Influence of probiotics on water quality in intensified Litopenaeus vannamei ponds under minimum-water exchange
Marwa A. Hassan, Mustafa A. Fathallah, Mohamed A. Elzoghby, Mohamed G. Salem, Mohamed Helmy
Abstract
Abstract The effects of two probiotics on NH 3 degradation, as well as the magnetic field (21.56 m tesla) on the germination and proliferation of Bacillus spores, were studied in-vitro. Additionally, the effect of these probiotics on water quality maintenance in Litopenaeus vannamei holding ponds was investigated. For 180 min, NH 3 degradation was assessed as follows: Set 1: ammonia-free tap water with NH 3 ; Probiotic A (5 × 10 10 viable Bacillus spores/g) with NH 3 ; Probiotic B (multi spp. 2 × 10 9 CFU/g) with NH 3 ; and Set 2: same as set 1 with 30 mg L −1 OM. The magnetic field was tested on Probiotic A (3.5 × 10 7 CFU) for 36 h in triplicate. In the presence of organic matter, both probiotics degrade NH 3 . The viable Bacillus count increased within 6 h of being exposed to the magnetic field, reaching its peak after 36 h. Firstly, fifteen ponds (250,000 PL/acre) were investigated, then 360 water samples were collected from the same corresponding pond for 8 weeks, and subjected to T1: control; T2: Probiotic A (0.007 g/m 3 /2 weeks); T3: Probiotic B (0.03 g/m 3 /2 weeks). Both probiotics with TVC and NH 3 demonstrated a negative correlation, on the other hand, they showed a significant (P ≤ 0.01) improvement in DO and pH. Overall, both probiotics were able to degrade NH 3 and the magnetic field (21.56 m tesla) was efficient to improve the germination and proliferation of Bacillus spores in-vitro. Probiotics were also effective for reducing TVC and NH 3 levels by increasing dissolved oxygen and pH in pond water.