A probiotic that helps inhibit highly virulent Vibrio
(Research and Development Department – Than Vuong Co., Ltd.)
1. Samples for antibacterial testing
The test concentrations for MAX 4000 New were 10%, 20%, 30% and 50%.
Method
- Vibrio spp. strains were activated in MHB medium supplemented with 1.5% NaCl and incubated at 30°C; after 24 h they were subcultured onto TCBS agar to check purity.
- Once a pure strain was obtained, a single colony was selected and inoculated into 10 ml of MHB. 3 ml of the bacterial suspension was drawn off and its OD600nm was measured to determine absorbance.
- The required volume of bacterial suspension was calculated and diluted to OD600nm = 0.1 (equivalent to 3.0 × 108 CFU/ml)*.
- MHA medium was poured and left to set naturally. A sterile cotton swab was dipped in the diluted bacterial suspension at the appropriate concentration and spread evenly over the MHA surface. A 1 mL pipette tip was used to punch wells for the test samples.
- Samples at the appropriate test concentrations were prepared in falcon tubes containing diluent (MRD medium with an extra 10% Sinopol) and dissolved. 100 µL of sample was pipetted into each well.
- After filling the wells, the test plates were incubated at 30°C. Results were read and recorded after 24 h.
| Required test concentration (%) | Product weighed in (g) | Diluent added (mL) |
|---|---|---|
| 10 | 1 | 9 |
| 20 | 2 | 8 |
| 30 | 3 | 7 |
| 50 | 5 | 5 |
(Each concentration was run on 2 plates, each with 3 wells.)
2. Antibacterial results
MAX 4000 New. Each cell gives the clear-zone sizes of the 3 wells on plate 1 and, on the next line, plate 2.
| Test concentration (%) | Corresponding microbial density | Clear zone at 20 h (cm) | Clear zone at 24 h (cm) | Average inhibition zone (cm) | Result |
|---|---|---|---|---|---|
| 10 | 1.39 × 108 CFU/g | 0 - 0 - 0 0 - 0 - 0 | 0 - 0 - 0 0 - 0 - 0 | – | No inhibition |
| 20 | 2.78 × 108 CFU/g | 0 - 0 - 0 0 - 0 - 0 | 0 - 0 - 0 0 - 0 - 0 | – | No inhibition |
| 30 | 4.17 × 108 CFU/g | 2.0 - 2.0 - 2.1 2.0 - 2.0 - 1.8 | 1.7 - 1.3 - 1.4 1.3 - 1.4 - 1.4 | 1.70 | Inhibition |
| 50 | 6.95 × 108 CFU/g | 2.4 - 2.4 - 2.0 2.4 - 2.2 - 2.8 | 2.4 - 2.4 - 2.0 2.4 - 2.2 - 2.8 | 2.37 | Inhibition |
Conclusion: MAX 4000 New showed no antibacterial activity against Vibrio spp. at the 2 lower test concentrations (10–20%), and formed clear zones at the 30–50% test concentrations, with an average zone size of 1.7–2.37 cm.
Plate photos
- Figure 01: control plate (no product added), Vibrio (+) on MHA.
- Figure 02: antibacterial test of MAX 4000 New at 10% (no clear zones).
- Figure 03: antibacterial test of MAX 4000 New at 20% (no clear zones).
- Figure 04: antibacterial test of MAX 4000 New at 30% after 20 h, marked "inhibition".
- Figure 05: antibacterial test of MAX 4000 New at 30% after 24 h, marked "inhibition".
- Figure 06: antibacterial test of MAX 4000 New at 50% after 20 h, marked "inhibition".
MAX 4000 New: a probiotic that helps inhibit highly virulent Vibrio, rare on the market
MAX 4000 New, tablet form, 227 g pack.
- Helps reduce pressure from unfavourable bacteria at high pond densities.
- Helps keep the pond environment stable so the shrimp maintain their immunity in the cold season.
English text adapted from Than Vuong's original Vietnamese infographic.
