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Soybean meal, preferred for its high nutritional value, is the main source of protein for broilers. The cost of importing feed ingredients such as soybean meal and corn to formulate poultry diets is one of the most important impediments to achieving high productivity. The protein requirements of broiler chick with adequate growth performance and body weight are high ( 2, 3). Poultry production necessitates the provision of adequate protein and amino acids to chicks for normal growth and maximum production ( 1). In conclusion, a 30% blue lupine seed diet with the addition of probiotics could provide a cheap source of protein without negative effects on the growth performance, carcass characteristics, immune organs and gut morphology of broilers. For example, a 30% blue lupine diet resulted in a significant increase in the duodenum length percentage of 35 d-old broilers the addition of probiotics had no-effects on the dressing, thigh, and leg percentages of 21- and 35 d-old broilers and the drumstick and leg percentages of 35 d-old broilers. Overall, chicks fed blue lupine meal diets, especially at the 30% rate, showed improved growth, feed performance parameters, and carcass characteristics in comparison to chicks fed a soybean meal-based diet. Three experimental diets containing 0, 20, and 30% of blue lupine, with or without probiotics, were formulated and fed to 144 day (d)-old Ross 308 broiler chickens. This study aimed to investigate the effects of different dietary levels of blue lupine ( Lupinus angustifolius) seed meal with or without probiotics ( Bacillus subtilis) in broiler diets on the growth performance, carcass characteristics, internal and immune organs, and gut morphology. 4Department of Arid Land Agriculture, College of Meteorology, Environment and Arid Land Agriculture, King Abdualziz University, Jeddah, Saudi Arabia.3Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia.2Arabian Agriculture Services Company (ARASCO), Riyadh, Saudi Arabia.1King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia.