Effect of zinc supplementation from inorganic and organic sources on growth and blood biochemical profile in crossbred calves

The effect of zinc supplementation from inorganic and organic sources on some physiological and biochemical profile was investigated in 15 male crossbred calves (age 14-15 months, liveweight 226.0±9.06 kg) randomly divided into three groups of five animals in each. Animals in group I (control) were fed a basal diet comprised of wheat straw and concentrate mixture (33 mg Zn kg^-1 diet) with out any supplemental Zn, while those in group 2 and group 3 were given basal diet supplemented with 35 mg Zn kg^-1 feed from zinc sulphate and zinc propionate, respectively. All the animals were fed individually on these dietary treatments for a period of 180 days. Body weights of all the calves were recorded fortnightly. Blood samples were collected from all the animals at 0 day and subsequently at an interval of 30 days to estimate certain serum minerals, enzymes, vitamins and hormones. There was no significant difference in the body weight gain among different groups. Zinc intake in groups 2 and 3 was significantly (P<0.001) higher as compared to group 1, but serum zinc and copper concentration did not differ among the groups. Mean activity of alkaline phosphatase, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and super oxide dismutase was also similar in control and Zn supplemented groups. Mean concentrations of different serum vitamins (retinol, ß-carotene and α-tocopherol) and hormones (triiodothyronine, thyroxin, insulin and testosterone) were not affected by zinc supplementation from inorganic and organic sources in crossbred calves. It may be concluded that supplementation of zinc in the diet of crossbred calves was not effective in improving the growth rate and concentration of minerals, enzymes, vitamins and hormones in blood serum or plasma in crossbred calves, which may be due to relatively small dose of zinc (35 mg Zn kg^-1 diet) used in this study.