مطالعه ساختار شجره و اثرات ناشی از افت همخونی بر صفات رشد در گوسفندان بومی استان لرستان

نوع مقاله : علمی پژوهشی- ژنتیک و اصلاح دام و طیور

نویسندگان

1 دانشگاه رامین خوزستان

2 دانشگاه کشاورزی و منابع طبیعی رامین خوزستان

3 مرکزتحقیقات کشاورزی و منابع طبیعی استان لرستان

4 علوم کشاورزی و منابع طبیعی ساری

چکیده

هدف از مطالعه حاضر بررسی شجره و افت همخونی بر صفات رشد در گوسفند لری می باشد. برای انجام پژوهش حاضر از اطلاعات شجره و رکوردهای مرتبط با صفات رشد شامل وزن‌ تولد، وزن‌شیرگیری، وزن شش‌ماهگی و وزن‌نه‌ماهگی 6440 رأس بره حاصل از 273 رأس قوچ و 1955 رأس میش که طی سال‌های 1380 تا 1389 از مرکز تحقیقات کشاورزی و منابع طبیعی استان لرستان جمع‌آوری شده بود، استفاده گردید. تجزیه شجره از برنامه Pedigree ، برآورد ضریب‌همخونی از برنامه CFC و برای محاسبه میزان تابعیت صفات از همخونی، از نرم افزار WOMBAT استفاده گردید. در کل جمعیت تعداد حیوانات همخون 2126 دام بودند که 33 درصد گله را شامل می‌شد. میانگین ضریب‌همخونی کل جمعیت 69/0 درصد و میانگین ضریب ‌همخونی جمعیت همخون 24/2 درصد برآورد گردید. روند تغییرات سالیانه ضریب ‌همخونی 21/0 درصد بود که به لحاظ آماری معنی‌دار می‌باشد. کمترین و بیشترین مقدار همخونی به ترتیب صفر و 85/26 درصد محاسبه شد. پایین بودن ضریب‌همخونی گله می‌تواند ناشی از نامعلوم بودن شجره برخی حیوانات، نوسانات مدیریتی و تا حدی ممانعت از آمیزش‌ خویشاوندان نزدیک باشد. اثر همخونی در جمعیت گوسفندان لری با استفاده از مدل‌های حیوانی مناسب برای هر صفت تولیدی بررسی شد. با افزایش هر یک درصد افزایش در همخونی، وزن‌تولد 4 گرم، وزن‌شیرگیری 3/20 گرم، شش ‌ماهگی 247 گرم و نه‌ماهگی 5/4 گرم کاهش پیدا کرده است. استفاده از یک برنامه آمیزش مستقیم تحت کنترل در گله حاضر می‌تواند جایگزینی مناسب برای حفظ سطح همخونی شود.

کلیدواژه‌ها


عنوان مقاله [English]

Study of pedigree structure and effects of inbreeding depression on growth traits in Lorestan native sheep

نویسندگان [English]

  • zahra yeganehpour 1
  • Hedayat allah Roshanfekr 2
  • Jamal fayazi 2
  • Mir Hasan Beiranvand 3
  • Mohammad Ghaderzadeh 4
1 , Ramin Agriculture Natural Resources University,Mollasani, Khoozestan
2 , Ramin Agriculture Natural Resources University,Mollasani, Khoozestan
3 Member of Department of Agriculture and Natural Resources Research Center, Lorestan
4 Sari Agricultural Sciences and Natural Resources University
چکیده [English]

Inroduction: Inbreeding is defined as the probability that two alleles at any locus are identical by descent and occur when related individuals are mated to each other. The initial consequence of inbreeding is inbreeding depression reducing the performance of growth, production, health, fertility, and survival traits. This concern has become more serious in animal breeding nowadays, in which selection responses are maximized using animal model best linear unbiased predictors (BLUP) of breeding value. The use of these breeding values alone may result in more closely related selection candidates preferred for selection, with increased levels of inbreeding since they share most of their familial information. The unavoidable mating of related animals in closed populations leads to accumulation of inbreeding and decreased genetic diversity. Inbreeding has deleterious effect on additive genetic variance as well as on phenotypic values. Heterozygosity and allelic diversities can be lost from small, closed, selected populations at a rapid rate. The rates of inbreeding must be limited to maintain diversity at an acceptable level so that genetic variation will ensure that future animals can respond to changes in environment. Inbreeding depression has been found in a large proportion of species examined. Lori sheep breed is mainly raised in Lorestan Province in Iran. This study was conducted to identify pedigrees and inbreeding depression on growth traits in Lori sheep population from 2001 to 2010. The rate of inbreeding needs to be limited to maintain diversity at an acceptable level so that genetic variation will ensure that future animals can respond to changes in the environment and to selection. Without genetic variation, animals cannot adapt to these changes.

Material and Methods: For this study pedigree information and body weight at different ages (birth weight, weaning weight, 6-month weight, and 9-month weight) of 6440 lambs from 273 rams and 1955 ewes during the years 2001 to 2010 from Lorestan Agricultural and Natural Resources Research Center were used. The pedigree corrections were done by the Excel program and the estimation of inbreeding coefficients was done by pedigree software. To study the pedigree, Pedigree, program, or estimate inbreeding coefficient, CFC program, and for calculate the amount of inbreeding citizenship traits, wombat software were used.

Results and Discussion: In total population the number of inbred animals were 2126 (33%) of the herd. The average total population inbreeding coefficient and average inbreeding coefficient inbred of population were 0.69% and 2.24%, respectively. Annual changes in inbreeding coefficient was 0.21, which was statistically significant (p

کلیدواژه‌ها [English]

  • Animal model
  • Growth traits
  • Inbreeding depression
  • Inbreeding trend
  • Lori sheep
1- Adelikhah, M., R. Vaeztorshizi., M. Rokouei, and D. Tohidi. 2008. Inbreeding and its effect on productive traits in Zandi sheep. The 3th Congress on Animal Science. 2008.
2- Almasi, M., A. Rashidi., M. Razmkabir, and A. Mirza Mohammadi. 2012. Effects of inbreeding coefficient on pre-weaning traits in Markhoz goats The 5th Congress on Animal Science, August, 386-391.
3- Analla, M., J. M. Montilla, and J. M. Serradilla. 1998. Analysis of lamb weight and ewe litter size in various lines of Spanish Merino sheep. Small Ruminant Research, 29 (3):255-259.
4- Bahri Binabaj, F., H. Faraji Arogh., M. Rokuei., M. Jafari, and A. Mohammad Hashemi. 2012. Estimation of inbreeding trend and its effect on growth traits, longevity and skin score of Karakul Sheep breed. The 5th Congress on Animal Science August, 760-764.
5- Boujenane, I, and A. Chami. 1997. Effects of inbreeding on reproduction, weights and survival of Sardi and Beni Guil sheep. Journal of Animal Breeding and Genetics, 114(1-6): 23-31.
6- Dickerson, G. E. 1973. Inbreeding and heterosis in animals. Journal of Animal Science, 16(4) 73:54- 77.
7- Dorostkar, M., H. Faraji., A. Rough., J. Shodja., S. A. Rafat., M. Rokouei, and H. Esfabdyari. 2012. Inbreeding and inbreeding depression in Iranian Moghani sheep breed. Journal of Agricultural Science and Technology, 14(3): 549-556.
8- Falconer, D. S, and T. F. C. Mackay. 1996. Introduction to quantitative genetics. Forth edition, Longmans Green، Harlow, Essex, UK. Chapter 14, 15.
9- Farhadi, M. 2010. Study of inbreeding on productive and reproductive traits in Lori-Bakhtiari sheep. End of letter Masters Animal Sciences. Faculty of Agriculture. Shahrekord University.90pp.
10- Gholambabaeian, M., A. Rashidi., M. Razmkabir, and A. Mirza Mohammadi. 2012. Inbreeding coefficient estimate and its effects on pre-weaning traits in Moghani sheep. The 5th Congress on Animal Science, August, 71-75.
11- Gomez, M. D., M. Valera., A. Molina., J. P. Gutierrez, and F. Goyache. 2008. Assessment of inbreeding depression for body measurements in Spanish Purebred (Andalusian) horses. Livestock Science, 122: 149-155.
12- Hussain, A., P. Akhtar, S. Ali, M. younas., and M. Shafiq. 2006. Effect of inbreeding on pre weaning growth traits in thalli sheep. Pakistann Veterinary Journal, 26(3): 138-140.
13- Khaldari, M. 2006. Principles of sheep and goat breeding.Tehran Jahad daneshgahi Publications. 503 pages. (In Persian).
14- Mackinnon K. M. 2003. Analysis of Inbreeding in a Closed Population of Crossbred Sheep. MSc Thesis, Virginia Polytechnic Institute and StateUniversity Blacksburg, Virginia.
15- Mehman Navaz, Y., R. Vaeztorshizi., A. Salehi, and A. Shourideh. 2000. Inbreedind and its effect on productive traits in Baluchi sheep. The First Seminar on Genetics and Breeding Applied to Livestock, Poultry & Aquatics Faculty of Agriculture, Tehran University, Feb, 20-21.
16- Meyer, K. 2000. DFREML. Version 3. 0 â Program to estimate variance components by Restricted Maximum Likelihood using a derivative-free algorithm. User notes. Animal and breeding dept. university of New-England, Armidale, N. S. W. 84.
17- Mirza Mohammadi, A, and A. Rashidi. 2012. Estimation of genetic parameters and evaluation of inbreeding effects on birth weight and mortality in Zandi sheep. The 5th Congress on Animal Science, August, 561-565.
18- Mottaghinia, G., H. Farhangfar, and M. Janati. 2009. A study of inbreeding trend and its effect on wool weight of Baluchi sheep in Abbas Abad breeding center of Mashhad. Animal Science Researches, 22(2): 129-121.
19- Norberg. E., and A. C. Sørensen. 2007. Inbreeding trend and inbreeding depression in the Danish populations of Texel, Shropshire, and Oxford Down. Journal of Animal Science, 85(2):299–304.
20- Oyama, K., and F. Mukai. 1998. Determination of the optimum mating design with constraints on inbreeding level and mating frequency of sires via a simple genetic algorithm. Journal of Animal Science and Technology, 69(4): 333- 340
21- Pedrosa, V. B., J. R. Santana., P. S. Oliveira., J. P. Eler, and J. B. S. Ferraz. 2010. Population structure and inbreeding effects on growth traits of Santa Inês sheep in Brazil. Small Ruminant Research, 93(2): 139-135.
22- Rashedi Dehsahraei, A., J. Fayazi, and M. Vatankhah. 2013. Investigating inbreeding trend and its impact on growth traits of Lori-Bakhtiari Sheep. Journal of Ruminant Research, 1(3):65-78. (In Persian).
23- Rzewuska, K., J. Klewiec, and E. Martyniuk. 2005. Effect of Inbred on reproduction and body weight of sheep in a closed Booroola flock. J Animal Science Papers and Reports, 23:237-247.
24- Sargolzaei, M., H. Iwaisaki, and Jacques Colleau, J. 2006. A software packagefor pedigree analysis and monitoring genetic diversity.
25- SAS. 2003. Users Guide Statistics. Version 9.1, SAS Institute I nc., Cary, NC., USA
26- Sheikhlu, M., M. Tahmurespoor, and A. Aslaminejad. 2012. Study inbreeding of Baluchi sheep in Mashhad Abbas Abad station. Iranian Journal of Animal Science Research, 3(4): 453-458.
27- Van Wyk, J. B., M. D Fair, and S. W. P. Clorte. 2006. The effect of inbreeding on the production and reproduction traits in the Elsenburg dormer sheep stud. Livestock Science, 120 (3):19:21-28.
28- Van Wyk, J. B., M. D. Fair, and S. W. P. Cloete. 2009. Case Study: The effect of inbreeding on the production and reproduction traits in the Elsenburg Donner sheep stud. Livestock Science, 120: 218-224.