Male Fecundity Research Articles

Relationship between physical occupational exposures and health on semen quality: data from the Longitudinal Investigation of Fertility and the Environment (LIFE) Study

To study the relationship among occupation, health, and semen quality in a cohort of men attempting to conceive. Observational prospective cohort. Not applicable. A total of 501 couples discontinuing contraception were followed for 1year while trying to conceive; 473 men (94%) provided one semen sample, and 80% provided a second sample. None. Semen data obtained through at-home semen collection with next-day analysis/quantification. In all, complete data were available for 456 men, with a mean age of 31.8years. Work-related heavy exertion was consistently associated with lower semen concentration and total sperm count. Thirteen percent of men who reported heavy exertion displayed oligospermia, compared with 6% who did not report workplace exertion. Shift work, night work, vibration, noise, heat, and prolonged sitting were not associated with semen quality. Men with high blood pressure had significantly lower strict morphology scores compared with normotensive men (17% vs. 21%). In contrast, hyperlipidemia, diabetes, and composite of total comorbidities were not associated with semen quality. The number of medications a man was taking as a proxy of health status was associated with semen quality. There was a negative association between number of medications and sperm count. A negative relationship among occupational exertion, hypertension, and the number of medications with semen quality was identified. As these are potentially modifiable factors, further research should determine whether treatment or cessation may improve male fecundity.

Prevalence of Male Factor Infertility in Last Ten Years at a Rural Tertiary Care Centre of Central India: A Retrospective Analysis

Background: Male infertility accounts for 40-50% of infertility, affects 7% of all men. It is commonly due to deficiencies in semen, and semen quality is used as measure of male fecundity. Objective: To retrospectively study profile of male factor infertility, especially abnormal semen parameters in rural area of Central India over a period of 10 years and to find out prevalence of various abnormalities of sperm and sperm counts and also to know yearly variation in prevalence of such abnormalities. Material and Methods: A Retrospective analysis of 10 years was carried out at the Department of Obstetrics and Gynecology and Reproductive Biology Unit of Department of Physiology of a rural tertiary care centre of Central India from January 2005 to December 2014. The case records of total of 3084 male partners of infertile couples consulting the Gynecology Out Patient Department were collected from the Reproductive Biology Unit of Department of Physiology. On the basis of semen analysis report the cases were categorized into four groups; Normozoospermia, Oligozoospermia, Azoospermia and Asthenoteratozoospermia. The results were analyzed using SPSS software. Results: Out of total 3084 semen analysis reports of infertile couples, Normozoospermia was observed in 1104 (35.80%), Oligozoospermia in 1053 (34.14%), Asthenoteratozoospermia in 597 (19.35%) and Azoospermia in 330 (10.70%). Conclusion: Semen analysis is cornerstone for evaluation of infertility in men. It gives an idea about abnormalities of sperm and sperm count. Present study revealed no significant rise in prevalence of male infertility over last 10 years in this region of India. Key words: Fertility; Infertility; Normozoospermia; Semen analysis, Sperm.

Persistent organic pollutants and semen quality: The LIFE Study

Growing evidence suggests that persistent environmental chemicals such as polychlorinated biphenyls may adversely affect human fecundity. The purpose of this study was to evaluate associations between persistent environmental chemicals and semen quality among 501 male partners of couples discontinuing contraception for purposes of becoming pregnant. Men provided a blood specimen and two fresh semen samples collected approximately a month apart that underwent next day analysis for 35 semen quality endpoints. Serum samples were analyzed for 36 polychlorinated biphenyls (congeners #18, 28, 44, 49, 52, 66, 74, 87, 99, 101, 114, 118, 128, 138, 146, 149, 151, 153, 156, 157, 167, 170, 172, 177, 178, 180, 183, 187, 189, 194, 195, 196, 201, 206, 209); 1 polybrominated biphenyl (#153); 9 organochlorine pesticides; and 10 polybrominated diphenyl ethers (congeners #17, 28, 47, 66, 85, 99, 100, 153, 154183) using high resolution mass spectrometry. To estimate the effect of chemicals on semen quality, we regressed each semen marker on each chemical while adjusting for research site, age, body mass index, serum lipids, and cotinine levels. Males with chemical concentrations in the fourth quartile, as compared to the first quartile, showed significant associations for several individual chemicals in each chemical class and type of semen quality parameter indicating negative and positive associations with semen quality. Polybrominated diphenyl ethers in particular were associated with several measures of increased abnormal morphology. These exploratory results highlight the role of environmental influences on male fecundity, and are of particular interest given the ubiquitous exposures to these compounds.

Protracted oogenesis and annual reproductive periodicity in the deep‐sea pennatulacean Halipteris finmarchica (Anthozoa, Octocorallia)

AbstractHalipteris finmarchica is one of the most common species of deep‐sea pennatulacean corals in the Northwest Atlantic; it was recently determined to act as a biogenic substrate for other species and as a nursery for fish larvae. Its reproductive cycle was investigated in colonies sampled in 2006 and 2007 along the continental slope of Newfoundland and Labrador (Canada). Halipteris finmarchica exhibits large oocytes (maximum diameter of 1000 μm), which are consistent with lecithotrophic larval development. Female potential fecundity based on mature oocytes just before spawning was ~6 oocytes · polyp−1 (500–6300 oocytes · colony−1); male potential fecundity was 16 spermatocysts · polyp−1 (5500–57,400 spermatocysts · colony−1). Based on statistical analysis of size‐probability frequency distributions, males harboured one cohort of spermatocysts that matured inside 8–11 months, whereas females harboured two distinct cohorts of oocytes; a persistent pool of small ones (≤400 μm) and a small number (~20%) of larger ones that grew from ~400 to >800 μm over a year. Despite this difference in the tempo of oogenesis and spermatogenesis, a synchronic annual spawning was detected. A latitudinal shift in the spawning period occurred from south (April in the Laurentian Channel) to north (May in Grand Banks and July–August in Labrador/Lower Arctic), following the development of the phytoplankton bloom (i.e. sinking of phytodetritus). Prolonged oogenesis with the simultaneous presence of different oocyte classes in a given polyp is likely not uncommon in deep‐sea octocorals and could hamper the detection of annual/seasonal reproduction when sample sizes are low and/or time series discontinued or brief.

Evaluating the post-copulatory sexual selection hypothesis for genital evolution reveals evidence for pleiotropic harm exerted by the male genital spines of Drosophila ananassae.

The contemporary explanation for the rapid evolutionary diversification of animal genitalia is that such traits evolve by post-copulatory sexual selection. Here, we test the hypothesis that the male genital spines of Drosophila ananassae play an adaptive role in post-copulatory sexual selection. Whereas previous work on two Drosophila species shows that these spines function in precopulatory sexual selection to initiate genital coupling and promote male competitive copulation success, further research is needed to evaluate the potential for Drosophila genital spines to have a post-copulatory function. Using a precision micron-scale laser surgery technique, we test the effect of spine length reduction on copulation duration, male competitive fertilization success, female fecundity and female remating behaviour. We find no evidence that male genital spines in this species have a post-copulatory adaptive function. Instead, females mated to males with surgically reduced/blunted genital spines exhibited comparatively greater short-term fecundity relative to those mated by control males, indicating that the natural (i.e. unaltered) form of the trait may be harmful to females. In the absence of an effect of genital spine reduction on measured components of post-copulatory fitness, the harm seems to be a pleiotropic side effect rather than adaptive. Results are discussed in the context of sexual conflict mediating the evolution of male genital spines in this species and likely other Drosophila.

The progress of sperm functional proteins regulating the process of fertilization

The process of mammalian fertilization involves a series of sperm functional activities, including the sperm transportation, hyperactivation and capacitation, acrosome reaction and sperm-egg fusion, etc. The semen proteins play indispensable roles in these processes, and they are closely associated with the fecundity of males. So these proteins can be biomarkers to evaluate the fertilization capacity of mammalian semen. In this review, we mainly introduce some semen proteins relevant to spermatozoa functions and illustrate their important regulatory roles on the fertilization processes, involving spermatozoa motility, capacitation, acrosome reaction, penetrating the zona pellucida and sperm-egg fusion, etc. Moreover, their potential applications in the evaluation of heredity in livestock are also summarized.

Performance of Three Adelphocoris spp. (Hemiptera: Miridae) on Flowering and Non-flowering Cotton and Alfalfa

The genus Adelphocoris (Hemiptera: Miridae) is a group of key insect pests in cotton fields in China that includes three dominant species: A. suturalis (Jakovlev), A. lineolatus (Goeze) and A. fasciaticollis (Reuter). Previous field surveys have found that adults of these Adelphocoris species usually move onto specific host plants when the plants enter the flowering stage. To determine the potential trade-offs for this host-plant preference behavior, the performance of these three Adelphocoris spp. on flowering and non-flowering cotton and alfalfa were compared in the laboratory. The results showed that Adelphocoris spp. had significantly higher nymphal developmental and survival rates, along with increased adult longevity and fecundity on flowering cotton and alfalfa than on non-flowering plants of either species. In addition, compared with cotton plants, alfalfa generally promoted better performance of these three Adelphocoris species, especially for A. lineolatus. Simple correlation analysis indicated that female adult longevity was positively correlated to male adult longevity and female fecundity, and female fecundity was positively correlated to nymphal development and survival rates. This study demonstrated a positive correlation between adult preference and offspring/adult performance for all three Adelphocoris species, with no evidence of any trade-offs for this preference for flowering host plants. These findings support the hypothesis that hemimetabolous insects such as mirid bugs have positive adult preference-adult/nymphal performance relationships, which is likely due to the similar feeding habits and nutritional requirements of adults and nymphs.

Distinct male reproductive strategies in two closely related oak species.

Reproductive strategies of closely related species distributed along successional gradients should differ as a consequence of the trade-off between competition and colonization abilities. We compared male reproductive strategies of Quercus robur and Q. petraea, two partly interfertile European oak species with different successional status. In the studied even-aged stand, trees of the late-successional species (Q. petraea) grew faster and suffered less from intertree competition than trees of the early-successional species (Q. robur). A large-scale paternity study and a spatially explicit individual-based mating model were used to estimate parameters of pollen production and dispersal as well as sexual barriers between species. Male fecundity was found to be dependent both on a tree's circumference and on its environment, particularly so for Q. petraea. Pollen dispersal was greater and more isotropic in Q. robur than in Q. petraea. Premating barriers to hybridization were strong in both species, but more so in Q. petraea than in Q. robur. Hence, predictions based on the competition-colonization trade-off are well supported, whereas the sexual barriers themselves seem to be shaped by colonization dynamics.

Effects of combined exposure to 17α-ethynylestradiol and dibutyl phthalate on the growth and reproduction of adult male zebrafish (Danio rerio)

To evaluate the combined effects of 17α-ethynylestradiol (EE2) and dibutyl phthalate (DBP) on the growth and reproduction of male zebrafish, three-month-old fish were exposed to 0.005 or 0.020µg/L EE2, 100 or 500µg/L DBP or their binary mixtures under semi-static conditions. Investigated parameters include the length, weight, condition factor, vitellogenin (VTG) induction, acyl-CoA oxidase (AOX) protein level, histopathological alteration of testis, liver and gill, and reproductive capacity. After 21d exposure, no statistical difference was found among the weights, lengths and condition factors of different treatment groups. In all binary mixture groups, decreased VTG levels were detected compared to EE2-only groups; and the AOX levels were significantly lower than DBP-only treatments while both chemicals can individually induce AOX synthesis. Therefore, EE2 and DBP may act additively on VTG and antagonistically on AOX induction in males. After 45d exposure, delayed gametogenesis was observed for the DBP-only groups, indicated by fewer spermatozoa and more spermatocytes, which was further aggravated with the addition of EE2. The developmental delay of testis partially recovered after a 30d depuration in clean water. Combined exposure also caused liver and gill lesions, which were not alleviated during the 30d depuration, suggesting a nonreversible harmful effect the same as single exposure. Mixed EE2 and DBP were observed to impair the reproductive capability (the fecundity and fertilization rate) of males, while single exposure did not. Co-exposed to 0.020µg/L EE2 and 100µg/L DBP promoted the early hatching of offspring (F1 generation) at 48h post-fertilization (hpf), but the survival rates of the F1 generation were similar in all treatments. Our findings indicate that the effects of mixed EE2 and DBP at environmentally relevant levels can be either antagonistic or additive relying on the specific toxicological endpoints and the respective doses of each chemical.

Stabilizing selection on nectar concentration in wild Petunia axillaris, as revealed by genetic analysis of pollen dispersal

Most animal-pollinated plants produce nectar as a pollinator reward. Despite the main role that nectar plays in plant-pollinator interactions, the impact of natural variation in nectar traits on realized male fitness is poorly known. Here, we assessed this relation for a wild Petunia axillaris population using paternity-based direct selection gradient analysis, which allowed us also to infer pollen dispersal patterns. Because male fecundity may depend on other traits which could be associated with nectar characteristics (i.e. volume and concentration), we also considered selection on other key reproductive traits. The analysis revealed that P. axillaris was a strict outcrosser, but that successful pollination occurred mainly among neighbours. Individual plants varied greatly in their male fecundity. Nectar concentration, a key feature of nectar that determines its profitability, was subjected to stabilizing selection. Selection through male function also affected corolla area (positive directional selection), corolla tube length (negative directional selection), and floral display size (stabilizing selection), but none of these traits were phenotypically correlated with nectar characteristics. Because nectar concentration affects the ability and foraging efficiency of different flower visitors to feed on nectar, stabilizing selection may reflect either the preference of the most effective pollinators, or antagonistic selection driven by pollinators and non-pollinating nectar consumers.

Lipid concentrations and couple fecundity: the LIFE study.

A role of lipids in human fecundity is hypothesized as cholesterol is the main substrate for steroid synthesis and has also been shown to affect the hormonal milieu and steroidogenesis in both men and women. The objective of the study was to evaluate the association between male and female serum lipid concentrations and time to pregnancy (TTP). A population-based prospective cohort study recruiting couples from 16 counties in Michigan and Texas (2005-2009) using sampling frameworks allowing for identification of couples planning pregnancy in the near future. Five hundred one couples desiring pregnancy and discontinuing contraception were followed up for 12 months or until a human chorionic gonadotropin pregnancy was detected. Fecundability odds ratios (FORs) and 95% confidence intervals (CIs) were estimated after adjusting for age, body mass index, race, and education in relationship to female, male, and joint couple lipid concentrations. Serum free cholesterol levels were higher on average among male and female partners of couples who did not became pregnant during the study follow-up (female, P = .04; male, P = .009), and levels in female partners were associated with significantly longer TTP in models based on both individual and couples concentrations (individual models: FOR 0.98, 95% CI 0.97, 0.99; couple models: FOR 0.98, 95% CI 0.97, 0.99). Male free cholesterol concentrations were associated with TTP only in the couple-based models (FOR 0.98, 95% CI 0.97, 0.99). Sensitivity analyses suggested that the observed associations are unlikely to be explained by potential unmeasured confounding such as diet. Our results suggest that serum free cholesterol concentrations in both men and women have an effect on TTP, highlighting the importance of cholesterol and lipid homeostasis for male and female fecundity.

Heterosis in age‐specific selected populations of a seed beetle: Sex differences in longevity and reproductive behavior

We tested mutation accumulation hypothesis for the evolution of senescence using short-lived and long-lived populations of the seed-feeding beetle, Acanthoscelides obtectus (Say), obtained by selection on early- and late-life for many generations. The expected consequence of the mutation accumulation hypothesis is that in short-lived populations, where the force of natural selection is the strongest early in life, the late-life fitness traits should decline due to genetic drift which increases the frequency of mutations with deleterious effects in later adult stages. Since it is unlikely that identical deleterious mutations will increase in several independent populations, hybrid vigor for late-life fitness is expected in offspring obtained in crosses among populations selected for early-life fitness traits. We tested longevity of both sexes, female fecundity and male reproductive behavior for hybrid vigor by comparing hybrid and nonhybrid short-lived populations. Hybrid vigor was confirmed for male virility, mating speed and copulation duration, and longevity of both sexes at late ages. In contrast to males, the results on female fecundity in short-lived populations did not support mutation accumulation as a genetic mechanism for the evolution of this trait. Contrary to the prediction of this hypothesis, male mating ability indices and female fecundity in long-lived populations exhibited hybrid vigor at all assayed age classes. We demonstrate that nonhybrid long-lived populations diverged randomly regarding female and male reproductive fitness, indicating that sexually antagonistic selection, when accompanied with genetic drift for female fecundity and male virility, might be responsible for overriding natural selection in the independently evolving long-lived populations.

Lipid concentrations and semen quality: the LIFE study

The decline in sperm count rates over the last 50 years appears to parallel the rising prevalence of obesity. As lipid levels are strongly associated with obesity, high lipids levels or hyperlipidaemia may thus play an important role in the decline in fertility in addition to other environmental or lifestyle factors. The objective of this population based cohort study was to evaluate the association between men's serum lipid concentrations and semen quality parameters among 501 male partners of couples desiring pregnancy and discontinuing contraception. Each participant provided prospectively up to two semen samples (94% of men provided one or more semen samples, and 77% of men provided a second sample approximately 1 month later). Linear mixed effects models were used to estimate the associations between baseline lipid concentrations and semen quality parameters, adjusted for age, body mass index and race. We found that higher levels of serum total cholesterol, free cholesterol and phospholipids were associated with a significantly lower percentage of spermatozoa with intact acrosome and smaller sperm head area and perimeter. Our results suggest that lipid concentrations may affect semen parameters, specifically sperm head morphology, highlighting the importance of cholesterol and lipid homeostasis for male fecundity.

TESTING SEX RATIO THEORY WITH THE MALARIA PARASITEPLASMODIUM MEXICANUMIN NATURAL AND EXPERIMENTAL INFECTIONS

The malaria parasite (Plasmodium) life history accords well with the assumptions of local mate competition (LMC) of sex ratio theory. Within a single meal of the blood-feeding vector, sexually dimorphic gametocyte cells produce gametes (females produce one, males several) that mate and undergo sexual recombination. The theory posits several factors drive the Plasmodium sex ratio: male fecundity (gametes/male gametocyte), number and relative abundance of parasite clones, and gametocyte density. We measured these traits for the lizard malaria parasite, Plasmodium mexicanum, with a large sample of natural infections and infections from experiments that manipulated clonal diversity. Sex ratio in single-clone infections was slightly female-biased, but matched predictions of theory for this low-fecundity species. Sex ratio was less female-biased in clonally diverse infections as predicted by LMC for the experimental, but not natural infections. Gametocyte density was not positively related to sex ratio. These results are explained by the P. mexicanum life history of naturally low clonal diversity and high gametocyte production. This is the first study of a natural malaria system that examines all traits relevant to LMC in individual vertebrate hosts and suggests a striking example of sex ratio theory having significance for human public health.

Epidemiologic methods for investigating male fecundity

Fertility is a couple concept that has been measured since the beginning of demography, and male fecundity (his biological capacity to reproduce) is a component of the fertility rate. Unfortunately, we have no way of measuring the male component directly, although several indirect markers can be used. Population registers can be used to monitor the proportion of childless couples, couples who receive donor semen, trends in dizygotic twinning, and infertility diagnoses. Studies using time-to-pregnancy (TTP) may identify couple subfecundity, and TTP data will correlate with sperm quality and quantity as well as sexual activity and a number of other conditions. Having exposure data available for couples with a fecund female partner would make TTP studies of interest in identifying exposures that may affect male fecundity. Biological indicators such as sperm quality and quantity isolate the male component of fertility, and semen data therefore remain an important source of information for research. Unfortunately, often over half of those invited to provide a sperm sample will refuse, and the study is then subject to a selection that may introduce bias. Because the most important time windows for exposures that impair semen production could be early fetal life, puberty, and the time of ejaculation; longitudinal data over decades of time are required. The ongoing monitoring of semen quality and quantity should continue, and surveys monitoring fertility and waiting TTP should also be designed.

Mortality effects of the parasitoid flesh fly Blaesoxipha japonensis (Diptera: Sarcophagidae) in relation to body size of the adult grasshopper Parapodisma tanbaensis (Orthoptera: Catantopidae)

Body size is a significant factor for organisms because it has a profound effect on almost all of their physiological, life-history, ecological, and evolutionary traits. Sexual size dimorphism (SSD) is one of the sources creating intraspecific variation in body size. In general, female adults are larger than male adults in insects. Whereas much research has examined the significance of male competition and fecundity as causes of SSD in insects, relatively less is known about the effects of parasitoids on host insect size. To investigate the effects of the parasitoid fly Blaesoxipha japonensis Hori on the body size of the adult grasshopper Parapodisma tanbaensis Tominaga et Kano, we examined the relationship between adult host size and host mortality rate caused by B. japonensis when adult grasshoppers captured in the field were reared in the laboratory. The results showed that females were larger than males and that the host mortality rate caused by B. japonensis was inversely related to host size in females, whereas there was no significant relationship between male size and host mortality rate. These results suggest that the effect of this parasitoid on host body size is one factor favoring the female-biased SSD in this adult grasshopper.

Semen analysis: Indispensable, yet non-ideal

Women’sHealthHospital,Dept. ofObstetricsG accepted 3 November 20131. IntroductionAbout 15% of sexually active, non contracepting couples donot achieve pregnancy within 1 year of marriage and aretherefore described as infertile (1). No cause of infertility canbe found using routine diagnostic work-up in 10–15% of thecouples. A male contribution to infertility is encountered in45–50% of the remaining cases (2). Male and female infertilityfactors often coexist. In 30–45%, the cause of abnormal semenparameters remains enigmatic (idiopathic male infertility)(3,4).Semen analysis is of great value in the initial investigationof the male and its results are often taken as a surrogatemeasure of male fecundity and chances of pregnancy. It alsoprovides information on the functional integrity of thegerminal epithelium, epididymis and accessory sex glands.Additionally, reference ranges for semen parameters from afertile population may provide important data from whichthe diagnosis of infertility or prognosis of fertility can beextrapolated. Routine semen analysis should provide adequateinformation about the physical characteristics of semen(liquefaction, viscosity, pH, color, odor and volume), spermcount, sperm motility and progression, sperm morphology,leukocyte quantification and fructose detection in cases ofazoospermia or oligospermia.From an evidence-based perspective, are the measuredsemen parameters truly and wholly reflective of a man’s repro-ductive capacity? Are those parameters carefully chosen toencompass the multifaceted and complex nature of suchprocess? Are the currently acceptable values for a normalsemen analysis considered accurate ‘pass marks’ for parenthood?Will a normal semen analysis guarantee a successful culminationof a man’s endeavor to father a child? Does an abnormal semenanalysis necessarily designate abnormality?Regrettably, negation is the answer to most, if not all, theaforementioned questions. That said, two fundamental issuesfollow, why and how. Why is the currently applied semenanalysis short of providing an adequate evidence-basedsubstantiation of a man’s fertile capacity? How could we addvalue to such an important and non-invasive investigatory tool?2. Why is the currently adopted semen analysis inadequate?The prognostic value of semen components such as spermcount, motility and morphology, as surrogate markers of malefertility, is confounded by several variables. The fertility poten-tial of a man is influenced by sexual activity, function of acces-sory sex glands and other confounders. Routine semen analysisitself has its own limitations, and does not assess for spermdysfunction such as immature chromatin or fragmentedDNA. Results from at least two, preferably three, properlyspaced separate seminal analyses must be obtained before adefinitive conclusion can be drawn as wide biological variabil-ity exists within the same individual. The numerous character-istics assayed by semen analysis are only few of the many facetsreflecting semen quality. Almost one third of men with anormal semen analysis actually have abnormal sperm function.In contradistinction, men with poor semen analysis results maygo onto father children. Semen analysis should follow theWHO guidelines, laboratory manual for the examination andprocessing of human semen (5). Semen analysis may show adecreased number of sperm (oligozoospermia), decreasedmotility (asthenozoospermia), and many abnormal forms onmorphologic examination (teratozoospermia). These

The Effects of Chemotherapy with Bleomycin, Etoposide, and Cis-Platinum (BEP) on Rat Sperm Chromatin Remodeling, Fecundity and Testicular Gene Expression in the Progeny1

During spermiogenesis, histones are replaced first by transition proteins and then by protamines, resulting in a very condensed sperm DNA structure that is absolutely critical for normal sperm function. We have demonstrated previously that, despite a 9-wk recovery period, mature sperm from rats treated for 9 wk with bleomycin, etoposide, and cis-platinum (BEP), the drugs used to treat testicular cancer, have reduced levels of protamine 1 and a concomitant upregulation of specific histones, highlighting a problem in histone eviction. Here, we demonstrate that regulators of histone removal are increased in elongating spermatids following recovery; however, Ac-H4 and gamma H2AX histones remain elevated in elongating spermatids or caudal epididymal spermatozoa 9 wk post-BEP treatment. This indicates that chromatin remodelers and effector proteins that respond to histone removal cues may be a target of BEP treatment. A decrease in the expression of SMARCE1 in elongating spermatids may explain the persistent retention of histones in cauda epididymal sperm 9 wk after the cessation of BEP treatment. Remarkably, proteins implicated in the translational control and posttranslational processing of protamine 1 are also significantly elevated 9 wk post-BEP treatment, suggesting that histone eviction may dictate the DNA availability for protamine binding. Males mated to control females 9 wk after BEP treatment have reduced litter sizes; moreover, the profile of gene expression in the developing testes of their pups is altered. Altering the proportion of histones to protamine in mature spermatozoa has an adverse impact on male fecundity, with modifications to epigenetic marks potentially threatening normal progeny development.

Effects of Increasing Age on Fecundity of Old-aged Canada Geese (Branta canadensis)

Abstract. Senescence is a decline in body function with advanced age that manifests itself in birds as a decrease in survival rates or reproduction. Senescence is difficult to study in free-ranging birds because few birds reach old age and few studies last long enough to identify those birds that do. For 21 years, I studied lifelong reproduction among Canada Geese (Branta canadensis) nesting in New Haven County, Connecticut. These data were used to determine the impact of old age on female and male fecundity during the current year and during the remainder of the birds' lives. Old-aged geese were relatively common in this population; 15% of recruited geese lived 10 years, 3% lived 15 years, and one female lived 20 years. Females that nested when they were between 5 and 9 years old had a mean clutch size of 4.5, brood size at hatching of 3.4, and brood size at fledging of 2.9. Females that nested when they were at least 10 years old had a mean clutch size of 4.7, brood size at hatching of 3.4, and brood si...

Seasonality in reproduction of the deep-water pennatulacean coral Anthoptilum grandiflorum

The deep-sea pennatulacean coral Anthoptilum grandiflorum exhibits a cosmopolitan distribution and was recently determined to serve as habitat for other invertebrates and fish larvae in the northwest Atlantic. Colonies collected at bathyal depths between 2006 and 2010 in eastern Canada were analysed to determine their fecundity and characterize spatial and temporal trends in their reproductive cycle. Anthoptilum grandiflorum is a gonochoric broadcast spawner with a sex ratio that does not differ significantly from equality (although one hermaphrodite colony was observed). In male colonies, all the spermatocysts synthesized become mature over the annual cycle, while only ~21 % of the initial production of oocytes reaches maturity in female colonies. Female potential fecundity based on mature oocytes just before spawning was on average 13 oocytes polyp−1; male potential fecundity was 48 spermatocysts polyp−1. The spawning period of A. grandiflorum differs between geographic regions, from April (in southern Newfoundland) to July (in Labrador), closely following regional spring phytoplankton blooms after accounting for the deposition of planktic detritus. Release of oocytes by a live colony held in the laboratory was recorded in April 2011, coincident with field data for similar latitudes. Seawater temperatures at the time of spawning were around 3.6–4.8 °C in all regions and in the laboratory. Early stages of gametogenesis were detected in colonies collected shortly after the spawning season, and early and late growth stages occurred successively until December. Mature colonies were observed between April and July (depending on latitude). The diameter of mature oocytes (~1,100 μm maximum diameter) is consistent with lecithotrophic larval development.