Study of testicular immunolocalization of inhibin subunits and epididymal histological structures among different antler status in rusa deer (Rusa timorensis)

Abstract

The number of rusa deer (Rusa timorensis) raising farms has highly increased in Thailand. Basic data on the reproduction of rusa deer are essential for improvement in deer farming reproduction and the assisted reproductive technologies (ARTs) of endangered deer species. This study aimed to determine the relation of antler changes to testicular and epididymis histological structure and cellular source of testicular inhibin subunits in rusa deer. Eighteen rusa deer testes and epididymis were collected from a slaughterhouse located in Kamphaeng Saen, Nakhon Pathom, Thailand. The male rusa deer used in this study were separated into three groups depending on antler stages (velvet, intermediate and hard antlers). Histological observations of the testes and epididymis were performed. The testes sections of three different antler stages were immunostained by polyclonal antisera raised against inhibin α, βA and βB subunits. Means (±SEM) of testicular weight and seminiferous tubule diameter in the hard antler group (76.25±9.80 g and 256.10±7.28 μm) were significantly higher than those of the velvet antler group (40.86±7.41 g and 197.25±7.23 μm) (p<0.05). The epididymis of the intermediate and hard antler groups was filled widely with numerous spermatozoa, which, in contrast, were sporadically observed in the velvet antler group. In addition, the inhibin α and inhibin βA subunits were expressed in both Sertoli cells and Leydig cells while the inhibin βB subunit was only expressed in Leydig cells. This study suggests that the rusa deer testes secrete inhibin in all antler stages. The present study also clearly demonstrates that rusa deer antler changes are related to testicular weight, seminiferous tubule diameter and epididymal spermatozoa, indicating that antler change is a useful indicator for testicular function in rusa deer.