Effects of Caponization and Testosterone on Bone and Blood Parameters of SCWL Male Chickens

  • Chen, Kuo-Lung (Department of Animal Science, National Chiayi University) ;
  • Tsay, Shiow-Min (Department of Animal Science, National Chiayi University) ;
  • Lo, Dan-Yuan (Department of Veterinary Medicine, National Chiayi University) ;
  • Kuo, Feng-Jui (Department of Biomechatronic Engineering, National Chiayi University) ;
  • Wang, Jiann-Hsiung (Department of Veterinary Medicine, National Chiayi University) ;
  • Chiou, Peter Wen-Shyg (Department of Animal Science, National Chiayi University)
  • Received : 2006.03.20
  • Accepted : 2006.06.30
  • Published : 2007.05.01


This study was to investigate the caponization effects on bone characteristics in male chickens, and the optimum testosterone implantation dosage on bone characteristics improvement. Healthy Single Comb White Leghorn cockerels were caponized at 12-wk-old and selected at 16-wk-old for a 10-wk feeding experiment. Fifteen intact male and caponized male chickens (capon) respectively were assigned to trial 1. Ten sham-operated chickens and 40 capons (randomly allocated into four treatments) were implanted with cholesterol (1.62 mm i.d., 3.16 mm o.d., $9.24{\pm}0.36$ mg), low (1 mm i.d., 3 mm o.d., $5.88{\pm}0.23$ mg), medium (1.62 mm i.d., 3.16 mm o.d., $9.81{\pm}0.17$ mg) or high dose (2 mm i.d., 4 mm o.d., $16.7{\pm}0.24$ mg) of testosterone in trial 2. The results from trial 1 showed that the tibia length, relative tibia weight, breaking strength, bending moment and stress in intact males were higher than capons (p<0.05). The blood phosphorus concentration in capons was higher than the intact male chickens (p<0.05). Caponization also resulted in more antrums and osteoclasts within periosteum and cortical bone from histological observation. In trial 2, the adverse impact of caponization on the bone breaking strength, bending moment and stress could be alleviated through medium dose testosterone implantation. It appears that caponization reduced androgen secretion hence influenced the biomechanical characteristics of bone (tibia) and these adverse effects could be alleviated through appropriate dose of testosterone implantation.


Bone Characteristic;Caponization;Male Chicken;Testosterone Implantation


Supported by : National Science Council of Taiwan


  1. Crenshaw, T. D., Jr., E. R. Peo, A. T. Lewis and B. D. Moser. 1981. Bone strength as a trait for assessing mineralization in swine: a critical review of techniques involves. J. Amin. Sci. 53:827-835.
  2. Galvanovskii, Y. Y., M. Y. Valinietse and V. K. Bauman. 1985. Effect of vitamin D on the transport of inorganic phosphorus and activity of alkaline phosphatase in the small intestine of chickens. Sechenova. 71:243-247.
  3. Hsieh, T. Y. 2003. Effects of castration in Taiwan country chicken cockerels on growth performance and lipid metabolism. Master Thesis. National Chung-Hsing University, Taichung, Taiwan.
  4. Landauer, W. 1937. Studies on the creeper fowl. XI Castration and length of the appendicular skeleton of in normal and creeper fowl. Anat. Rec. 69:247-253.
  5. Manolagas, S. C., S. Kousteni and R. L. Jilka. 2002. Sex steroids and bone. Recent Prog. Horm. Res. 57:385-409.
  6. Steel, R. G. D. and J. H. Torrie. 1960. Principles and procedures of statistics. McGraw-Hill. New York.
  7. SAS. 1985. SAS/STAT. Guide for personal computers (Version 6.08). SAS Inc., Cary, NC.
  8. Compston, J. E. 2001. Sex steroids and bone. Physiol. Rev. 81:419-447.
  9. Ono, Y., H. Iwamoto and H. Takahara. 1982. Studies on the growth skeletal muscle of capon. Effects of castration on the weights of skeletal muscle, abdominal fat, intermuscular fat, skin, bone and viscera. Sci. Bull. Fac. Agr. Kyushu Univ. 34:39-46.
  10. Chen, K. L., C. P. Wu and R. G. R. Chou. 2000. Effect of caponization age on growth performance and postmortem change in muscles of Taiwan country chicken. J. Agric. Assoc. China. 1:54-63.
  11. Shafty, T. W., M. W. Mcdonald and R. A. E. Pym. 1990. Effects of dietary calcium, available phosphorus and vitamin on growth rate food utilization, plasma and bone constituents and calcium and phosphorus retention of commercial broiler strain. Br. Poult. Sci. 31:587-602.
  12. Fennell, M. J. and C. G. Scanes. 1992. Inhibition of growth in chickens by testosterone, $5{\alpha}$-dihydrotestosterone and 19-nortestosterone. Poult. Sci. 71:357-366.
  13. Kung, A. W. C. 2003. Androgen and bone mass in men. Asian J. Androl. 5:148-154.
  14. Chen, K. L., W. T. Chi and P. W. S. Chiou. 2005. Caponization and testosterone implantation effects on blood lipid and lipoprotein profile in male chickens. Poult. Sci. 84:547-552.
  15. Chen, K. L., T. T. Chen, K. J. Lin and P. W. S. Choiu. 2007. The effects of caponization age on muscle characteristics in male chicken. Asian-Aust. J. Anim. Sci. (accepted).
  16. Bell, D. J. and B. M. Freeman. 1971. Physiology and biochemistry of the domestic fowl. Academic Press, London and New York.
  17. Lin, C. Y. and J. C. Hsu. 2002. Comparison of some selected growth, physiological and bone characteristics of capon, slip and intact birds in Taiwan country chicken cockerels. Asian-Aust. J. Anim. Sci. 16:50-56.
  18. Li, P. H., H. M. Chiang and T. T. Hsu. 1987. Serum testosterone concentrations and semen quality in landrace and duroc boars housed in a tropical area. J. Chin. Soc. Anim. Sci. 16:31-39.
  19. Chen, K. L., T. Y. Hsieh and P. W. S. Chiou. 2006b. Caponization effects on growth performance and lipid metabolism in Taiwan country chicken cockerels. Asian-Aust. J. Anim. Sci. 19(3): 438-443.
  20. Lesson, S., J. D. Summers and J. P. Walker. 1976. The effect of light and diet on performance and carcass quality of capons. Poult. Sci. 55:438-440.
  21. Chen, K. L., M. H. Chang, S. M. Tsay, H. Y. Hurng and P. W. S. Chiou. 2006a. Effects of caponization on bone characteristics and histological structure in chickens. Asian-Aust. J. Anim. Sci. 19:245-251.
  22. Fennell, M. J., A. L. Johnson and C. G. Scanes. 1990. Influence of androgens on plasma concentrations of growth hormone in growing castrated and intact chickens. Poult. Sci. 77:466-475.
  23. Pederson, L., M. Kremer, J. Judd, D. Pascoe, T. C. Spelsberg, B. L. Riggs and M. O. Oursler. 1999. Androgens regulate bone resorption activity of isolated osteolasts in vitro. Proc. Natl. Acad. Sci. USA. 96:505-516.
  24. Rath, N. C., W. E. Huff, J. M. Balog and G. R. Bayyari. 1996. Effect of gonadal steroid on bone and other physiological parameters of male broiler chickens. Poult. Sci. 75:556-562.
  25. Hutt, F. B. 1929. Sex dimorphism and variability in the appendicular skeleton of the Leghorn fowl. Poult. Sci. 8:202-218.
  26. Johnson, A. L. and V. T. Rendano. 1984. Effects of castration, with and without testosterone replacement, on leg bone integrity in the domestic fowl. Am. J. Vet. Res. 45:319-325.
  27. Notelovitz, M. 2002. Androgen effects on bone and muscle. Fertil. Steril. 77:34-41.

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