Abstract:A 10-week feeding experiment in indoor flowing-through water system was conducted to investigate the effects of dietary taurine, methionine and cysteine on growth and amino acid composition of Japanese seabass [mean initial weight (8.13±0.05) g]. A basal diet (as control) was formulated with 15% fish meal, 30% soybean meal, 13% corn gluten meal and 12% wheat gluten. The four experimental diets were supplemented with 1.0%, 2.0% taurine, 0.5% methionine and 0.5% cysteine (named as T-1, T-2, M-0.5 and C-0.5, respectively) to the basal diet to formulate isonitrogenous and isolipidic diets. Triplicate groups of 25 fish were fed to apparent satiation twice daily. During the experimental period, water temperature ranged in 23.2-28.8℃, and the dissolved oxygen content was approximately 7 mg/L. The results showed that the final body weight (FBW), specific growth rate (SGR), weight gain (WGR) and feed intake (FI) of T-1, T-2, M-0.5 and C-0.5 groups were significantly higher than those in the control group (P<0.05). Fish fed the diets with taurine, methionine and cysteine supplementation had significantly higher whole-body crude protein and crude lipid contents (P<0.05), while the whole-body moisture followed the opposite pattern. The taurine contents of liver and muscle in T-1 and T-2 groups were significantly higher than that in T-0 group (P<0.05), however, the taurine contents of liver and muscle in M-0.5 and C-0.5 groups showed no significant difference with T-0 group (P>0.05). Compared to the control, fish in T-1, T-2 and C-0.5 groups had higher liver essential amino acids and total amino acids contents (P<0.05), while these values were not significantly different in the M-0.5 group (P>0.05). The muscle essential amino acids content of the M-0.5 group was significantly higher than that of T-0 group (P<0.05), while fish in T-1, T-2 and M-0.5 groups had significantly higher muscle total amino acids contents than T-0 group (P<0.05). It is concluded that dietary taurine, methionine and cysteine could promote the growth of juvenile Japanese seabass under the experimental conditions, it can also improve the amino acids deposition in liver and muscle.
