饲粮添加铜水平对育成期水貂生长性能、营养物质消化率及氮代谢的影响

本试验旨在研究饲粮铜添加水平对育成期水貂生长性能、营养物质消化率及氮代谢的影响.选择(60±3)日龄健康雄性水貂80只,随机分成8组,每组10个重复,每个重复1只貂.8组水貂分别饲喂铜添加水平为0(Ⅰ组)、4(Ⅱ组)、8(Ⅲ组)、16(Ⅳ组)、32(V组)、64(Ⅵ组)、128(Ⅶ组)、256 mg/kg(Ⅷ组)的试验饲粮.预试期7d,正试期60 d.结果表明:Ⅴ组的末重和平均日增重极显著高于Ⅷ组(P＜0.01),而料重比则极显著低于Ⅷ组(P＜0.01).Ⅴ组的平均日采食量极显著高于Ⅰ和Ⅶ组(P＜0.01),显著高于Ⅲ组(P＜0.05).Ⅴ组的干物质采食量极显著高于Ⅷ组(P＜0.01).Ⅴ组的干物质消化率极显著高于Ⅵ组(P＜0.01),显著高于Ⅱ和Ⅷ组(P＜0.05).Ⅴ组的蛋白质消化率极显著高于Ⅷ组(P＜0.01),显著高于Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅵ和Ⅶ组(P＜0.05).Ⅳ和Ⅴ组的脂肪消化率显著高于Ⅷ组(P＜0.05).Ⅴ组的食入氮极显著高于Ⅷ组(P＜0.01).Ⅴ组的氮沉积极显著高于Ⅱ、Ⅲ、Ⅵ和Ⅷ组(P＜0.01),显著高于Ⅰ和Ⅳ组(P＜0.05).Ⅴ组的净蛋白质利用率显著高于Ⅱ、Ⅲ、Ⅵ和Ⅷ组(P＜0.05).Ⅴ组的蛋白质生物学价值极显著高于Ⅲ组(P＜0.01),显著高于Ⅰ、Ⅱ、Ⅵ和Ⅷ组(P＜0.05).由此得出,饲粮铜添加水平为32 mg/kg(总铜水平为39 mg/kg)时,营养物质消化率、氮沉积、净蛋白质利用率及蛋白质生物学价值较为理想,且可获得较佳的生长性能.

Effects of Dietary Copper Supplemental Level on Growth Performance, Nutrient Digestibility and Nitrogen Metabolism of Growing Minks

This experiment was conducted to study the effects of dietary copper supplemental level on growth performance,nutrient digestibility and nitrogen metabolism of growing minks.Eighty healthy male minks at the age of(60±3) days were randomly divided into 8 groups with 10 replicates each and 1 mink per replicate.The minks in the 8 groups were fed experimental diets with copper supplemental levels of 0(group Ⅰ),4(group Ⅱ),8(group Ⅲ),16(group Ⅳ),32(group Ⅴ),64(group Ⅵ),128(group Ⅶ) and 256 mg/kg(group Ⅷ),respectively.The pre-test period lasted for 7 days and the trial period lasted for 60 days.The results showed as follows: the final weight and average daily gain in the group Ⅴ were extremely significantly higher than those in the group Ⅷ(P<0.01),while the feed/gain in the group Ⅴ was extremely significantly lower than that in the group Ⅷ(P<0.01).The average daily feed intake in the group Ⅴ was extremely significantly higher than that in the groups Ⅰ and Ⅶ(P<0.01),and was significantly higher than that in the group Ⅶ(P<0.05).The dry matter(DM) intake in the group Ⅴ was extremely significantly higher than that in the group Ⅷ(P<0.01).The DM digestibility in the group Ⅴ was extremely significantly higher than that in the group Ⅵ(P<0.01),and was significantly higher than that in the groups Ⅱ and Ⅷ(P<0.05).The protein digestibility in the group Ⅴ was extremely significantly higher than that in the group Ⅷ(P<0.01),and was significantly higher than that in the groups Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅵ and Ⅶ(P<0.05).The fat digestibility in the groups Ⅳ and Ⅴ was significantly higher than that in the group Ⅷ(P<0.05).The nitrogen intake in the group Ⅴ was extremely significantly higher than that in the group Ⅷ(P<0.01).The nitrogen deposition in the group Ⅴ was extremely significantly higher than that in the groups Ⅱ,Ⅲ,Ⅵ and Ⅷ(P<0.01),and was significantly higher than that in the groups Ⅰ and Ⅳ(P<0.05).The net protein utilization in the group Ⅴ was significantly higher than that in the groups Ⅱ,Ⅲ,Ⅵ and Ⅷ(P<0.05).The biological value of protein in the group Ⅴ was extremely significantly higher than that in the group Ⅲ(P<0.01),and was significantly higher than that in the groups Ⅰ,Ⅱ,Ⅵ and Ⅷ(P<0.05).In conclusion,when the dietary copper supplemental level arrives at 32 mg/kg(total copper level is 39 mg/kg),the nutrient digestibility,nitrogen deposition,net protein utilization and biological value of protein of growing minks are more ideal,and the growth performance is better.