Different stocking density effects on growth performance, muscle protein composition, and production cost of Nile tilapia (Oreochromis niloticus) juveniles in on-growing stage in biofloc system

Abstract

Nile tilapia stocking density effect is determined by growth performance, muscle protein composition, and production cost in the on-growing stage. Randomized Nile tilapia were stocked at three densities 59 (D59), 89 (D89), and 117 (D117) fish m⁻³ in four tanks per treatment. The experiment was performed in 12 indoor 40 m⁻³ rectangular tanks with brackish water (4 ppt salinity) and constant aeration for 69 days, analyzing final body weight (FBW), feed conversion ratio (FCR), final biomass (FB), food consumption (FC), average weight gain (AWG), biomass gain (BG), carcass yield (CY), fillet yield (FY), crude protein (CP), digestible protein (DP), true protein (TP), and unit production cost (UPC). Stocking density affected FBW, FCR, FB, FC, AWG, BG, CP, and DP (P < 0.05). FBW and AWG decreased significantly, and FCR, FB, FC, and BG increased significantly with increasing stocking density (P < 0.05); CP and DP ranged from 66.8 to 72.2% and 66.7 to 72.0% respectively, being higher in D59 and lower in D89. Stocking density had no effect on CY, FY, and TP of Nile tilapia (P > 0.05). Stocking density had a direct effect on UPC increasing with stocking density. Overall, high stocking density had a negative effect on growth performance, muscle protein composition, and production cost of Nile tilapia juveniles. These findings are important for vertically integrated tilapia farms due to high stocking densities resulting in a more expensive product with lower quality, which affects the tilapia production chain.