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The impacts of commercial probiotics as water additives to the zero-water exchange system on water quality, production efficiency, gut microbiota, antioxidant, and immunological responses of Nile tilapia (Oreochromis niloticus) were investigated. Five treatments, with three triplicates, were randomly designed, where in each replicate 150 fish (100 ± 4.5 g) were stocked in 20-m3 concrete ponds. Different water probiotics were added to ponds' water as follows: T1 (Control: no probiotic added); T2 (Prozym powder Ultra ® at 0.002 g/ m3/ day); T3 (Microban aqua ® at dose 0.002 g/ m3/ day); T4 (Aquastar ® at dose 0.0015 g/ m3/ day); and T5 (Sanolife PRO-W ® at dose 0.0010 g/ m3/ day). For eight weeks, fish in each group were fed a commercial feed (30% crude protein) up to satiety three times a day. After the experimental period, dissolved oxygen in ponds' water was significantly improved, while ammonia, nitrite, and nitrate levels were significantly lowered by water additives as compared to the control group. Compared to the control group, yield, specific growth rate, and total feed intake were significantly improved, while feed conversion ratio was not significantly changed among different treatments. Significant (p |
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