围产期饲喂β-胡萝卜素对奶牛免疫性能的影响

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。

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

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),treatmentⅠ(control diet+300 mg β-Carotene/head/day),treatmentⅡ(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 treatmentⅠ,treatmentⅡ 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.