اثرات تراكم ذخيره سازي و دفعات غذادهي بر شاخص هاي رشد و هماتوكريت در بچه ماهي كلمه

Effects of stocking density and feeding frequency on the growth parameters and hematocrit of the Rutilus rutilus caspicus juvenile

دفعات تغذيه و تراكم ذخيره سازي از فاكتورهاي مهم موثر بر رشد و بلوغ ماهيان پرورشي است. هدف اين مطالعه تعيين اثرات تراكم (10، 20، 30 و 40 قطعه ماهي در آكواريوم) و دفعات تغذيه (2، 3 و 4 نوبت غذادهي در روز) بر پارامتراهاي رشد و هماتوكريت ماهي كلمه (Rutilus rutilus caspicus) است. آزمايش در دو تكرار و به مدت 45 روز انجام شد. نتايج اين مطالعه نشان داد كه پارامترهاي رشد شامل افزايش وزن، ضريب تبديل غذا و نرخ رشد ويژه به طور معني داري تحت تاثير تراكم قرار گرفتند (05/0>P)، اما دفعات غذادهي اثر معني داري نداشت (05/0P). همچنين، اثرات متقابل تراكم و دفعات غذادهي بر پارامترهاي رشد معني دار نبود (05/0P). كمترين سطح هماتوكريت در تراكم 10 و با دو وعده غذادهي در روز مشاهده شد. نتايج اين مطالعه نشان داد كه تراكم بر رشد اثر معني داري دارد، اما افزايش دفعات غذاذهي تاثيري بر رشد ماهي كلمه ندارد.

Feeding frequency and stocking density are important factors affecting growth and maturation of cultured fish. The aims of this investigation were to determine the effects of stocking density (10, 20, 30 and 40 fish per aquarium) and feeding frequency (2, 3 and 4 times on daily) on growth parameters and hematocrit of the Rutilus rutilus caspicus juveniles. The experiment was continued for 45 days in two replicates. The results of this study showed that growth parameters, including weight gain (WG), feed conversion ratio (FCR) and specific growth rate (SGR) were affected significantly by stocking density(P<0.05), but not significantly affected by feeding frequency (P>0.05). The highest WG and SGR were recorded with the lowest stocking density (10 fish / aquarium). The least FCR was obtained in density of 10 fish/aquarium, FCR value was significantly higher with high stocking density (P<0.05). Also, interactions between stocking density and feeding frequency were no significant on growth parameters (P>0.05). Density and feeding frequency had no significant effect of hematocrit concentration (P>0.05). On the other hand, interactions between stocking density and feeding frequency significantly affected hematocrit levels (P<0.05). The lower level of hematocrit was observed in density of 10 fish/aquarium at two times / day feeding frequency. The results of this study indicated that density is significantly affected the growth, but increasing of feeding frequency there is not effect on growth in the Rutilus rutilus caspicus.