Biofloc System and Stocking Density Effect on Water Quality, Feed Utilization, and Growth Performance of the Nile Tilapia (Oreochromis niloticus)

          To assess the impact of varying stocking densities under the Biofloc system (BFS) on water quality, feed utilization, and growth performance of the Nile tilapia fingerlings, the current study was carried out over 90 days. It was implemented in 12 production rectangular concrete ponds (5.5×13×1.40m) with a water volume of about 100m³ and different stocking densities (40, 60 or 80 fish/m³) under Biofloc and Traditional system treatments. Overall, the Biofloc treatments outperformed the Traditional system treatments in terms of the water quality indicators. Regardless of stocking density, the water quality indicators were within the range advised for tilapia production. Biofloc system treatments showed elevated growth performance rates and reduced FCR, unlike Traditional system ponds. The total yield directly increased with stocking densities (40, 60, and 80 fish/m³) in BFS. Generally, our results indicated that the higher fish densities relate to higher productivity but lower growth performance and survival rates. According to the feed consumption findings, the feed-saving rate under the Biofloc culture system improved significantly, reaching 29.83% at the stocking density of 40 fish/m³ and 9.83% at the stocking density of 60 fish/m³. The results also showed that, in contrast to the Traditional systems, the higher the fish stocking density, the more feed was consumed and the lower the saving rate. The findings also demonstrated that the Biofloc system had 0% daily water change rates in contrast to Traditional culture systems. Monthly water change rates were lower in the Biofloc treatments than in the Traditional systems, although it increased with the higher stocking density.