Key Considerations for Using Probiotics in Aquaculture

Biological products are not a panacea, and their effectiveness—whether a product is high-quality or low-cost—depends on how they are used. To ensure effective use, aquaculturists should consider the following points:?

1. Components, Forms, and Types of Probiotics?

- Components: Probiotics contain beneficial bacteria such as Bacillus, Lactobacillus, Nitrosomonas, and Nitrobacter, along with nutrients that support bacterial activity, including monosaccarides, calcium salts, and magnesium salts.?

- Forms: Probiotics typically come in two forms: liquid and powder. Powdered probiotics usually have a higher concentration of beneficial bacteria (≥ 10^9 CFU/g), while liquid probiotics have a lower concentration (≥ 10^7 CFU/ml).?

- Types: There are probiotics designed for environmental treatment (with Bacillus as the primary bacteria) and those to be mixed into feed (with Lactobacillus as the primary bacteria) for the animals.?

2. Effects of Probiotics in Aquaculture?

?2.1. Effects on pond/tank water?

• Stimulate the growth of beneficial microorganisms.?
• Compete with harmful microorganisms for resources, stabilizing the pond environment.?
• Aid in decomposing organic matter like excess feed, algae, and detritus into non-toxic forms for fish and shrimp.?
• Convert harmful substances like Ammonia (NH3) and Nitrite (NO2-) into non-toxic forms such as Ammonium (NH4+) and Nitrate (NO3-), thus stabilizing water quality and pond bottom conditions.?

2.2. Effects on the digestive tract of fish and shrimp:?

• Promote the growth of beneficial bacteria, reducing the number of pathogenic bacteria in the gut.?
• Assist in metabolism, vitamin production, and nutrient conversion from feed, providing energy for the animals.?
• Produce antibiotics, enzymes, or chemicals that suppress or kill pathogens, enhancing the animals' resistance.?
• Stimulate feeding behavior and feed conversion, improving feed efficiency.?

3. Principles for Using Probiotics:?

Note:? Avoid using probiotics simultaneously with antibiotics or antimicrobial chemicals, those may inactive benefictial bacteria in Probiotic.?

• Follow the recommended dosage; more is not necessarily better.?
• For powdered probiotics, dissolve them in pond water and optionally add molasses, then aerate strongly for 2-4 hours before application to increase bacterial biomass.?
• For liquid probiotics, anaerobically ferment to increase biomass before use.?
• Apply probiotics between 8-10 AM on sunny, clear days with high dissolved oxygen levels for best results.?
• Regularly apply probiotics to maintain appropriate bacterial density, control water and pond bottom environments, stabilize pond conditions, and prevent pathogenic bacteria, harmful algae, and potential pathogens.?

4. Factors Affecting Probiotic Effectiveness:??

• Dissolved Oxygen: Aerobic (Bacillus) and strict aerobic bacteria (nitrate bacteria) require adequate dissolved oxygen to be effective. Low oxygen levels reduce efficacy.?
• Alkalinity and Salinity: Water with alkalinity from 80-150 mg /l maintains stable pH, while water with ≤ 50 mg/l causes pH fluctuations and reduced probiotic effectiveness. Excessive salinity can inhibit bacterial growth or kill bacteria.?
• Weather: Weather affects algae growth, water color, and probiotic effectiveness. Probiotics perform best in clear morning conditions.?
• Nutrients: Vitamin C is necessary for nitrate bacteria to effectively convert N-NH3 to NO3?

5. Timing and Frequency of Use:?

• Use probiotics from the start of the season for optimal results. At the start of the season, apply every 7-10 days. From mid to late season apply every 3-4 days since shrimp growth big and release more waste.?
• Probiotics applied from mid-season to the end are less effective than those applied from the beginning.?
• Probiotics usually do not have an immediate effect. Therefore, it is not used for emergencies but for prevention or to stabilize the pond after disease/environmental treatment.?

6. Dosage:?

• Follow the manufacturer’s guidelines.?
• Overuse can disrupt ecological balance and stress the animals.?
• Underuse may result in inadequate effectiveness.?

7. Cultivation for Increased Bacterial Biomass:?

• Some probiotics need cultivation to increase bacterial numbers. Anaerobic cultivation is necessary to avoid contamination.?
• Probiotics with high bacterial density may be used directly but should be mixed with water and aerated before application.?

8. Other Factors Affecting Probiotic Effectiveness:?

• Excessive protozoa can consume bacteria, reducing probiotic density.?
• Concurrent use of antimicrobial agents, antibiotics, or water changes can diminish probiotic effectiveness.?

Store probiotics away from direct sunlight to prevent killing beneficial microorganisms. Seal any unused portions tightly to avoid moisture and clumping. Choose products with clear brand registration, quality declarations, and ensure they are approved for use in Vietnam.?