Effect of dietary addition of organic zinc on performance and carcass traits in commercial broiler chicken

An experiment was conducted to study the effect of dietary Zn supplementation from organic source (zinc glycinate, Zn-gly) at lower concentrations on growth performance and carcass traits in broilers. One hundred and twenty, day old commercial broiler chicks were randomly allotted to 24 replicates with 5 chicks in each and the replicates were distributed randomly to 4 dietary treatments. The birds were raised in battery brooders under uniform management for 0 to 42 days of age. A corn-soybean meal basal diet (BD) was prepared for starter and finisher broiler chicks to meet the nutritional requirements, except Zn. Experimental diets were viz., BD with 40 ppm Zn supplementation from ZnSO₄ (inorganic) and BD with Zn supplemented as Zn-gly (organic) at 30, 20 and 10 ppm. Body weights, feed intake and feed conversion ratio (FCR) were measured at weekly intervals and at the end of the experiment, 2 birds were randomly selected from each replicate to study the carcass traits. Reducing the Zn supplementation up to 10 ppm as Zn-gly did not affect the growth, feed intake during starter and finisher phase and carcass traits (dressing percentage, organ weight, breast yield and abdominal fat) in broiler chicks, and was comparable to those fed 40 ppm Zn from inorganic source. The FCR did not differ among the dietary treatments during the starter phase, but during the finisher phase the FCR improved with 30 ppm Zn from Zn-gly compared to other dietary treatments and this trend was also reflected in total FCR. Based on the results it can be concluded that dietary Zn supplementation could be reduced up to 10 ppm when supplemented as Zn glycinate without affecting growth performance and carcass traits. Furthermore the dietary replacement of 40 ppm inorganic Zn with 30 ppm organic Zn significantly improved feed efficiency in broilers.