Morphometric Studies on the Testis of Korean Ring-necked Pheasant (Phasianus colchicus karpowi) during the Breeding and Non-breeding Seasons

Abstract

The purpose of this study was to obtain detailed quantitative information on all cell types in the testis interstitium of Korean ring-necked pheasants and to combine these data with changes in the steroidogenic function of the testis during the breeding and non-breeding seasons. For animals collected during the breeding season, their testis weights, sperm production, serum testosterone levels and leuteinizing hormone (LH)-stimulated testosterone secretion were significantly (p < 0.01) increased compared to the non-breeding season. Testes of the pheasants during the non-breeding season displayed a 98% reduction in testis volume that was associated with a decrease in the absolute volume of seminiferous tubules (98% reduction), tubular lumen (100%), interstitium (90%), blood vessels (84%), lymphatic spaces (97%), Leydig cells (79%), mesenchymal cells (51%) and myoid cells (61%) compared to the breeding season. The numbers of Leydig cells, mesenchymal cells and myoid cells per testis in the breeding season were much higher than in the non-breeding season. Although the mean volume of a Leydig cell was 74% lower in the non-breeding season, the mean volumes of myoid and mesenchymal cells remained unchanged. These results demonstrate that there are striking differences in the testicular structure of the Korean ring-necked pheasant during the breeding and non-breeding seasons. Every structural parameter of the Leydig cell was positively correlated with both testosterone serum levels and LH-stimulated testosterone secretion. The correlation of changes in hormonal status with the morphometric alterations of Leydig cells suggests that the Korean-ring necked pheasant may be used as a model to study structure-function relationships in the avian testis.

Histological and morphometric analyses of seasonal testicular variations in the Jungle Crow (Corvus macrorhynchos)

“…However, the proportions of interstitium vary among species and between gonadally inactive and active states. For example, the interstitial area in gonadally inactive and active states has been reported to be 27.5 and 12.5% in the Emu (Malecki et al 1998) and 32.4 and 6.75% in the Korean Ring-necked Pheasant (Tae et al 2005); for the Jungle Crow, we obtained values of 44.43 and 7.89%, respectively, in our study.…”

Drought leads to reproductive quiescence in smooth‐billed anis: Phenotypic evidence for opportunistic breeding and reproductive readiness

“…The present study provides a detailed morphological description of the reproductive system of the smooth‐billed ani and reports about intense reproductive remodeling as evidence of opportunistic breeding behavior following rainfall variations in a semiarid area. The findings of this study (1) showed that the reproductive morphology of the smooth‐billed ani was similar to that observed in other birds such as domestic quail, fowl, emu, ostrich, goose, parakeet and drake (Aire, 2002; Aire & Soley, 2000; Leska, Kiezun, Kaminska, & Dusza, 2015; Parizzi et al, 2008; Peixoto et al, ; Reed, Cope, & Blackford, 2011); (2) indicated intense gonadal activity throughout the wet season that was consistently similar to what is described in other birds during the breeding season (Baraldi‐Artoni et al, ; Kim & Yang, ; Leska & Dusza, ; Peixoto et al, ; Tae et al, ); (3) and revealed remarkable signs of gonadal involution and low gametogenic activity after precipitation decreased. Birds inhabiting areas with adverse climate characteristics exhibit flexibility with regard to the timing and intensification of breeding activity whenever environmental conditions are satisfactory to ensure reproductive success and offspring survival (Cruz‐McDonnell & Wolf, ; Dybala, Eadie, Gardali, Seavy, & Herzog, ; Quintero, González‐Caro, Zalamea, & Cadena, ; Sandoval, ; Selwood et al, ).…”

Seasonal changes in the expression of the androgen receptor in the testes of the domestic goose (Anser anser f. domestica)

“…Histological and morphometric analyses revealed that gander testes undergo marked structural seasonal changes as it has been described in Bilgoraj goose (Anser anser) and Canadian goose (Branta canadensis) [28,31,32] and other bird species [1,20,25,42]. Interestingly, structural changes in testicular tissue in the sexual reactivation phase remain weakly researched, especially in geese.…”