Applications and benefits of Bacillus subtilis in aquaculture

1. Introduction

With the growing demand for environmentally friendly and sustainable aquaculture production, microbial probiotics have become essential tools in modern farming. Bacillus subtilis, a safe and highly effective probiotic strain, is widely used in fish, shrimp, and crab farming. This article explores the functions, application methods, and benefits of Bacillus subtilis in aquaculture, helping farmers improve water quality and increase farming efficiency.

2. Main Characteristics of Bacillus subtilis

High Resistance and Excellent Survival Ability

Due to its spore-forming structure, it can withstand high temperatures, acidic conditions, and harsh environments.

Environmentally Safe and Non-Toxic

It is recognized as a safe probiotic suitable for long-term application.

Rapid Reproduction and Strong Competitive Exclusion

It helps beneficial bacteria dominate the water and intestinal environment while suppressing harmful microorganisms.

3. Main Functions in Aquaculture

1. Improve Water Quality by Decomposing Organic Matter

Bacillus subtilis produces enzymes such as protease, cellulase, and amylase that help break down:

· Feed residues

· Feces

· Organic sludge

Effectively reducing ammonia, nitrite, and hydrogen sulfide levels.

2. Suppress Harmful Bacteria and Stabilize the Micro-Ecosystem

It helps inhibit:

· Vibrio species

· Escherichia coli

· Fungi

Thus preventing disease outbreaks and maintaining a stable aquatic environment.

3. Improve Digestion and Immunity in Aquatic Animals

After colonizing the intestinal tract, it:

· Regulates microbial balance

· Improves feed utilization

· Enhances immunity

leading to improved growth performance and higher survival rates.

4. Reduce Costs and Increase Economic Benefits

Lower disease risk and improved survival and growth performance significantly enhance overall farming profitability.

4. Application Methods and Recommended Dosage

1. Water Treatment

· Apply once every 7–10 days.

· Standard dosage: 100–200 g per acre-meter.

· Activation before use is recommended.

2. Feed Mixing

· Add 1–3 g per kg of feed.

· Can be combined with molasses or vitamin C for enhanced effectiveness.

3. Precautions

· Do not use simultaneously with disinfectants or antibiotics.

· Ensure complete dissolution or activation before application.

5. Conclusion

Bacillus subtilis plays a vital role in improving water quality, enhancing immunity, and promoting the healthy development of aquaculture. As eco-friendly farming continues to expand, this probiotic will remain one of the most valuable microbial tools for sustainable aquaculture development.