الفهرس 
Cover Page Title in EnglishOnly 14 pages are availabe for public view
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Abstract
Modern aquaculture is in danger of becoming the victim of its own achievements; nature and the environment are beginning to show symptoms of stress. The routine use of antibiotics during fish culture to minimize the risk of disease is not advisable since it may adversely affect the indigenous microflora of juveniles or adult fish and may increase the risk of promoting antibiotic- resistant microorganisms Thus, the use of probiotics (Yeast cell wall) in the culture of aquatic organisms, is increasing with the demand for more environment-friendly aquaculture practices Yucca schidigera extract (YE) contains two active ingredients: the steroidal saponin fraction, which has surface active properties, and the glyco-component fraction, which binds to ammonia. Saponins also improve animal immunity and performance Because of these properties, the use of YE ,YCW in feed and water can reduce ammonia levels in ponds of aquaculture and improve feed conversion and production The aim of the study : The objective of our study was conducted to evaluate the effects of both Yeast cell wall (YCW) and Yucca schidigera extract (YE) supplementation to both diets and water of cultured Oreochromis niloticus on water quality ,growth performance and some blood and serum parameter .