The influence of administration of different doses of arginine and lysine coupled with zinc in the lactating ewes on the zinc concentration in milk

Zinc (Zn) plays an essential role in the human and animal body system. Zinc deficiency might cause many disorders, so it is important to provide a sufficient amount of this microelement in both animals and humans. One of the most important sources of Zn is milk. The purpose of this study was to determine whether Zn can pass through the mammary epithelial cell into milk by a cotransport system with amino acid in the lactating ewes. This experimental research included 54 lactating ewes collected from the Agriculture-Jahad Organization of Tehran Province, that were allocated into 9 groups as follows: groups which received inorganic form as Zn chloride (1, 2 and 4 mg/kg), and groups which received organic Zn with different doses of arginine or lysine (1, 2 and 4 mg/kg) in chelate form. Milk samples were taken 30 min before and 6 h after intravenous injection of Zn preparations. Zinc concentration in milk was measured using the flame atomic absorption spectrometric method. There were no significant differences (P>0.05) between groups in Zn concentration of the milk before administration of inorganic or organic Zn. Data analysis showed that administration of inorganic Zn caused a significant increase of Zn concentration in the milk in a dose dependent manner. While administration of arginine or lysine with Zn in chelate form caused a significant decline in Zn concentration of milk compared to inorganic Zn in a dose dependent manner. According to our results, administration of different forms of Zn influenced the Zn concentration in milk.