Periódicos Brasileiros em Medicina Veterinária e Zootecnia

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Histological and morphometric examination of the testes of boars and male pigs immunocastrated with Improvac®

Stojanovic, SlobodanUscebrka, GordanaZikic, DraganStukelj, Marina

Background: Surgical castration of male piglets is frequently performed to prevent development of an unpleasant taste and flavor in meat of mature males, called boar taint. Disadvantages of this method are primarily related to the lower feed efficiency of surgically castrated male pigs, production of less lean meat and more fat on the carcasses than boars, as well as ethical issues associated with the procedure itself. Immunocastration is a method of immunization against gonadotropinreleasing hormone (GnRH) and represents an alternative to avoid boar taint. This study aimed to examine the influence of immunocastration on histological and morphometric parameters of male pig testes.Materials, Methods & Results: A total of 60 crossbred male pigs selected from 30 litters were assigned to two experimental groups: boars (n = 30) and immunocastrated males (n = 30). Two doses (2 mL per dose) of the Improvac® vaccine were given to pigs scheduled for immunocastration. The first injection was given at 10 weeks of age, and the second injection at 20 weeks of age. All pigs were fed the same commercial diet ad libitum, group-housed (15 pigs/pen) and slaughtered at 25 weeks of age. After slaughter, testicle weights were measured and samples of testicular tissue were taken for histological examination. Immunocastrated males had lower testicle weights than boars (P < 0.01). Furthermore, structural damage to the germinal epithelium was visible in the seminiferous tubules of vaccinated pigs. In the testicular interstitium of these animals, the number of Leydig cells were reduced; almost all of these cells exhibited different degrees of abnormality. Moreover, the diameter of the seminiferous tubules and thickness of the germinal epithelium were greater (P < 0.01), and the percentage of germinal epithelium in the seminiferous tubules as well as percentage of blood vessels in the interstitium were higher in boars as compared to immunocastrated males (P < 0.01).[...](AU)

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