REPLACING FISHMEAL BY SAFFLOWER MEAL IN THE DIET OF THE MARINE ALGAEVOROUS TELEOST, SIGANUS RIVULATUS

Fish meal has been used for a long time as the main protein source for animal feeds used in aquaculture. Unfortunately, this practice exerts pressure on wild fish resources. In addition, the price of fish meal is in continuous increase. Thus, it is imperative to replace fish meal by plant protein sources to ensure the sustainable success of commercial aquaculture operations. The aim of the present work was to assess the effect of replacing fish meal protein with safflower meal (SFM) on survival, growth, proximate composition, feed efficiency and protein efficiency of the marine herbivore Siganus rivulatus. For that purpose, five experimental diets were formulated with an increasing replacement of fishmeal by safflower meal. The percentages of fishmeal replacement were 0, 25, 50, 75 and 100 % for D1, D2, D3, D4 and D5 respectively. Groups of fifteen size sorted fish were stocked in each of fifteen aquaria. Fish were fed at 5% body weight three times daily. Weight gain, specific growth rate, feed efficiency ratio and protein efficiency ratio significantly decreased as the proportion of SFM increased with 100% SFM inclusion resulting in the least growth among treatments. The results showed no significant effect of SFM inclusion on viscerosomatic index, whole body protein, body ash and packed cell volume while Hepatosomatic index and lipid content were significantly different among the five treatments. In conclusion, the replacement of fish meal by safflower meal in the diets of Siganus rivulatus led to decreased growth performance and hence it is not suitable to replace fish meal by safflower meal in the diets of this marine herbivore.