Effect of probiotic Bacillus spp.-supplemented feed on the growth, length-weight relationship, and condition factor of Nile tilapia (Oreochromis niloticus)

Abstract

This study was carried out to evaluate the effect of two probiotic Bacillus spp. (RM10 and BFAR9) on the growth, length-weight relationship (LWR), and condition factor (k) of Nile tilapia (Oreochromis niloticus). For this, one hundred thirty-five fingerlings (1.12±0.08 g weight and 1.26±0.15 cm length) were divided into three groups (Control, RM10, and BFAR9) and distributed into nine circular concrete tanks. The fish were fed with commercial (control) and Bacillus spp. supplemented diets at 5% of body weight for 56 days. The results of the study revealed better (P<0.05) growth concerning average body weight (ABW - 17.12±0.71g), specific growth rate (SGR - 4.89±0.22 g·day-1), absolute growth (AG - 16.02±0.78 g), and feed conversion ratio (FCR - 1.31±0.09) in the group fed with Bacillus sp. RM10 as compared to the control (ABW- 13.25±2.34g; SGR - 4.41±0.17g·day-1; AG - 12.13±2.25g; FCR - 1.62±0.11). The LWR in all experimental treatments showed a significant correlation (P<0.05) with an R2 value of 0.988, 0.966, and 0.979 for Control, RM10, and BFAR9, respectively. The k value revealed that all treatments are in good condition as k value is greater than 1 (1.913, 2.038, and 1.896 for control, RM10, and BFAR9 respectively). The result of the current study revealed that application of Bacillus sp. RM10 improves the growth and feed utilization in Nile tilapia.