Effects of Dietary Zinc Level on Growth Performance,Nutrient Digestibility and Nitrogen Metabolism of Growing Blue Foxes ( Alopex lagopus)

This experiment was conducted to study the effects of dietary zinc level on growth performance,nutrient digestibility and nitrogen metabolism of growing blue foxes.Nighty 8-week-old healthy blue foxes with an average body weight of(2.21 ± 0.49) kg were divided into 5 groups with 18 foxes per group,each group had 9 male foxes and 9 female foxes,and the average body weight of each group showed no significant difference(P 0.05).The blue foxes were fed the diets with dietary zinc levels of 39.75(group Ⅰ),60.00(group Ⅱ),80.00(group Ⅲ),100.00(group Ⅳ) and 120.00 mg /kg(group Ⅴ),respectively.The pretest lasted for 7 days and the trial period lasted for 60 days.The results showed as follows: 1) there was no significant difference in the average daily gain of male foxes among all groups(P 0.05);the average daily gain of female foxes in group Ⅱ was significantly higher than that in group Ⅴ(P 0.01).2) The dry matter digestibility of male foxes in group Ⅱ was significantly higher than that in groups Ⅰ and Ⅳ(P 0.01),and was significantly higher than that in groups Ⅲ and Ⅴ(P 0.05);the fat digestibility in group Ⅱ was significantly higher than that in groups Ⅰ,Ⅲ and Ⅳ(P 0.01);the protein digestibility in group Ⅱ was significantly higher than that in groups Ⅰ,Ⅳ and Ⅴ(P 0.01).3) The nitrogen intake of male foxes in groups Ⅰand Ⅳ was significantly higher than that in group Ⅱ(P 0.01);the fecal nitrogen in groups Ⅰ,Ⅳ and Ⅴ was significantly higher than that in group Ⅱ(P 0.01).The urine nitrogen of female foxes in groups Ⅲ and Ⅴ was significantly higher than that in group Ⅱ(P 0.05);the nitrogen deposition in groups Ⅰ and Ⅱ was significantly higher than that in group Ⅴ(P 0.01),and significantly higher than that in group Ⅲ(P 0.05);the net protein utilization in groups Ⅰ and Ⅱ was significantly higher than that in group Ⅴ(P 0.01),and significantly higher than that in group Ⅲ(P 0.05);the biological value of protein in group Ⅱ was significantly higher than that in group Ⅴ(P 0.01),and the biological value of protein in groups Ⅰand Ⅱ was significantly higher than that in groups Ⅲ and Ⅴ(P 0.05).In conclusion,dietary zinc level at 60.00 mg / kg can improve the growth performance and net protein utilization,and decline the drain of fecal nitrogen and urine nitrogen.