عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In this study effect of dietary burdock root powder on some growth indices and proximat composition of fray rainbow trouts were evaluated. The root powder with the values of 0, 1, 3, 5 and 7% (w/w) was added to the basal diet of fish (initial average weight of 45± 2.8g) during of 45 days of the culturing period. Physicochemical parameters of the water were recorded weekly during the experiment. Biometry was performed once every 15 days and growth parameters including condition factor (CF), survival rate (SR), daily growth rate (DGR), feed conversion ratio (FCR), specific growth rate (SGR) and weight gain percent (WG) were calculated. The results showed that weight and length gain of the fish groups fed with burdock root powder were higher than control group (p<0.05). Maximum fish weight (168.0 ± 25.45 g) were obtained in the 5% group compared to other treatments (p<0.05). In the treatment of 5% highest DGR value was recorded (2.74 ± 0.08) in comparison to the control group (8.98 ± 0.04) (p<0.05). The mortality rate in the treatments fed with burdock root powder was higher than control group (p<0.05). FCR value showed no significant difference between 5% and 7% treatment (p>0.05). The WG in 5% (274.5 ± 3.2%) was higher than the control (198.6 ± 4.2%) (p<0.05). The highest and lowest level of SGR was calculated in 5% treatment (2.8 ± 0.05%) and 7% treatment (2.4 ± 0.02%), respectively (p<0.05). The highest amount of protein and fat was reached in 5% treatment (22.3 ± 0.6%) and control (6.65 ± 0.23%), respectively (p<0.05). All in all, adding 5% of draied burdock root powder in rainbow trout diet can be used in the feed factory to increase some growth factors of the fish.