半胱胺对冬毛期雄性水貂生产性能、营养物质消化率及氮代谢的影响

本试验旨在研究半胱胺对冬毛期雄性水貂生产性能、营养物质消化率及氮代谢的影响。试验采用双因子试验设计,影响因素为半胱胺添加水平和添加方式。选取167日龄、体重相近的健康雄性水貂56只,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基础上添加60、90、120 mg/kg半胱胺的试验饲粮,半胱胺添加方式为连续添加,Ⅴ、Ⅵ、Ⅶ组试验饲粮分别同Ⅱ、Ⅲ、Ⅳ组,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51 d。结果表明:1)Ⅲ、Ⅴ、Ⅵ、Ⅶ组的平均日增重极显著高于对照组和Ⅳ组(P0.01),料重比极显著低于对照组和Ⅳ组(P0.01);间隔添加组的平均日增重、料重比极显著优于连续添加组(P0.01);90 mg/kg组料重比极显著低于120 mg/kg组(P0.01)。各半胱胺添加组的毛皮品质均有所改善,Ⅵ、Ⅶ组皮长及针毛、绒毛长度显著高于对照组(P0.05),间隔添加组针毛长度极显著高于连续添加组(P0.01),90 mg/kg组针毛长度显著高于60和120 mg/kg组(P0.05)。半胱胺添加水平和添加方式的交互作用对平均日增重、料重比及针毛、绒毛长度产生了显著或极显著影响(P0.05或P0.01)。2)各半胱胺添加组粗蛋白质消化率均极显著高于对照组(P0.01),干物质、粗脂肪消化率各组间无显著差异(P0.05)。3)各半胱胺添加组粪氮排出量较对照组显著或极显著降低(P0.05或P0.01),Ⅵ组氮沉积显著高于对照组及Ⅱ、Ⅳ组(P0.05),间隔添加组氮沉积、净蛋白质利用率、蛋白质生物学价值较连续添加组显著升高(P0.05)。由此可见,饲粮添加半胱胺能够促进冬毛期雄性水貂的生长,并提高毛皮品质、营养物质消化率及氮代谢。综合考虑各项指标,在本试验条件下,冬毛期雄性水貂饲粮中半胱胺的最适添加水平为90 mg/kg,添加方式为间隔添加(连续添加1周,间隔1周)。

Effects of Cysteamine on Performance,Nutrient Digestibility and Nitrogen Metabolism of Male Minks in Fur Development Period

This experiment was conducted to investigate the effects of cysteamine on performance, nutrient di-gestibility and nitrogen metabolism of male minks in fur development period. The experiment was designed in a double factorial experiment with the influence factors of cysteamine supplemental way and supplemental level. Fifty six male minks aged about 167 days were randomly divided into 7 groups with 8 replicates per group and 1 mink per replicate. The minks in control group ( groupⅠ) were fed the basal diet, the minks in groupsⅡ,Ⅲ and Ⅳ were continuously fed the experimental diets supplemented with 60, 90 and 120 mg/kg cysteamine, respectively , and the minks in groupsⅤ,ⅥandⅦwere fed the same diets as groupsⅡ,ⅢandⅣ, respec-tively, but the supplemental way was interval addition ( interval 1 week after continuously added 1 week) . The adaptation period lasted for 7 days and the formal period lasted for 51 days. The results showed as follows:1) the average daily gain of groups Ⅲ, Ⅴ, Ⅵ and Ⅶ was significantly higher than that of control group and group Ⅳ ( P<0.01) , and the feed/gain was significantly decreased compared with control group and groupⅣ( P<0.01) . The average daily gain and feed/gain in interval addition group were significantly better than those in continuous addition group ( P<0.01) . The feed/gain in 90 mg/kg group was significantly lower than that of 120 mg/kg group ( P<0.01) . The fur quality of cysteamine addition groups was improved, and the skin length and aciculum, villus length of groups Ⅵ and Ⅶ were significantly higher than those in control group ( P<0.05) . The aciculum length in interval addition group was significantly increased compared with continuous ad-dition group ( P<0.01) , and that in 90 mg/kg group was significantly higher than that in 60 and 120 mg/kg groups ( P<0.05) . The interaction effect of cysteamine supplemental way and supplemental level significantly affected the average daily gain, feed/gain, aciculum and villus length (P<0.05 or P<0.01). 2) The crude protein digestibility in cysteamine addition groups was significantly higher than that in control group ( P<0.01) , but no significant differences in the dry matter and ether extract digestibility among groups ( P>0.05) . 3) The fecal nitrogen output of cysteamine addition groups was significantly decreased compared with control group (P<0.05 or P<0.01). The nitrogen retention of group Ⅵ was significantly higher than that of control group, groups ⅡandⅣ( P<0.05) . The nitrogen retention, net protein utilization and biological value of pro-tein in interval addition group was significantly higher than those in continuous addition group (P<0.05). In conclusion, dietary with cysteamine can promote the performance, and improve the fur quality, nutrient digest-ibility and nitrogen metabolism of male minks in fur development period. Comprehensive consideration of all indicators, the cysteamine in diets for male minks is appropriate to add at the level of 90 mg/kg at weekly in-tervals ( interval 1 week after continuously added 1 week) in fur development period.