The Influence of Dietary Zinc-Methionine Substitution for Zinc Sulfate on Broiler Chick Performance

Abstract

The present study was performed to evaluate the effects of dietary zinc-methionine (ZnMet) supplementation on broiler performance and carcass characteristics. Three added zinc levels (40, 80 and 120 mg kg-1) from each of zinc sulfate or ZnMet were used in a 2x3 factorial arrangement with four replicates of ten birds. Two hundred-forty day-old broiler chicks were fed with the experimental diets from 1 to 42 days of age and at the final day of experiment two randomly selected birds from each replicate were slaughtered and carcass parameters were measured. Inclusion of ZnMet into the diets caused to significant (p<0.01) increase in feed intake. Almost in all cases, increasing supplemental Zn level as either Zn sulfate or ZnMet sources lowered feed consumption. Body weight gain was affected (p<0.01) by zinc source in all experimental periods, with the highest weight gains assigned to chicks fed on ZnMet-supplemented diets. Except for week 1, feed conversion efficiency was not affected by Zn source or dietary Zn concentration. Increasing supplemental Zn level from 40 to 80 mg kg-1 from both Zn sources caused increase in liver weight percentage, but this parameter was reversely affected by further increase to 120 mg added Zn kg-1 of diet. Pancreas, heart and thigh weight percentages were not affected by dietary treatments; however, carcass and breast meat percentages were increased by dietary ZnMet supplementation. The present results suggest that dietary supplementation with more available Zn sources can improve production economics.