Growth response and carcass composition of rabbitfish, Siganus canaliculatus (Park) fed diets supplemented with dehydrated seaweed, Enteromorpha sp.

A trial to incorporate dehydrated Enteromorpha in the diet of rabbitfish fry averaging 0.25 ± 0.04 g was undertaken for a period of 12 weeks. Four isonitrogenous (39% crude protein) and isoenergetic (19 kJ/g) diets were fed to fish. The dehydrated Enteromorpha was incorporated in the diets at a rate of 0 (control), 10, 20 and 30%. A fifth group of fish was fed control diet and supplemented with known weight of fresh Enteromorpha placed in plastic baskets at the bottom of the rearing tanks. The survival rate, growth performance and feed utilization efficiency were observed to decrease with increasing inclusion levels of dehydrated algae (p < 0.05). The best results of all parameters were achieved by fish fed control diet and fresh Enteromorpha (P< 0.05). Carcass protein was not affected by the different treatments while lipid content was observed to increase inthe group of fish supplemented with fresh Enteromorpha (P< 0.05). It is concluded that further studies are needed on the dehydration techniques of Enteromorpha as well as on the digestibility and assimilation of diets containing dehydrated algae.