نوع مقاله: مقاله پژوهشی

نویسندگان

1 کارشناس ارشد شیلات، دانشگاه علوم کشاورزی و منابع طبیعی گرگان

2 دکتری بیولوژی دریا. گروه زیست شناسی دانشگاه الزهرا

چکیده

رنگ پوست در ماهیان از نظر فیزیولوژیکی، رفتاری و اکولوژیکی دارای اهمیت بوده و می تواند به عنوان شاخصی از آرامش ماهی در زمان پرورش و همچنین به عنوان یک فاکتور کیفی مهم در زمان فروش در نظر گرفته شود. در این مطالعه اثر دوزهای مختلف هورمون متیل تستوسترون تجاری (0، 300، 400 و 1000 میلیگرم در کیلوگرم غذا) بر خصوصیات سه بعدی ظاهری رنگ (روشنایی (L*)، ته رنگ (Hºab) و کروما (C*ab)) و شاخص کلی رنگ ((ECI این ماهی مورد بررسی قرار گرفت. جهت آنالیز داده ها بعلت ماهیت آنها از آزمون های مربوط به توزیع دایره ای استفاده گردید. در تمام سطوح مختلف هورمون بجز دوز 1000، میزان روشنایی پوست  ناحیه  باله دمی بطور معنی داری بیشتر از ناحیه تنه ماهی گوپی بود. همچنین میزان روشنایی ناحیه تنه با افزایش دوز هورمون کاهش و سپس در بالاترین دوز افزایش معنی دار نشان داد. به طور کلی، با افزایش دوز هورمونی افزایش تمایل به ته رنگ قرمز در هر دو ناحیه ی باله ی دمی و قسمت جانبی بدن قابل مشاهده بود. ضمن آنکه در تمامی دوزهای مورد بررسی بین ناحیه ی تنه و دم از نظر میزان ته رنگ اختلاف دیده شد. به طور کلی می توان اینگونه نتیجه گرفت که با افزودن میزان هورمون بر مقدار رنگدانه های قرمز و در نتیجه میزان جذابیت جنسی ماهیان افزوده شده، ضمن آنکه این تغییرات رنگی بر جذابیت ماهیان جهت فروش نیز می تواند تاثیر گذار باشد.

کلیدواژه‌ها

عنوان مقاله [English]

New method for comparison of color factors in fishes: its effect of commercial methyltestosterone on color pattern in male Guppy (Poecilia reticulate)

نویسندگان [English]

  • Mohamad Hosein Ebreahimi 1
  • Fatemeh Abbassi 2

1 MSc. Student, Dep. fisheries, Gorgan University of Agricultural Sciences and Natural Resources

2 PhD. Graduates, Dep. Biology, Alzahra University

چکیده [English]

Skin coloration patterns in fish are of great physiological, behavioral and ecological importance, can be considered as an index of animal welfare in aquaculture and as an important quality factor for the retail value. In the present study the effect of different doses (0, 300, 400 and 1000 mg/kg of diet) of commercial methyltestosterone on three-dimensional characteristics of skin color appearance (lightness — L*, hue — H ab and chroma —Cab) with a new index named Entire Color Index (ECI) were investigated. For data analyzing, because of the nature of the color factors, circular distribution was used. The lightness of the caudal fin was significantly (p<0.05) higher than body in all the doses except 1000 mg/kg. The lightness of the body area primarily decreased and then increased in 1000 mg/kg. With increasing the doses, the tendency to the redness Hue was increased. In addition we had significant difference in Hue values between body and caudal fin area. As a result, with increasing the dose of hormone, red pigments, and therefore attractiveness of the male were increased and this differences in color factors could be resulted to the increasing the retail values.

کلیدواژه‌ها [English]

  • Guppy
  • color pattern
  • methyltestosterone

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