الفهرس 
REVIEW OF LITRATUROnly 14 pages are availabe for public view
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Abstract
The influence of dietary protein levels and two types of pro-nutrients e.g. enzyme mixture containing phytase or probiotics on growth performance, carcass characteristics, meat quality and plasma biochemical constituents of broiler chicks was studied herein as means of improving protein utilization and decreasing feed cost. In the 1st trial A complete randomized factorial design was conducted including two levels of crude protein 22 and 20% CP in the starting and 20 and 18% CP in the growing-finishing periods. Each CP level was fed either without or with enzyme mixture containing phytase or probiotics. Thus, there were 6 dietary experimental treatments, each one was fed to 24 one d-old unsexed broiler chicks divided equally among four replicates of 6 chicks each housed in a battery (30×35×40 cm). At the end of the experiment, 3 chicks of each treatment were slaughtered to determine carcass characteristics and meat quality traits. Furthermore, four plasma blood samples of each treatment were collected to determine some biochemical constituents. Also, nutrients digestibility and economic efficiency of treatments were also calculated. In the 2nd trial the influence of different dietary protein sources and two types of pro-nutrients e.g. enzyme mixture containing phytase and probiotics on growth performance, carcass characteristics, meat quality and plasma biochemical constituents of broiler chicks was studied herein as means of improving the utilization of diets containing different plant protein sources and decreasing feed cost. A complete randomized straight run experimental design including 10 dietary treatments was conducted. A basal control corn-soybean meal diet containing 22 and 20% CP in the starting and growing-finishing periods, respectively was formulated. Sunflower meal (SFM) and rocket (Eruca sativa) meal (RM) individually or as a mixture of (1:1; Wt::Wt ) replaced 25% of soybean meal protein. Thus, there were four main experimental diets. Moreover, the diets containing SFM and/or RM was either supplemented or not with enzyme mixture containing phytase (Natuzyme) or probiotics (Nutri-Bio Plus). Thus, there were 10 experimental treatments, Each diet was fed to 24, one d-old unsexed broiler chicks divided equally among four replicates of 6 chicks each housed in a battery (30×35×40 cm). At the end of the experiment (49 d of age), 3 chicks of each treatment were slaughtered to determine carcass characteristics and meat quality traits. Furthermore, four blood samples per treatment were collected to determine some biochemical constituents. Also, a digestibility trail and an economic efficiency study were carried out. In conclusion, low crude protein diet e.g. 20 and 18% in the starter and grower-finisher diets, respectively could be fed to broiler chicks when supplemented with probiotics cocktail containing Bacillus subtillis fermentation extract, Brewers yeast extract, lactic acid, citric acid, calcium propionate, sodium aluminosilicate and DL-methionine without adverse effects on growth performance and carcass quality, moreover it improved economic efficiency. Furthermore, SFM and/or RM could be included in broiler diets to replace 25% of soybean meal protein without adverse effects on growth performance and economic efficiency. Also, probiotics supplementation resulted in improved growth performance and economic efficiency. whereas, probiotics supplemented-diet containing a mixture of SFM and RM resulted in the best productive performance and economic efficiency.