Reevaluation of the Dietary Protein Requirements and Optimum Dietary Protein to Energy Ratios in Japanese Eel, Anguilla japonica (original) (raw)

2007, Journal of the World Aquaculture Society

A 2 3 3 factorial design was used to reevaluate the dietary protein requirements and to determine the optimum dietary protein to energy (P/E) ratios in Japanese eel, Anguilla japonica, reared in the recirculating system. For each of two experiments, six experimental diets (45 P 16 , 45 P 17 , 45 P 19 , 50 P 16 , 50 P 17 , and 50 P 19) were formulated and prepared to contain two protein levels (45 and 50%) and three energy levels (16, 17, and 19 kJ/g diet) at each protein level. In the first experiment, glass eel of initial weight 0.1 6 0.02 g (mean 6 SD) were used, while the second experiment was conducted with juvenile eel of initial weight 15.0 6 3 g (mean 6 SD). The first and second experimental periods were 6 and 16 wk for the glass and juvenile eel, respectively. At the end of the first experiment, there were no protein, energy, and their interaction effects. Also, there were no significant differences in weight gain (WG), specific growth rate (SGR), feed efficiency (FE), and protein efficiency ratio (PER) for glass Japanese eel fed all diets. Although there were no significant differences in growth parameters of glass eel fed all experimental diets, these parameters were higher for fish fed 50 P 16 than for fish fed the other diets. For the second experiment, there were significant protein effects on WG, SGR, and PER (P , 0.05). However, there were neither significant energy effects nor protein and energy interaction effects on WG, SGR, FE, and PER. Fish fed 45 P 19 had a higher WG, SGR, and PER than did fish fed 45