|Other Abstract||Five growth trials were conducted to evaluate the requirements of arginine, histidine, phenylalanine, tryptophan and taurine for gibel carp Carassius auratus gibelio. Semi-purified experimental diets were formulated to be isonitrogenous and isocaloric. L-crystalline amino acids except test amino acid were supplemented corresponding to the amino acid profile of muscle protein of gibel carp. In the trial for determining the arginine requirement, seven test diets using casein as intact protein were formulated to contain different levels of arginine (0.51%, 0.86%, 1.25%, 1.65%, 2.03%, 2.43% and 2.84% of dry diet). In the trial for determining the histidine requirement, seven diets using casein and getaline as sources of intact protein were formulated to contain different levels of histidine (0.39%, 0.53%, 0.66%, 0.88%, 0.97%, 1.08% and 1.22% of dry diet). In the trial for determining the phenylalanine experiment, seven diets using casein and getaline as sources of intact protein were formulated to contain different levels of phenulalanine (0.73%, 0.89%, 1.09%, 1.26%, 1.33%, 1.58% and 1.67% of dry diet) with fixed tyrosine level (1.04%). In the trial for determing the tryptophan trail, nine diets were formulated with white fishmeal and getaline as intact protein sources. Seven diets contained different tryptophan levels (0.15%, 0.19%, 0.27%, 0.40%, 0.72%, 1.14% and 1.73% of dry diet) with 100mg kg-1 niacin supplemented. Two diets were supplemented 0 and 32mg kg-1 niacin at 1.10% tryptophan level (NA0 and NA32). In the trial for determining the taurine requirement, nine diets were prepared using casein and getaline as sources of intact protein. Seven of them were formulated with different levels of taurine (0.00%, 0.19%, 0.36%, 0.52%, 0.71%, 0.86% and 1.78% of dry diet), two were added 1.00% and 2.00% cysteine (Cys-1 and Cys-2). In these experiments, specific growth rate (SGR), feeding rate (FR), feed efficiency (FE), protein efficiency ratio (PER), hepatosomatic index (HSI), condition factor (CF), body composition, biochemical indices were determined.
The main results were shown as the following:
1.Dietary arginine, histidine, phenylalanine, tryptophan and taurine requirments of gible carp Carassius auratus gibelio are 1.55%、0.82%、1.09% (Tyr=1.04%)、0.26% (NA=100mg/kg) and 0.40% of dry diet, corresponding to 4.44%、2.21%、3.02% (Tyr=2.98%)、0.78% (NA=100mg/kg) and 1.07% of dietary protein, respectively；
2.It indicated tryptophan may be a precursor of niacin for juvenile gibel carp；
3.It suggested that taurine could not be synthesized from cysteine in juvenile gibel carp.|