Table 1. Formulation and proximate composition of the experimental diets (dry matter basis, %) and vitamin C level (mg/kg)

Ingredients	No vitamin C supplement	100 mg vitamin C	200 mg vitamin C	400 mg vitamin C	600 mg vitamin C	800 mg vitamin C	1, 000 mg vitamin C
Fishmeal (%)	64.44	64.44	64.44	64.44	64.44	64.44	64.44
Soybean meal (%)	7	7	7	7	7	7	7
Wheat gluten (%)	3	3	3	3	3	3	3
Rice bran (%)	3	3	3	3	3	3	3
Squid meal (%)	11	11	11	11	11	11	11
Corn gluten meal (%)	2	2	2	2	2	2	2
Wheat flour (%)	3	3	3	3	3	3	3
Fishoil (%)	1.5	1.5	1.5	1.5	1.5	1.5	1.5
Soybean oil (%)	1.36	1.36	1.36	1.36	1.36	1.36	1.36
Lecithin (%)	1	1	1	1	1	1	1
Vitamin–mineral premix (%)	1.1	1.1	1.1	1.1	1.1	1.1	1.1
Polymethylcarbamide (%)	0.5	0.5	0.5	0.5	0.5	0.5	0.5
Mono-cal (%)	0.03	0.03	0.03	0.03	0.03	0.03	0.03
Limestone/oyster shell (%)	1	1	1	1	1	1	1
Lysine (%)	0.05	0.05	0.05	0.05	0.05	0.05	0.05
Methionine (%)	0.02	0.02	0.02	0.02	0.02	0.02	0.02
Vitamin C supplement (mg/kg)	0	100	200	400	600	800	1,000
Proximate compositions
Crude protein (%)	55.35 ± 0.13	55.28 ± 0.03	55.32 ± 0.04	55.38 ± 0.02	55.33 ± 0.05	55.37 ± 0.07	55.41 ± 0.08
Crude lipid (%)	9.01 ± 0.07	9.05 ± 0.02	9.06 ± 0.03	9.07 ± 0.03	9.08 ± 0.06	9.11 ± 0.05	9.14 ± 0.07
Moisture (%)	10.11 ± 0.05	10.84 ± 0.03	10.85 ± 0.04	10.53 ± 0.03	10.57 ± 0.05	10.59 ± 0.06	10.61 ± 0.08
Ash (%)	12.58 ± 0.10	12.16 ± 0.07	12.15 ± 0.08	12.06 ± 0.03	12.08 ± 0.07	12.11 ± 0.05	12.15 ± 0.06
Vitamin C (mg/kg)	23.2	124.5	235.2	423.8	626.7	824.6	1,027.3