饲粮蛋白质水平对育成期母貂生长性能、营养物质消化代谢及血清生化指标的影响

本文旨在探讨饲粮蛋白质水平对育成期母貂生长性能、营养物质消化代谢及血清中与氮代谢相关的生化指标的影响。选择健康（５０±３）日龄断奶的雌性水貂 ６０只，平均体重为（０．５７７±０．０７３）ｋｇ，随机分成 ６组，每组 １０个重复，每个重复 １只，单笼饲养。６组水貂分别饲喂蛋白质水平为 ２８％、３０％、３２％、３４％、３６％、３８％的试验饲粮。在水貂 ６５、８０、９５、１１０日龄时各进行 １次消化代谢试验，分析各日龄水貂的蛋白质消化率、脂肪消化率、氮沉积、蛋白质生物学价值、饲料转化率及体增重等指标。结果表明：５０～６５日龄，３８％蛋白质组体增重极显著高于２８％和 ３２％蛋白质组（Ｐ＜０．０１），３８％蛋白质组饲料转化率极显著优于 ２８％和 ３２％蛋白质组（Ｐ＜０．０１）；５０～１１０日龄，３２％和 ３４％蛋白质组体增重显著高于 ２８％蛋白质组（Ｐ＜０．０５）。９５日龄时，３２％、３４％和 ３８％蛋白质组的蛋白质消化率极显著高于 ２８％和 ３０％蛋白质组（Ｐ＜０．０１）。１１０日龄时，３４％蛋白质组蛋白质生物学价值和净蛋白质利用率极显著低于其他试验组（Ｐ＜０．０１）。１１０日龄时，３８％蛋白质组尿素氮含量极显著高于其他各组（Ｐ＜０．０１）；３４％和３６％蛋白质组总氨基酸含量显著高于 ２８％蛋白质组（Ｐ＜０．０５）。综合试验中的测定指标，建议５０～６５日龄，水貂饲粮蛋白质水平为 ３６％ ～３８％；６６～８０日龄，水貂饲粮蛋白质水平为 ３４％ ～３６％；８１～１１０日龄，水貂饲粮蛋白质水平为 ３２％ ～３４％。

Effects of Dietary Protein Levels on Growth Performance,Digestibility of Nutrients,and Serum Biochemical Parameters in Growing Female Minks

The purpose of this experiment was to study the regularity of growth performance,nutrient digestibility,and serum biochemical parameters with different dietary protein levels in growing female minks(Mustela vison).Sixty aged(50±3) days female minks were randomly divided into six groups according to a single-factor design.Each group included ten replications in which one mink fed in a single cage.The minks were fed experimental diets with protein levels of 28%,30%,32%,34%,36% and 38%,respectively.The metabolism trial was used to analyze the digestibility of protein and fat,nitrogen deposition,protein biological value,feed conversion ratio,and body weight gain of minks at 65,80,95 and 110 days of age.The results showed as follows: at 50 to 65 days of age,body weight gain and feed conversion ratio of minks fed diet with 38% protein were significantly higher than those of minks fed diets with 28% and 32% protein(P<0.01).At 50 to 110 days of age,body weight gain of minks fed diets with 32% and 34% protein was significantly higher than that of minks fed diet with 28% protein(P<0.05).Compared with the 28% and 30% protein groups,the minks in 32%,34% and 38% protein groups had greatly significant digestibility of crude protein(P<0.01) at 95 days of age.The protein biological value and net protein utilization in 34% protein group were the lowest among all the groups(P<0.01) at 110 days of age.At 110 days of age,the serum urea nitrogen content in 38% protein group was significantly higher than that in the other groups(P<0.01),and the total amino acid content in 34% and 36% protein groups was significantly higher than that in 28% protein group(P<0.05).Considering the determination of indexes,it is recommended that dietary protein levels are 36% to 38% for minks aged 50 to 65 days;dietary protein levels are 34% to 36% for minks aged 66 to 80 days;dietary protein levels are 32% to 34% for minks aged 81 to 110 days.