管饲对缺锌大鼠体内锌与维生素A相互作用的实验研究

INTERACTION BETWEEN ZINC AND VITAMIN A IN RATSFED WITH ZINC DEFICIENT DIET BYGASTRIC TUBE

饲料含锌二个水平(1.41、100ppm),含维生素A(VA)三个水平(0、7、46mg/kg),将SD雄性大鼠44头分为六组。管饲喂养18天后,于实验第19天处死,测定各组大鼠血清及组织锌与VA的含量、血清AKP活力、总蛋白和Hb含量。结果表明,管饲缺锌饲料后,大鼠血清和组织中锌含量以及AKP活力明显降低,缺锌缺VA和缺锌正常VA组大鼠的血清VA含量亦明显降低。缺锌大剂量VA组大鼠的血清锌虽然低于对照组,但明显高于VA缺乏和正常的缺锌大鼠,该组大鼠的血清VA含量耒见降低。上述结果提示,缺锌可影响大鼠肝脏VA的正常释放,使血中VA含量降低,但这一影响可能发生在血锌含量的某一“阈浓度”之下。实验还发现,不同剂量的VA对缺锌大鼠有不同的影响,VA缺乏,会加重缺锌损害,增加VA的摄入量,可明显减轻缺锌损害。

Rats were divided into 6 groups fed with 2 levels of zinc (1.41 and 100 ppm) and 3 levels of vitamin A (retinyl acetate 0, 7 and 46 mg/kg). Each group of the rats was tube-fed for 18 days and killed on the 19th day of experiment. Growth rate, zinc and vitamin A levels in serum and tissues, alkaline phosphatase (AKP) activity in serum, total protein and hemoglobin concentrations were measured. Both zinc levels in serum and tissues and AKP activity of the zinc deficient groups were significantly lower than those of the control group. The serum vitamin A values were distinctively depressed in the vitamin A free and vitamin A normal group. The serum vitamin A values in the vitamin A enriched group were not affected by zinc deficient diet and its serum zinc levels was higher than vitamin A free and normal group. The results suggest that zinc deficiency will interfere the release of vitamin A from liver and lead to the decrease of blood vitamin A, which may occurs only when the blood zinc is lower than a certain 'critical level' . Different levels of vitamin A have different effect on rats of zinc deficiency, such as vitamin A deficiency will aggravate the zinc deficient symptoms and the increase of vitamin A intake can alleviate zinc deficient harms.