Jacková A, Pleva J, Baranová M, Mal'a P, Siklenka P
Ustav experimentálnej veterinánej medicíny, Kosice.
Vet Med (Praha). 1992 Sep-Oct;37(9-10):493-500.
Changes of methaemoglobin levels were investigated in the blood of suckling calves. Transrenal passage of nitrates was determined in dependence on the ingested amount of nitrates. The experiments were conducted under defined husbandry conditions; no excessive nitrate and nitrite supplementation of the calves by feeds and water could be stated. Imitation of possible field conditions when mainly water, but feeds too, may contain higher nitrate and nitrite levels, was carried out by peroral administration of an aquaeous solution of KNO3 to calves. The administered dose was increased from one to 2, 5 and 10 g per animal and day, respectively, in weekly intervals. MtHb determination in the blood of experimental calves on day 1 and 5 of the administration of 1 g KNO3 revealed no significant values. On day 1 and 5 of the administration of 2, 5 and 10 g KNO3 per animal and day, respectively, a significant increase of MtHb levels in the blood of calves was observed 2 and 3 hours after administration, followed by a decrease 4 hours after administration. The maximum values of MtHb in the blood of experimental calves, observed 3 hours following application of the respective KNO3 dose, were within the tolerance limits of the reference values. In urine, 3 hours after the administration of 10 g of KNO3 a mean nitrate value of 941.40.
对哺乳犊牛血液中的高铁血红蛋白水平变化进行了研究。根据硝酸盐的摄入量测定了硝酸盐的经肾排泄情况。实验在规定的饲养条件下进行；未发现饲料和水对犊牛有过量的硝酸盐和亚硝酸盐补充。通过给犊牛口服硝酸钾水溶液来模拟可能的实际情况，即主要是水，但饲料中也可能含有较高水平的硝酸盐和亚硝酸盐。给药剂量分别以每周为间隔，从每只动物每天1克增加到2克、5克和10克。在给予1克硝酸钾的第1天和第5天，对实验犊牛血液中的高铁血红蛋白进行测定，结果无显著差异。在分别给予每只动物每天2克、5克和10克硝酸钾的第1天和第5天，给药后2至3小时观察到犊牛血液中的高铁血红蛋白水平显著升高，给药后4小时下降。在给予相应剂量的硝酸钾3小时后，实验犊牛血液中高铁血红蛋白的最大值在参考值的耐受范围内。在给予10克硝酸钾3小时后的尿液中，硝酸盐平均含量为941.40。
