الفهرس 
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Abstract
Two feeding trials were conducted to evaluate the impact of a feed supplement and nano-mineral on growth performance, carcass traits, immune response, histomorphological profile, serum calcium and phosphorus and bone mineralization in broiler chickens. Experiment I was carried out using 1092 one-day-old unsexed broilers of Ross 308 strain were randomly allocated into two treatment groups, each group consisted of 546 birds divided into 6 replicates with 91 birds each. The first group fed a basal diet without yeast-based Zn, Se and Cr supplementation (control). The second group fed the basal diet supplemented (per kg diet) with 1.5 mg, 0.15 mg and 2 µg of Zn, Se, and Cr, respectively offered as yeast-based one mix, added at the rate of 50 g/ton. Experiment II was assigned using 160 One-day-old un-sexed Arbor Acres Plus broiler chickens which were randomly divided into four treatment groups of four replicates with 10 birds in each replicate. group 1 served as control and fed diet containing 2% DCP (100% DCP); group 2 having 1% DCP plus 0.1% NHA (50% DCP); group 3 having 0.5% DCP plus 0.1% NHA (25% DCP); group 4 having a 0.1% NHA only (0% DCP). Addition of yeast-based Zn, Se and Cr increased (P<0.05) the growth rate, carcass weight, dressing percentage, and both breast and thigh yield, but decreased feed intake and feed conversion ratio compared to the control. The antibody titer against Avian Influenza and the relative weight of bursa, thymus and spleen were increased (P < 0.05) in broilers supplemented with yeast-based Zn, Se, and Cr compared to those fed the control. The intestinal villi height and crypt depth and bursa diameters were increased in broilers fed the yeast-based Zn, Se and Cr supplemented diet compared to those fed the control diet. The dietary supplementation of 0.5% DCP plus 0.1% of NHA (diet 3) or 0.1% of NHA (diet 4) decreased the excreted P (P<0.05) without negative impacts on body weight gain, feed intake and feed conversion ratio compared to the control group. The serum Ca-P profile, tibial bone ash, Ca and P levels did not differ significantly (P>0.05) among experimental diets. In conclusion, dietary supplementation of yeast-based Se, Cr, and Zn in combination has a positive effect on growth performance, carcass traits, immune responses and histo-morphological parameters in broiler chickens. Also, we can safely conclude that dietary supplementation of 0.1% of NHA could be used instead of 100% inorganic DCP in broiler diets without negative effect on growth performance.