Effect of Feeding Duckweed (Lemna Minor) Based Diets on the Growth Performance of Rohu, Labeo Rohita (Ham.)

An experiment was conducted to assess the efficacy of sun dried duckweed (Lemna minor) in the diet of Indian major carp, Labeo rohita. Two duckweed based experimental diets were prepared by incorporating Lemna powder @ 20% by replacing rice bran (D II) and mustard cake (D III) in the control diet (D I) containing these two ingredients in the ratio of 1:1. Ten fingerlings (Average initial length and weight 8.50±0.10 cm, 7.90±0.24 g) of L. rohita were stocked in 500 liters plastic pools and fed with experimental diets and control @ 5% of their body weight daily for 80 days. The water quality parameters (temperature, pH, dissolved oxygen, total alkalinity, free CO₂) were analyzed at 20 days intervals. The differences were non-significant for all the water quality parameters. Diet D III and control (D I) showed significant higher growth (p<0.05) in terms of weight gain (20.14±0.57g, 22.0±0.78g) percent weight gain (266.05±0.50g, 270.27±0.81g) and specific growth rate (1.621±0.55% bw d-1, 1.636±0.75% bw d-1). The results revealed that sundried Lemna powder can be incorporated in rohu diet @ 20% as a protein supplement for mustard cake replacement without affecting the water quality and fish growth besides lowering the feed cost by 36%.