围产期饲喂β-胡萝卜素对奶牛免疫性能的影响

Effect of β-Carotene on Immune Function in Dairy Cow During Periparturient Period

试验选择胎次相同、产奶量、体重和体况相近的中国荷斯坦奶牛36头,随机分为3组,分别饲喂对照日粮(基础日粮+150 000 IU维生素A),处理Ⅰ日粮(对照日粮+300 mg-β胡萝卜素),处理Ⅱ日粮(对照日粮+600 mg-β胡萝卜素),预试期15 d,试验期120 d。结果表明:添加-β胡萝卜素对奶牛血液白细胞数量和白细胞分类计数没有显著影响,但提高了围产期奶牛血液淋巴细胞的转化率(P<0.01)。-β胡萝卜素的添加提高了血浆中-β胡萝卜素和维生素A的浓度;在产后8-12周,处理组奶中-β胡萝卜素的浓度显著提高(P<0.005),而且奶中-β胡萝卜素的浓度随着-β胡萝卜素添加量的增加而上升,但-β胡萝卜素的添加对产后4周内奶中的-β胡萝卜素的浓度没有影响。

Thirty-six Holstein cows with the same parity, similar milk production, body weight and body condition score were randomly divided into three groups： control group （basic diet＋150 000 IU VA/head/day）, treatment Ⅰ （control diet＋300 mg β-Carotene/head/day）, treatment Ⅱ （control diet＋600 mg β-Carotene/head/day）, 15 days for adaptation, and 120 days for experiment, The results indicated that no effect was observed in leucocyte counts and classified counting of leucocyte, but the lymphocyte proliferation during periparturient period was increased （P 〈 0.01 ）. At the level of 150,000 IU VA/d/cow, β-Carotene and VA concentration in plasma is increased with the adding of β-Carotene. In 8-12 wk postpartum, β-Carotene concentrations in milk had significant difference among treatment Ⅰ, treatment Ⅱ and control （P 〈 0.005）, and β-Carotene concentration in milk was increased with the adding of β-Carotene, but there was no difference in 4 wk postpartum in milk β-Carotene concentrations.