The effect of oregano essential oil and Bacillus subtilis supplements on winter fur growth in raccoon dogs (Nyctereutesprocyonoides)

A total of 160 healthy raccoon dogs with no significant difference in body weight were selected and randomly divided into 10 groups, with each group having 4 replicates and each replicate consisting of 4 individuals. The pre-test period lasted for 7 days, followed by a formal test period of 82 days. The raccoon dogs in the 10 groups were fed basal diet supplemented with 50 mg/kg chlortetracycline and 100 mg/kg quinocetone (control group), 100 mg/kg OEO and 150 mg/kg BS (group I), 100 mg/kg OEO and 300 mg/kg BS (group II), 100 mg/kg OEO and 450 mg/kg BS (group III), 200 mg/kg OEO and 150 mg/kg BS (group IV), 200 mg/kg OEO and 300 mg/kg BS (group V), 200 mg/kg OEO and 450 mg/kg BS (group VI), 300 mg/kg OEO and 150 mg/kg BS (group VII), 300 mg/kg OEO and 300 mg/kg BS (group VIII), 300 mg/kg OEO and 450 mg/kg BS (group IX). The results showed that there were no significant difference in final weight and average daily gain among all groups (P > 0.05). The ADFI of group IV was the least, which was significantly lower than that of the control group (P < 0.05). The F/G in group IV was significantly higher than that in groups I, II, III, V, VII and VIII (P < 0.05). There were no significant differences in DM output, DM digestibility, protein digestibility and fat digestibility among groups (P > 0.05). There were no significant differences in nitrogen intake, fecal nitrogen, urine nitrogen, nitrogen retention, net protein utilization rate and protein biological value among the ten groups (P > 0.05). There was no significant difference in serum SOD activity, GSH-PX activity, MDA content and T-AOC activity between the groups supplemented with OEO and BS compared with the antibiotic group (P > 0.05). There was no significant difference in body length, skin length, skin weight, guard hair length and underfur length between each level group and the control group (P > 0.05). The feed input cost of the other experimental groups was lower than that of the control group except for the experimental groups II, VIII and IX. The cost of feed additives in each experimental group was higher than that in the control group. The income of group III, VII and IX was higher than that of the control group, and the income of group III was the highest. In conclusion, under the experimental conditions, dietary supplementation of OEO and BS to the diet can improve the growth performance, fur quality as well as absorption of nutrients and antioxidant level by the body of raccoon dogs in winter fur period. The optimum supplemental levels of OEO and BS in the diet of raccoon dog in winter fur period were 100 mg/kg and 450 mg/kg.