Abstract: To study effect of cysteamine on the growing function for silver fox in rearing period, 224 (112♂ +112♀) of two-month-old healthy silver foxes were selected, and the male weigh about 2.50 kg (P＞0.05),while the female around 2.10 kg (P＞0.05). Among them, 200 (100♂ +100♀) foxes were randomly selected for the test group, and the other 24 (12♂ +12♀) individuals were for the control group. Feeding experiments last about three months (from June 10 to August 31 in 2004). Experiment design of factor analysis, a multiple factor design, was adopted, in which two factors were repeated in experiments. Different amount of cysteamine (10 mg, 40 mg, 70 mg, 100 mg, 130 mg per kg of body weight BW) were added respectively at 5 different time intervals (1 d, 3 d, 5 d, 7 d and 9 d). There were 12 repeats of test in control groups, and a couple of individuals for each one. Finally, body weight gain, feed conversion ratio and feed intake were measured. Results showed that only the combination of 70 mg/kg BW of cysteamine added every 5days would produce the highest body weight gain and feed conversion ratio among total 25 combinations, meanwhile it increased by 15.08% (P<0.05) and 20.21%(P<0.01) respectively compared with those of the control group. However, feed intake of the test groups silver fox was lower than that of the control group, individuals of the combination of 70 mg/kg BW of cysteamine added every 5days decreased 4.52% (P<0.05) of feed intake compared with control group. 

Key words: cysteamine; silver fox; body weight gain; feed conversion ratio