Velichkova, K., Sirakov, I. & Veleva, P.(2020). Use of Lemna minuta Kunth. for composition of sustainable diets and influence on hydrochemical, technological and blood biochemical parameters in common carp (Cyprinus carpio L.) cultivated in aquaponics recirculation systems. Bulg. J. Agric. Sci., 26 (3), 674–679

The purpose of this study was to investigate the influence of aquaponically grown L. minuta used as a part of biofilter in recirculation aquaculture systems, with its subsequent inclusion in the composition (50 and 100% content of daily feed ratio) in sustainable diets on hydrochemical, biochemical blood and technological parameters in common carp (Cyprinus carpio L.) fingerlings cultivated in aquaponics recirculation systems. At the end of the experiment were calculated average final weight, specific growth rates, feed conversion ratio, meat quality and blood biochemical parameters. The inclusion of up to 100% duckweed (L. minuta) in feed for common carp fingerlings decreases the quantity of ammonium, nitrite, nitrate and phosphate accordingly with 66%, 71.4%, 38.8% and 44.1% compared with the quantities of these parameters found for experimental groups fed with feed without inclusion of L. minuta. The carps fed with inclusion of up to 50% duckweed showed better growth of fish, SGR and FCR compared with fish fed with a diet without substitution of duckweed.