饲粮维生素D和钙水平对育成期水貂生长性能、营养物质消化率及氮代谢的影响

本试验旨在研究在钙磷比固定的条件下,饲粮维生素D和钙水平对育成期水貂生长性能、营养物质消化率及氮代谢的影响。选取(60±5)日龄健康短毛黑公水貂117只,随机分成9组,每组13个重复,每个重复1只。试验采用3×3双因素随机试验设计,饲粮钙磷比固定为2,设3个维生素D水平,分别为2 100、4 100、6 100 IU/kg,3个钙水平,分别为2.3%、2.7%、3.1%,共配制9种试验饲粮,9种饲粮的钙与维生素D水平分别为2.3%与2 100 IU/kg(Ⅰ组)、2.3%与4 100 IU/kg(Ⅱ组)、2.3%与6 100 IU/kg(Ⅲ组)、2.7%与2 100 IU/kg(Ⅳ组)、2.7%与4 100 IU/kg(Ⅴ组)、2.7%与6 100 IU/kg(Ⅵ组)、3.1%与2 100 IU/kg(Ⅶ组)、3.1%与4 100 IU/kg(Ⅷ组)、3.1%与6 100 IU/kg(Ⅸ组)。预试期13 d,正试期60 d。结果表明:1)饲粮维生素D和钙水平对育成期水貂的末重、平均日增重、料重比均有极显著的影响(P0.01),末重、平均日增重均以Ⅷ组最高,Ⅰ组最低,料重比以Ⅷ组最低,Ⅰ组最高。2)育成期水貂脂肪消化率组间差异极显著(P0.01),Ⅱ、Ⅳ、Ⅴ组极显著高于Ⅶ、Ⅷ组(P0.01)。饲粮钙水平对育成期水貂干物质排出量有显著影响(P0.05),以钙水平为3.1%时最高;饲粮钙水平对育成期水貂脂肪消化率有极显著影响(P0.01),钙水平为3.1%时极显著低于钙水平为2.3%和2.7%时(P0.01)。饲粮维生素D水平极显著影响育成期水貂的干物质排出量(P0.01),以维生素D水平为4 100 IU/kg时最低;饲粮维生素D水平显著影响育成期水貂的干物质消化率、脂肪消化率(P0.05),二者均以维生素D水平为4 100 IU/kg时最高。3)饲粮钙水平对育成期水貂的氮沉积有显著影响(P0.05),且氮沉积呈现随饲粮钙水平的升高而增加的趋势,以钙水平为3.1%时最高。饲粮维生素D水平对育成期水貂的净蛋白质利用率、蛋白质生物学价值有显著影响(P0.05),且均以维生素D水平为4 100 IU/kg时最高。饲粮维生素D和钙水平对育成期水貂的净蛋白质利用率、蛋白质生物学价值均有显著的交互作用(P0.05),二者以Ⅷ组最高。综合各项指标,在本试验条件下,饲粮中钙磷比为2、维生素D水平为4 100 IU/kg、钙水平为3.1%时,育成期水貂可以获得较好的生长性能、较高的营养物质消化率及氮利用率。

Effects of Dietary Vitamin D and Calcium Levels on Growth Performance,Nutrient Digestibility and Nitrogen Metabolism of Growing Minks

The aim of this experiment was to investigate the effects of dietary vitamin D and calcium levels on growth performance, nutrient digestibility and nitrogen metabolism of growing mink at a fixed ratio of calcium to phosphorus. One hundred and seventeen healthy short black male minks at the age of (60±5) days with the similar body weight were randomly divided into 9 groups with 13 replicates per group and 1 mink per replicate. Nine experimental diets were formulated by using 3 × 3 double factorial experiment design. Dietary calcium to phosphorus ratio was fixed at 2, and three vitamin D levels were 2100, 4100 and 6100 IU/kg, respectively, while three calcium levels were 2.3%, 2.7% and 3.1%, respectively. The levels of calcium and vitamin D in the 9 diets were 2. 3% and 2100 IU/kg ( group Ⅰ) , 2. 3% and 4100 IU/kg ( group Ⅱ) , 2. 3% and 6100 IU/kg (group Ⅲ), 2.7% and 2100 IU/kg (group Ⅳ), 2.7% and 4100 IU/kg (group Ⅴ), 2.7%and 6100 IU/kg ( group Ⅵ) , 3. 1% and 2100 IU/kg ( group Ⅶ) , 3. 1% and 4100 IU/kg ( group Ⅷ) , 3.1% and 6100 IU/kg ( groupⅨ) , respectively. The pretrial lasted for 13 days, and the formal trial lasted for 60 days. The results showed as follows: 1 ) dietary vitamin D and calcium levels had extremely significant effects on the final weight, average daily gain and feed/gain ( P<0.01) , and the final weight and average dai-ly gain was the highest in groupⅧ, the lowest in groupⅠ, feed/gain ratio was just the opposite. 2) There was an extremely significant difference in the fat digestibility of growing minks among groups ( P<0.01) , and the fat digestibility in groupsⅡ,ⅣandⅤwas extremely significantly higher than those in groupsⅦandⅧ( P<0.01) . The dry matter output of growing minks was significantly affected by the dietary calcium level ( P<0.05) , and it reached the highest when the dietary calcium level was 3. 1%. The fat digestibility of growing minks was extremely significantly affected by the dietary calcium level ( P<0.01) , and it was extremely signif-icantly lower when the dietary calcium level was 3.1% than that when the dietary calcium level was 2.3% and 2.7% (P<0.01). Dietary vitamin D level extremely significantly affected the dry matter output of growing minks ( P<0.01) , and it reached the lowest when the dietary vitamin D level was 4100 IU/kg. Dietary vita-min D level significantly affected the dry matter digestibility and fat digestibility of growing minks ( P<0.05) , and both of them reached the highest when the dietary vitamin D level was 4100 IU/kg. 3) Dietary calcium level had a significant effect on the nitrogen deposition of growing minks ( P<0.05) . And nitrogen deposition showed a tendency to increase with the increase of dietary calcium level, and it was the highest at the 3.1% cal-cium level. Dietary vitamin D level had significant effects on net protein utilization and protein biological value of growing minks (P<0.05), and both of them reached the highest when the dietary vitamin D level was 4100 IU/kg. Dietary vitamin D and calcium levels had significant interaction effects on the net protein utiliza-tion and protein biological value of growing minks (P<0.05), and the highest values of them were found in the group Ⅷ. Comprehensive analysis of various indicators, when the dietary calcium to phosphorus ratio of is 2, the vitamin D level is 4100 IU/kg, and the calcium level is 3.1%, growing minks can get the better growth performance, and the higher nutrient digestibility and nitrogen utilization in the present study.