Kongkiat SrisuwatanasagulNawarus PrapaiwanSayamon SrisuwatanasagulAnnop KunavongkritAtthaporn RoongsitthichaiChulalongkorn UniversityMahidol UniversityMahasarakham University2019-08-282019-08-282018-10-01Journal of Veterinary Medicine Series C: Anatomia Histologia Embryologia. Vol.47, No.5 (2018), 475-48014390264034020962-s2.0-85050374171https://repository.li.mahidol.ac.th/handle/123456789/47453© 2018 Blackwell Verlag GmbH This study aimed to investigate the immunoexpression of Ki-67 protein, androgen receptor (AR), and estrogen receptor beta (ERβ) in testicular tissues of male pigs immunocastrated using GnRH vaccine (Improvac™, Zoetis Co., Ltd., Thailand) with different times. Totally, 30 male pigs were classified by castration protocol into three groups: T1 (n = 10) consisted of pigs immunocastrated at 14 and 18 weeks of age, T2 (n = 10) included pigs immunocastrated at 9 and 19 weeks of age, and C (n = 10) contained intact pigs. The results revealed that testicular length of pigs in C was longer than that of both T1 (8.1 ± 0.76 vs 6.5 ± 0.5 cm, p < 0.001) and T2 (8.1 ± 0.76 vs 6.9 ± 1.0, p = 0.007). Spearman correlation coefficients showed negative correlation between testicular length and H-score of AR (r = −0.38, p = 0.037), as well as positive correlation between testicular length and Ki-67 index (r = 0.602, p < 0.001). Generally, mean Ki-67 index and mean H-scores of AR and ERβ of pigs in T1 were not different from those in T2 (p > 0.05). However, mean Ki-67 index and mean AR H-scores of T1 and T2 were significantly different from C group (p < 0.05). In summary, the immunocastration significantly affected testicular length, including expressions of Ki-67, AR, and ERβ in pig testes. Moreover, the duration between two shots of GnRH vaccine could be extended from 4 to 10 weeks without difference in Ki-67 protein, AR, and ERβ immunoexpressions.Mahidol UniversityVeterinaryArticleSCOPUS10.1111/ahe.12386