Spermatozoa retention by Sertoli cells during the decline in fertility in aging roosters

Genital stones: Radiological, histopathological, ultrastructural, and molecular analysis in rooster

Epididymal lithiasis, characterized by the formation of stones in the epididymis, has been associated with a decline in fertility in roosters. This study aimed to investigate the reproductive performance, ultrastructural characteristics, and expression of aromatase cytochrome P450 (CYP19) and aquaporin 9 (AQP9) in aged broiler breeder roosters affected by epididymal lithiasis. X-ray analysis confirmed the presence of genital stones in both the epididymis and testicular tissue regions. While there was a significant decrease in sperm concentration in the affected roosters compared to non-affected roosters, no significant differences were observed in total and progressive sperm motility between the two groups. Furthermore, the affected roosters exhibited significant abnormalities in semen parameters, except for sperm concentration and morphology. Transmission electron microscopy (TEM) revealed the depletion and deciliation of ciliated cells in the distal efferent ductules of the epididymis in affected roosters. Additionally, the expression of CYP19 and AQP9 was found to be increased in the epididymal region of affected roosters. Notably, we report the presence of testicular stones for the first time in this study, in addition to epididymal stones. Considering the male reproductive tract lesions observed, we propose the term "genital stones" to describe these conditions. Moreover, our findings suggest that the overexpression of AQP9, which is associated with a high copy number of the CYP19 gene in the epididymal region of affected aged roosters, may contribute to the formation of genital stones by promoting increased reabsorption of fluids in the epididymis. The condensation of epididymal duct contents and reduction in the population of ciliated cells further impairs semen movement and can lead to the blockage of extra-testicular ducts, resulting in the low fertility syndrome observed in aged roosters.

Effect of orally administrated letrozole on reproduction performance and gene expression of FOXJ1, LPR2 and PVRL3 in reproductive tract in aged roosters

letrozole is an aromatase inhibitor that stops the production of estrogen through interrupting the entrance of hormone androgen into a small amount of estrogen. Therefore, the current study was developed to estimate orally administrated Letrozole on the reproductive performance and relative abundance of Foxj1, PVRL3, and LPR2 mRNA in aged roosters. Fifty-five-week old ROSS 308 breeder roosters (n = 18) were orally treated using letrozole. Primarily, the body weight of the animals was recorded, and they were randomly classified into three groups (n = 6 birds/group) receiving different doses of Letrozole, including 0, 0.015, and 0.03 mg/kg body weight/day for three weeks. At the end of the trial, seminal traits, plasma, testicular hormone levels (testosterone, estradiol, and FSH), histopathological studies, in vitro fertility, and relative abundance of testis PVRL3, epidydimal Foxj1, and LPR2 mRNA were evaluated. Based on the results, the sperm quality variables were statistically higher in the 0.03 group compared to the controls. Greater histologic parameters, such as diameter of seminiferous tubules, thickness of seminiferous epithelium, categorized epididymal region, and in vitro fertility rates were estimated for the treated groups(p < 0.001). Plasma and testicular testosterone, estradiol concentrations, and plasma FSH levels were significantly influenced by letrozll treatment (p < 0.001). Relative mRNA transcript abundance increased for PVRL3 and decreased for Foxj1 and LPR2 in treated groups. Overall, aromatase inhibitors can enhance the reproductive performance of aged commercial broiler breeder roosters. However, it can impact endocytosis and ciliogenesis events via reducing estradiol.

Nutritional modulation of fertility in male poultry

The increased consumption of protein derived from poultry demands greater poultry production, but increased poultry production (meat and eggs) is dependent on the fertility of the parent flocks. Clearly, the fertility of poultry flocks is associated with the fertility of both males and females, but the low numbers of males used for natural or artificial insemination mean that their role is more important. Thus, enhancing the semen volume, sperm concentration, viability, forward motility, and polyunsaturated fatty acids in sperm, as well as protecting against oxidative damage, could help to optimize the sperm membrane functionality, mitochondrial activity, and sperm-egg penetration, and thus fertility. Therefore, this review summarizes the nutritional factors that could improve the fertility of poultry males as well as their associated mechanisms to allow poultry producers to overcome low-fertility problems, especially in aging poultry males, thereby obtaining beneficial impacts on the poultry production industry.

Comparative effects of nano-selenium and sodium selenite supplementations on fertility in aged broiler breeder males

It is well documented that aging has negative effects on fertility. With increasing age, the activity of antioxidant enzymes are reduced and because of roosters sperm composition, a high proportion of polyunsaturated fatty acids (PUFAs), the probability of sperm damage increases. The objective of the present study was to compare the effects of nano-selenium and sodium selenite on fertility in aged male broiler breeder chickens. Thirty-five male broiler breeders (Cobb 500)® at 50 weeks of age were randomly divided into five equal groups: The control group was fed on a commercial diet, group T1 was fed on a commercial diet supplemented with sodium selenite (0.30 mg kg-1 feed), group T2, T3 and T4 were fed on a commercial diet supplemented with nano-selenium (0.15, 0.30 and 0.60 mg kg-1 feed, respectively). Sperm characteristics (sperm count, motility, viability, and maturity) as well as testicular histomorphometric features [tubule differentiation (TDI), spermiation (SPI), Sertoli cell (SCI) and meiotic (MI) indices] were assessed. The results showed that sperm characteristics were gradually decreased with age in the control group, however, it increased in group T3. Also, TDI, SPI, SCI, and MI in group T3 were higher than those of other groups. Our findings revealed that dietary supplementations with nano-selenium boosted fertility in aged male broiler breeders and the best results were obtained when the roosters received 0.30 mg kg-1 nano-selenium. Supplementation of nano-selenium in aged broiler breeder males might be effective to maintain flock fertility and/or increase the flock fertility.

An evolutionary approach to recover genes predominantly expressed in the testes of the zebrafish, chicken and mouse

Background

Previously, we have demonstrated that genes involved in ovarian function are highly conserved throughout evolution. In this study, we aimed to document the conservation of genes involved in spermatogenesis from flies to vertebrates and their expression profiles in vertebrates.

Results

We retrieved 379 Drosophila melanogaster genes that are functionally involved in male reproduction according to their mutant phenotypes and listed their vertebrate orthologs. 83% of the fly genes have at least one vertebrate ortholog for a total of 625 mouse orthologs. This conservation percentage is almost twice as high as the 42% rate for the whole fly genome and is similar to that previously found for genes preferentially expressed in ovaries. Of the 625 mouse orthologs, we selected 68 mouse genes of interest, 42 of which exhibited a predominant relative expression in testes and 26 were their paralogs. These 68 mouse genes exhibited 144 and 60 orthologs in chicken and zebrafish, respectively, gathered in 28 groups of paralogs. Almost two thirds of the chicken orthologs and half of the zebrafish orthologs exhibited a relative expression ≥50% in testis. Finally, our focus on functional in silico data demonstrated that most of these genes were involved in the germ cell process, primarily in structure elaboration/maintenance and in acid nucleic metabolism.

Conclusion

Our work confirms that the genes involved in germ cell development are highly conserved across evolution in vertebrates and invertebrates and display a high rate of conservation of preferential testicular expression among vertebrates. Among the genes highlighted in this study, three mouse genes (Lrrc46, Pabpc6 and Pkd2l1) have not previously been described in the testes, neither their zebrafish nor chicken orthologs. The phylogenetic approach developed in this study finally allows considering new testicular genes for further fundamental studies in vertebrates, including model species (mouse and zebrafish).

Electronic supplementary material

The online version of this article (10.1186/s12862-019-1462-8) contains supplementary material, which is available to authorized users.

Testicular histomorphometrics including Sertoli cell quantitation for evaluating hatchability and fertility issues in commercial breeder-broiler roosters

Testicular histomorphometric methods were developed for the investigation of fertility and hatchability problems in commercial broiler-breeder roosters. Sertoli cell (SC) evaluations were emphasized in view of their role in influencing embryonic testicular organogenesis and spermatogenesis in adults. H&E stained sections prepared from formalized tissues were examined. SC evaluations were mostly made from computer generated images using image analysis software, but were also compared to direct counting with ocular grid reticle. Other measurements were germinal epithelial and total seminiferous tubule widths, quantification of individual spermatozoa and sperm clusters, and determinations of stromal area. Age-associated changes in SC occurred between 15 to 54 wk of age. A significant reduction in SC concentration occurred at 29 wk of age (P < 0.001) that corresponded with the histologic initiation of spermatogenesis. Expanded morphometric evaluations were performed on 59-week-old roosters comparing a flock having good body condition and footpad scores with normal testicular and body weights (optimal profile or OP group) to a second flock demonstrating relatively poor expression of these parameters and decreased fertility (sub-optimal profile or SOP group). Significant reductions (P < 0.05) in SC concentration, spermatozoa, and tubular widths, but an increased percentage of stroma area occurred in SOP compared to OP flocks. SC results also correlated well with testes weight. A unique finding was a significant relationship between decreasing SC concentration and increasing severity scores for footpad lesions. Differences in all histomorphometric parameters occurred between flocks demonstrating good hatchability compared to flocks exhibiting either low or decreasing hatchability. Significant reductions in SC and other morphometric parameters were observed for the poor relative to good hatchability group. A strong positive association was observed for SC results using computer generated images and direct reticle ocular counting (R = 0.80). Replicate counts on control sections demonstrated generally good reproducibility of methods between experiments. The findings are supportive of the value of testicular histomorphometrics for evaluations of hatchability issues in commercial roosters.

D-Aspartate amends reproductive performance of aged roosters by changing gene expression and testicular histology

Male broiler breeders (n = 32) of 55 weeks of age were administered four different doses of capsulated d-aspartate (DA; 0, 100, 200 or 300 mg kg−1 day−1, p.o. (DA0, DA100, DA200 and DA300 respectively)) for 12 successive weeks to assess reproductive performance, blood testosterone, testicular histology and transcript levels of steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc), androgen receptor (AR), LH receptor (LHR), 3β-hydroxysteroid dehydrogenase (3BHSD), proliferating cell nuclear antigen (PCNA), glutamate ionotropic receptor NMDA type subunit 1 (GRIN1) and glutamate ionotropic receptor NMDA type subunit 2B (GRIN2B). Blood samples and ejaculates were collected, and bodyweight was recorded weekly for 10 weeks. AI was performed weekly for the last 2 weeks to determine the number of sperm penetration holes in the perivitelline layer, fertility and hatchability. Testes histology and transcript levels were evaluated in the 12th week. Bodyweight, numbers of Leydig cells and blood vessels, testis index and levels of sperm abnormalities were not affected (P > 0.05) by the treatment. However, sperm total and forward motility, plasma membrane integrity and functionality of sperm, ejaculate volume, testosterone concentration and fertility were higher (P < 0.05) in both the DA200 and DA300 groups compared with the other groups. In the DA100 and DA200 groups, sperm concentration, number of spermatogonia, thickness of the seminiferous epithelium and the diameter of tubules were significantly higher (P < 0.05) than the other DA-treated groups. The number of penetration holes, hatchability and malondialdehyde concentration were higher in the DA200, all DA-treated and DA300 groups respectively compared with the control and other treatment groups. Except for P450scc, AR, LHR and PCNA transcript levels in the DA300 groups, the relative expression of the genes evaluated improved significantly in the other DA-treated groups. Based on these experimental findings, it is concluded that DA improves reproductive performance of aged roosters.

Escores de cloaca e de crista e morfometria testicular em galos de matriz pesada com 71 semanas de idade e três categorias de peso corporal

Em galos de matriz pesada, o peso dos testículos se associa positivamente com a produção diária de espermatozoides e com a fertilidade. Contudo, os testículos de aves se localizam na cavidade abdominal, não sendo acessíveis para exame andrológico como os testículos de mamíferos. A avaliação reprodutiva de galos de matriz pesada é subjetiva e se baseia em características como peso corporal (PC), qualidade de pés e pernas e morfologia de cloaca e crista. Estudos que validem o potencial de associação dessas características fenotípicas com parâmetros da morfometria testicular são raros, principalmente quando se consideram galos de matriz pesada manejados em lotes comerciais. Escores de cloaca e de crista e parâmetros da morfometria testicular foram avaliados em galos Cobb 500 Slow adultos das categorias de PC leve (<4,300kg), médio (entre 4,300 e 5,250kg) e pesado (≥5,250kg). O coeficiente de variação para PC foi de 12%. Os galos da categoria de PC pesado apresentaram testículos mais pesados e maiores escores de cloaca e de crista do que os galos da categoria de PC leve. Não houve diferença estatística entre as categorias de PC, considerando-se índice gonadossomático, porcentagens de túbulo seminífero e de tecido intersticial, diâmetro de túbulo seminífero e altura de epitélio seminífero. Correlação positiva, moderada e significativa foi observada entre peso de testículo e características de PC, escores de cloaca e de crista, diâmetro de túbulo seminífero e altura de epitélio seminífero. Um dos seis galos da categoria de PC leve avaliados quanto à histologia de testículo apresentou atrofia testicular. Em galos Cobb 500 Slow, conclui-se que o PC influencia o peso e a qualidade histológica de testículos e que os escores de cloaca e de crista podem ser utilizados com potencial moderado de predição para identificar galos com baixo peso de testículos.

Effects of mono-(2-ethylhexyl) phthalate (MEHP) on chicken germ cells cultured in vitro

In recent decades, many toxicological tests based on in vivo or in vitro models, mainly from mammalian (rat-mouse) and fish species, were used to assess the risks raised by contact or ingestion of molecules of pharmaceutical, agricultural, or natural origin. But no, or few, in vitro tests using other non-mammalian models such as bird have been explored despite their advantages: the embryonic gonads of birds have a high plasticity of development sensitive to estrogen, and sperm production is nearly two times faster than in rodents. Hence, we have established an in vitro culture of germ cells and somatic cells from chicken post-natal testis, and we have evaluated the sensitivity against the endocrine disruptor compound mono-(2-ethylhexyl) phthalate (MEHP) in comparison to previous studies using rodent and human models. After 96 h of exposure in presence of 10 μM MEHP, chicken seminiferous tubules cultures present a structural alteration, a reduction in cell proliferation and in germ cells population. Apoptosis of germ and somatic cells increases in presence of 1 μM MEHP. Furthermore, MEHP does not affect inhibin B and lactate production by Sertoli cells. These results are in accordance with previous studies using rat, mice, or human culture of testicular cells and in similar range of exposures or even better sensitivity for some "end-points" (biological parameters). In conclusion, the establishment of this postnatal testicular cells culture could be considered as an alternative method to in vivo experiments frequently used for evaluating the impact on the terrestrial wildlife species. This method could be also complementary to mammal model due to the limiting number of animals used and its elevated sensitivity.

Age-related changes in gonadal and serotonergic axes of broiler breeder roosters

Fertility of domestic roosters decreases at ≈ 50 wk of age. In a previous study on aging white leghorn roosters, low fertility was accompanied by low levels of both hypothalamic vasoactive intestinal peptide (VIP) and pituitary prolactin (PRL) mRNA expression; however, their role in aging broiler breeder rooster reproduction is still unclear. In this study we compared reproductive activities of young (35-wk-old) and aging (73-wk-old) broiler breeder roosters. Weekly semen volume; concentration and ejaculation grade; and concentrations of plasma testosterone, estradiol, and PRL were examined. Every other week, 10 roosters from each group were euthanized, their testes weighed, and hypothalamus and pituitary removed to determine mRNA expression of hypothalamic GnRH-I, pituitary FSH, pituitary LH, hypothalamic VIP, and pituitary PRL. Aging roosters had significantly lower testis weight and semen volume, sperm concentration, ejaculation grade and plasma testosterone and low hypothalamic GnRH-I, pituitary FSH, and pituitary LH mRNA expression than young roosters (P ≤ 0.05). Aging roosters had higher concentrations of plasma estradiol and PRL and higher hypothalamic VIP and pituitary PRL mRNA expression than young roosters (P ≤ 0.05). We suggest that PRL, which is known to inhibit the gonadal axis, and its releasing factor, VIP, play an important role in the reproductive failure associated with age in broiler breeder roosters.

The effect of active immunization against vasoactive intestinal peptide (VIP) and inhibin on reproductive performance of aging White Leghorn roosters

Decreasing fertility in aging domestic roosters is a well-known phenomenon. Aging is manifested by a decrease in plasma testosterone level, testis function, and spermatogenesis, resulting in a low level of fertility. The roles of vasoactive intestinal peptide (VIP) and testicular inhibin in this aging process are not clear. The effects of active immunization against VIP, inhibin, or the combination of both hormones on the reproduction of aging White Leghorn (WL) roosters were assayed. In experiment 1a, 60 White Leghorn roosters (67 wk of age) were divided into 4 groups (n = 15/group). The first group was actively immunized against VIP, the second against inhibin, the third against VIP and inhibin, and the fourth served as a control. Active immunization against VIP decreased semen quality parameters, plasma steroid levels, and gene expression of gonadotropin-releasing hormone-I (GnRH-I), follicle-stimulating hormone (FSH), luteinizing hormone (LH), LH receptor, VIP, and prolactin (Prl). Immunization against inhibin increased some of the semen quality parameters and FSH mRNA gene expression but decreased inhibin gene expression. In experiment 1b, at 94 wk of age, we took the actively immunized against VIP group and the control group and divided them into 2 subgroups (n = 7 or 8): the first group was injected with 1 mg of ovine Prl (oPrl) daily for 7 d, and the second group served as a control. Administration of oPrl to previously VIP-immunized birds significantly elevated semen quality parameters. We suggest that VIP, Prl, and inhibin have an important effect on the reproductive axis in aging roosters. Active immunization against VIP-depressed reproductive activity and Prl administration restored their reproduction, indicating that both VIP and Prl are essential for reproduction in aging roosters. Immunization against inhibin improved FSH mRNA gene expression, suggesting a negative role of inhibin on FSH secretion in aging roosters. Not all semen quality parameters increased significantly after immunization against inhibin, even though FSH mRNA gene expression increased, suggesting interference in testicular function in aging roosters.

Characterization of chicken Sertoli cells in vitro

In the testis, Sertoli cells play a key physiological role in that they support, nourish, and protect germ cells. Because of the importance of Sertoli cells, several laboratories have established a culture system of Sertoli cells. These cultures have been well developed in mammalian species, but to our knowledge no purified avian Sertoli cells culture has been described. The aim of this study was to isolate avian Sertoli cells and to investigate their function using a chicken model in an in vitro test system. Immature chicken Sertoli cells in culture present morphology similar to that of mammalian cells and conserve expression of the specific Sertoli marker, anti-Müllerian hormone. Furthermore, in contrast to mammals, they express the 3β-hydroxysteroid dehydrogenase enzyme. Stimulation of Sertoli cells with ovine follicle-stimulating hormone rapidly activates the 3 main downstream signaling pathways of the follicle-stimulating hormone receptor: cyclic( )adenosine monophosphate/protein kinase A, phosphatidylinositol 3-kinase/Akt, and mitogen-activated protein kinase pathways. In vitro, Sertoli cells are able to secrete lactate and inhibin and have conserved the phagocytosis property. Finally, avian Sertoli cells present 3 interesting characteristics: they actively proliferate in vitro, can be passaged several times, and are suitable for freezing in nitrogen. A direct consequence of these properties is to use this cell culture test system as an alternative method to bird reprotoxicity studies.

Epididymal lithiasis in roosters: in the middle of the way there was a stone

The epididymal region plays an important role in the reproduction of roosters, as it is the site of functions important in the maintenance of fertility, including fluid and calcium reabsorption and sperm surface modifications. About 10 years ago, a reproductive dysfunction characterized by the formation of luminal calcium stones in the epididymal region of roosters was described. This anomaly, known as epididymal lithiasis, is associated with a significant decrease in the fertility of affected roosters. This reproductive anomaly has been observed in multiple countries and is thought to negatively impact the poultry industry; however, the cause of epididymal lithiasis has not been fully determined. Several hypotheses have been proposed to explain the origin of epididymal lithiasis, including the presence of an infectious agent within the epididymal region, an autoimmune response, increased dietary calcium and vitamin D3 intake and the presence of genetic susceptibility factors; however, none of these has been proven to be the primary cause of the calcium stone formation. Nonetheless, considerable evidence suggests that regardless of the primary cause of epididymal lithiasis, this anomaly could result from a hormonal imbalance or a local impairment of calcium homeostasis in the epididymal region. The objectives of this mini-review are to 1) summarize the reproductive alterations observed in animals affected by epididymal lithiasis, 2) discuss the hypotheses proposed to explain the cause of luminal stone formation and 3) provide perspectives for future studies of this reproductive disorder.

Expression of chicken zygote arrest 1 (Zar1) and Zar1-like genes during sexual maturation and embryogenesis

Maternal mRNAs, which are expressed in oocytes, play an important role in the success of early embryo development, as they allow the first cleavages to occur. Zygote arrest 1 (Zar1) is an oocyte-specific maternal-effect gene that functions at the oocyte-to-embryo transition in many vertebrate species including human, pig, cattle, sheep, mouse, rat, frog and zebrafish. Recently, through in silico studies, a gene structurally related to Zar1, called Zar1-like has been identified in many vertebrates, including the chicken. The objectives of this study were to investigate the expression of the chicken Zar1 and Zar1-like genes in chicken tissues and embryos and to determine whether sexual maturation affects their mRNA abundance. RNA was extracted from various organs of chickens aged from one month up to two years old and from chicken embryos until day ten of embryonic development. Expression analysis of the genes was performed using RT-PCR and real-time PCR. RT-PCR analysis revealed that both genes were preferentially expressed in chicken oocytes, ovary and testes and in embryos during embryonic development. Quantitative real-time PCR analysis revealed a significant up regulation of Zar1 in the mature ovary, and also a significant up regulation of Zar1 and Zar1-like genes in the testes of sexually mature roosters, suggesting a key role of these genes in the chicken fertility. In contrast, expression of Zar1-like was not affected by age in the chicken ovary. Our results indicate that the chicken Zar1 and Zar1-like transcripts are co-expressed in high levels in the chicken gonads. In addition their expression beyond the stage of embryonic genome activation suggests an embryonic and not only a maternal origin of these transcripts.

Acute and chronic effects of perfluorobutane sulfonate (PFBS) on the mallard and northern bobwhite quail

Perfluorobutane sulfonate (PFBS) can be a final degradation product of perfluorobutane sulfonyl fluoride (PBSF)-based chemicals. Surfactants based on this chemistry are potential replacements for perfluorooctane sulfonate (PFOS)-related products and have many potential applications in industrial and commercial processes and applications. To evaluate the potential hazard that PFBS may pose to avian species, acute dietary studies with juvenile mallards and northern bobwhite quail, as well as a quail dietary chronic study of reproduction were conducted. In the acute studies, 10-day-old mallards and quail were exposed to nominal dietary concentrations of 1,000, 1,780, 3,160, 5,620 or 10,000 mg PFBS/kg feed, wet weight (ww) for 5 days and the birds were then fed an untreated diet and observed for up to 17 days. No treatment-related mortalities were observed in the study up to 10,000 mg PFBS/kg, ww feed. Body weight gains of quail exposed to 5620 or 10,000 mg PFBS/kg feed were statistically less than that of unexposed controls. Weight gain of mallards exposed to 10,000 mg PFBS/kg feed was statistically less than that of controls. There were no statistically significant effects on feed consumption of either species. In the acute studies, no observed adverse effect concentration (NOAEC) for mallards and quail were 5620 and 3160 mg PFBS/kg, ww feed, respectively. In a reproduction study, adult quail were exposed to nominal dietary concentrations of 100, 300, or 900 mg PFBS/kg, ww feed for up to 21 weeks. There were no treatment-related mortalities or effects on body weight, weight gain, feed consumption, histopathology measures, or reproductive parameters evaluated in the study when compared to the control group. Concentrations of PFBS in blood serum, liver, and eggs were dose-dependent but were less than the administered dose, indicating biodiminution. Based on the results from the quail reproduction study, the dietary NOAEC was 900 mg PFBS/kg, ww feed (equivalent to an ADI of 87.8 mg PFBS/kg bw/d).

Effects of perfluorooctane sulfonate on mallard and northern bobwhite quail exposed chronically via the diet

Adult mallard ducks and northern bobwhite quail were exposed to 0, 10, 50, or 150mg perfluorooctane sulfonate (PFOS)/kg in the diet for up to 21 weeks. Adult health, body and liver weight, feed consumption, gross morphology and histology of body organs, and reproduction were examined. Due to mortality, birds exposed to 50 or 150mg PFOS/kg feed were terminated by Week 7. In quail, the lowest observable adverse effect level (LOAEL) was 10mg PFOS/kg feed based on decreased survivorship of 14-day-old quail offspring. For adult female quail fed 10mg/kg feed, there was a slight but statistically significantly PFOS-related increase in liver weight when compared to controls. When liver weight was normalized to body weight, the statistically significant differences were still observed indicating that PFOS affected liver size. However, no other pathological effects were observed livers of quail from this treatment group which suggests that this enlargement may have been an adaptive response. For adult mallards, no treatment-related effects on feed consumption, body or liver weight, growth, or reproductive performance were observed. There was a slightly greater incidence of small testes (length) in adult male mallards and quail exposed to 10mg PFOS/kg, feed when compared to controls. However, spermatogenesis was not affected and there was no effect on the rates of egg fertilization. Due to transfer to eggs, concentrations of PFOS measured in the liver and blood at study termination were greater in male birds than female birds.

Ecotoxicological evaluation of perfluorooctanesulfonate (PFOS)

Based on available toxicity data, protective screening-level concentrations of PFOS were calculated for aquatic and terrestrial organisms. Using the Great Lakes Initiative, water concentrations of PFOS were calculated to protect aquatic plants and animals. The screening plant value (SPV) protective of aquatic algae and macrophytes was calculated as 2.3 mg PFOS/L. The secondary chronic value protective of aquatic organisms was 1.2 microg PFOS/L. The screening-value water concentrations less than or equal to 1.2 microg PFOS/L would not pose a potential risk to aquatic organisms. Because the aquatic benchmark is based on the most sensitive species, this benchmark should also be protective of other aquatic organisms, including amphibians. The tissue-based TRV for fish was determined to be 87 mg PFOS/kg ww. For terrestrial plants, a screening benchmark was determined to be 1.3 mg PFOS/kg soil ww or 1.5 mg PFOS/kg soil dw, whereas for soil invertebrates such as earthworms the benchmark value was 39 mg PFOS/kg dw soil or 33 mg PFOS/kgww soil. For avian species, dietary, ADI, and egg yolk-based benchmarks were determined as 0.28mg PFOS/kg diet, 0.021mg PFOS/kg bw/d, and 1.7 microg PFOS/mL yolk, respectively. Benchmarks for serum and liver for the protection of avian species were 1.0 microg PFOS/mL and 0.6 microg PFOS/gww, respectively. However, no-effect levels in laboratory studies suggest actual population-level effects would not be expected to occur until a concentration of 6.0mg PFOS/kg in the diet, 5.0 microg PFOS/gww in the liver, or 9.0 microg PFOS/mL in the serum was exceeded, thus indicating the conservative nature of the benchmarks.

Avian toxicity reference values for perfluorooctane sulfonate

Toxicity reference values (TRVs) and predicted no effect concentrations (PNECs) were derived for perfluorooctane sulfonate (PFOS) based on the characteristics of a top avian predator. On the basis of the protective assumptions used in this assessment, the benchmarks are protective of avian populations and were based on acute and chronic dietary exposures of northern bobwhite quail and mallard. Toxicological endpoints included mortality, growth, feed consumption, and histopathology. Reproductive endpoints included egg production, fertility, hatchability and survival, and growth of offspring. On the basis of the U. S. Environmental Protection Agency Great Lakes Initiative methodology, and a lowest observable adverse effect concentration (LOAEC) of 10 mg PFOS kg(-1) feed, an uncertainty factor of 36 was derived. The TRV based on PFOS dietary intake was 0.021 mg PFOS kg(-1) body weight day(-1), while for serum, liver, and egg, TRVs were 1.7 microg PFOS mL(-1), 0.6 microg PFOS g(-1) wet weight, and 1.7 microg PFOS mL(-1), respectively. On the basis of the European Commission methodology, a correction factor of 2 (for lowest observed effect level to no observable effect level) and an assessment factor of 30, for a total adjustment of 60, were used to derive PNECs. PNECs based on dietary, mean serum, liver, and egg PFOS concentrations were 0.013 mg PFOS kg(-1) body weight day(-1), 1.0 microg PFOS mL(-1), 0.35 microg PFOS g(-1) wet weight, and 1.0 microg PFOS mL(-1), respectively.

Effects of environmental lighting on early semen production and correlated hormonal responses in turkeys

Recent work at our institution on lighting turkey males for semen production and correlated changes in plasma luteinizing hormone (LH) and testosterone (T) are summarized in this paper. In sexually mature males, both LH and T are secreted in pulses, with a pulse of LH about 10 min prior to a pulse of T. Pulses of LH and T occurred about every 2 h and were equally distributed between the light (L) and dark (D) portions of a 14 h L:10 h D d. The pattern of secretion and overall concentrations of LH and T were not affected by intermittent photoperiod lighting (1 L:2 D, 8 x d) in comparison to continuous photoperiod lighting (14 L:10 D) lighting. Pulses of LH or T were not entrained by L or D with the intermittent or continuous lighting treatment. To study the interaction of age and lighting treatment, males were exposed to one of two lighting treatments: long-day photoperiods (16 L:8 D) d(-1) from 10 to 12 or 29 wk of age (WOA) (Treatment LDLD) or short-day photoperiods (6 L:18 D d(-1) from 10 or 12 to 29 WOA, then long-day photoperiods (Treatment SDLD). Males in the LDLD treatment attained puberty earlier (25 WOA) than those in the SDLD treatment. In the later treatment, most of the males attained puberty after 29 WOA. Both LH and T were low until 18 WOA in the LDLD males, then both increased to adult levels over the next 2 to 3 wk. In the SDLD males, LH and T were lower than in the LDLD males until 48 h after switching to long-day photoperiods, when both were transiently higher before declining to lower adult levels by 35 WOA. Secretory patterns of LH and T were estimated at 13, 23, and 35 WOA, under both lighting treatments. At 13 WOA, LH and T were secreted in pulses, but levels of both hormones were low and not different between lighting treatments, and none of the birds (0/4) in either treatment were producing semen. At 23 WOA, LH and T were secreted in robust pulses, with the LDLD males having higher concentrations of LH and T than the SDLD males. At 23 WOA, most of the males in the LDLD group (3/4) but none in the SDLD group (0/4) were producing semen. At 35 WOA, 6 wk after photostimulation of the SDLD group, all males (4/4) in both groups were producing semen, and LH and T were at adult levels. However, fewer pulses of T were noted for males in the SDLD treatment.

Fertility decline in aging roosters is related to increased testicular and plasma levels of estradiol

The relationships between testicular and plasma hormone levels and the decline in fertility in aging roosters were examined. Body mass, testicular mass, and fertility were measured in roosters from 20 to 72 weeks of age. Plasma was assayed for LH and testosterone, and estradiol and testicular extracts were assayed for testosterone and estradiol contents. Fertility increased rapidly in young roosters to a peak of 96.2 +/- 3.9% at 37 weeks of age. Thereafter, fertility declined and by 72 weeks of age was significantly lower than at 37 weeks. Plasma LH reached 16.8 +/- 2.5 ng/ml at 27 weeks and remained high until 60 weeks of age, when it decreased significantly. Plasma and testicular testosterone levels increased from low levels in young birds to a peak that coincided with highest fertility and declined thereafter. Plasma and testicular estradiol showed a striking inverse relationship with testosterone. Plasma estradiol was 29.4 +/- 4.0 pg/ml in 20-week-old birds, decreased rapidly as testosterone increased, and increased again in older birds as testosterone decreased. Thus, the decline in fertility in aging roosters was associated with a decrease in plasma LH and testosterone and an increase in plasma and testicular estradiol. It is suggested that plasma levels of LH and testosterone in roosters are regulated by a negative feedback mechanism involving estradiol that is produced not only by the aromatization of testosterone in the brain but also by peripheral estradiol originating in the testes and that estradiol has a major role in the decline in fertility in aging roosters.

Low fertility in aging roosters is related to a high plasma concentration of insulin and low testicular contents of ACTH and lactate

Fertility in roosters peaks between 30 and 40 weeks of age and declines rapidly from about 50 weeks of age. Low-fertility, aging roosters have a higher density of elongated spermatids attached to Sertoli cells than do high-fertility roosters, but display normal spermatogenesis and ejaculated spermatozoa. Plasma levels of insulin and lactate and testicular contents of ACTH and lactate were compared in Cornish roosters aged 27 weeks (early state of sexual maturity), 37 weeks (high fertility), 67 weeks (reduced fertility), and 72 weeks (low fertility). Insulin may act as an endocrine regulator of Sertoli cell function, and ACTH as an autocrine regulator of Leydig cells for androgen production and as a paracrine regulator of Sertoli cells by amplifying FSH response. Lactate is the primary energy substrate of spermatocytes and spermatids in the adluminal compartment. Roosters aged 67 and 72 weeks had higher (P < 0.05) plasma insulin levels but lower (P < 0.05) testicular lactate content than roosters aged 27 and 37 weeks. The lower lactate content in testes of low-fertility roosters may reflect an increased consumption of lactate due to the higher density of elongated spermatids. Furthermore, the content of testicular ACTH was lower in low-fertility roosters than in 27-week-old roosters. These results suggest that ACTH may be involved indirectly in the mechanism responsible for the high density of spermatids in the tubuli and the lower spermatozoa concentration in the ejaculate of low-fertility roosters, as was reported in previous studies, since this hormone may serve as a paracrine regulator of Sertoli cell function.

Leydig cell functional structure and plasma androgen level during the decline in fertility in aging roosters

In roosters, fertility peaks to 96% at 32 weeks, shortly after sexual maturation, and then declines rapidly to 68% at 70 weeks and to less than 10% at 110 weeks, as a result of intratesticular retention of spermatozoa. The reduction in fertility is associated with functional structural changes of the interstitial tissue, reflected in decreased plasma androgen levels from 2.7 ng/ml at 32 weeks to less than 0.5 ng/ml at 110 weeks. In high fertility roosters, the interstitial tissue is tightly packed with Leydig cells, which contain relatively large amounts of rough endoplasmic reticulum and lipid droplets, both related to androgen synthesis. In the old rooster, which has a low fertility, the interstitial tissue contains only occasional Leydig cells within an enlarged intercellular space. These Leydig cells contain small amounts of endoplasmic reticulum, mainly rough, and there are low plasma androgen levels. It is concluded that differentiation of roosters' interstitial tissue is reflected by plasma levels of androgen. This, in turn, is related to the mechanism of spermatozoa release from Sertoli cells and, consequently, with the level of fertility.

Age effect of male and female broiler breeders on sperm penetration of the perivitelline layer overlying the germinal disc

An experiment was conducted to test the effect of age (male and female) on the number of spermatozoa penetrating the perivitelline layer (PL) overlying the germinal disc (GD) in broiler breeders. Eighty young broiler breeder hens (39 wk old, Y), and 80 old spent broiler breeder hens (69 wk old, O) were randomly divided into eight groups of 20 hens each by age. Hens were inseminated weekly for 4 consecutive wk with 5 x 10(7) pooled sperm/50 microL from either young or old broiler breeder males. Sperm penetration (SP) of the PL at the GD was assessed in a random sample of 12 oviposited eggs from each hen group for each day postinsemination, with the remainder of the eggs incubated for 10 d to obtain fertility values. For the main effect of sex, and for age within sex, there were differences in mean SP (7.3 vs 4.8; Y vs O hens; P < 0.02) and fertility (73.7 vs 54.9%; Y vs O hens; P < 0.002) values. Old males had higher mean SP values and fertility (7.2 and 70.6%) than young males (4.8 and 58.0%; P < 0.03 and 0.01, respectively). Following artificial insemination of a constant number of sperm, age of hens appears to contribute more to the decrease in SP and fertility than the age of male broiler breeders. Eggs were obtained from naturally mated broiler breeder flocks from different strains (A and B), lines (male and female), and ages. There was an effect on overall mean SP values due to strain (105.8 vs 78.6 holes per GD area; Strains A and B, respectively; P < 0.0001), and line within Strain B (106.4 vs 50.8 holes per GD; male and female line, respectively; P < 0.0001). There was a quadratic relationship between SP of the PL and age in Strain A with values ranging from 153.3 to 20.0 holes per GD area (P < 0.003). In Strain B, SP holes in the PL decreased in the male line due to age (127.8 to 59.7 per GD; P < 0.01), with an effect of age on the female line also (62.1 vs. 37.8 holes per GD; P < 0.05).

Intratesticular retention of sperm and premature decline in fertility in the domestic rooster, Gallus domesticus

In domestic roosters, which were originally seasonal breeders and that are now kept under unnatural and unchanging conditions throughout the year, fertility peaks at 32 weeks of age (96%) but it subsequently declines rapidly to only 5% at 110 weeks despite the fact that roosters can live for about 10 years. Roosters exhibiting this low-fertility syndrome have reduced levels of spermatozoa in the ejaculate. Concomitantly, however, superabundant but apparently normal spermatozoa are found attached to Sertoli cells and, in addition, the seminiferous epithelium fails to show evidence of the regression of atrophy that characterizes both aging non-seasonal breeders and true seasonal breeders during non-reproductive periods. This syndrome of premature low fertility appears to stem from impaired spermiation with resultant retention of spermatozoa by Sertoli cells. To examine this problem, we compared intratesticular incorporation of 3H-thymidine between high-fertility (32-week-old) and low-fertility (82-week-old) roosters. Radioactivity associated with spermatozoa, 33 days post-injection, was almost 50% higher in the low-fertility roosters than in the high-fertility ones. By contrast, both groups showed similar characteristics with respect to a) intratesticular incorporation of 3H-thymidine, b) dynamics of spermatogenesis, c) intratesticular level of radioactivity just before the initiation of spermiation, and d) the duration of both spermatogenesis and the time required for sperm to pass through the genital tract. Our results confirm that intratesticular retention of sperm occurs in roosters with premature low-fertility syndrome and suggest new possibilities for the study of the complex relationship between Sertoli cells and spermatozoa and the effects of this relationship on fertility.

Oviductins possess chitinase- and mucin-like domains: a lead in the search for the biological function of these oviduct-specific ZP-associating glycoproteins

Over the last 10 years considerable progress has been made in the immunological and biochemical characterization of oviduct-specific glycoproteins. It is now well established that a subclass of these secretory products, designated as oviductins, associate with the zona pellucida of the ovulated oocyte and with the early embryo. Recent reports on the cloning of cDNAs of oviductins from various species, including that of golden hamster (Mesocricetus auratus) oviductin by our laboratory, allowed us to compare their deduced amino acid sequences with those of other proteins. Optimal alignment analysis showed that oviductins contain regions of significant similarity with catalytically inactive mammalian members of the bacterial and microfilarial chitinase protein family. Most importantly, a close examination of the hamster and human deduced amino acid sequences revealed that both glycoproteins possess contiguous Ser/Thr rich repeated units, clustered in their carboxy-terminal portions. These mucin-type motifs are similar in the hamster and human glycoprotein, although hamster oviductin contains more of these complete units. This striking feature might indicate that these molecules play a similar role to mucin-type glycoproteins, e.g., in protecting the oocyte and early embryo against attacks from their environment. We propose a model whereby oviductins are targeted to the oocyte via the interaction of their chitinase-like domains with specific oligosaccharide moieties of the zona pellucida. Once localized to this structure, oviductin molecules would act as a protective shield around the oocyte and early embryo by virtue of their densely glycosylated mucin-type domains.

Immunological detection and characterization of an estrus-associated antigen in the goat oviduct

The present study was designed to investigate the possibility that the goat oviduct produces specific substance(s) similar to the oviductal glycoprotein (BOGP) of the bovine oviduct. Oviductal flushings obtained from goats at the follicular and luteal phases of the estrous cycle were examined by immunoblotting for the presence of material that cross-reacted with monoclonal antibodies (MAbs) specific for BOGP. The MAbs immunoreacted with a broad band with a molecular mass of protein of about 97 kDa in the flushings of goat oviducts after fractionation of proteins by electrophoresis under reducing conditions. The antigen was present in flushings obtained from the ampullar segments of oviducts from goats at the follicular stage, but this antigen could hardly be detected in the flushings from the ampulla at the luteal phase and or the flushings from the isthmus at either the follicular or the luteal phase. This antigen was not detected in uterine flushings, follicular fluid, or serum. An immunohistochemical study demonstrated that the MAbs reacted specifically with the epithelial cells of the goat oviduct. Intense labeling was observed in the ampullar and fimbrial epithelia of goat oviducts at the follicular phase, but the immunohistochemical reaction was very weak at the luteal phase. In the isthmus, the reaction was faint during both the follicular and the luteal phase. No specific immunohistochemical reactivity with the MAbs was observed with other tissues from the reproductive tract or with nonreproductive tissues. Immunofluorescent staining showed that the antigen was associated with the zona pellucida of goat ovarian eggs that had been incubated with ampullar flushings from goats at the follicular stage.(ABSTRACT TRUNCATED AT 250 WORDS)