الفهرس 
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Abstract
This work was carried out at the Nutrition and Veterinary Clinical Nutrition Department, Faculty of Veterinary Medicine, Alexandria University during middle of November and terminated on December 2015 to investigate the effect of different dietary supplemental zinc sources and levels in broiler chicken’s diets on growth performance, blood picture and biochemical parameters, immune response, carcass characteristics and intestinal morphology of broiler chickens.
Two hundred and twenty-five of one day-old unsexed Avian chicks with average body weight of about 40.8 g. The birds were individually weighed, randomly allocated into 9 groups (25 chicks per each group), in which broiler the experimental birds were fed on the experimental basal diet containing similar nutrient content with different zinc sources and levels; group 1 was fed basal diet supplemented with (60 ppm) inorganic zinc which meet zinc requirement according to NRC (1994) recommendation, groups 2, 3, 4 and 5 were fed basal diet contained 100%, 75%, 50%, 25% from the NRC recommendation zinc polysaccharide, respectively, while groups 6, 7, 8 and 9 were fed basal diet contained 100%, 75%, 50%, 25% from the NRC recommendation nano zinc oxide, respectively. The obtained results are summarized in the following.
• It was observed that nano zinc supplementation at 60, 45 or 15mg/kg diet non-significantly (P≥0.05) reduced final body weight compared with broiler chick groups fed on the basal diet with 60, 45 or 15mg of organic zinc/kg diet. While inclusion of 30mg/kg of both nano or organic zinc sources achieved nearly the same body weight.
• It was observed that nano zinc supplementation at 60, 45 or 15mg/kg diet non-significantly (P≥0.05) reduced total weight gain by about 4.6%, 5.3% and 9.9% respectively when compared with broiler chick groups fed on the basal diet with 60, 45 or 15mg of organic zinc/kg diet. While inclusion of 30mg/kg of both nano or organic zinc sources showed nearly the same body weight gain.
• Using organic or nano zinc instead of inorganic zinc source reduced total feed intake of broiler chicken.
• Broilers fed 60 or 45mg zinc polysaccharide complex/kg instead of inorganic zinc oxide improved FCR, PER, EEU and performance index of broiler chicken while, lower supplementation levels (30 or 15mg/kg) had no significant effect.
• Zinc nanoparticles supplementation at 60, 45 or 30mg/kg improved the previous mentioned items while lower level (15mg/kg) significantly reduced broiler performance and feed efficiency parameters.
• Supplementation of polysaccharide zinc complex or zinc nanoparticles instead of inorganic source increased WBCs, RBCs counts, Hb% and PCV% except lowest level (15mg/kg) of nano zinc reduced total WBCs count.
• Regarding blood serum calcium and phosphorus levels, it was observed that dietary replacement of inorganic zinc oxide with lower levels of organic or nano zinc increased blood serum calcium or phosphorus levels while higher levels of organic zinc (60mg/kg) reduced blood serum calcium level compared with broiler chicken fed on the basal diet with inorganic zinc oxide supplementation.
• Broilers fed on different levels of organic or nano zinc reduced blood serum creatinine concentration, while had no significant (P≥0.05) effect on blood serum uric acid and GOT concentrations and non-significantly (P≥0.05) increased blood serum GPT and ALP activities when compared with broiler chick groups fed on the basal diet with inorganic zinc supplementation.
• Replacement of inorganic zinc with different levels of polysaccharide zinc complex or with zinc nano particles non significantly (P≥0.05) reduced blood serum triglycerides while increased total cholesterol and HDL and had no significant effect on blood serum LDL and VLDL concentrations.
• Replacement of dietary inorganic zinc with low levels of zinc polysaccharide complex had no significant effect on blood serum GPx or MDA activities, while nano zinc supplementation non-significantly reduced blood serum GPx or MDA activities compared to broiler chicken fed on inorganic zinc supplemented diet.
• Broilers fed on basal diet with 60mg/kg diet of organic or nano zinc significantly reduced heterophil%, while other levels non-significantly reduced heterophil% compared with broiler chicks fed on the basal diet with inorganic zinc supplementation. Moreover, organic or nano zinc supplementation increased lymphocyte% and consequently reduced heterophil/lymphocyte ratio. On the other hand, replacement of inorganic zinc with lower levels of organic or nano zinc had variable effect of eosinophil, basophil and monocyte percentages.
• Broilers fed on different levels of organic or nano zinc non-significantly (P≥0.05) improved phagocytic activity and index except 45mg of zinc nanoparticle/Kg diet significantly (P≤0.05) improved phagocytic index compared to broiler chick group fed on the basal diet with inorganic zinc supplementation.
• Dietary replacement of inorganic zinc oxide with lower levels of organic zinc or zinc nano particles improved antibody titer against New castle disease vaccine at 21th, 28th, 35th and 42th day of broiler age.
• Dietary replacement of inorganic zinc oxide with lower levels of organic zinc or zinc nano particles improved (P≥0.05) thymus and spleen weight and relative weights while reduced (P≥0.05) bursa weight and relative weight except higher level of zinc polysaccharide complex increased bursa weight when compared with broiler chick group fed on the basal diet with inorganic zinc supplementation.
• Dressing percentage was improved (P≥0.05) with dietary replacement of inorganic zinc by lower levels of organic or nano zinc while decreased liver and abdominal weight and relative weight.
• It was observed that dietary replacement of 60mg inorganic zinc oxide with 30 mg of organic zinc or by 45 and 30 mg of nano zinc/kg diet significantly (P≤0.05) increased jejunum villi length while other levels of organic and nano zinc non significantly improved villi length. Moreover, different levels of organic supplementation instead of inorganic zinc oxide had no significant effect on villi width and crypt depth while, nano zinc supplementation increased villi width and 45mg of nano zinc increased crypt depth compared with broiler chick group fed on the basal diet with inorganic zinc oxide supplementation. On the other hand, birds fed on the experimental diet with 30 or 15mg of organic zinc and 30 mg of nano source increased (P≤0.05) villi length/crypt depth ratio compared with group fed on diet supplemented with inorganic zinc source.