Biological and economic performance of Nile tilapia (Oreochromis niloticus) in two conventional and limited water exchange systems

Abstract

The use of modern systems in the cultivation of economical fish such as tilapia is important. In the present study, the effect of conventional and limited water exchange systems on water quality, growth, nutritional performance, and the economic aspect of farming systems were investigated in Nile tilapia. For this purpose, juvenile tilapia with an average weight of 1.79 g were reared in fiberglass tanks with a volume of 170 liters of water at a density of one fish per liter of water for 5 weeks. Two treatments were considered in three replications. In the system with limited water exchange, molasses carbonaceous material was added to develop biofloc and maintain optimal water quality. The results showed a significant difference between water quality parameters in the two cultivation systems (P <0.05) so that a lower amount of total ammonia nitrogen (1.07 mg /L) was observed in the system with limited water exchange. The highest increase in body weight, biomass and survival ratio (98.82%) were obtained in the treatment with limited water exchange. The economic evaluation showed that water consumption is lower (61.47 L/ Kg), less food is required (1042.5 gr), higher production is obtained and thus limited water exchange had better profitability in the system. In general, the present study showed that the system with limited water exchange is more economical than the conventional system for the cultivation of Nile tilapia on the mentioned scale.

Keywords

• biofloc
• cultivation system
• economic
• growth performance
• nile tilapia