The Effect of Prepubertal Castration on Wool Diameter and Blood Testosterone in Ghezel Breed
محورهای موضوعی : Camelف. نظری-زنوز 1 , ق. مقدم 2 , س.ع. رافت 3 , ز. عبدی 4 , ک. اعتماد گرگان 5 , ر. نبوی 6
1 - Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
2 - Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
3 - Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
4 - Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
5 - Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
6 - Department of Animal Science, University of Nebraska-Lincoln, Nebraska, USA
کلید واژه: Testosterone, Sheep, wool, castration,
چکیده مقاله :
Wool growth depends on hormones activity. Owing to hormonal status is extensively affected by surgical excision of endocrine glands, disease or severe congenital abnormalities, wool growth will be altered. This study intends to assess the effect of prepubertal castration at different ages on wool traits and testosterone with draw in male lambs. One month of age Ghezel male lambs (n=20) were selected and allotted in 5 groups (n=4 lambs per group), 4 groups (1, 2, 3, 4 month ages) were surgically castrated, while the fifth group served as control. All animal were fed with the same ration for 240 days. At 9-month of age, hair samples were taken from the mid-side and shoulder regions and analyzed by image analysis. Blood samples were taken from all animals from 1 month of age to 9 month monthly to measure plasma levels of testosterone. The average fiber diameter in castrated lambs was lower compared with intact males (35.21 µm vs. 36.40 µm; P<0.05). Also, 4-month castrated lambs showed significant differences in the average diameter of wool fiber in comparison to the other castrated groups (P<0.05). The plasma level of testosterone in castrated lambs remained in basal levels (0.51 ng/mL), contrasting to values recorded in intact male lambs at 9-month of age (2.33 ng/mL; P<0.05). The diameter of fibers was strongly correlated (P<0.05) with testosterone plasma concentration (r=0.94) in castrated and in intact lambs (r=0.86). Therefore, it is concluded that testosterone concentration affects the diameter of wool.
رشد پشم به فعالیت هورمون ها بستگی دارد. در تغییرات وضعیت هورمونی متأثر از حذف غدد درونریز توسط جراحی، بیماریها یا ناهنجاریهای مادرزادی شدید، رشد پشم به طور قابل ملاحظه ای تغییر میکند. هدف از این مطالعه بررسی اثر اخته کردن در سنین مختلف در دوره قبل از بلوغ بر روی صفات پشم و تغییرات غلظت تستوسترون می باشد. بدین منظور 20 رأس بره یک ماهه نژاد قزل انتخاب شد و در 5 گروه (4 بره در هر گروه) قرار گرفت. گروه اخته شده ها، 4 گروه (1، 2، 3، 4 ماهه) در سنین مختلف اخته شدند، در حالی که گروه پنجم به عنوان گروه کنترل در نظر گرفته شد. تمام حیوانات به مدت 240 روز با جیره غذایی یکسان تغذیه شدند. در 9 ماهگی، نمونه های پشم از قسمت میانی و کتف بدن برداشته شده و توسط روش آنالیز تصویر مورد تجزیه و تحلیل قرار گرفت. از تمامی حیوانات نمونه خون از سن 1 ماهگی تا 9 ماهگی به صورت ماهانه و به منظور اندازه گیری سطح تستوسترون پلاسما گرفته شد. میانگین قطر الیاف پشم در بره های اخته شده در مقایسه با نرهای سالم کمتر بود (35.21 میکرومتر در مقابل 36.40 میکرومتر؛ P<0.05). همچنین میانگین قطر فیبر پشم در بره های اخته شده 4 ماهه تفاوت معنی داری با سایر گروه های اخته شده داشت (P<0.05). سطح تستوسترون پلاسما در 9 ماهگی در بره های اخته شده در مقدار پایه خود (0.5 نانوگرم در میلی لیتر) در مقایسه با بره های نر سالم (2.33 نانوگرم در میلی لیتر) باقی ماند (P<0.05). قطر الیاف با غلظت تستوسترون پلاسما در اخته شده ها (r=0.94) و بره های سالم (r=0.86) همبستگی زیادی داشت (P<0.05). بنابراین، می توان نتیجه گیری کرد که غلظت تستوسترون موجب افزایش قطر پشم می شود.
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