IMPACTS OF COMMERCIAL PROBIOTICS ON GROWTH PERFORMANCE, DISEASE RESISTANCE AND PROFITABILITY OF NILE TILAPIA (Oreochromis niloticus) UNDER STOCKING DENSITY STRESS

The current research aimed to reduce the effects of increasing Nile tilapia (Oreochromis niloticus) fish stocking density (SD) as stress factor by using dietary commercial probiotic supplementation (biogen® or Bactocell®). The experimental Nile tilapia (mean weight of 4.00 g) were distributed by random into 18 hapa (1.5 X 2 X 2 m), representing to 6 treatments (3 replicates per treatment). In a 2 × 3 factorial arrangement, fish were divided into two main groups. The first group was stocked at 100 fish/m3 and the second was stocked at 150 fish/m3. Each group was divided into 3 sub-groups; the 1st sub-group was fed on a diet without supplementation with commercial probiotics, the 2nd and 3rd sub-groups were fed on diet supplemented with 2 g Biogen and 0.5 g Bactocell/kg diet, respectively. The obtained results showed that all tested water quality measurements were suitable for rearing Nile tilapia fingerlings. With increasing fish stocking density, final body weight (FBW), daily weight gain (DWG), specific growth rate (SGR) and daily feed intake (DFI) of fish significantly (P