الفهرس 
History of Zinc
Effect of Zinc on Growth Performance of BroilersOnly 14 pages are availabe for public view
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Abstract
The present study was carried out under supervision of Animal Production Department, Faculty of Agriculture, Tanta University, during the period from May to August 2017, to investigate the effects of in ovo and post hatch feeding with different levels of Nano-zinc oxide on post-hatch performance and physiological status of broiler chicken. This study was conducted at two stages: 1-First experiment: This experiment was conducted to study the effect of in ovo feeding by different levels of Nano-zinc oxide upon improving hatchability and hatching performance of broiler chicks. One thousand and five hundreds fertile eggs from a flock (Inshas strain, 10 wks. in lay), were obtained from a commercial hatchery. At 7 and 14 day of incubation, eggs were individually candled and eggs that were unfertilized, contaminated, or contained dead embryos were discarded and recorded. A 1275 of them which contained embryos were weighed and chosen for this study. On d 18 of incubation, the fertile eggs were randomly divided into 5 experimental groups with 3 replicate (85 eggs in each). Embryonic amnion sac using a 23 gauge needle and depth of 25 mm, were injected with 0.5 ml of in ovo feeding solutions according to the following treatment descriptions: 1) Control group (without any treatment). 2) 0.5 ml of normal saline (0.9 % NaCl) 3) 0.5 ml of normal saline (0.9 % NaCl) + 60 μg Nano Zno/egg 4) 0.5 ml of normal saline (0.9 % NaCl) + 80 μg Nano Zno/egg 5) 0.5 ml of normal saline (0.9 % NaCl) + 100 μg Nano Zno/egg After injection, holes were covered by commercial glue and transferred to hatcher Hatch time for each treatment replication was monitored every 12 h from 19.5 d to 21.5 d. Hatchability was calculated and expressed as a percentage of fertilized eggs. Also, hatch weight of chicks and chick weight is to egg weight ratio were studied. 2-Second experiment: This experiment was conducted to study the post-hatch performance of chicks belonging to the previous treatments. A total of 600 one-day-old unsexed Inshas strain chicks were obtained from the previous first experiment, individually weighted and distributed into ten treatments resulted from 5×2 factorial arrangement (60 birds each). Birds were allocated to five groups according to in ovo feeding with Nano-Zn (as mentioned previously). Each group was divided into two sub-groups according to adding basal diet along with Nano-Zn supplementation levels (0 and 30 mg/kg diet). The chicks were reared for 10 wks. in an environmental controlled brooder house previously disinfected.