The present work  was  conducted at Ras Suder Research station (Desert Research Center ) South Sinai to study the effect of feeding  Atriplex lentiformis (Quail salt bush) , irrigated in  different irrigation intervals (15,30 and 45 days) on feed intake , nutrients digestibility ,nutritive values , nitrogen balance , water balance , serum biochemical parameters and body weight changes of experimental animals (sheep) .              Fifteen mature Barki male sheep were divided into three equal groups with an average body weight 34.2 kg. The first group fed ad libitium on Quail salt bush(Atriplex lentiformis) irrigated every 15 days. The second was fed ad libitium on Quail salt bush irrigated every 30 days. The third was fed ad libitium on Quail salt bush irrigated every 45 days. All groups of sheep were supplemented with  ground date seeds to cover 25% of their energy maintenance requirements .The experiment  comprised two trials .The palatability trial which extended for 30 days followed by a digestibility trial for 15 days.              Data indicated that voluntary feed intake was  gradually increased and recorded the maximum values at the  fourth week  then remain constant to the end of the palatability trial  .There was a noticeable  decrease in body weight  from  the beginning of experiment to the end of palatability trial , and the body weight loses ranged from 4.4 to 7.2 kg .With regard to crude protein  (CPI),neutral detergent fiber(NDF) intakes, no significant differences were detected among animal groups  and their values were comparable during the digestibility trial. The same trend was observed for dry matter (DM), crude protein (CP), crude fiber (CF), and organic matter (OM) digestibility coefficients and total digestible nutrients percentage (TDN%). On the other hand, digestible crude protein percentage (DCP%) significantly varied due to type of ration effect and recorded the higher value (9.23%) for ration 1 (R1) followed by R2 and R3 in descending order. Nitrogen balance was negative for all animal groups. Water balance did not significantly vary and recorded comparable values for the three animal groups.             There were no significant changes in serum alanine aminotransferase (ALT) among animal groups whereas; serum aspartate aminotransferase (AST) showed a significant increase. Total proteins concentrations decreased (p < 0.05) especially in-group 1 which fed ration 1(R1). Serum albumin recorded similar values for the animal groups, which fed the conventional ration (R1) and ration 2 (R2) respectively.  Serum globulin level showed the same trend of total proteins. Blood urea-nitrogen, creatinine, cholesterol, calcium and potassium significantly increased for the three animal groups which fed R1, R2 and R3 compared to the control group which fed the conventional ration but serum sodium showed insignificant variation among animal groups.              Sheep cannot depend only on Atriplex lentiformis cultivated under conditions of Wadi Sudr in their feeding for long time as a basic diet even with 25% of its energy maintenance requirements from date stone. Further studies should be directed twards improving the feeding value of Atriplex by ensiling or treatment biologically or chemicals and energy supplementation i.e.barley grains .