spp preparation 2×1011 CFU/g to help antagonize Vibrio parahaemolyticus:
– 2-3 days before stocking, mix 1 packet of TPD CONTROL + 2 kg of heat-sterilized molasses + 40 liters of water + aerate for 8-12 hours, each 40 liters of this type can be used for 500 m3 of pond water to create beneficial microorganisms, creating color for the pond.
– 30 minutes before stocking, mix and splash into the pond with 1 packet of TPD CONTROL for 500 m3 of water.
– Continue to maintain beneficial microorganisms by regularly using TPD CONTROL, combining direct mixing and splashing and proliferation with molasses to achieve maximum efficiency. After stocking, every 4 days (1 cycle), TPD CONTROL will be added twice on the 2nd and 4th days; on the 2nd day, TPD CONTROL will be used directly, 1 packet for 500 m3, and on the 4th day, TPD CONTROL will be used in the form of proliferation with molasses. 1 packet of TPD CONTROL + 2 kg of heat-sterilized molasses + 40 liters of water + aeration for 8-12 hours, each 40 liters of this form can be used for 500 m3 of pond water. Repeat the process continuously until the shrimp are old enough and no longer afraid of the effects of TPD.
3. Increase nutritional supplements: Supplement intestinal enzymes, vitamin C, betaglucan… to enhance shrimp resistance:
– Use MULTACID – a product with high organic acid content, to break down the “defense” biofilm of Vibrio parahaemolyticus. Use MULTACID 5 days after stocking with a dose of 2 liters/1,000 m3 of pond, then repeat every 10 days, will help to antagonize TPD more easily. In addition to direct spraying, MULTACID should be supplemented daily with a dose of 2 ml/kg of food to keep the shrimp’s intestines healthy, easy to digest and absorb.
– OLIGO-MOS: a product containing high levels of Beta-glucan and Mannan oligosaccharides to enhance shrimp resistance, stimulate the growth of beneficial bacteria in the intestines, prevent the invasion of pathogens into cell tissues, and help shrimp stay healthy. Use OLIGO-MOS at a dose of 2.5 g/1 kg of feed, feed daily at the times when shrimp eat the most healthily. Combine mixing and splashing OLIGO-MOS directly into the pond at a dose of 1 kg/1,000m3 of pond water, 4 days/time for optimal effectiveness. 4. Limit the uncontrolled use of antibiotics: Do not overuse antibiotics because it can make bacteria resistant to drugs, causing difficulties in treatment later. Prioritize disease prevention measures using herbs such as BLACK GARLIC EXTRACT – Contains high levels of Polyphenol and Flavonoid which are antioxidants that are beneficial for health, helping shrimp stay healthy and easily fight harmful bacteria, especially Vibrio parahaemolyticus that causes TPD. Use BLACK GARLIC EXTRACT at a dose of 5 ml/kg of feed, feed daily at the times when shrimp eat the most healthily, combined with mixing and splashing directly into the pond at a rate of 1 liter/500 m3, every 4 days/time to keep shrimp healthy.
CONCLUSION
TPD disease in shrimp causes many big challenges in control and treatment. Because there is no specific medicine, farmers need to focus on disease prevention through management of breed, environment and nutrition. Close monitoring and maintaining good water quality are key factors in limiting this disease.
Hopefully, Truong Hai Tien’s sharing will help you limit the harmful effects caused by TPD disease. Wishing you a successful farming season!
