A factorial approach to defining the energy and protein requirements of Tra Catfish, Pangasianodon hypothalamus

This study assessed the protein and energy requirements of Tra catfish (Pangasianodon hypothalamus) using a bio-energetic factorial approach. To examine these parameters, a series of inter-related studies were undertaken to define the various factorial parameters. Studies included controlled laboratory experiments and field-data collection from commercial farms in the Mekong Delta region of Vietnam. Key components of the model include parameters for maintenance energy (39.7 kJ kg(-0.844) day(-1) at 32 degrees C) and protein (0.467 g kg(-0.833) day(-1) at 32 degrees C) demands, the effect of animal live-weight and temperature on growth and maintenance energy demands, the efficiencies of energy and protein utilization at various energy and protein intake levels and the variability in whole body composition with varying live-weight. Interestingly, both the energy [0.510 (Energy intake) - 11.143] and protein [0.322 (Protein intake) + 0.665] utilization efficiencies at near satiety feed intake levels were substantially lower than that observed from other fish species. Modelling using these equations was used to iteratively derive optimal diet designs and feeding rations for growing Pangasius catfish.