SPARING EFFECTS OF COBALT OR NICKEL ON ZINC NUTRITION AND THE DIFFERENCE IN ZINC ABSORPTION BETWEEN ANCONA AND NEW HAMPSHIRE X LEGHORN CROSS CHICKS

Experiments were conducted to determine whether supplemental cobalt (Co) or nickel (Ni) would prevent the signs of zinc (Zn) deficiency in chicks fed a high calcium (1.5%) corn-soybean diet and to examine the difference in $^{65}Zn$ absorption rates between inbred Ancona and crossbred New Hampshire X Single Comb White Leghorn chicks. In the initial experiment, the supplementation of 27 ppm Ni, 27 ppm Co or 54 ppm Co to a basal diet increased weight gain and reduced feather defects; 54 ppm Ni tended to increase weight gain but did not reduce feather defects. In further experiments, chicks fed the diet supplemented with 54 ppm Co usually showed increased weight gain and reduced feather defects; however, chicks fed a diet supplemented with 54 ppm Ni less frequently showed these effects. In another test, Ancona chicks fed a diet supplemented with 30 ppm Zn (except during a $^{65}Zn$ absorption study period) showed lower weight gain, more feather defects and less $^{65}Zn$ absorption than did New Hampshire X Leghorn cross chicks. Similar results were achieved with two strains of chicks fed the basal and 54 ppm Ni, 54 ppm Co or 60 ppm Zn supplemented diets. The sparing effects of Co on Zn which were commonly observed and the lesser effect of Ni or Zn were shown to be, at least in part, the result of increased availability of dietary Zn. That Ancona chicks required more Zn than New Hampshire cross chicks for the development of feathers and for growth is partly the result of decreased Zn absorption from the type of diets fed.