THE DUCK WEED (WOLFFIA ARRHIZA) AS FEED INGREDIENT FOR NURSERY REARING OF LABEO ROHITA AND LABEO CALBASU

To reduce feed cost, sewage grown Wolffia arrhiza (WA) was used as feed, singly and in combination with conventional feed, to examine its performance in rearing of rohu (Labeo rohita) and calbasu (Labeo calbasu) for 210 days. Three treatments, viz. fish fed with only WA (TR1, TC1), only conventional feed (TR2, TC2) and a combination of WA and conventional feed (TR3, TC3) were fed to L. rohita and L. calbasu fry. Result showed that the mean weight gain (22.58g and 6.82g for rohu and calbasu), gross production (227g and 73.7g for rohu and calbasu), net production (217.8g and 65.6g for rohu and calbasu) and SGR (1.52 and 1.06 for rohu and calbasu respectively) were recorded significantly (P < 0.05) higher in TR3 and TC3 than those in other treatments. Fish fed mixture of feed (WA+CF) showed higher profitability (340% and 155%) than that of CF fed fish in rearing rohu and calbasu respectively. Thus W. arrhiza used @ 12.5% in mixture with conventional feed increased fish growth and reduced feed cost and may be incorporated in feed for nursery rearing of L. rohita and L. calbasu. Key words : Wolffia arrhiza, feed, Labeo rohita, Labeo calbasu, fry rearing