The effect of low levels of dietary cobalt on the chemiluminescence response of polymorphonuclear leukocytes of goats

Twenty ten-week-old newly weaned male Batinah goats were randomly assigned to a control (n=10) and a treated (n=10) group and were fed a diet containing 0.1mg/kg DM cobalt (Co). Goats in the treated group received bi-monthly subcutaneous injections of 2000 microg of hydroxycobalamin. The phagocytic function of the polymorphonuclear leukocytes (PMN) were tested using a luminol-dependent chemiluminescence assay with opsonized zymosan as the phagocytic target. One month after the onset of the experiment PMN from the control group exhibited a significantly (p0.05) lower CL response, which continued for the second month. The results of the present study demonstrated that low levels of dietary cobalt leads to an early impairment of phagocytic function. This may at least in part, be an explanation as to why at the field level in Oman young goats fed diets containing low levels of Co appear to be more susceptible to infections.