The effect of probiotics (lysinibacillus fusiformis LFUG) on the growth performance and survival of juvenile nile tilapia (oreochromis niloticus)

Abstract

Probiotics play a crucial role in improving the water quality, growth, and resistance of fish against pathogenic organisms. They have shown great potential for application in aquaculture and could be safer alternatives to antibiotics. The present study was conducted to evaluate the effect of Lysinibacillus fusiformis LFUG dietary inclusion on the growth performance and survival of juvenile Oreochromis niloticus, and on the physiochemical water quality parameters. Two different concentrations of the bacteria (1X106) (LFUGT1) and 1X108 (LFUGT2) CFUml-g) were incorporated in a commercial diet (Koudijs) to make the experimental test diet whereas the negative control diet had no bacteria added (normal saline only). Nile tilapia juveniles of average body weight 1.7230.4g were subjected to the respective experimental diets for a period of fifty days with 10-day sampling intervals for weight (g), total length (cm) and standard length (cm). Fish fed on diets supplemented with the bacteria showed significantly better growth performance than those that were not (control) (P < 0.05). Fish in the LFUGT2 treatments significantly added more weight (5.649±1.253) than LFUGT1 (5.286±1.236) the Control (4.407±1.817) after the 50 days of feeding on the test diets. There wasn’t any negative effect of the bacteria on the health of the fish fed on feeds enriched with the different concentrations since there was no significant difference in the survival rates as compared to the control. (Control - 92.7±1.5%, LFUGT1 - 94.6±0.6% and LFUGT2 - 95.3±2.5%). Furthermore, the Ammonia, Nitrites and Nitrates were better controlled respectively in LFUGT2 (0.25±0.01mg/l, 0.5±0.01mg/l and 15±5mg/l) and LFUGTT1(0.5±0.02mg/l, 0.5±0.01mg/l and 10±5mg/l) than that in the control treatment (1±0.02mg/l, 0.6±0.02mg/l and 20±5mg/l). Throughout the experiment, the mean temperature and dissolved Oxygen (DO) were (Temp 26±0.5oC, 26±0.2oC, and 26±0.4oC, DO 4.3mg/l, 4.9mg/l and 4.5mg/l) for control, LFUG T1 and LFUG T2 respectively. Therefore, Lysinibacillus fusiformis dietary inclusion at the two concentrations used in this study enhanced growth of juvenile Nile tilapia, improved water quality, and did not have any biosafety concerns for the 50 days of the experiment. Thus, the bacterium is a promising candidate for use in Nile tilapia fish farming as a probiotic.