The Effects Of Partially Replacing Fishmeal with Azolla (Azolla Sp.) On Growth Parameters Of Shabbout Fish (Tor grypus H. 1843)

Abstract

In this study, the effect of replacement of fishmeal by azolla meal in prepared diet was investigated in Shabbout fish fingerlings. Four different experimental diets (all containing mean 41.7% crude protein and 3026.2 digestible energy) at a various ratios of azolla has prepared. Control diet (D1) was composed of fishmeal completely. Experimental diets (D2, D3 and D4) were composed of 10%, 20% and 30% azolla meal respectively instead of fishmeal. The experiment was carried out in a closed rearing system with recirculated filtered water for 12 weeks. According the to the results of the experiment, the mean specific growth rate (SGR) and mean weight gain values were the highest for the group fed with D2 after D1. There was no difference among four groups with respect to the mean final condition factor (K), feed conversion ratio (FCR) and protein efficiency ratio (PER) values at P>0.05 statistical significance level. However, mean weight gain and mean final weight were no significantly different among the groups fed with D2, D3 and D4 (P<0.05). SGR and mean final length were significantly different in all groups. Based on all measured criteria, it is suggested that approximately 10% of fish protein from fishmeal can be replaced by azolla meal without adverse effect on fish performance.