The effect of combined salinity at elevated temperature on protein and energy requirement for maintenance and feed utilization of hybrid red tilapia (Oreochromis sp.)

Abstract

Climate change is one of reasons which mainly affects to aquatic ecosystems,predicted to increase the environmental temperature and rising of sea level leading to increase estuary salinity and salinity intrusion into the fresh water bodies. This study was conducted to assess the protein and energy requirements for maintenance and protein -energy utilization of red tilapia (Oreochromis sp.) in conditions of different salinity at elevated temperature. Red tilapia (13.0 g) were fed at five different feeding rates: 0%, 25%, 50%, 75% and 100% satiation for 28 days at different salinities at elevated temperature (0ppt – normal temperature, 6ppt – 34oC and 12ppt – 34oC). The results showed that the highest survival ration (93.3%) was in (0ppt – normal temperature with feeding rate 0.75% of body weight) and lowest survival (66.7%) was in (12ppt – 34oC without feeding). The best growth performance: 0ppt- normal temperature and 12ppt – 34oC. Protein utilization efficiencies of red tilapia increased with increased salinity – temperature and the opposite trend was seen in the protein requirement for maintenance. Energy utilization efficiencies increased with increased of salinity – temperature that led to the energy requirement for maintenance in higher salinity – temperature was lower than in freshwater.