Tsang C P, Grunder A A, Narbaitz R
Animal Research Centre, Agriculture Canada, Ottawa, Ontario.
Poult Sci. 1990 Oct;69(10):1702-12. doi: 10.3382/ps.0691702.
The optimal dietary level of 1 alpha,25-dihydroxycholecalciferol [1,25-(OH)2D3] for eggshell quality was established. White Leghorn hens, 59 wk of age, were fed one of eight diets that contained the same basal ingredients, including 3.1% calcium, but different levels (microgram/kg) or forms of calciferol supplements: no calciferol supplement of any form (56 hens); 27.5 (control) or 55.0 micrograms of cholecalciferol (56 hens each); 3, 5, or 7 micrograms of 1,25-(OH)2D3 (28 hens each); 5 micrograms of 24,25-dihydroxycholecalciferol [24,25-(OH)2D3] with 28 hens; 5 micrograms each of 1,25-(OH)2D3 and 24,25-(OH)2D3 (28 hens). All groups were fed the control diet prior to the 21-wk treatment. The group fed 5 micrograms 1,25-(OH)2D3/kg diet ranked first in specific gravity (SG), e.g., 1.081 versus 1.077 for the control group at Week 21 (P less than .05). The group fed 7 micrograms 1,25-(OH)2D3/kg consumed 30% less feed and laid 20% fewer eggs than the control, but shell quality was not affected. The groups receiving no calciferol supplement or receiving only 24,25-(OH)2D3 laid eggs with significantly lower SG than the control after 2 wk of treatment (1.072 or less versus 1.082 at Week 2). The rest of the treatment groups mentioned were comparable to the control in eggshell quality and egg production. Groups fed the combination of 1,25-(OH)2D3 and 24,25-(OH)2D3 per kilogram of feed, or 1,25-(OH)2D3 alone at 5 micrograms/kg, had significantly higher tibial weights relative to the control group. All groups receiving the diets without cholecalciferol supplementation had markedly reduced hatchability. It was concluded that the optimal dietary level of 1,25-(OH)2D3 for improving eggshell quality without affecting egg production was approximately 5 micrograms/kg and the toxic level was 7 micrograms/kg.
确定了1α,25 - 二羟基胆钙化醇[1,25-(OH)₂D₃]对蛋壳质量的最佳日粮水平。选用59周龄的白来航母鸡，饲喂8种日粮中的一种，这些日粮含有相同的基础成分，包括3.1%的钙，但维生素D补充剂的水平（微克/千克）或形式不同：不添加任何形式的维生素D补充剂（56只母鸡）；27.5（对照）或55.0微克胆钙化醇（各56只母鸡）；3、5或7微克1,25-(OH)₂D₃（各28只母鸡）；5微克24,25 - 二羟基胆钙化醇[24,25-(OH)₂D₃]（28只母鸡）；每千克日粮中1,25-(OH)₂D₃和24,25-(OH)₂D₃各5微克（28只母鸡）。在21周的处理期之前，所有组均饲喂对照日粮。每千克日粮饲喂5微克1,25-(OH)₂D₃的组在比重（SG）方面排名第一，例如，在第21周时为1.081，而对照组为1.077（P＜0.05）。每千克日粮饲喂7微克1,25-(OH)₂D₃的组比对照组少消耗30%的饲料，产蛋量少20%，但蛋壳质量未受影响。在处理2周后，未添加维生素D补充剂或仅添加24,25-(OH)₂D₃的组所产鸡蛋的SG显著低于对照组（第2周时为1.072或更低，而对照组为1.082）。上述其余处理组在蛋壳质量和产蛋量方面与对照组相当。每千克饲料饲喂1,25-(OH)₂D₃和24,25-(OH)₂D₃组合的组，或每千克饲料单独饲喂5微克1,25-(OH)₂D₃的组，其胫骨重量相对于对照组显著更高。所有未添加胆钙化醇补充剂的日粮组孵化率均显著降低。得出结论，在不影响产蛋量的情况下，提高蛋壳质量的1,25-(OH)₂D₃的最佳日粮水平约为5微克/千克，毒性水平为7微克/千克。
