Use of oil by product in rainbow trout diet

Abstract

The present experiments evaluated effects of various level of oil by product (Soybean) in diet on weight gain (WG), feed conversion ratio (FCR) and flesh chemical composition for rainbow trout. Test diets included 0, 5, 10 , 15 and 20 percent of oil by product and also factory diet (ready diet) only for comparing of performance with test diets. This study carried out in a compeletly randomized design with 4 triplicates for 5 weeks in a concret pond. 24 cages used with 7 fishes in each cage and averag weight 180 ± 5 gr. Resaults showed diet with to percent oil by product had no significant difference with control diet 0% oil by product for WG, SGR and FC (P>0.05) but had better effects related to other diets. Also diet content 10 percent oil by product showed best FCR and had significantly difference with control and factory diets (P<0.05). Control diet with highest value for dry matter and fat content of flesh had significantly differences related to other diets. Increasing the level of oil by product in diet caused increasing fat content in liver. Finally, regarding to results, it is recommended 10 percent oil by product in diet for rainbow trout. Key words: rainbow trout, oil by product, Fles chemical composition, weight gain, feed conversation ratio.