Dietary protein requirement of juvenile shi drum, Umbrina cirrosa (L.)

This study was undertaken to determine the dietary protein requirement of shi drum (Umbrina cirrosa L.) with an initial weight of 86.3 +/- 0.4 g. The fish were fed five isoenergetic diets containing dietary protein levels ranging from 35% to 59% by 6% increments [the estimated digestible protein (DP) levels ranged between 29.6% and 52.8%], and the growth response over a 10-week period was monitored. Each experimental diet was given to triplicate groups of fish. The final weight, weight gain and daily growth coefficient increased with the dietary protein level, reaching a plateau at the dietary level of 47% protein. The feed conversion ratio improved with increasing dietary protein level. The daily feed intake was significantly lower in fish fed 53% and 59% protein diets compared with those fed 35% protein diet. However, protein intake showed an increasing trend with increasing dietary protein and became significantly different between the 59% and the 35% protein diets. The protein efficiency ratio, protein retention and condition factor were not affected significantly by the dietary treatments. The final body composition was not influenced by the treatments. The recommended dietary protein percentage and DP/digestible energy (DE) ratio for juvenile shi drum diets are 51.4% (45.6% DP) and 28.5 g DP MJ DE-1 respectively.