Aquaponics the bio-integration of aquaculture and hydroponics is a sustainable production system. Indian major carp rohu Labeo rohita fry (3.68±0.001 g) were cultured in three different sets of Aquaponics Systems kept inside the Aquahouse. Each Aquaponics System was consisted of three tanks (3000 L each) for the culture of fish. The water spinach Ipomea aquatica were grown in the Aquaponics Systems. The stocking density of fish was 300/ tank. Twin-screw Extruder made pelleted diets SP-0, SP-30 and SP-40 were formulated with inclusion of greater duckweed Spirodela polyrhiza at three different levels of 0, 30 and 40% using the Interactive Fish Feed Designer, IFFD software. There was no significant (P>0.05) difference in the protein, lipid and moisture contents of SP-0, SP-30 and SP-40 diets. The ash content and calorific value were significantly (P<0.05) higher in SP-40 and SP-0 diets, respectively compared to other diets. The inclusion of duckweed S. polyrhiza influenced the fatty acid composition of diets. Rohu were fed with one of the three diets for 90 days.
The final average weight and specific growth rate (SGR) were significantly (P<0.05) higher in SP-30 diet fed rohu compared to other two diets fed fish. The protein, lipid and ash contents were significantly (P<0.05) higher in SP-30 diet fed rohu compared to others. The calorific value was significantly (P<0.05) higher in SP-40 diet fed rohu fed compared to others. Feeding of rohu with greater duckweed supplemented diets influenced the fatty acid composition of fish. Total saturated (SFAs), monounsaturated (MUFAs), n-6 and n-3 polyunsaturated (n-6 PUFAs, n-3 PUFAs) fatty acids contents were significantly (P<0.05) higher in SP-30 diet fed rohu compared to the fish cultured in other two feeding regimes. The palmitic, oleic and linoleic acids were the dominant fatty acids regardless of treatments. The α-linolenic acid, eicosapentaenoic acid, docosapentaenoic acid and docosahexaenoic acid contents were significantly (P<0.05) higher in SP-30 diet fed fish compared to others. The amylase, total protease, trypsin, chymotrypsin and lipase activities were significantly (P<0.05) higher in SP-30 diet fed fish compared to other treatments. Water temperature, pH, dissolved oxygen, ammonia, nitrite and nitrate were monitored regularly from the culture units. The Aquaponics systems helped in the maintenance of optimum water quality in the fish culture systems and I. aquatica (500 g/system/10 days) were harvested regularly from each system.