天然富硒牛奶的实验研究

Experimental Studies on Natural Selenium rich Milk

１６头泌乳期相近的健康荷斯坦奶牛，随机分为４组，Ⅰ组不予处理作为对照，Ⅱ、Ⅲ、Ⅳ组每天分别按低、中、高（０．５×１０－６，１．０×１０－６，１．５×１０－６）３个剂量水平于精料中添加亚硒酸钠。实验前及投硒后每隔２０ｄ采集血液、乳汁和毛样１次，检测各项指标。实验观察期８０ｄ。结果表明，奶牛日粮中添加不同水平的无机硒盐，能显著提高试验牛血清、乳汁和被毛中的硒含量，其升高幅度与投硒量成正相关；Ⅳ组牛的奶硒含量达到稳定高台期约需６０ｄ，其平均值为０．０９０ｍｇ／Ｌ，比对照组提高约４倍；而奶中乳糖、乳脂、乳蛋白等成分以及钙、磷、铜、锌、铁等矿物元素无明显变化（Ｐ＞０．０５）。在整个实验观察期，试验牛红细胞数、血红蛋白量等血常规指标，血清钙、磷、锌等矿物元素含量，以及ＧＯＴ、ＣＰＫ、ＡＬＰ、ＵＮ等１０余项肝、心、肾功能指标均无显著性改变（Ｐ＞０．０５），临床表现及产奶量亦无明显变化；血清硒、毛硒含量远低于中毒标准的下限，表明本添加剂连续投服８０ｄ对奶牛无毒副作用。Ⅲ、Ⅳ组牛的淋巴细胞转化率、淋巴细胞数以及γ球蛋白含量增加，表明奶牛免疫机能有所增强。

Sixteen healthy black white cows, with similar milk output were randomly divided into four groups of four each. Group Ⅱ,Ⅲ,Ⅳ were administered inorganoselenite at low, middle and high dose levels daily, respectively, and group Ⅰ was used as negative control. Prior to the treatment and at intervals of 20 days throughout the experimental period, samples of blood, fleece and milk were collected. The experiment lasts for a period of 80 days. The experimental results showed that Se concentration in serum, milk and fleece of experimental cows were significantly increased and the increasing extent correlated positively with the inorganoselenite doses added in the ration. In group Ⅳ the milk Se concentration come on to a stable plateau at day 60, with the average value of 0.090 mg/L, about four fold higher than that of control. There were no significant changes in the nutritional compositions and the mineral elements of milk. None of the indicators of blood routine test, serum mineral elements and serum biochemical test showed significant changes throughout the experimental period. The Se levels of serum and fleece were far lower than its poisoning limit. It was shown that the supplemental levels of selenium in the present experiment couldn′t result in any toxicity and side effects on cows.