Effect of Probiotics on Growth Performance, Feed Utilization, and Water Quality Parameters of the Nile Tilapia (Oreochromis niloticus) Fingerlings

This study aimed to investigate the impact of water and feed probiotics on the growth performance, feed utilization and water quality of the Nile tilapia (Oreochromis niloticus) fingerlings. Three isonitrogenous (30% dietary crude protein) diets were prepared from commercial components. Five different levels of probiotics were used: P0 (no probiotics), Pd0.5 (0.5g probiotics/kg diet), Pd1.5 (1.5g probiotics/kg diet), Pw0.5 (0.5g probiotics/kg diet + 0.05g probiotics/L water), and Pw1.5 (1.5g probiotics/kg diet + 0.05g probiotics/L water). Rectangular glass aquariums (15 aquariums) were used. The Nile tilapia fingerlings (7g) were transferred to the experimental aquariums at a rate of 10 fingerlings per aquarium. The water quality in the system was daily monitored. One-third of the aquarium water was daily changed in the no-probiotic treatments, while in the treatments with water probiotics, the water remained  unchanged during the experiment. The control treatment and all probiotic-treated groups exhibited significantly higher (P< 0.05) final body weights, weight gains, and specific growth rates compared to the Pw0.5 group, with no significant difference between the Pw0.5 and Pw1.5 groups. Additionally, the condition factor showed no significant differences (P> 0.05) among the experimental groups. There were also no significant differences (P> 0.05) in survival rates between the probiotic treatments and the control group. The feed conversion ratio (FCR) and protein efficiency ratio (PER) did not differ significantly among the experimental groups, with the Pw0.5 group achieving the lowest values. The protein productivity value (PPV) in the control group was significantly the highest, while the Pw0.5 group recorded the lowest value, showing no statistical difference from the Pd0.5, Pd1.5, and Pw1.5 groups.