Abstract
Three major carps viz. Catla catla, Labeo rohita and Cirrhina mrigala were reared under pond fertilization with broiler droppings on five nitrogen levels (0.10,0.13,0.16,0.19 and 0.22 g nitrogen per lOOgwet fish weight daily) under polyculture condition. Proximate composition of fish was determined at the start and end of one year experiment. Fat and protein contents of fish increased and ash and carbohydrate decreased among the three fish species after pond fertilization trials. With the increase of nitrogen level, the body fat and protein contents of fish increased up to 0.16 g level of nitrogen. Both Catla catla and Labeo rohita had the highest fat and protein contents under the influence of 0.16 g nitrogen level, while Cirrhina mrigala accumulated ample fat and protein under 0.13 and 0.10 g nitrogen levels respectively. A significant increase in both fats and proteins in fish body under different fertilization levels was due to the better performance under these treatments towards planktonic productivity indices, especially zooplankton. Key words: broiler droppings, major carps, pond fertilization, proximate composition
