Wyatt C L, Jensen L S, Rowland G N
Department of Poultry Science, University of Georgia, Athens 30602.
Poult Sci. 1990 Nov;69(11):1892-9. doi: 10.3382/ps.0691892.
Experiments were conducted to investigate the effect of feeding cimetidine (CIMET), ranging from 0 to 750 mg/kg, on vitamin D3 metabolism and eggshell calcification in laying hens fed two levels of vitamin D3 (500 and 2,000 ICU/kg). Final BW and feed intake were not significantly affected by either CIMET or vitamin D3 level. Feeding 500 and 750 mg of CIMET significantly decreased total egg production in hens fed either level of vitamin D3, but no differences were observed at lower CIMET levels. Tibia ash decreased significantly in hens fed 150 to 750 mg of CIMET, regardless of the vitamin D3 level. Plasma Ca and inorganic P concentrations were decreased in hens fed high CIMET levels (500 and 750 mg/kg) at Week 2, but no differences were observed at Week 4. Feeding CIMET (500 and 750 mg/kg) significantly decreased plasma 25-hydroxycholecalciferol (25-OHD3) levels at Week 2 in hens fed both vitamin D3 diets but not at Week 4. Eggshell breaking force, shell thickness, and percentage shell weight were decreased significantly by CIMET in all experiments; however, in one experiment, shell quality recovered by Week 8. These results suggest that the CIMET-induced reduction in bone mineralization, eggshell quality, and plasma 25-OHD3 levels could be due to interference of CIMET with vitamin D3 metabolism in vitamin D3-replete laying hens. Shell quality decreased in CIMET-treated hens fed the higher vitamin D diet even though 250-HD3 plasma levels were three times higher than in hens fed the lower vitamin D diet, suggesting that CIMET affected shell quality through some mechanism other than inhibition of 250-HD3 synthesis.
进行了实验，以研究在饲喂两种维生素D3水平（500和2,000国际雏鸡单位/千克）的产蛋母鸡中，喂食0至750毫克/千克西咪替丁（CIMET）对维生素D3代谢和蛋壳钙化的影响。最终体重和采食量均未受到CIMET或维生素D3水平的显著影响。喂食500和750毫克CIMET显著降低了饲喂任一维生素D3水平的母鸡的总产蛋量，但在较低CIMET水平下未观察到差异。无论维生素D3水平如何，喂食150至750毫克CIMET的母鸡胫骨灰分均显著降低。在第2周，喂食高CIMET水平（500和750毫克/千克）的母鸡血浆钙和无机磷浓度降低，但在第4周未观察到差异。在饲喂两种维生素D3日粮的母鸡中，喂食CIMET（500和750毫克/千克）在第2周显著降低了血浆25-羟基胆钙化醇（25-OHD3）水平，但在第4周未降低。在所有实验中，CIMET均显著降低了蛋壳破裂强度、蛋壳厚度和蛋壳重量百分比；然而，在一项实验中，蛋壳质量在第8周恢复。这些结果表明，CIMET诱导的骨矿化、蛋壳质量和血浆25-OHD3水平降低可能是由于CIMET干扰了维生素D3充足的产蛋母鸡的维生素D3代谢。在喂食较高维生素D日粮的CIMET处理母鸡中，蛋壳质量下降，尽管250-HD3血浆水平比喂食较低维生素D日粮的母鸡高三倍，这表明CIMET通过抑制250-HD3合成以外的某种机制影响了蛋壳质量。
