饲料中不同水平重金属铬对牛乳中铬的影响

Effects of different levels of heavy metal chromium in feed on the content of chromium in raw milk

选择15头泌乳期荷斯坦奶牛,随机平均分为3组,以烟酸铬的形式分别对各组奶牛饲喂0.47,1.50,4.74 g/d的铬,连续饲喂40 d,研究其对牛乳中铬含量的影响。建立了石墨炉原子吸收光谱法检测牛乳中铬质量分数。研究表明,检测方法稳定性好、精密度高,检测限可达0.005 mg/kg,适于原料乳中重金属铬的检测。向奶牛饲喂0.47,1.50,4.74 g/d的铬,对牛乳中铬的质量分数无显著影响,铬的量维持在一个相对恒定的质量分数范围内,无明显的升降趋势,且铬在牛乳中残留与饲喂剂量无显著相关性,表明饲料中的重金属铬不易经牛体向牛乳中迁移沉积。

Fifteen lactation Holstein cow were randomly divided into 3 groups. The test groups were used to determine the effects of feeding dairy cows different doses of chromium with nicotinic acid chromium on milk chromium concentrations. The doses of chromium was 0.47, 1.50,4.74 g/d for each cow of different groups respectively in 40 days. A graphite furnace atomic absorption spectrometry method was estab- lished for determination of chromium in the milk. The results showed that this method is good stability and high precision and applicable to determine chromium in the milk. The detection limit was 0.005 mg/kg. Chromium concentrations in raw milk were not significantly affect- ed by different doses of chromium feeding. Chromium concentrations were maintained at a relatively constant concentration range without obvious trend of rise and fall. It was showed that chromium was not easy to migrate into the raw milk.