育成期水貂饲粮中半胱胺适宜添加水平和添加方式的研究

摘要

This study was conducted to investigate effects of dietary cysteamine ( CS) on growth performance, nutrient digestibility and nitrogen metabolism of growing minks, and to find the dietary cysteamine appropriate supplemental level and supplemental way. The experimental method of double-factor design was adopted. Fifty-six (86±5)-day-old healthy black short-haired female minks with similar body weight were randomly assigned into 7 groups with 8 replicates per group and 1 mink per replicate. Minks in groupⅠ( control group) were fed a basal diet;minks in groupsⅡ,Ⅲ andⅣ were fed the basal diet supplemented with 60, 90 and 120 mg/kg CS, respectively, the supplemental way was continuous;minks in groupsⅤ,ⅥandⅦwere fed the basal di-et supplemented with 60, 90 and 120 mg/kg CS, respectively, the supplemental way was interval ( continuous supplemented 1 week, 1 week interval) . The preliminary experimental period lasted for 7 days and the experi-mental period lasted for 53 days. The results showed as follows:1) dietary CS had significantly effects on the average daily feed intake and feed to gain ratio of minks ( P<0.01) , but had no significant effects on average daily gain ( P>0.05) . The feed to gain ratio in groupⅤwas significantly lower than that in groupsⅠ,ⅡandⅣ ( P<0.01); the average daily gain got the highest value in group Ⅴ, and interval group was higher than continuous group. 2) Dietary CS had significantly effects on the crude protein digestibility and ether extract di-gestibility of minks ( P<0.05) , as well as the dry matter digestibility ( P<0.01) , and the highest values were observed in group Ⅴ. The CS supplemental way had significantly effects on the dry matter digestibility ( P<0.01), and the interval group was significantly higher than continuous group (P<0.01). 3) Dietary CS had significantly effects on the nitrogen metabolic indices of minks ( P<0.05 or P<0.01) . The nitrogen deposition in groups Ⅴ, Ⅵ and Ⅶ was significantly higher than that in group Ⅰ (P<0.05), the net protein utilization and biological value of protein in groups Ⅴ, Ⅵ and Ⅶ were significantly higher than those in group Ⅰ ( P<0.01) , and the highest values were observed in group Ⅴ. The CS supplemental way had significantly effects on the nitrogen intake content, urinary nitrogen output, net protein utilization and biological value of protein of minks ( P<0.01) . The nitrogen intake content and urinary nitrogen output of minks in interval group were sig-nificantly lower than those in continuous group ( P<0.01) , the nitrogen deposition in interval group was signif-icantly lower than that in continuous group ( P<0.05) , the net protein utilization and biological value of protein in interval group were significantly lower than those in continuous group ( P<0.01) . The CS supplemental level had significantly effects on fecal nitrogen output of minks ( P<0.05) , and the fecal nitrogen output of minks in 90 mg/kg group was significantly lower than that in 60 mg/kg group ( P<0.05) . In conclusion, the dietary CS appropriate supplemental level of minks is 60 mg/kg, and the appropriate supplemental way is interval supple-mentation.%本试验旨在通过研究饲粮中半胱胺对育成期水貂生长性能、营养物质消化率及氮代谢的影响,确定饲粮中半胱胺的适宜添加水平和添加方式.试验采用双因子试验设计,选取56只(86±5)日龄、体重相近的健康雌性短毛黑水貂,随机分为7个组,每组8个重复,每个重复1只.Ⅰ组(对照组)饲喂基础饲粮;Ⅱ、Ⅲ、Ⅳ组分别在基础饲粮中添加60、90、120 mg/kg半胱胺,添加方式为连续添加;Ⅴ、Ⅵ、Ⅶ组分别在基础饲粮中添加60、90、120 mg/kg半胱胺,添加方式为间隔添加(连续添加1周,间隔1周).预试期7 d,正试期53 d.结果表明:1)饲粮中添加半胱胺极显著影响水貂的平均日采食量和料重比(P<0.01),对平均日增重无显著影响(P>0.05).Ⅴ组料重比极显著低于Ⅰ、Ⅱ、Ⅳ组(P<0.01);平均日增重以Ⅴ组最高,间隔添加组高于连续添加组.2)饲粮中添加半胱胺显著影响水貂的粗蛋白质消化率和粗脂肪消化率(P<0.05),极显著影响干物质消化率(P<0.01),且均以Ⅴ组最高.半胱胺添加方式极显著影响水貂的干物质消化率(P<0.01),间隔添加组极显著高于连续添加组(P<0.01).3)饲粮中添加半胱胺显著或极显著影响水貂的氮代谢指标(P<0.05或P<0.01).Ⅴ、Ⅵ、Ⅶ组氮沉积显著高于Ⅰ组(P<0.05),Ⅴ、Ⅵ、Ⅶ组净蛋白质利用率和蛋白质生物学价值均极显著高于Ⅰ组(P<0.01),且以Ⅴ组最高.半胱胺添加方式极显著影响水貂的食入氮含量、尿氮排出量、净蛋白质利用率和蛋白质生物学价值(P<0.01).间隔添加组水貂的食入氮含量和尿氮排出量极显著低于连续添加组(P<0.01);间隔添加组的氮沉积显著低于连续添加组(P<0.05);间隔添加组的净蛋白质利用率和蛋白质生物学价值极显著高于连续添加组(P<0.01).半胱胺添加水平显著影响水貂的粪氮排出量(P<0.05),90 mg/kg组水貂的粪氮排出量显著低于60 mg/kg组(P<0.05).综合各项指标,育成期水貂饲粮中半胱胺的适宜添加水平为60 mg/kg,适宜添加方式为间隔添加.