Abstract: This experiment was conducted to study the effects of dietary copper on the fur quality, organ index, serum biochemical indices and relative genes expression of fur growing Raccoon dogs. One hundred and five healthy male Raccoon dogs were randomly divided into 7 groups with 15 replicates per group and 1 Raccoon dog per replicate. The Raccoon dogs were fed 7 diets with different copper supplemental levels (as methionine chelated copper)：0 (control group), 30(group Ⅰ), 45(group Ⅱ), 60 (group Ⅲ), 75 (group Ⅳ), 90 (group Ⅴ) and 200 mg·kg^-1 (group Ⅵ). The pre-test period lasted for 7 days and the trial period lasted for 60 days. At the end of the experiment, 8 Raccoon dogs in each group were selected for blood collection and slaughter. The related indices and genes expression were detelted. The results showed as follows: 1) Copper addition level had a significant effect on the skin length, body length, guard hair fibre length, guard hair fibre fineness(P<0.05), but had no significant effect on skin weight, underfur hair fibre length, underfur hair fibre fineness. 2) Dietary copper su-pplementation had no significant effect on the heart index, liver index, kidney index and spleen index of Raccoon dogs. 3) With the increase of copper level, serum GLU content also significantly increased (P<0.05), and different copper addition doses had significant effects on serum LDH, AST and ALT activity (P<0.05), and the serum CER, T-SOD and Cu-Zn SOD activity increased first and then tended to be stable (P<0.05). 4) Different dietary copper levels had significant on Liver CER, Cu-Zn SOD、GHR、IGF-1 genes expression. The expression levels of CER and Cu-Zn SOD genes in the liver of the groups of 90 and 200 mg·kg^-1 were significantly higher than that in the group of 30 mg·kg^-1, and the expression levels of CER and Cu-Zn SOD genes in the group of 30 mg·kg^-1 were significantly higher than that in control group (P<0.05). The expression level of GHR and IGF-1 genes in the group of 90 mg·kg^-1 were significantly higher than that in the control group (P<0.05).When the dietary copper level was 60-75 mg·kg^-1, the fur quality of Raccoon dogs was the best; The CER and Cu-Zn SOD activity in serum did not change significantly with the change of copper level and there was no significant change in serum AST, ALT and LDH enzyme activity; in addition, the expression of GHR and IGF-1 genes in liver increased to promote the growth of Raccoon dogs. Combined with the above determination indicators, it is recommended that the dietary copper content of Raccoon dogs is 60-75 mg·kg^-1.

Key words: copper, Raccoon dog, fur quality, CER, Cu-Zn SOD