Water lettuce and water spinach as potential feed ingredients for Nile tilapia Oreochromis niloticus

Abstract

Nile tilapia (Oreochromis niloticus) is an omnivore and is considered as one of the important aquaculture commodities. Different plant-based ingredients like corn, “ipil-ipil” leaves and even micro and macroalgae were already tested to reduce the cost on the use of animalbased protein source. This preliminary study therefore, is an attempt to assess the potential of water lettuce and water spinach as feed ingredients through average body weight (ABW), specific growth rate (SGR), survival rate and feed conversion ratio (FCR) of juvenile O. niloticus. Three treatments [water lettuce (WL), water spinach (WS), water lettuce and water spinach (WL+WS)] were prepared in the form of three different diets [Diet 1 (1:1 water lettuce: fish meal), Diet 2 (1:1 water spinach: fish meal) and Diet 3 (1:0.5:0.5) (fish meal: water lettuce: water spinach)] each replicated thrice and fed to tilapia for 60 days. Tilapia growth showed no significant differences in all diets. The diet with water spinach (Ipomoea aquatica) significantly improved the SGR. Based on the result, the I. aquatica could be included both in a simple or complex diet together with water lettuce (Pistia stratiotes). It took 30 days for O. niloticus to adjust to the introduced diets as reflected to their survival rate but the FCR was higher when fed with the test diets compared to the recorded commercially-fed tilapia. Overall, I. aquatica has an excellent performance for O. niloticus culture.