The effect of olive oil cake on growth, body composition and sensory evaluation of rainbow trout (Oncorhynchus mykiss)

This study was conducted to investigate the effect of olive oil cake on growth and sensory evaluation of rainbow trout. Four practical diets containing 0 (control)، 5، 10 and 15% of olive cake (dried and well powdered) was formulated and fed to triplicate groups of fish. Two hundred and forty fish with average initial weight of 71. 3 ± 5 g were randomly distributed into 12 circular concrete ponds with 3m diameter and 1 m height. River water with flow rate 1L. Sec-1 was flowed; the water temperature and pH were 10 ± 3ºC، 6. 7-8. 1 respectively، during 70 days of experimental trial. The fishes were fed at 1-1. 5% body weight in three times daily (8، 12 and 18). The final weight، WG، SR، CF، SGR، BWI، FCR، HIS and body composition of trial fishes were indicated that to maximum 5% olive oil cake be replaced. The poor growth، feeding efficiency and body carcass composition was observed in treatment 4 with 15% olive cake inclusion and significant with other treatments (P<0. 05). The result of sensory evaluation showed that adding olive cake to the diet has not affected color (P>0. 05); however it has positive effect on small and taste as compare with control diet (P<0. 05) and caused diet palatability for fishes. Generally، it can be concluded that inclusion of 5% olive oil cake in diet of rainbow trout is useful.