الفهرس 
approximate composition and amino acids contentsOnly 14 pages are availabe for public view
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Abstract
The present study was designed to evaluate the productive performance of commercial broiler chicks fed yeast (saccharomyces cerevisiae) and mushroom (pleurotus ostreatus) as nutrition feed additives containing diets. Three hundred and seventy five (375) one-day-old unsexed Cobb chicks were obtained from commercial hatchery, individually weighed and assigned randomly to five equal experimental groups. All chicks were kept under the same managerial, hygienic and environmental condition, throughout the entire experimental period that lasted for 6 weeks. Birds fed corn-soy bean basal diet was formulated to meet or exceed the National Research Council recommendation for broiler chick diets. The feeding periods in the current investigation included two periods: the first (starting period) where the basal diet contained 23 % crud protein and 3000 Kcal ME/kg diet. The second period (finishing period), contained 21 % crud protein and 3100 Kcal ME/kg diet. The experimental basal diet was supplemented with different levels of 1, 2g yeast or mushroom/kg diet at the starting and finishing periods. As follows: Control (basal diet) • T1 and T2 fed basal diet supplemented with 1, 2g yeast/kg diet respectively. • T3 and T4 fed basal diet supplemented with 1,2g mushroom/kg diet respectively. The obtained results could be summarized as follow: 1- At the end of experimental periods, birds fed 2g yeast /kg or 2g mushroom/kg diet yielded a significantly heavier body weight by 5.3% and 3.7% followed by 3.5% and 3.7% of those fed 1g yeast or 1g mushroom /kg containing diet, compared to control group, respectively. 2- The highest weight gain value was (2151.8, 2113.0, and2114.5) noticed in birds fed 1 or 2g yeast or 2g mushroom /kg diet. 3- Birds fed of 2g yeast and 2g mushroom consumed significantly (P≤0.05) less by 3.9% and 4.2% followed by 2.6% of those fed dietary treatment 2 compared to other two treatments group, which consumed approximated equal amount of feeds. 4- At the end of experimental period, the superior (P≤0.05) feed conversion ratio were 1.7 of group fed 2gm yeast/kg diet of followed by 1.81, 1.8 and 1.84 of those fed 1,2/gm. mushroom and 1g yeast/kg diet, compared to control group, respectively. 5- Viability percentage was improved by yeast or mushroom supplemented diets. 6-Birds fed either 1 or 2 g yeast/kg containing diet recorded heavier (P≤0.05) carcass weight percentage and total edible parts by 1.4% or 2.6% and 1.5% or 2.5% of those fed either 1 or 2 g mushroom compared to control respectively. 7- Data presented showed that, relative weights of pancreas, bursa of fabricius and thymus were significantly (P≤0.05) increased of groups fed either 1, 2g yeast or 1, 2g mushroom containing diet. 8- The present results showed insignificant increase in packed cell volume (PCV %) of birds fed 1, 2g yeast and 2g mushroom /kg diet compared with control group, respectively. Red and white blood cells were significantly (P≤0.05) improved of chicks fed either 1g, 2g yeast or 1g, 2g mushroom/kg containing diet compared with control group, respectively. 9- The concentration of triglycerides and cholesterol in blood plasma significantly (P≤0.05) decreased with inclusion 1, 2g yeast and 1, 2g mushroom in the diet. 10- Using yeast or mushroom levels in broiler feed were insignificantly (P≤0.05) improved the color, odor and tenderness of broiler meet, while, a significant (P≤0.05) improvement was observed of meet taste yielded from birds fed 1 or 2 g mushroom containing diet. 11- The highest net revenue (37.90, 39.1 LE) and (36.64, 37.80 LE) were observed of groups fed 1, 2g yeast or mushroom containing diet compared to (34.7 LE) for these fed control basal diet.