ABSTRACT
Numerous abnormalities and clinical syndromes have been associated with vitamin A and zinc deficiency in large animals. In addition, zinc status influences several aspects of vitamin A metabolism including its mobilization from liver to other tissues. The purpose of the present study is to determine the vitamin A and zinc status and their relationship in cattle. Vitamin A and zinc concentrations in blood plasma and liver samples of 114 to 130 male slaughtered cattle [under 18 months old] in Urmia were assessed and their status and correlations were analyzed. In 15.6, 25.4, 5.4 and 3.8% of samples, the concentrations of vitamin A and zinc in plasma and liver were less than minimum recommended concentration, respectively. In 24.8% of samples vitamin A in liver was more than maximum recommended concentration. The mean concentrations [ +/- standard error] of vitamin A and zinc in plasma and vitamin A and zinc in liver were 59.7 +/- 4.5 microg/dL, 99.1 +/- 4.7 microg/dL, 161.9 +/- 6.2 microg/g wet weight and 103.2 +/- 4.7 microg/g wet weight, respectively. In cattle with zinc levels lower than minimum reference value, vitamin A in plasma and zinc concentration in liver were significantly [p<0.0005] less than those of cattle with normal plasma zinc levels. In cattle with inadequate zinc status a direct significant correlation [p<0.01, r=0.481] between plasma and liver vitamin A levels was observed. However, in cattle with adequate zinc status, the plasma zinc had a positive significant correlation with plasma vitamin A [p<0.01, r=0.466], liver vitamin A [p<0.01, r=0.411] and liver zinc [p<0.01, r=372]. Deficiency of vitamin A and zinc are relatively common in Urmia and the deficiency probably leads to subclinical and clinical abnormalities. Furthermore, zinc had significant effects on plasma and liver vitamin A status