Table 1.

Formulation and chemical proximate composition of the experimental diets.

Ingredients (gkg−1)	G0	G100	G200	G400	G800
Soybean protein concentrate1	300	300	300	300	300
Fish meal2	200	200	200	200	200
Wheat middling3	200	200	200	200	200
Extruded soybean4	145	145	145	145	145
Chicken meal5	50	50	50	50	50
Fish oil6	20	20	20	20	20
Soybean oil	30	30	30	30	30
Soybean phospholipid	30	30	30	30	30
Calcium dihydrogen phosphate	10	10	10	10	10
Vitamin premix7	3	3	3	3	3
Mineral premix8	6	6	6	6	6
GSH (mgkg−1)	0	100	200	400	800
Glycine	6	5.9	5.8	5.6	5.2
Proximate analysis of experimental diet
Moisture	9.23	9.18	9.19	9.20	9.21
Crude protein	437.1	436.8	436.6	435.8	436.9
Crude lipid	109.3	108.6	109.1	109.2	109.5
Ash	6.68	6.71	6.53	6.61	6.56
Gross energy (MJkg−1)	18.65	18.59	18.61	18.56	18.62

¹Dalong Feed Company, Harbin, China.

²Dalong Feed Company, Harbin, China.

³Huada Feed Company, Harbin, China.

⁴Dalong Feed Company, Harbin, China.

⁵Dalong Feed Company, Harbin, China.

⁶Huludao Chia Tai Feed Corporation, Huludao, China.

⁷Vitamin premix (mgkg⁻¹): ascorbic acid 200, alpha-tocopherol 100, menadione sodium bisulfate 5, retinol acetate 5.2, cholecalciferol 0.07, thiamin 25, riboflavin 40, pyridoxine 25, cyanocobalamin 0.8, nicotinic acid 275, folic acid 8, biotin 5, pantothenic acid 100.

⁸Mineral premix (mgkg⁻¹): MgSO₄·7H₂O 2000, KCl 1,500, FeSO₄·7H₂O 1,000, CuSO₄·5H₂O 20, MnSO₄·4H₂O 100, ZnSO4·7H₂O 150, KI 3, NaCl 500, CoCl₂ 5, Na₂SeO₃ 3.