Effects of Organic and Inorganic Sources of Zinc on Performance and Some Blood Parameters of Fattening Lambs

The role of trace minerals in animal production is an area of strong interest for producers, feed manufactures, veterinarians and scientists. Zn (Zn) is one of the most important elements that has been recognized as a essential catalytic factor for more than 300 enzymes enzyme. Zinc also has an essential role in metabolism of nucleic acids, proteins, lipids, and carbohydrates. The National Research Council (1985 and 2007) recommended about 30 mg/kg zinc for ewes and growing lambs. However, the soil status and zinc concentration in native plants are also affected. In many regions of Iran, the Zn content of soil and plants is commonly low (less than 0.8 mg/kg). As a result, health and performance of animals reared on mainly homegrown roughage and grains may be affected as a consequence of nutritional deficiency. Recently, the use of organic sources of mineral supplements (complexes, chelates and proteinates) has increased. However, the results of organic and inorganic sources in ruminants are contradictory. Furthermore, few studies have investigated the effect of zinc on lipid parameters in ruminants. Therefore, the aim of the present study was to compare the effect of supplementation of 30 mg/kg Zn from the three organic sources and conventional inorganic source on performance, hematological parameters and mineral profile of Mehraban growing lambs.

 Thirty male lambs with 4-5 months of age and 30.8±2.8 kg average in weight randomly allotted to 5 groups. Treatments were: 1) Basal diet without zinc supplement (containing 19.72 mg/kg DM zinc); 2) Basal diet+30 mg/kg DM zinc as zinc methionine; 3) Basal diet +30 mg/kg DM zinc as zinc proteinate; 4) Basal diet +30 mg/kg DM zinc as zinc glycinate, and 5) Basal diet +30 mg/kg DM zinc as zinc sulfate. This trial lasted for 70 days. The dry matter intake, daily gain and feed conversion ratio were determined. Blood samples were taken on days 0, 35 and 70 before the morning meal. Chemical composition of experimental samples including (crude protein, neutral detergent fiber, acid detergent fiber, and dry matter) and blood parameters including (hematological, mineral and lipid profiles) were measured according to standard methods. This experiment was analyzed in a completely randomized design.

Average daily gain and dry matter intake for all groups fed the supplement were significantly higher than control group and feed conversion ratio also improved (p