Table 1.

The formulation and approximate composition analysis of the six diets

Ingredients, %	Dietary protein levels, %
	15.91	19.39	22.10	25.59	28.53	31.42
Fish meal	5.40	6.43	7.46	8.48	9.51	10.54
Casein	12.89	15.34	17.78	20.23	22.68	25.12
Gelatin	2.50	2.97	3.44	3.92	4.39	4.86
α-starch	18.00	18.00	18.00	18.00	18.00	18.00
Corn starch	44.60	41.11	37.61	34.13	30.60	27.10
Microcrystalline cellulose	6.68	6.34	6.00	5.64	5.33	5.00
Fish oil	2.43	2.34	2.26	2.17	2.09	2.00
Soybean oil	1.76	1.76	1.76	1.76	1.76	1.76
Vitamin premixa	1.00	1.00	1.00	1.00	1.00	1.00
Mineral premixb	2.00	2.00	2.00	2.00	2.00	2.00
Ca(H2PO4)2	1.67	1.64	1.61	1.59	1.56	1.53
Choline chloride premixc	1.00	1.00	1.00	1.00	1.00	1.00
Ethoxyquin	0.05	0.05	0.05	0.05	0.05	0.05
L-Trp	0.03	0.03	0.03	0.04	0.04	0.05
Nutrient contents, %
Protein	16.00	19.00	22.00	25.00	28.00	31.00
Lipid	4.70	4.70	4.71	4.71	4.72	4.72
n-3	1.02	1.02	1.02	1.02	1.02	1.02
n-6	0.94	0.94	0.94	0.94	0.94	0.94
Digestive energy, KJ/g	13.89	13.89	13.89	13.89	13.89	13.89

^aPer kilogram of vitamin premix (g/kg): retinyl acetate (500,000 IU/g), 0.19; cholecalciferol (500,000 IU/g), 0.20; DL-α-tocopherol acetate (50%), 23.2; menadione (50%), 0.38; cyanocobalamin (1%), 0.94; D-biotin (2%), 0.75; folic acid (95%), 0.17; thiamine nitrate (98%), 0.09; ascorhyl acetate (95%), 9.77; niacin (99%), 3.44; meso-inositol (98%), 28.5; calcium-D-pantothenate (98%), 3.85; riboflavin (80%), 0.73; pyridoxine hydrochloride (98%), 0.45. All ingredients were diluted with corn starch to 1 kg

^bPer kilogram of mineral premix (g/kg): MnSO₄·H₂O (31.8% Mn), 2.66; MgSO₄⋅H₂O (15.0% Mg), 256.79; FeSO₄·H₂O (30.0% Fe), 12.61; ZnSO₄·H₂O (34.5% Zn), 8.87; CuSO₄.5H₂O (25.1% Cu), 0.95; Ca (IO₃)₂ (3.2% Ca), 0.0668 g; Na₂SeO₃ (45% Se), 6.07. All ingredients were diluted with corn starch to 1 kg

^cPer kilogram of choline chloride premix contains choline chloride (50%) 261.95 g, the rest diluted with corn starch to 1 kg