Crude oil contamination has been shown to impair reproduction in aquatic animals through carcinogenic and genotoxic properties. Here, we assessed the endocrine-disrupting function of crude oil on male reproductive system based on testicular histology, sex steroid hormones, and fertility endpoints in adult male goldfish (Carassius auratus), which were exposed to 0.02- to 2-mg/L crude oil for 21 days (Experiment #1) or to 5- to 250-mg/L crude oil for 9 days (Experiment #2). The crude oil contained 0.22-mg/L nickel (Ni), 1.10-mg/L vanadium (V), and 12.87-mg/L polycyclic aromatic hydrocarbons (PAHs). Twenty-four hours after adding crude oil, the sum of PAHs ranged from 0.30 to 2.28 μg/L in the aquaria containing 0.02- and 250-mg/L crude oil, respectively. Water analyses for heavy metals in Experiment #2 showed high concentrations (mg/L) of Ni (0.07-0-09) and V (0.10-0.21). For both experiments, exposure to crude oil did not impact gonadosomatic index; however, testes showed histopathological defects including hyperplasia or hypertrophy of Sertoli cells, depletion of the Leydig cells, necrosis of germ cells, and fibrosis of lobular wall. In Experiment #1, sperm production and motility, testosterone (T), and 17β-estradiol (E2) were not significantly different among treatments. In Experiment #2, the number of spermiating males decreased by ~50% following exposure to 250-mg/L crude oil. Sperm production, motility kinematics, T, and the T/E2 ratio significantly decreased in males exposed to ≥ 50-mg/L crude oil; however, E2 remained unchanged. Results show crude oil-induced imbalance of sex steroid hormones disrupts spermatogenesis resulting in diminished sperm production and motility.
- MeSH
- Water Pollutants, Chemical * toxicity MeSH
- Endocrine Disruptors * toxicity MeSH
- Goldfish * physiology MeSH
- Sperm Motility * drug effects MeSH
- Gonadal Steroid Hormones * metabolism blood MeSH
- Petroleum * toxicity MeSH
- Reproduction drug effects MeSH
- Spermatozoa * drug effects pathology MeSH
- Testis * drug effects pathology MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
The bisphenol A (BPA)-disrupted reproductive functions have been demonstrated in male animals. In fish, it has been shown that environmentally relevant concentrations of BPA decrease sperm quality associated with inhibition of androgen biosynthesis. However, BPA effects on neuroendocrine regulation of reproduction to affect testicular functions are largely unknown. In the present study, reproductive functions of hypothalamus and pituitary were studied in mature male goldfish exposed to nominal 0.2, 2.0 and 20.0 μg/L BPA. At 90 d of exposure, sperm volume, velocity, and density and motility were decreased in goldfish exposed to 0.2, 2.0, and 20.0 μg/L BPA, respectively (p < 0.05). At 30 d of exposure, there were no significant changes in circulatory LH levels and mRNA transcripts of kiss1, Kiss2, gpr54, and gnrh3. At 90 d of exposure, circulatory LH levels showed trends toward increases in BPA exposed goldfish, which was significant in those exposed to 2.0 μg/L (P < 0.05). At this time, Kiss2, gpr54, and gnrh3 mRNA levels were increased in goldfish exposed to any concentrations of BPA (p < 0.05). This study shows that BPA-diminished sperm quality was accompanied by an increase in circulatory LH levels associated with increases in mRNA transcripts of upstream neuroendocrine regulators of reproduction in goldfish. Further, this is the first study to report circulatory levels of LH in fish exposed to BPA.
Aging is the most critical factor that influences the quality of post-ovulatory oocytes. Age-related molecular pathways remain poorly understood in fish oocytes. In this study, we examined the effect of oocyte aging on specific histone acetylation in common carp Cyprinus carpio. The capacity to progress to the larval stage in oocytes that were aged for 28 h in vivo and in vitro was evaluated. Global histone modifications and specific histone acetylation (H3K9ac, H3K14ac, H4K5ac, H4K8ac, H4K12ac, and H4K16ac) were investigated during oocyte aging. Furthermore, the activity of histone acetyltransferase (HAT) was assessed in fresh and aged oocytes. Global histone modifications did not exhibit significant alterations during 8 h of oocyte aging. Among the selected modifications, H4K12ac increased significantly at 28 h post-stripping (HPS). Although not significantly different, HAT activity exhibited an upward trend during oocyte aging. Results of our current study indicate that aging of common carp oocytes for 12 h results in complete loss of egg viability rates without any consequence in global and specific histone modifications. However, aging oocytes for 28 h led to increased H4K12ac. Thus, histone acetylation modification as a crucial epigenetic mediator may be associated with age-related defects, particularly in oocytes of a more advanced age.
- MeSH
- Acetylation MeSH
- Histone Acetyltransferases genetics MeSH
- Histones genetics MeSH
- Carps genetics growth & development MeSH
- Oocytes growth & development metabolism MeSH
- Protein Processing, Post-Translational genetics MeSH
- Aging genetics MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
Fish spermatozoa acquire potential for motility in the sperm duct where they are immotile. Osmolality of the seminal plasma is a key factor to maintain spermatozoa in the quiescent state in either freshwater or marine fishes. However, potassium (K+) ions prevent spermatozoa motility in salmonid and sturgeon fishes, while CO2 inhibits spermatozoa motility in flatfishes. Once, spermatozoa are released at spawning, their motility is initiated in hypo-osmotic and hyper-osmotic environments in freshwater and marine fishes, respectively. Some substances produced by the testes (a progestin), or released from oocytes (peptides) induce spermatozoa hypermotility in some marine fishes including the Atlantic croaker and Pacific herrings, respectively. Duration of spermatozoa motility is short, lasting for a few seconds to few minutes in most fishes due to rapid depletion of energy required for the beating of the motility apparatus called axoneme. In the osmotic-activated spermatozoa, K+ and water effluxes occur in freshwater and marine fishes, respectively, which trigger spermatozoa motility signaling. In general, initiation of axonemal beating is associated with an increase in intracellular calcium (Ca2+) ions in spermatozoa of both freshwater and marine fishes and a post- or pre-increase in intracellular pH, while cyclic adenosine monophosphate (cAMP) remains unchanged. However, axonemal beating is cAMP-dependent in demembranated spermatozoa of salmonid and sturgeon fishes. Calcium from extracellular environment or intracellular stores supply required Ca2+ concentration for axonemal beating. Several axonemal proteins have been so far identified in fishes that are activated by Ca2+ and cAMP, directly or mediated by protein kinase C and protein kinase A, respectively. The present study reviews differences and similarities in complex regulatory signals controlling spermatozoa motility initiation in fishes, and notes physiological mechanisms that await elucidation.
- MeSH
- Species Specificity MeSH
- Sperm Motility physiology MeSH
- Fishes physiology MeSH
- Signal Transduction physiology MeSH
- Spermatozoa physiology MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
The effect of antifreeze proteins on sterlet, Acipenser ruthenus sperm motility variables and fertilization rate were investigated after cryopreservation. Two types of antifreeze proteins (AFPI or AFPIII) were used at concentrations of 0.1, 1, 10 and 100 μg/mL. The motility variables of fresh and cryopreserved sperm with and without addition of antifreeze proteins were evaluated by the Computer Assisted Semen Analyzer (CASA). The fertilization rate using about 200,000 spermatozoa per egg was evaluated after 54 h incubation at 17 °C during the early stage of organogenesis. The motility, curvilinear velocity and straight-line velocity of fresh sperm was 93 ± 5%, 128 ± 13 μm/s and 89 ± 9 μm/s, respectively. There was a significant decrease of sperm motility rate between fresh sperm and cryopreserved sperm with/without addition of antifreeze proteins. The greatest motility among thawed samples was in the sperm cryopreserved with 10 μg/mL of AFPI (56 ± 20%), however, these data were not different compared to the sperm without antifreeze proteins (49 ± 14%). No statistical variations were detected in curvilinear velocity nor straight-line velocity. The fertilization rate with fresh sperm was 67 ± 7%. No significant differences were detected in fertilization rate between fresh and cryopreserved spermatozoa with/without addition of antifreeze proteins, except the sperm cryopreserved with 100 μg/mL of AFPIII (39 ± 14%). Thus, it is concluded that addition of antifreeze proteins to cryopreservation medium do not improve nor have toxicity effects on the quality and fertilization capacity of sterlet sperm after thawing.
- MeSH
- Fertilization MeSH
- Cryopreservation methods veterinary MeSH
- Antifreeze Proteins pharmacology MeSH
- Sperm Motility * drug effects physiology MeSH
- Fishes physiology MeSH
- Spermatozoa physiology MeSH
- Semen Preservation MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
The loss of sperm quality in sterlet (Acipenser ruthenus) due to freeze-thaw process in cryopreservation was investigated in the present study. Two antifreeze proteins (AFPI or AFPIII) were used at different concentrations of 0.1, 1, 10, and 100 μg/mL. We compared motility, curvilinear velocity, and plasma membrane integrity of fresh, cryopreserved sperm, and sperm cryopreserved in the presence of antifreeze proteins. Fresh sperm (control) had 85 ± 4% motility and 160 ± 2 μm/s curvilinear velocity, respectively. After cryopreservation, the motility of frozen-thawed sperm without addition of antifreeze proteins significantly decreased (44 ± 9%), compared to the control. The highest motility of frozen-thawed sperm was obtained in cryopreserved sperm with addition of 1 μg/mL of AFPIII (58 ± 14%). No significant differences were observed in curvilinear velocity between fresh sperm and cryopreserved sperm with/without addition of AFPI or AFPIII. The flow cytometry analysis revealed that fresh sperm contained 94.5 ± 6% live cells, while the cryopreserved sperm only contained 26.6 ± 14% live cells. Supplementation of antifreeze proteins has significantly improved the percentage of live cells in frozen-thawed sperm, except 0.1 μg/ml of AFPI group. No significant difference in percentage of live cells was detected in the sperm cryopreserved with 10 μg/mL of AFPI or AFPIII, compared to fresh sperm. Thus, addition of antifreeze proteins to cryopreservation medium could be considered to improve the post-thawed sperm quality of sterlet.
Fish sperm cryopreservation is a well-established technique allowing for artificial insemination on a commercial scale. The extent of proteome alterations in seminal plasma and sperm due to cryopreservation, however, is not known. This study was conducted to evaluate the effect of cryopreservation on motility variables of sterlet Acipenser ruthenus sperm and to detect the differences in protein profiles of fresh and cryopreserved sterlet sperm and seminal plasma. Fresh sperm had 89 ± 3% motility and 160 ± 14 μm/s curvilinear velocity at 15 s post-activation. The motility rate of cryopreserved sperm (37 ± 5%) was less at 15 s post-activation. No difference (ANOVA; P > 0.05) in mean curvilinear velocity of fresh and cryopreserved sperm was detected. The protein profiles of seminal plasma and sperm were characterized using comparative proteomics to determine the influence of cryopreservation. Six altered protein spots in seminal plasma and thirteen altered spots in sperm were detected in fresh and thawed sperm. Subsequent protein characterization suggested that the proteins identified were involved in sperm metabolism, cytoskeleton, and stress response. The results broaden the understanding of the effects of cryopreservation and identify the proteins associated with cryo-injury. These data may help to determine the function of altered proteins and provide new insights into improving sperm cryopreservation.
- MeSH
- Cryopreservation veterinary MeSH
- Sperm Motility * MeSH
- Proteome * MeSH
- Fishes physiology MeSH
- Spermatozoa physiology MeSH
- Transcriptome MeSH
- Semen Preservation veterinary MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Paternal, compared to maternal, contributions were believed to have only a limited influence on embryonic development and larval fitness traits in fishes. Therefore, the perspective of male influence on early life history traits has come under scrutiny. This study was conducted to determine parental effects on the rate of eyed embryos of Ide Leuciscus idus and Northern pike Esox lucius. Five sires and five dams from each species were crossed using a quantitative genetic breeding design and the resulting 25 sib groups of each species were reared to the embryonic eyed stage. We then partition variation in embryonic phenotypic performance to maternal, paternal, and parental interactions using the Restricted Maximum Likelihood (REML) model. Results showed that paternal, maternal, and the paternal×maternal interaction terms were highly significant for both species; clearly demonstrating that certain family combinations were more compatible than others. Paternal effects explained 20.24% of the total variance, which was 2-fold higher than the maternal effects (10.73%) in Ide, while paternal effects explained 18.9% of the total variance, which was 15-fold higher than the maternal effects (1.3%) in Northern pike. Together, these results indicate that male effects are of major importance during embryonic development for these species. Furthermore, this study demonstrates that genetic compatibility between sires and dams plays an important role and needs to be taken into consideration for reproduction of these and likely other economically important fish species.
- MeSH
- Breeding MeSH
- Species Specificity MeSH
- Embryonic Development * MeSH
- Phenotype MeSH
- Crosses, Genetic MeSH
- Larva growth & development MeSH
- Reproduction physiology MeSH
- Fishes embryology MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
The morphology of the reproductive system of acipenseriform fishes is quite different from that of teleostean species, but an associated unique physiological difference in male sturgeons was not discovered until recently; sperm of sturgeons passes through the kidneys then via Wolffian ducts into the environment rather that emptying directly through seminal ducts. The mixing of sperm with excretory products has been found to be a requisite for the capacity to be activated (maturation step) instead of being deleterious. In the current review we summarize results of studies performed in our laboratory on physiological processes involved in sturgeon sperm maturation, namely changes in: 1) ionic environment; 2) sensitivity of spermatozoa to calcium ions (Ca2+); 3) antioxidant enzymes and proteolytic activities; and 4) content in macroergic phosphates arising during this maturation process. We also discuss taxa-specific aspects of sturgeon sperm maturation in relation to hormonal regulation of spermiation, and the unusual features of sturgeon sperm maturation relative to using testicular sturgeon sperm in aquaculture.
- MeSH
- Genitalia, Male anatomy & histology physiology MeSH
- Fishes physiology MeSH
- Spermatozoa physiology MeSH
- Sperm Maturation physiology MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
To survive low temperature is required for a long-term storage (cryopreservation), cells should be vitrified to a state in which intracellular water is solidified without ice crystal formation. Two different approaches are described for fish sperm cryopreservation: 1) sperm conventional cryopreservation, in which extracellular water is partially crystallized and 2) sperm vitrification, in which both intra- and extra-cellular liquids are vitrified. Sperm vitrification has been applied to some fish species with limited success. Traditional vitrification requires rapid cooling/warming rates, small sample carriers, and using high permeable cryoprotectant concentrations. The latter cause cytotoxic effects which must be well managed and will require continuous effort to match an appropriate cryoprotectant with suitable apparatus and warming methods. Novel cryoprotectant-free sperm vitrification approach has been applied to several fishes. This review summarizes development of basic procedures and discusses advantages and disadvantages of vitrification when applied it to fish sperm.
- MeSH
- Species Specificity MeSH
- Cryopreservation methods veterinary MeSH
- Fishes physiology MeSH
- Semen Preservation methods veterinary MeSH
- Vitrification * MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
