Rajaraman V, Nonnecke B J, Franklin S T, Hammell D C, Horst R L
USDA, ARS, National Animal Disease Center, Metabolic Diseases and Immunology Research Unit, Ames, IA 50010-0070, USA.
J Dairy Sci. 1998 Dec;81(12):3278-85. doi: 10.3168/jds.S0022-0302(98)75892-8.
This study evaluated the effects of dietary vitamin A and E on the in vitro capacity of blood mononuclear leukocytes from calves to produce nitric oxide. Calves fed milk replacer received 100 IU/d of vitamin E as RRR-alpha-tocopherol or RRR-alpha-tocopheryl acetate and 0, 1700, 34,000, or 68,000 IU of vitamin A as retinyl acetate. Leukocytes from calves produced greater amounts of nitric oxide relative to leukocytes from adult cattle. The greater production of nitric oxide by calf leukocytes may be typical of the immature neonatal immune system. Nitric oxide production by calves fed RRR-alpha-tocopherol and either 1700 or 34,000 IU of vitamin A was less than that of calves in other groups and was more typical of production by leukocytes from cows. Our data suggest that optimal amounts of dietary vitamins A and E prompt the maturation of this response toward one that is more typical of adult cattle. Leukocytes from 1-wk-old calves produced less nitric oxide and were less responsive to stimuli than were leukocytes from older calves, a possible consequence of suppressive factors that were present in the ingested colostrum or in the circulation at birth.
本研究评估了日粮维生素A和E对犊牛血液单核白细胞体外产生一氧化氮能力的影响。用代乳粉喂养的犊牛，维生素E以RRR-α-生育酚或RRR-α-生育酚醋酸酯的形式每日摄入100 IU，维生素A以醋酸视黄酯的形式每日摄入0、1700、34000或68000 IU。与成年牛的白细胞相比，犊牛的白细胞产生的一氧化氮量更多。犊牛白细胞产生更多的一氧化氮可能是未成熟新生免疫系统的典型特征。饲喂RRR-α-生育酚和1700或34000 IU维生素A的犊牛产生的一氧化氮量低于其他组犊牛，更类似于母牛白细胞的产生情况。我们的数据表明，日粮中适量的维生素A和E能促使这种反应成熟，使其更接近成年牛的典型反应。1周龄犊牛的白细胞产生的一氧化氮较少，对刺激的反应也比大龄犊牛的白细胞弱，这可能是由于出生时摄入的初乳或循环系统中存在抑制因子所致。
