本试验旨在研究半胱胺对育成期雄性水貂生长性能、营养物质消化率及氮代谢的影响。采用双因子试验设计,选取56只(86±5)日龄、体重相近的健康雄性水貂,随机分为7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组分别饲喂在基础饲粮风干基础上添加60、90和120 mg/kg半胱胺的试验饲粮,添加方式为连续添加,Ⅴ、Ⅵ、Ⅶ组试验饲粮分别同Ⅱ、Ⅲ、Ⅳ组,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)间隔添加组的末重及平均日采食量、平均日增重显著或极显著高于连续添加组(P<0.05或P<0.01)。90 mg/kg组平均日采食量显著高于60 mg/kg组(P<0.05),60和90 mg/kg组料重比均显著低于120 mg/kg组(P<0.05)。半胱胺的添加方式和添加水平对水貂各生长性能指标的影响无显著交互作用(P>0.05)。2)间隔添加组干物质、粗脂肪消化率显著或极显著高于连续添加组(P<0.05或P<0.01)。半胱胺添加水平对水貂各营养物质消化率无显著影响(P>0.05),但均以90 mg/kg组最高。半胱胺的添加方式和添加水平对水貂各营养物质消化率的影响无显著交互作用(P>0.05)。3)半胱胺添加方式和添加水平均显著影响水貂食入氮(P<0.05),间隔添加组极显著高于连续添加组(P<0.01),90 mg/kg组显著高于60 mg/kg组(P<0.05),但对粪氮、尿氮排出量及净蛋白质利用率和蛋白质生物学价值无显著影响(P>0.05)。此外,半胱胺添加方式和添加水平对水貂尿氮排出量存在显著交互作用(P<0.05)。综合各项指标,育成期雄性水貂饲粮中半胱胺的适宜添加量为90 mg/kg,添加方式为间隔添加(连续添加1周,间隔1周)。

This experiment was conducted to investigate the effects of cysteamine on growth performance, nutrient digestibility and nitrogen metabolism of male minks in growing period.The experiment was designed in a double factorial experiment, and fifty-six healthy male minks aged (86±5) days were randomly divided into 7 groups with 8 replicates per group and 1 mink per replicate.The minks in control group (group Ⅰ) were fed a basal diet, the minks in groups Ⅱ, Ⅲ and Ⅳ were continuously fed the experimental diets which supplemented with 60, 90 and 120 mg/kg cysteamine on the basis of the basal diet (air-dry basis), respectively, and the groups Ⅴ, Ⅵ and Ⅶ were fed the same diets with groups Ⅱ, Ⅲ and Ⅳ, respectively, but at interval supplementation (continuously supplemented 1 week and at interval of 1 week).The adaptation period lasted for 7 days and the formal period lasted for 53 days.The results showed as follows: 1) the final weight, average daily gain and average daily feed intake of interval supplementation group were significantly higher than those of continuous supplementation group (P<0.05 or P<0.01).The average daily feed intake of 90 mg/kg group was significantly higher than that of 60 mg/kg group (P<0.05), and the feed/gain of 60 and 90 mg/kg groups was significantly lower than that of 120 mg/kg group (P<0.05).There were no significant interactions on growth performance indices between cysteamine supplemental way and supplemental level (P>0.05).2) the dry matter and ether extract digestibility of interval suppletentation group were significantly higher than those of continuous supplementation group (P<0.05 or P<0.01).Cysteamine supplemental level had no significant effects on all nutrient digestibility (P>0.05), but the highest values of them were found in 90 mg/kg group.There were no significant interactions on all nutrient digestibility between cysteamine supplemental way and supplemental level (P>0.05).3) Cysteamine supplemental way and supplemental level had significant effects on nitrogen intake (P<0.05), but had no significant effects on fecal nitrogen and urinary nitrogen excretion, net protein utilization and biological value of protein (P>0.05).The way of interval feeding had significantly higher nitrogen intake than continuous feeding (P<0.01), and the group supplemented with 90 mg/kg cysteamine had significantly higher nitrogen intake than supplemented with 60 mg/kg cysteamine (P<0.05).There was significant interaction on urinary nitrogen excretion between cysteamine supplemental way and supplemental level (P<0.05).Considering above all indices, the cysteamine in diets for male minks in growing period is appropriate to add at the level of 90 mg/kg at interval supplementation (continuously suplemented 1 week and at interval of 1 week).