The effect of organic and inorganic supplements of zinc on growth parameters, carcass characteristics and serum Sanjabi Lambs.

The aim of this study was to determine the effects of Zn-methionine (Zn-Met) and Zinc sulfate (ZnSo4) supplementation on growth performance, carcass characteristics, serum zinc and copper and zinc concentrations in some tissue i.e. length, weight, internal and external offal items in Sanjabi lambs. All lambs were slaughtered at end of fattening period and biometry of carcass was determined, also zinc concentration in five carcass tissues were analyzed. The results showed that ZnSo4 supplementation reduced dry matter intake, final body weight, carcass weight without fat-tail and carcass length as compared to the control group (P<0.05). The hind leg and fore leg length increased in the Zn-Met group (p=0.001). The Zn concentration of Quadriceps femoris and Longissimus dorsi were not significantly affected by organic and inorganic Zn supplementations, however, pancreas, lounges and heart concentrations of Zn were higher (P<0.01) in organic Zn groups as compared to other groups. The Zn concentration of feces showed that zinc sulfate bioavailability was lower compared to the Zn-Met group (p=0.001). The concentrations of Zn and Cu of serum were not affected by Zn supplementation in treated lambs (P> 0.05). The result of this study showed that zinc sulfate supplementation reduced lams growth and DMI, however feed efficiency ratio was not affect by treatments. The Zn-Met was not affected on growth of lamb, however the lounges and heart Zn concentrations increased.