本试验旨在研究饲粮蛋白质水平和限饲对冬毛期水貂生产性能、消化代谢和血清生化指标的影响。选择150日龄健康美国短毛黑公貂40只,随机分为4组,每组10个重复,每个重复1只。Ⅰ、Ⅱ、Ⅲ组水貂分别饲喂蛋白质水平为22%、32%、42%的试验饲粮,Ⅳ组为限饲组,饲喂蛋白质水平为32%的试验饲粮,饲喂量为Ⅱ组的50%。预试期7 d,正试期53 d。结果表明:饲粮蛋白质水平对水貂的165日龄体重、体长、鲜皮长、鲜皮重、针毛长度和绒毛长度均无显著影响(P>0.05),但均以Ⅱ组的值最高。Ⅱ组的180和195日龄体重显著高于Ⅲ组(P<0.05),针毛细度和绒毛细度极显著高于Ⅰ、Ⅲ组(P<0.01)。饲粮蛋白质水平对水貂的干物质采食量无显著影响(P>0.05)。Ⅱ组的干物质排出量显著低于Ⅰ组(P<0.05),干物质、粗脂肪和碳水化合物消化率则极显著高于Ⅰ组(P<0.01),与Ⅲ组无显著差异(P>0.05)。Ⅱ组的沉积氮、净蛋白质利用率和蛋白质生物学价值显著或极显著高于Ⅰ、Ⅲ组(P<0.05或P<0.01)。Ⅰ、Ⅱ和Ⅲ组的血清白蛋白和球蛋白含量无显著差异(P>0.05),但Ⅱ组的血清总蛋白含量显著高于Ⅲ组(P<0.05)。Ⅱ组的血清谷草转氨酶活性极显著高于Ⅰ、Ⅲ组(P<0.01),血清碱性磷酸酶活性则显著低于Ⅰ组(P<0.05)。与Ⅱ组相比,Ⅳ组的针毛细度、绒毛细度、干物质采食量、干物质排出量、干物质消化率、粗蛋白质消化率、粗脂肪消化率、碳水化合物消化率、食入氮、沉积氮、净蛋白质利用率、蛋白质生物学价值以及血清谷草转氨酶活性显著或极显著降低(P<0.05或P<0.01),而血清谷丙转氨酶活性显著升高(P<0.05)。由此得出,冬毛期水貂饲粮适宜的蛋白质水平为32%。50%限饲对冬毛期水貂的体长、鲜皮长、鲜皮重、针毛长度和绒毛长度无显著影响,但是对针毛细度、绒毛细度以及蛋白质、脂肪和碳水化合物的消化率有显著影响。因此,在不影响水貂营养物质消化代谢和生产性能的基础上,适宜的限饲水平还有待于进一步研究。

This experiment aimed at studying the effects of dietary protein level and restricted feeding on performance, digestion and metabolism, and serum biochemical indices of minks during pelting period. Forty 150-day-old healthy American shorthair black male minks were randomly divided into 4 groups with 10 replicates per group and 1 mink per replicate. The minks in groups Ⅰ, Ⅱ and Ⅲ were fed experimental diets with the protein levels of 22%, 32% and 42%, respectively. Group Ⅳ was restricted group, and the minks in this group were fed the experimental diet with 32% protein level, and with 50% feed intake of group Ⅱ. The pretest period lasted for 7 days and the test period lasted for 53 days. The results showed as follows: dietary protein level did not significantly affect the 165-day-old body weight, body length, fresh skin length, fresh skin weight, aciculum length and villus length (P>0.05), and the highest values of above indices were all found in group Ⅱ. The 180 and 195-day-old body weights in group Ⅱ were significantly higher than those in group Ⅲ (P<0.05), and aciculum fineness and villus fineness in group Ⅱ were significantly higher than those in groups Ⅰ and Ⅲ (P<0.05). Dietary protein level had no significant effect on dry matter intake (P>0.05). The dry matter output in group Ⅱ was significantly lower than that in group Ⅰ (P<0.05), and the digestibility of dry matter, ether extract and carbohydrate in group Ⅱ was significantly higher than that in group Ⅰ (P<0.01), but no significant difference in those indices between groups Ⅱ and Ⅲ was found (P>0.05). The nitrogen retention, net protein utilization and biological value of protein in group Ⅱ were significantly higher than those in groups Ⅰ and Ⅲ (P<0.05 or P<0.01). No significant difference in the contents of serum albumin and globulin among groups Ⅰ, Ⅱ and Ⅲ was found (P>0.05), but the serum total protein content in group Ⅱ was significantly higher than that in group Ⅲ (P<0.05). The serum aspartate aminotransferase activity in group Ⅱ was significantly higher than that in groups Ⅰ and Ⅲ (P<0.01), but the serum alkaline phosphatase activity in group Ⅱ was significantly lower than that in group Ⅰ (P<0.05). Compared with group Ⅱ, the aciculum fineness, villus fineness, dry matter intake, dry matter output, dry matter digestibility, crude protein digestibility, ether extract digestibility, carbohydrate digestibility, nitrogen intake, nitrogen retention, net protein utilization, biological value of protein and serum aspartate aminotransferase activity in group Ⅳ were significantly decreased (P<0.05 or P<0.01), while the serum alanine aminotransferase activity was significantly increased (P<0.05). In conclusion, the suitable dietary protein level is 32% of minks during pelting period. 50% of restricted feeding has no significant effects on the body length, fresh skin length, fresh skin weight, aciculum length and villus length, but has significant effects on the aciculum fineness, villus fineness, and digestibility of crude protein, ether extract and carbohydrate of minks during pelting period. Restricted feeding to some extent will not greatly affect performance and nutrient digestibility, which will require further study.