Effects of Dietary Zinc Level on Growth Performance,Nutrient Digestibility,Nitrogen Metabolism and Fur Quality of Blue Foxes during Growing-Furring Period

This experiment was conducted to study the effects of dietary zinc level on growth performance,nutrient digestibility,nitrogen metabolism and fur quality of blue foxes during the growing-furring period,and to find the appropriate dietary zinc level for the blue foxes. Ninety 16-week-old healthy blue foxes with the average body weight of( 5.80±0.60) kg were randomly divided into 5 groups with 18 foxes per group,each group had 9 male foxes and 9 female foxes. The blue foxes were fed the experimental diets with dietary zinc levels of 41.25( group Ⅰ),60.00( group Ⅱ),80.00( group Ⅲ),100.00( group Ⅳ) and 120.00 mg / kg( group Ⅴ),respectively. The pretest period lasted for 7 days and the test period lasted for 60 days. The results showed as follows: 1) the final weight of male foxes in group Ⅲ was significantly higher than that in groups Ⅰ and Ⅱ( P0.05); there was no significant difference in the average daily gain of male foxes and female foxes among all groups( P0.05). 2) There was no significant difference in dry matter output,dry matter digestibility and protein digestibility of male foxes and female foxes among all groups( P0.05); the fat digestibility of male foxes in group Ⅴ was significantly higher than that in group Ⅰ( P0.05). 3) There was no significant difference in nitrogen intake,fecal nitrogen,urinary nitrogen,nitrogen deposition,net protein utilization and biological value of protein of male foxes among all groups( P0.05). The fecal nitrogen of female foxes in group Ⅰ was significantly higher than that in group Ⅲ( P0.05); the nitrogen deposition and net protein utilization of female foxes in groups Ⅲ,Ⅳ and Ⅴ were significantly higher than those in group Ⅰ( P 0.01); the biological value of protein of female foxes in group Ⅳ was significantly higher than that in group Ⅰ( P0.05). 4) There was no significant difference in body length,guard fur length,under fur length and dry fur length of male foxes among all groups( P 0.05). The guard fur length of female foxes in group Ⅴ was significantly higher than that in other groups( P0.01); the under fur length of female foxes in group Ⅴ was significantly higher than that in groups Ⅰ and Ⅲ( P 0.05). In conclusion,the appropriate dietary zinc level for blue foxes during the growing-furring period is 80 to 120 mg / kg,which can be possible to meet the requirement for blue foxes and have better growth performance and fur quality.