Endocrine and testicular changes in a short-day seasonally breeding bird, the emu (Dromaius novaehollandiae), in southwestern Australia

Malecki, Irek; Martin, Graeme B.; O’Malley, Patrick; Meyer, Geoffrey; Talbot, Richard; Sharp, P. J.

doi:10.1016/s0378-4320(98)00110-9

Cited by 46 publications

(31 citation statements)

References 31 publications

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“…The data obtained from this experiment may be compared to those of seasonal breeding mammals. The general composition of the testis interstitium of Korean ring-necked pheasants is similar to that of mammals (Belt and Cavazos, 1971;Suzuki and Racey, 1978;Hochereau-de Reviers et al, 1985;Mendis-Handagama et al, 1988;Rey et al, 1996;Ariyaratne and Mendis-Handagama, 2000), but the proportions of interstitium vary between species; for the gonadally active and inactive states, respectively, these are 6.5% and 16.5% in hamsters (Sinha-Hikim et al, 1988), 12.5% and 27.5% in emus (Malecki et al, 1998) and 6.75% and 32.4% in Korean ring-necked pheasants. These results suggest that there are many more changes in the interstitium during the reproductive cycle in birds than in mammals and that the changes of cell type in the interstitium are more notable and sensitive to the changes of the external environment.…”

Section: Discussionmentioning

confidence: 54%

“…Seasonal breeding mammals have been used to allow the study of the structuref unction relationships of testis (Pearson et al, 1952;Suzuki and Racey, 1978;Lincoln, 1981;Hochereau-de Reviers et al, 1985;Sinha-Hikim et al, 1989;Malecki et al, 1998), and the changes in the testis due to experimentally induced alteration, including hypophysectomy (Ahmad et al, 1975) and exposure of the animals to irradiation (Kerr et al, 1985) or to various chemical agents (Jackson et al, 1986) have been observed. So far, only the simple histological compositions of testis and the hormonal changes during the reproductive cycle have been described in studies of seasonal breeding avians (Donham, 1979;Dittami, 1981;Degen et al, 1994;Aire, 1997;Malecki et al, 1998;Kim and Yang, 2001).…”

Section: Discussionmentioning

confidence: 99%

“…So far, only the simple histological compositions of testis and the hormonal changes during the reproductive cycle have been described in studies of seasonal breeding avians (Donham, 1979;Dittami, 1981;Degen et al, 1994;Aire, 1997;Malecki et al, 1998;Kim and Yang, 2001). To our knowledge, there are no reports or morphometric studies of testis interstitium during the reproductive cycle in seasonal breeding avians, including the Korean ring-necked pheasant (Kim and Yang, 2001).…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2005

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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.

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Section: Discussionmentioning

confidence: 54%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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

et al. 2005

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“…The seminiferous tubules, in transverse sections, presented almost circular shapes (Fig.2). The testicular parenchyma of the Greater Rhea is composed by seminiferous tubules that, in transverse sections, show almost circular shapes, different to what is witnessed in the domestic Rooster (Lake 1971) and the Quail (Baraldi Artoni et al 1999), which present hexagonal shapes, and similar to the Emu, which also presents circular shapes (Malecki et al 1998). Phylogenetically, the Emu is close to the Greater Rhea, and both species are part of the Ratite bird group.…”

Section: Resultsmentioning

confidence: 88%

Aspects of spermatogenesis and microscopic testicular morphology in Greater Rhea, Rhea americana (Linnaeus, 1758)

2016

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ABSTRACT.-Freneau G.E., Carvalho S.F.M., Saboia-Morais S.M. T. & Freneau B.N. 2016 The purpose of this study was to study the microscopic morphology of the testicular parenchyma of Rhea americana birds. Fifty-four 2.5±0.5 year-old male adults bred in captivity. were used. During commercial slaughter, samples of testis were collected in November respectively. Microscopic measures of seminiferous tubules, spermatic cells and diameter of the nuclei were presented. These data confirm reproductive seasonality, with breeding season in spring-summer with sperm production. A great variation n parenchyma, when compared breeding was noticeable.

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“…The usefulness of a number of histological parameters to characterize the seasonal testicular cycle in bird testes, such as the diameter of the seminiferous tubules, height of the seminiferous epithelium, thickness of the tunica albuginea, number of germinal and the interstitial cells, has been explored (Fuenzalida et al 1989; Baraldi-Artoni et al 1997). Additionally, seasonal changes in avian testes at ultrastructural, endocrinological, physiological, and molecular levels have been examined in a considerable number of avian species (Malecki et al 1998;Young et al 2001;Aire and Ozegbe 2007;Jenkins et al 2007;Rengaraj et al 2008). However, little is known about the histology of the seasonal testicular cycle of the Jungle Crows (Corvus macrorhynchos) of Japan, and the available data are limited to behavioral aspects.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2009

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A histological and morphometric study was conducted to examine the seasonal testicular variations in the Jungle Crow (Corvus macrorhynchos) of the Kanto area, Japan, from January to July. The paired testes mass, diameter and number of germ cells of the seminiferous tubules, and proportion of seminiferous tubule area and interstitium were examined. Hematoxylin and eosin-stained testis sections and ImageJ Software were used. Paired testes weight was found to increase by 55-fold from January to late March-early May, thereafter declining by 18-fold by June-July. Seminiferous tubule diameter increased fivefold from January to late March-early May, followed a fourfold decrease in June-July. The increase in testes weight correlated well with the increase in the diameter of the seminiferous tubule. In January, the seminiferous tubules constituted 56% of the testicular tissue and the interstitium 44%. During late March-early May, there was very little testicular interstitium (7.9%), and the seminiferous tubules were significantly enlarged (P < 0.05) (92%); this was followed by a gradual increase in the interstitial regression of testes. In January, the seminiferous epithelium contained a single layer of spermatogonia and Sertoli cells. The number of spermatogonia, primary and secondary spermatocytes, spermatids, and maturing spermatozoa were significantly increased (P < 0.05) in late March-early May, followed by regression from mid May. Our results indicate that the Jungle Crow has a non-breeding season in January, a pre-breeding season during February-mid March, a main breeding season during late March-early May, a transition period during mid May-late May, and a post-breeding season beginning in June.

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Endocrine and testicular changes in a short-day seasonally breeding bird, the emu (Dromaius novaehollandiae), in southwestern Australia

Cited by 46 publications

References 31 publications

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

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

Aspects of spermatogenesis and microscopic testicular morphology in Greater Rhea, Rhea americana (Linnaeus, 1758)

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

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