شاخص هاي رشد، كارايي تغذيه و بازماندگي بچه ماهيان قزل آلاي رنگين كمان (Oncorhynchus mykiss) تغذيه شده با سطوح مختلف عصاره هاي سرخارگل (Echinacea angustifolia) و مرزنجوش (Origanum majorana)

Growth indices, feeding efficiency and survival of rainbow trout (Oncorhynchus mykiss) fed diets containing different levels of Echinacea angustifolia and Origanum majorana extracts

اين مطالعه به منظور ارزيابي تاثير سطوح مختلف عصاره هاي سرخارگل (Echinacea angustifolia) و مرزنجوش (Origanum majorana) بر عملكرد رشد، كارايي تغذيه و بازماندگي بچه ماهيان قزل آلاي رنگين كمان (Oncorhynchus mykiss) انجام گرفت. هفت جيره آزمايشي حاوي صفر (براي گروه كنترل)، 0/1، 0/2 و 0/4 درصد سرخارگل و 0/1، 0/2 و 0/4 درصد مرزنجوش تهيه گرديد. بچه ماهيان قزل آلاي رنگين كمان با ميانگين وزني 0/3± 2/6 گرم به صورت تصادفي به 7 گروه (در 3 تكرار) تقسيم و به مدت 4 هفته با جيره هاي آزمايشي تغذيه شدند. در انتهاي دوره آزمايش، شاخص هاي رشد، كارايي تغذيه و بازماندگي محاسبه گرديد. درپايان آزمايش شاخص هاي رشد و تغذيه اي مانند نرخ رشد ويژه (SGR)، ضريب تبديل غذايي (FCR)، درصد افزايش وزن بدن، كارايي غذايي، ميانگين وزن نهايي و كارايي پروتئين به طور معني داري تحث تاثير سطوح مختلف عصاره هاي اين گياهان قرار گرفتند (005>P). تيمارهاي مورد آزمايش هيچ گونه تاثير معني داري بر روي طول نهايي و ضريب چاقي نداشتند (0/05P). با توجه پارامترهاي رشد و تغذيه اي در اين آزمايش، مي توان گفت كه ميزان 0/2 درصد عصاره سرخار گل و 0/1 درصد مرزنجوش در جيره مي توانند موجب بهبود عملكرد رشد اين ماهي شوند.

This study was conducted to evaluate the effects of different levels of Echinacea angustifolia and Origanum majorana extracts on growth performance, feed efficiency and survival of rainbow trout (Oncorhynchus mykiss) juveniles. Seven experimental diets with 0 (control), 0.1, 0.2 and 0.4% E. angustifolia and 0.1, 0.2 and 0.4% O. majorana were prepared. Fish with initial weight 2.6 ± 0.3 g were randomly divided into 7 groups in triplicates and were fed with experimental diet for 4 weeks. At the end trial, the growth parameters, feed efficiency and survival were calculated. Growth and feed indices such as specific growth rate (SGR), Feed conversion ratio (FCR), weight gain, feed efficiency, average final weight, protein efficiency ratio were significantly affected by different levels of plant extracts (P<0.05). Experimental treatments were not significantly affect on condition factor and final length (P>0.05). However, condition factor was higher in fish fed higher levels of plant extracts. No mortality was observed during the experiment. Regression analyses showed relationship between SGR and FCR in fish fed O. majorana extracts (P<0.05). According to the results of growth parameters and feed efficiency, it can be concluded that dietary 0.2% extract of E. purpurea and 0.1% of O. majorana have growth enhancement effects in this fish.