Effects of dietary meals containing different levels of phytoestrogens on reproductive function in Bilgoraj ganders

Semen characteristics of ganders kept as genetic resources conservation program

The creation of genetic reserves of domesticated animal species and breeds almost become a necessity in the recent years, but there is a question what is the value of semen of males kept ex situ in vivo as gene conservation flocks. Presented studies assessed the response to semen collection by dorso-abdominal massage and the quantitative and qualitative semen characteristics of six goose breeds (Pomorska, Garbonosa, Kuban, Landes, Roman and Slovakia) covered by the genetic resources' protection program. Fourteen semen collection attempts were performed per male. In each breed there were ganders with low and high sensitivity to massage. The most positive reactions were stated in Pomorska ganders (67.9%), and the least in Kuban breed (52.60%). Individual male evaluation showed that only in three breeds (Pomorska, Garbonosa and Kuban) there were individuals showing 100% susceptibility to semen collection, in some breeds only 1-4 positive reactions (ending with ejaculation) were noted. Results obtained indicated breed and male effect on analyzed semen traits, with the exception of sperm motility. The highest number of live normal sperm (44.2% on average), sperm concentration (530 x10⁶ mL^-1 ), the highest Semen Quality Factor (92.9) and sperm motility (50.30%) were found in semen of Kuban ganders, while the lowest values of these traits (28.7%; 230 x10⁶ mL^-1 ; 11.4, respectively) in Slovakia ganders. The lowest sperm motility (38.3%) was observed in ganders of Roman breed, but comparing to the other breeds existing differences were not significant. Significant differences in sperm morphology between individual ganders were also observed.

Characteristics of semen collected from gander included in the genetic resources conservation program

Conservative breeding ex situ in vivo is one of the most popular methods of creating genetic reserves. Unfortunately, keeping animals in small closed populations leads to inbreeding which reduces their reproductive capacity. The aim of the study was to characterize the sperm quality of 6 genetic groups of geese (northern and southern breeds) kept in Poland for many generations as genetic reserve flocks. Each breed was represented by 10 randomly selected 1-yr-old ganders, semen was collected 14 times, individually from each male, and the number of positive reactions (ended with ejaculation), semen volume, sperm concentration, and morphology were assessed. The obtained results showed a significant difference between breeds and individuals of the same group, both in males’ reaction and semen quantitative and qualitative traits. From the northern breeds 193 ejaculates were obtained in total (i.e., 45.9% of all attempts), from the southern breeds 242 ejaculates (57.6%). The volume of single ejaculate varied from 0.01 mL (one drop allowing only histological smear and sperm morphology evaluation) to 0.65 mL; sperm concentration varied from 23.0 × 10⁶mL⁻¹ to 2376.0 × 10⁶mL⁻¹; the amount of total live sperm was at a similar level in all breeds (89.6%–97.7%), while live normal cells ranged between 15.2% and 67.9% depending on breed and individuals. When keeping the genetic reserves ex situ in vivo, attention should be paid to the quality of semen and males that are poor in this respect should be eliminated, in order not to lead to an excessive weakening of the reproductive capacity of the flocks covered by the genetic resources protection program.

Associations between semen phytoestrogens concentrations and semen quality in Chinese men

BACKGROUND

Phytoestrogens (PEs) are naturally estrogen-like chemicals, and increasing evidences have indicated their endocrine disruption effects on male reproductivity, but the conclusions from previous epidemiological studies were controversial.

OBJECTIVE

To examine the associations between nine phytoestrogens in semen and semen quality in a Chinese population.

METHODS

In this cross-sectional study, a total of 1319 reproductive-aged men were recruited from Shenzhen, China. Semen phytoestrogens were measured by ultra-performance liquid chromatography and tandem mass spectrometry. Semen quality was assessed by sperm concentration, sperm count, progressive motility, total motility, volume, and the sperm motion parameters. Both multivariate linear regression and logistic regression models were conducted to evaluate the associations between semen phytoestrogens and semen quality with adjustment for confounders.

RESULTS

In logistic regression models, we found significant associations between semen secoisolariciresinol (SEC) and lower sperm concentrations (odd ratios (OR): 2.38; 95% confidence interval, 95% CI: 1.47, 3.93), sperm counts (OR: 2.27; 95% CI: 1.34, 3.94), and total motility (OR: 1.55; 95% CI: 1.08, 2.24). Negative associations were also observed for semen genistein (GEN) with sperm counts (OR: 2.28; 95% CI: 1.29, 4.14; p for trend = 0.04) and sperm concentrations (OR: 1.98; 95% CI: 1.21, 3.03; p for trend = 0.07). Semen naringenin (NAR) were found to be positively associated with progressive motility (OR: 0.57; 95% CI: 0.38, 0.83) and total motility (OR: 0.57; 95% CI: 0.40, 0.81). Results from multivariate linear regression models were similar to those from logistic regression models for semen SEC, GEN, and NAR.

CONCLUSIONS

We suggested that semen levels of phytoestrogens may be associated with semen quality in men. Further investigations are warranted to confirm the findings in prospective studies and to explore the underlying mechanism.

Effect of Seasonal Change on Testicular Protein Expression in White Roman Geese

The purpose of this study was to investigate the change in protein expression in the testes of ganders at various breeding stages. A total of nine 3-year-old male White Roman ganders were used. The blood and testis samples were collected at the nonbreeding, sexual reactivation, and breeding stages for sex hormone analysis and proteomic analysis, respectively. The testicular weight and serum testosterone observed for ganders at the breeding stage were higher than those for ganders at nonbreeding and sexual reactivation stages (P < 0.05). There were 124 protein spots differentially expressed in the testes of ganders at various reproductive stages. A total of 107 protein spots of 74 proteins was identified through mass spectrometry. Most of the differentially expressed proteins were responsible for the molecular functions of protein binding (24%) and catalytic activity (16%). A functional pathway analysis suggested that proteins involved in steroidogenesis, metabolism, and spermatogenesis pathways changed in the White Roman geese at various reproductive stages. In conclusion, ganders at various reproductive stages exhibited different levels of testosterone and protein expression in the testes. The varied levels of the proteins might be essential and unique key factors in seasonal reproduction in ganders.

Effects of dietary soybean isoflavones (SI) on reproduction in the young breeder rooster

Soybean isoflavones (SIs) are phytoestrogens that competitive with estrogens in body. Although SIs play an important role in reproduction, their role in testicular development in roosters is unknown. This study was conducted to investigate the effect of SIs on testicular development and serum reproductive hormone profiles in young breeder roosters (70-133days old). Gene expression of steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc), and 3β-hydroxysteroid dehydrogenase (3β-HSD), which are related to testosterone synthesis, in rooster testis were also evaluated after treatment with different SI doses. Although SIs had no significant effect on body weight, 5mg/kg SIs significantly increased the testis index and serum levels of reproductive hormones (gonadotropin releasing hormone, follicle- stimulating hormone, luteinizing hormone, and testosterone).To further investigate whether SIs regulate hormone synthesis via StAR, p450scc, 3β-HSD, real time-PCR was performed to measure the mRNA levels of the corresponding genes. The results showed that 5mg/kg of SIs significantly increased StAR mRNA levels. However, there were no significant effects on p450scc or 3β-HSD mRNA levels. Moreover, the spermatogonial development and the number of germ cell layers were increased by treatment with 5mg/kg of SIs. These results suggest that SIs promote testicular growth by increasing reproductive hormone secretion, which is closely related to StAR expression, to positively regulate reproduction in young roosters.

Concentrations of the adrenocorticotropic hormone, corticosterone and sex steroid hormones and the expression of the androgen receptor in the pituitary and adrenal glands of male turkeys (Meleagris gallopavo) during growth and development

Androgens take part in the regulation of puberty and promote growth and development. They play their biological role by binding to a specific androgen receptor (AR). The aim of this study was to evaluate the expression of AR mRNA and protein in the pituitary and adrenal glands, to localize AR protein in luteinizing hormone (LH)-producing pituitary and adrenocortical cells, to determine plasma concentrations of adrenocorticotropic hormone (ACTH) and corticosterone and the concentrations of corticosterone, testosterone (T), androstenedione (A4) and oestradiol (E2) in the adrenal glands of male turkeys at the age of 4, 8, 12, 16, 20, 24 and 28weeks. The concentrations of hormones and the expression of AR varied during development. The expression of AR mRNA and protein in pituitary increased during the growth. The increase of AR mRNA levels in pituitary occurred earlier than increase of AR protein. The percentage of pituitary cells expressing ARs in the population of LH-secreting cells increased in week 20. It suggests that AR expression in LH-producing pituitary cells is determined by the phase of development. The drop in adrenal AR mRNA and protein expression was accompanied by an increase in the concentrations of adrenal androgens. Those results could point to the presence of a compensatory mechanism that enables turkeys to avoid the potentially detrimental effects of high androgen concentrations. Our results will expand our knowledge of the role of steroids in the development of the reproductive system of turkeys from the first month of age until maturity.

Expression of the androgen receptor in the testes and the concentrations of gonadotropins and sex steroid hormones in male turkeys (Meleagris gallopavo) during growth and development

Androgens, including testosterone (T) and androstenedione (A4), are essential for puberty, fertility and sexual functions. The biological activity of those hormones is mediated via the androgen receptor (AR). The regulation of androgen action in birds is poorly understood. Therefore, the present study analysed mRNA and protein expression of AR in the testes, plasma concentrations of the luteinizing hormone (LH), follicle-stimulating hormone (FSH), T, A4 and oestradiol (E2), as well as the levels of T, A4 and E2 in testicular homogenates of male turkeys (Meleagris gallopavo) at the age of 4, 8, 12, 16, 20, 24 and 28weeks. Plasma concentrations of LH and FSH, as well as plasma and testicular levels of T and A4 began to increase at 20weeks of age. The lowest plasma levels of E2 were noted at 20weeks relative to other growth stages. The 20th week of life seems to be the key phase in the development of the reproductive system of turkeys. The AR protein was found in the nuclei of testicular cells in all examined growth stages. Higher expression of AR protein in the testes beginning at 20weeks of age was accompanied by high plasma concentrations of LH and high plasma and testicular levels of androgens. This relationship seems to be necessary to regulate male sexual function.

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

It is generally acknowledged that seasonal fluctuations in the morphology and function of bird testes are primarily regulated by seasonal changes in circulating concentrations of testosterone (T) which mediates its action via the androgen receptor (AR). However, it has not yet been elucidated whether gonadal sensitivity to androgens also varies across the bird reproductive cycle. In order to answer the above question, this study makes the first ever attempt to account for the gonadal expression of the AR gene and protein in relation to circulating and testicular T concentrations in the gonads of male birds during the reproductive cycle. The experimental model used in this study was the domestic goose, Anser anser f. domestica, a species with three distinct phases of the annual reproductive cycle: the breeding season in March, the non-breeding season in July and the sexual reactivation phase in November. The plasma and testicular T concentrations were highest in the breeding season, followed by a dramatic decline in the non-breeding season with a successive rise in the sexual reactivation phase. Interestingly, we observed the divergent effect of season on AR mRNA and protein expression. Whereas the AR gene expression showed a nearly inverse relationship with T levels, the seasonal variations in AR protein levels primarily reflected the differences in T concentrations. The results of our study also indicated that regardless of the examined phase of the season, an abundance of AR protein was found only in the nuclei of Leydig and Sertoli cells and myoid cells. The above supports the observation that somatic cells are the targets for androgen action in bird testes. Summarizing, this study revealed that seasonal variations in sensitivity to androgens in the gonads of male birds are reflected in variations in the availability of their cognate receptors. Furthermore, a different pattern of seasonal expression of the AR gene and protein suggests that the AR system is subject to complex regulation that includes both steroid-dependent and steroid-independent factors.

Are oestrogen receptors and protein tyrosine kinases involved in phytoestrogen-modulated steroid secretion by porcine adrenocortical cells?

The phytoestrogens genistein and daidzein had been found to affect the function of some tissues via oestrogen receptors (ER). In addition, genistein, but not daidzein, is considered to be a protein tyrosine kinase (PTK) inhibitor. Thus, the involvement of oestrogen receptors and PTK in phytoestrogen action on adrenocortical porcine steroidogenesis was examined in this study. The aims of the experiment were to test the effects of (i) ICI 182, 780 (ICI), an ER antagonist, on genistein- and daidzein-modulated cortisol and androstenedione (A4) secretion by adrenocortical cells isolated during the luteal and follicular phases of the porcine oestrous cycle; (ii) tyrphostin AG 957 (TAG), a nonsteroidal PTK inhibitor, on cortisol and A4 secretion by the cells and (iii) the phase of the porcine oestrous cycle on the mechanism of phytoestrogen action. Adrenals were harvested during the luteal (n = 5 animals) and follicular (n = 5 animals) phases of the oestrous cycle from locally slaughtered crossbred gilts. The isolated adrenocortical cells were incubated for 8 h (37 °C, 95% air, 5% CO2) with genistein (5 or 10 μM) or daidzein (5 or 10 μM) in the presence or absence of ICI (0.5 μM) or TAG (5 or 10 μM). Genistein and daidzein inhibited cortisol secretion and stimulated A4 secretion by porcine adrenocortical cells harvested during both the luteal and follicular phases of the oestrous cycle. The ER antagonist ICI did not eliminate phytoestrogen-induced changes in steroidogenesis. In contrast to genistein, TAG reduced the secretion of A4 and did not affect cortisol secretion. There was no observable effect due to the phase of the cycle. It is suggested that the mechanism of genistein and daidzein action in the adrenocortical cells of pigs is independent of ER and PTK. It is possible that PTK are involved in A4 secretion by porcine adrenocortical cells.