Gonadal Activity Research Articles

REPRODUCTIVE BIOLOGY OF THE FRESHWATER MUSSEL, NITIA TERETIUSCULA (PHILIPPI, 1847) (BIVALVIA: UNIONIDAE) FROM THE NILE RIVER IN EGYPT

Seasonal reproductive cycle, gonad structure, gametogenesis, larval development and sex ratio of the freshwater mussel, Nitia teretiuscula (Philippi, 1847) was investigated for the first time. A total of 200 mussels, were randomly collected each month from September 2016 to August 2017 from four regions along Nile River, Egypt: El-Kanater (Qaluobiya Governorate), Tura (Helwan Governorate) Geziret Bein El-Bahrein (Giza Governorate) and Geziret El-Dahab (Cairo Governorate). Histological examination of the gonads showed that N. teretiuscula is a dioecious species with a 1:1 sex ratio. The female and male gonads were found to be paired and asymmetrical organs, situated between the mantle and digestive gland. Female follicles contain edoogonia and oocytes that could be separated into, previtelogenin, vitelogenin and postvitelogenin stages. Male follicles contained spermatogonia and spermatocytes that could be classified as primary spermatocytes, secondary spermatocytes and spermatids. Moreover, the reproductive cycle of both sexes included four developmental stages, developing, ripened (mature), spawning and spent. The predominant stages were ripening (mature) and spawning, whereas spent gonads were rare. Gametogenesis began in early spring and spawning occurred in late spring. Although mature oocytes and spermatozoa were present for almost the entire year, gonadal activity seemed lowest in autumn months. Both sexes displayed the most gonadal activity during the winter months. Consequently, eggs and larval stages (glochidia) were incubated for a short period within both the outer and inner demibranchsso; N. teretiuscula can be considered atetragenic and tachytachtic species.

REPRODUCTIVE BIOLOGY OF THE FRESHWATER MUSSEL, NITIA TERETIUSCULA (PHILIPPI, 1847) (BIVALVIA: UNIONIDAE) FROM THE NILE RIVER IN EGYPT

Seasonal reproductive cycle, gonad structure, gametogenesis, larval development and sex ratio of the freshwater mussel, Nitia teretiuscula (Philippi, 1847) was investigated for the first time. A total of 200 mussels, were randomly collected each month from September 2016 to August 2017 from four regions along Nile River, Egypt: El-Kanater (Qaluobiya Governorate), Tura (Helwan Governorate) Geziret Bein El-Bahrein (Giza Governorate) and Geziret El-Dahab (Cairo Governorate). Histological examination of the gonads showed that N. teretiuscula is a dioecious species with a 1:1 sex ratio. The female and male gonads were found to be paired and asymmetrical organs, situated between the mantle and digestive gland. Female follicles contain edoogonia and oocytes that could be separated into, previtelogenin, vitelogenin and postvitelogenin stages. Male follicles contained spermatogonia and spermatocytes that could be classified as primary spermatocytes, secondary spermatocytes and spermatids. Moreover, the reproductive cycle of both sexes included four developmental stages, developing, ripened (mature), spawning and spent. The predominant stages were ripening (mature) and spawning, whereas spent gonads were rare. Gametogenesis began in early spring and spawning occurred in late spring. Although mature oocytes and spermatozoa were present for almost the entire year, gonadal activity seemed lowest in autumn months. Both sexes displayed the most gonadal activity during the winter months. Consequently, eggs and larval stages (glochidia) were incubated for a short period within both the outer and inner demibranchsso; N. teretiuscula can be considered atetragenic and tachytachtic species.

Adiponectin and Chemerin: Contrary Adipokines in Regulating Reproduction and Metabolic Disorders.

Metabolic disorders such as obesity and type 2 diabetes are one of the most familiar risk factors in the present time among every age-group. It is associated with altered levels of adipokines such as adiponectin, chemerin, leptin, resistin, visfatin, and so on. Adiponectin is one of the adipocyte-specific protein with novel applications pertaining to metabolism by promoting insulin sensitivity and regulating glucose and fatty acid catabolism, while chemerin is considered as an inhibitor of insulin signaling and glucose catabolism. Other than these established functions, both the adipokines are intimately involved in coordinating reproductive activities, but they exhibit contrary functions. This review is an amalgamation of recent information related to adiponectin and chemerin in male and female reproduction and further its association with metabolism-related reproductive disorders. The direct effect of adiponectin and chemerin on various reproductive parameters has been investigated, but there was a rampant failure to account for in vivo data which gives a broad outlook on the regulatory mechanism of both adiponectin and chemerin related to male and female reproductive functions. Adiponectin is known to promote gonadal activities, while chemerin exerts antigonadal actions. Recent research suggests that high chemerin/low adiponectin ratio plays a vital role in causing dyslipidemia and metabolic syndrome in patients. The dysregulated ratio of adiponectin to chemerin during various metabolic disorders makes it really worthy in relation to an application for therapeutics. Still, a lot regarding both the adipokines has to be explored and brought forward in order to deal with therapeutics of metabolism-related reproductive disorders.

Next-generation and further transgenerational effects of bisphenol A on zebrafish reproductive tissues

Next-generation effects and further transgenerational effects of an endocrine disruptor, bisphenol A (BPA), were investigated in zebrafish. The effects of BPA treatment through dietary administration in male and female zebrafish on reproductive factors, such as gonadal activity, fertility, hatching rate and malformation in subsequent generations, were examined through the third filial (F3) generation. BPA treatment of initial generation (F0) not only caused retraction of the ovaries and testes but also lowered the survival rate and increased the rate of malformation of the offspring. Although the overall phenotypes of the surviving first filial (F1) generation offspring of treated fish initially appeared to be normal, we found abnormalities in their reproductive tissues after they matured to adulthood. Although the juveniles were fed a normal diet, the ovaries of 40% of the F1 generation fish remained small and did not develop vitellogenic oocytes. Moreover, sterile male fish appeared at a higher percentage (48%) than control (10%). Adverse transgenerational effects on the fecundity of the second filial (F2) and F3 generation fish were also observed. In each generation, survival rate of embryos were significantly low and abnormal embryos were appeared in offspring from BPA treated ancestral. These results demonstrate that the effects of BPA are transferred to subsequent generations not only through oocytes but also through sperm.

Exonuclease Domain-Containing 1 Enhances MIWI2 piRNA Biogenesis via Its Interaction with TDRD12

PIWI proteins and their associated small RNAs, called PIWI-interacting RNAs (piRNAs), restrict transposon activity in animal gonads to ensure fertility. Distinct biogenesis pathways load piRNAs into the PIWI proteins MILI and MIWI2 in the mouse male embryonic germline. While most MILI piRNAs are derived via a slicer-independent pathway, MILI slicing loads MIWI2 with a series of phased piRNAs. Tudor domain-containing 12 (TDRD12) and its interaction partner Exonuclease domain-containing 1 (EXD1) are required for loading MIWI2, but only Tdrd12 is essential for fertility, leaving us with no explanation for the physiological role of Exd1. Using an artificial piRNA precursor, wedemonstrate that MILI-triggered piRNA biogenesis is greatly reduced in the Exd1 mutant. The situation deteriorates in the sensitized Exd1 mutant (Exd1-/-;Tdrd12+/-), where diminished MIWI2 piRNA levels de-repress LINE1 retrotransposons, leading to infertility. Thus, EXD1 enhances MIWI2 piRNA biogenesis via a functional interaction with TDRD12.

Transcriptomic analysis of mRNA expression and alternative splicing during mouse sex determination.

Mammalian sex determination hinges on sexually dimorphic transcriptional programs in developing fetal gonads. A comprehensive view of these programs is crucial for understanding the normal development of fetal testes and ovaries and the etiology of human disorders of sex development (DSDs), many of which remain unexplained. Using strand-specific RNA-sequencing, we characterized the mouse fetal gonadal transcriptome from 10.5 to 13.5 days post coitum, a key time window in sex determination and gonad development. Our dataset benefits from a greater sensitivity, accuracy and dynamic range compared to microarray studies, allows global dynamics and sex-specificity of gene expression to be assessed, and provides a window to non-transcriptional events such as alternative splicing. Spliceomic analysis uncovered female-specific regulation of Lef1 splicing, which may contribute to the enhanced WNT signaling activity in XX gonads. We provide a user-friendly visualization tool for the complete transcriptomic and spliceomic dataset as a resource for the field.

Reproductive Biology of The Solitary Ascidian, Herdmania momus (Ascidiacea: Hemichordta) from Hurghada Coasts, Red Sea, Egypt

The reproductive biology of the ascidian Herdmania momus (Savigny, 1816) was studied at anthropogenic impacted sites along Hurghada coasts, Red Sea, Egypt, during January - December 2013. The specimens of this species were collected monthly from the shallow subtidal zones, and varied from 1.20 to 7.0 cm in total length and from 1.28 to 50 g in total body weight. The results showed that, H. momus is hermaphrodite, carries ovaries and testes at the same individuals, but ovaries are larger in size and shapes than testes. The smallest immature individual has 1.2 cm in length; while the smallest mature individual measured 1.46 cm in length and 1.18 g in weight, with ovaries of 0.041g in weight. The sexually mature individuals of this species have ovaries containing oocytes varied in shapes and sizes, passing through four main stages of maturation reaching stage IV or late vitellogenic stage (ripe ova), with oocytes varied from 100 to 140 µm in diameter, characterized with deep orange color and dense accumulation of yolk granules. It was followed by stage V or spent stage of irregular resorbed eggs. The appearance of ripe ova at stage IV showed spatial and temporal variations. The monthly averages of gonadosomatic indices (GSI) exhibited that, the whole populations of this species at all sites have lengthy breeding season extends nearly all the year around and characterizes with high peaks in gonadal activity during January (6.21), April (6.15), June (6.47), July (6.28), declined slightly in May (5.86), and September (5.15), with remarkably spatial variations at the studied sites. The number of mature eggs or fecundity varied from 1481 to 3724 and averaged of 3082.96±769.96 eggs for all populations. These values exhibited greatly individual variations denoting to partially spawning for each individual. The relationship between total body length (cm) and mean the number of eggs (fecundity) showed an increase in egg number with an increase in animal length

Anti-Müllerian hormone profiling in prepubertal horses and its relationship with gonadal function

Anti-Müllerian hormone (AMH) has gained increasing interest as a biomarker for assessment of gonadal activity. The ability to predict the ovarian follicular reserve of prepubertal female horses (fillies) or to identify stallions with testicular pathologies already during their prepubertal life has not been analyzed so far. Both would help to select fertile horses and reduce costs associated with keeping animals. The objectives of the present study were to (1) assess AMH, LH, FSH, progesterone (females) and testosterone (males) dynamics in prepubertal horses from birth onwards and (2) determine whether AMH concentrations detected in plasma of prepubertal female and male horses are correlated with postpubertal gonadal development. Warmblood foals (n = 30, 14 females, 10 normal males and 6 males with abnormal testicular development) born between February and May of two consecutive years (n = 28 in the first year and n = 2 the next year), were included in the study. Information on gestational length, parity of the dam and placental weight was collected for all foals. Blood samples for hormone analysis were collected from birth onwards every four weeks up to the age of one year. At two years, blood samples were collected on the day when antral follicle count (AFC) and total testicular volume (TTV) were assessed. AMH was detectable in the plasma of all animals from birth onwards and its concentration was significantly higher (P < .001) in males than in females, regardless of testicular development. In males, AMH and testosterone concentration were similar for all animals during the first year of life, regardless of testicular development. At two years, AMH concentration was higher (P < .05) in males with abnormal testicular development than in those with normal testes. In females, AMH concentration at two years was correlated with AMH concentration at birth (P < .05) and with AFC (P < .001). At birth, LH concentration was lower (P < .05) in stallions with abnormal testes (0.3 ± 0.2 ng/ml) than in controls (0.6 ± 0.2 ng/ml). A high negative correlation between AMH concentration and gestation length was observed in males during the first eight weeks of life (P < .01, r = −0.64 to −0.71). Elevated progesterone concentrations over 1 ng/ml were observed in several females starting with 20 weeks of age. This was paralleled by an increase in AMH concentration and was preceded by FSH and LH increases. In conclusion, AMH determination can be reliably used from two years onwards to identify stallions with abnormal testicular development, but it is inconclusive before puberty. In female horses, determination of AMH concentration at a prepubertal age allows for prediction of AMH and AFC after puberty. We suggest that premature luteinisation occurs before the onset of puberty in female horses and that LH secretion in the perinatal period is involved in testicular development and descent in the horse.

Immunomorphometric variations of sustentacular cells of the male viscacha adrenal medulla during the annual reproductive cycle. Effects of androgens and melatonin

The adrenal medulla is crucial for the survival of species facing significant environmental changes. The parenchyma is composed mainly of chromaffin cells, ganglion cells and sustentacular cells (SC). The male viscacha exhibits seasonal variations of gonadal activity and other metabolic functions. The aim of this work was to investigate the influence of the reproductive conditions on the morphology of SC of this rodent. In addition, the effects of testosterone and melatonin on these cells were studied. Immunoexpression of S100 protein, GFAP and vimentin were analyzed. Furthermore, the distribution of adrenergic and noradrenergic chromaffin cells subpopulations was studied for the first time in this species. SC present long cytoplasmic processes in contact with chromaffin cells, probably generating an intraglandular communication network. Significant differences (p < 0.05) in the %IA (percentage of immunopositive area) for the S100 protein were observed according to winter (4.21 ± 0.34) and summer (3.51 ± 0.15) values. In castrated animals, the %IA (6.05 ± 0.35) was significantly higher in relation to intact animals (3.95 ± 0.40). In melatonin-treated animals the %IA (3.62 ± 0.23) was significantly higher compared to control animals (2.65 ± 0.26). GFAP immunoexpression was negative and no noradrenergic chromaffin cells were detected suggesting an adrenergic phenotype predominance. Vimentin was observed in SC, endothelial cells and connective tissue. Results indicate that SC exhibit variations along the annual reproductive cycle, along with castration and the melatonin administration. Our results suggest that in this rodent SC are not only support elements, but also participate in the modulation of the activity of the adrenal medulla; probably through paracrine effects.

EMBRYO YIELD OF COWS-DONORS AND FUNCTIONAL ASYMETRY OF THE OVARIES

In recent years, experiments aimed at studying the structural asymmetry of paired organs have been conducted increasingly in veterinary medicine. The main factor, which prompted this interest, was extensive use of reproductive biotechnology methods to solve the problems of infertility. In experiments on laboratory animals and in clinical medicine, several authors have found that the nature of pathological processes in paired organs had some differences. Parameters of species functional asymmetry at the level of systems and organs are considered in terms of enantiomorphousness as a trait of adaptive evolution. The study of structural features of physiological and pathological processes in paired gonads of cows will increase the efficiency of biotechnological methods of folliculogenesis stimulation and production of more viable eggs. On the other side, it will reduce the cost of expensive drugs and working time due to more efficient pre-selection of animals for producing embryos.&#x0D; The aim of the research was to study structure and pattern of functional asymmetry of ovaries of high-producing cows and its influence on the level of quality embryos formation.&#x0D; Material and methods of research. The researches were carried out during 2011-2012 at two dairy breeding farms – "Agro-Soyuz" JSC (Dnipropetrovsk region) and "RVD-Agro" PE (Cherkasy region). Two groups of high-producing cows were formed of milking breeding stock, yields of which during the best lactation exceeded the average of the herd by 20-60%&#x0D; The animals were tested during the phased comprehensive research on suitability to removing embryos from them and use of the selected cows in the group of regular donors of embryos, in accordance with applicable requirements of embryo transplantation technology for cattle. During the selection and preparation of cows-donors, washing embryos and their morphological evaluation, we simultaneously performed collecting and analysing data on the activity of functional entities of the left and the right ovaries during luteal phase by palpation according to the advanced approaches. The comparison was performed during cows’ induced cycles using injections of synthetic analogues of F2α prostaglandin on standard procedures and after hormonally induced polyovulation in donors using follicle stimulating hormone drugs and on the standard and prolonged procedures.&#x0D; Results. Pattern of relationship between functional asymmetry of ovaries of high-producing cows-donors and their level of embryo yield was found. Palpation revealed that at cows with sufficient technology and high embryo yield after hormonally induced superovulation, ratio of the number of corpora luteal of the left ovary to the right had a tendency to approach the universal proportion of 38%:62% which is typical for luteogenes of cows in the induced and spontaneous cycles. In group of cows with low yields of high-quality embryos, the ratio of ovarian corpora luteal L: R was significantly different. The observed indicator of functional ovarian asymmetry needs to be researched more and it can be used as a criterion for resource-raising effect at selection of stable donors of embryos at high-yielding herds in the future. The significant change of functional asymmetry of donors-cows’ ovaries after hormone stimulation of polyovulation was shown, including the found phenomenon of inversion of dominant activity of gonads. It was experimentally stated that the high level of producing qualitative embryos for transplantation (9,50-9,86 per washing) was characterized for the cows with sufficient functional asymmetry of ovaries after polyovulation.&#x0D; Conclusions. Based on the fact that high-quality embryos from high-producing cows of different breeds will have breeding, biological and economic values in the world market of genetic resources in the next years, it is necessary to step up scientific research to study the patterns of functional asymmetry of the cows’ reproductive system as one of important biological factors influencing on effectiveness of embryo transplantation technology.

Reproductive cycle of Hexaplex princeps (Broderip, 1833) from one artisanal fishery at the southern coast of Mexico

The reproductive cycle of the gastropod Hexaplex princeps (Broderip, 1833) from Puerto Angel was studied through gonadal histology during two annual periods. The sex proportion for the total collected individuals was not statistically different from parity although most of the time the number of males was slightly larger than that of females, which only outnumbered males during the spawning season. The histological analysis of gonad sections permitted to establish six maturity stages for females: 1 Initial oogenesis, 2 Previtellogenic maturity, 3 Vitellogenic maturity, 4 Maturity, 5 Spawning, 6 Resting, and five for males: 1 Initial spermatogenesis, 2 Maturity, 3 Spawning, 4 Onset of the rest, 5 Resting). Monthly variations in the gonad maturation stages showed that H. princeps has an annual reproductive cycle with a long period of gonadal activity. The spawning season comprised from November to March (females) and from December to March (males) with peaks of activity for both sexes in January. Resting periods of females comprised from March to October and for males May and June. Thus the reproductive events were related to high Chlorophyll concentrations which in turn are due to the upwelling processes resulting from the winds during winter months (November to March). This study provides baseline information that may serve to establish measures for adequate exploitation and for aquaculture implementation of this species in the future. Normal 0 21 false false false ES-MX JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Tabla normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Times New Roman; mso-bidi-theme-font:minor-bidi;}

Contribution to the assessment of the bioecological parameters of Razor clam Solen marginatus on the Moroccan Atlantic coast

Contribution to the assessment of the bioecological parameters of Razor clam Solen marginatus on the Moroccan Atlantic coast

140 Endocrine Profiling in Prepubertal Stallions with Abnormal Testicular Development

The use of anti-Müllerian hormone (AMH) as a biomarker for assessment of male gonadal activity has become increasingly widespread. Aberrant AMH concentration successfully detects cryptorchids or pathologic testes in postpubertal stallions, but the ability to use AMH to identify stallions with testicular pathologies during their prepubertal life has not been analysed so far. The objectives of this work were to (1) assess AMH, testosterone, LH, and FSH dynamics in male horses with or without testicular pathologies during the first year of life; and (2) find a reliable diagnostic approach that would enable the identification of animals that will develop abnormal testes at an early stage. Warmblood colts (n = 16) born from February to May on the same stud farm were used. Blood samples for hormone determinations were collected from birth onwards every 4 weeks until the age of 1 year. At 2 years, testicular development was assessed, total testicular volume calculated. and a blood sample collected. Concentrations of AMH, testosterone, LH, and FSH were determined in all samples; AMH (AL-115, Ansh Laboratories, Webster, TX, USA) and testosterone (DE1559, Demeditec, Kiel-Wellsee, Germany) concentrations were determined by ELISA, whereas LH and FSH concentrations were determined by radioimmunoassay. Statistical analysis (SPSS Statistics 24; IBM/SPSS, Armonk, NY, USA) was performed by ANOVA using a general linear model for repeated measures. In 2 stallions, unilateral cryptorchism, and in other 4 stallions, subnormal total testicular volume (&lt;mean minus SD) were diagnosed at 2 years. Concentrations of AMH, testosterone, and FSH changed over time (P &lt; 0.001) but were similar (P &gt; 0.05) within the first year of life irrespective of testicular morphology and location. Concentration of LH at birth was lower (P = 0.05) in stallions with abnormal testes (0.3 ± 0.2 ng mL−1) than in controls (0.6 ± 0.2 ng mL−1), but did not differ thereafter. At 2 years of age, AMH concentration was higher (P &lt; 0.01) in stallions with abnormal testes (39.7 ± 12.7 ng mL−1) than in controls (8.0 ± 0.2 ng mL−1), but no group differences with regard to LH, FSH, and testosterone existed. There was a low but significant negative correlation between AMH and FSH (P &lt; 0.001, r = –0.24), as well as between AMH and LH (P &lt; 0.05, r = –0.15). Also, testosterone concentration was positively correlated with FSH (P &lt; 0.05, r = 0.18) and LH (P &lt; 0.05, r = 0.16) concentrations. In conclusion, AMH determination can be reliably used from 2 years onwards to identify stallions with abnormal testicular development, but it is inconclusive before puberty. We concluded that LH secretion in the perinatal period is involved in testicular development and descent in the horse.

Expression of two glycoprotein hormone receptors in larval, parasitic phase, and adult sea lampreys

All jawed vertebrates have three canonical glycoprotein hormones (GpHs: luteinizing hormone, LH; follicle stimulating hormone, FSH; and thyroid stimulating hormone, TSH) with three corresponding GpH receptors (GpH-Rs: LH-R, FSH-R, and TSH-R). In contrast, we propose that the jawless vertebrate, the sea lamprey (Petromyzon marinus), only has two pituitary glycoprotein hormones, lamprey (l)GpH and l-thyrostimulin, and two functional glycoprotein receptors, lGpH-R I and II. It is not known at this time whether there is a specific receptor for lGpH and l-thyrostimulin, or if both GpHs can differentially activate the lGpH-Rs. In this report, we determined the RNA expression of lGpH-R I and II in the gonads and thyroids of larval, parasitic phase, and adult lampreys. A highly sensitive dual-label fluorescent in situ hybridization technique (RNAScope™) showed lGpH-R I expression in the ovaries of larval lamprey, and co-localization and co-expression of lGpH-R I and II in the ovaries of parasitic phase and adult lampreys. Both receptors were also highly co-localized and co-expressed in the endostyle of larval lamprey and thyroid follicles of parasitic and adult lampreys. In addition, we performed in vivo studies to determine the actions of lamprey gonadotropin releasing hormones (lGnRHs) on lGpH-R I and II expression by real time PCR, and determined plasma concentrations of estradiol and thyroxine. Administration of lGnRH-III significantly (p ≤ 0.01) increased lGpHR II expression in the thyroid follicles of adult female lampreys but did not cause a significant increase in RNA expression of lGpH-R I and II in ovaries. Concomitantly, there was a significant increase (p ≤ 0.01) of plasma estradiol without any significant changes of plasma thyroxine concentrations in response to treatment to lGnRH-I, -II, or -III. In summary, our results provide supporting evidence that the lamprey pituitary glycoprotein hormones may differentially activate the lamprey GpH-Rs in regulating both thyroid and gonadal activities during each of the three life stages of the sea lamprey.

Effect of Intermittent Feeding on Gonadal Function in Male And Female NMRI Mice During Chronic Stress

ABSTRACT Stress can inhibit gonadal activity via Hypothalamus-Pituitary-Gonad (HPG) axis activity suppression. In the present study, effects of intermittent feeding (IF) on gonadal function under stress in male and female mice were evaluated. Twenty eight male and twenty eight female mice's were divided into four groups. The control group received adequate food and water without stress. The second group received four days of electric shock without food deprivation. The third group was deprived of food two hours/day for a week, and the fourth group was deprived of food (2 hours/day for seven consecutive days) and then electric foot shock stress was applied to them for four days. Blood samples were collected from all animals for plasma testosterone, estrogen and/or Interlukin-6 (IL-6) evaluation. The animals’ gonads were also removed and fixed for the measure of their weight. Results showed that stress reduces both testosterone and estrogen levels, whereas IF did not change the hormone levels. In addition, stress increases blood IL-6 concentration. The combination of IF and stress, increased the hormone levels in animals. Stress and IF alone had no significant effect on gonadal weight in the male mice, whereas stress decreased gonadal weight in the females. Combination of stress with IF increased gonadal weight in both male and female mice. In conclusion stress showed a negative effect on gonadal function in both animals with more effect on females. Intermittent feeding inhibits the stress effect and even promotes the gonadal function in both sexes. The effect may be due to IL-6 reduction.

Changes in urinary androgen concentration indicate that male giant pandas (Ailuropoda melanoleuca) respond to impending female oestrus during and outside the typical spring breeding season.

Giant pandas have been described as mono-oestrus spring breeders, yet males exposed to aseasonal oestrous females in the autumn or winter exhibit breeding behaviours and interest in mating. In the present study, urinary androgens and sperm parameters were quantified for males exposed to females expressing oestrus during spring, autumn or winter to examine plasticity of reproductive seasonality in giant pandas. Monthly average androgen concentrations for two males exposed to females in either seasonal or aseasonal oestrus were greater (P<0.001) than baseline concentrations. Evaluation of daily androgen concentrations revealed a peak that was three- to fivefold greater than baseline, occurring an average of 5 days before ovulation for both seasonal and aseasonal cycles. There were no significant differences in testes volume, sperm motility, forward progression or sperm concentration in males between female seasonal and aseasonal cycle years. Male gonadal activity was more variable without a clear pattern in years when the female was anovulatory than when she was ovulatory (seasonal or aseasonal). These data show the flexible reproductive capacity of male giant pandas as demonstrated by a rapid physiological readiness to mate in response to female oestrous cues within or outside the normal breeding season and may suggest a facultative seasonal reproduction with a 'female-induced rut'.

Effect of melatonin on GnIH precursor gene expression in Nile tilapia, Oreochromis niloticus

Sexual maturation and gonadal development of fish is greatly influenced by photic information, an external environmental factor, and melatonin mediates this information to regulate gonadotropin (GTH) secretion and gonadal activation. The relationship between gonadotropin inhibiting hormone (GnIH) and melatonin in fish, however, has not been studied to date. Here, the GnIH expression pattern and daily change of melatonin levels were compared to each other in mature tilapia (body length 16.1 ± 0.2 cm, body weight 77.7 ± 3.43 g), and the effect of melatonin injection on GnIH gene expression was investigated. GnIH gene expression increased at night when the secretion of melatonin increased, whereas gene expression decreased during the day when melatonin secretion decreased. Injecting tilapia intraperitoneally with melatonin increased GnIH gene expression and decreased the expression of gonadotropin releasing hormone (GnRH) and GTH. Furthermore, the injection decreased the 11-KT concentration in male tilapia. These results indicate that melatonin is likely to suppress the hypothalamus-pituitary-gonad (HPG) axis via the action of GnIH in this species.

Two complementary methods to control gonadotropin-releasing hormone vaccination (Improvac®) misuse in horseracing: Enzyme-linked immunosorbent assay test in plasma and steroidomics in urine.

Since the availability on the European market of the vaccine Improvac® dedicated to male pig immunological castration, the risk of misuse of this product in horses is now considered as a threat for the horseracing industry. Immunological castration is not allowed by the racing codes (immune system, Article 6). Indeed, this vaccination against the hypothalamic hormone luteinizing hormone-releasing hormone or gonadotropin-releasing hormone (GnRH) will prevent the release from the anterior pituitary of luteinizing hormone and follicle stimulating hormone, which are required for the development and activity of gonads in males (testes) and female (ovaries) and therefore all their subsequent physiological functions. This treatment will induce a strong hormonal variation resulting in a behaviour modification of the animals. In this work, four male standardbreds treated with Improvac® vaccine (two intramuscular injections within 4weeks) were studied. Monitoring of the total scrotal width showed a decrease of the scrotum size (37%) and production of anti-GnRH antibodies was detected up to 200days after the first injection. Anti-GnRH antibodies were detected in plasma after caprylic acid precipitation followed by an enzyme-linked immunosorbent assay (ELISA) as a rapid and efficient screening method applicable to routine analysis. These results were correlated to a switch of the sexual status from male group to gelding/female group obtained by a steroidomic approach with urine based on ten endogenous compounds. Copyright © 2017 John Wiley & Sons, Ltd.

Effects of Photoperiod Manipulation on Gonadal Activity of the Damselfish, Chromis notata.

ABSTRACTThis study investigated the effect of different photoperiods (14L: 10D, 12L:12D and 10L:14D) on the gonadal development and GtH mRNA expression in the pituitary of damselfish. The results showed that gonadosomatic index (GSI) was significantly lower in shot photoperiod (10L:14D), in comparison with other photoperiodic group during the spawning season. After 60 days treatment, histological analysis of gonad tissue showed that the gonad of 10L:14D and 12L: 12D treatment groups were resting phase with spermatogonia and perinucleolus stage oocytes but the gonad of 14L:10D treatment group was still ripe phase with spermatozoa and mature stage oocyte. The FSHβ and LHβ mRNA expression in pituitary drastically decreased shot photoperiod treatment from July (spawning period). These results suggest that photoperiod is considered to be the most effective environmental factor in controlling the reproductive cycle of damselfish.

Prediction of Cortisol and Progesterone Concentrations in Cow Hair Using Near-Infrared Reflectance Spectroscopy (NIRS).

Concentrations of different steroid hormones have been used in cows as a measure of adrenal or gonadal activity and, thus, as indicators of stress or reproductive state. Detecting cortisol and progesterone in cow hair provides a long-term integrative value of retrospective adrenal or gonadal/placental activity, respectively. Current techniques for steroid detection require a hormone-extraction procedure that involves time, several types of equipment, management of reagents, and some assay procedures (which can also be time-consuming and can destroy the samples). In contrast, near-infrared reflectance spectroscopy (NIRS) is a multi-component predictor technique, characterized as rapid, nondestructive for the sample, and reagent-free. However, as a predictor technique, NIRS needs to be calibrated and validated for each matrix, hormone, and species. The main objective of this study was to evaluate the predictive value of the NIRS technique for hair cortisol and progesterone quantification in cows by using specific enzyme immunoassay as a reference method. Hair samples from 52 adult Friesian lactating cows from a commercial dairy farm were used. Reflectance spectra of hair samples were determined with a NIR reflectance spectrophotometer before and after trimming them. Although similar results were obtained, a slightly better relationship between the reference data and NIRS predicted values was found using trimmed samples. Near infrared reflectance spectroscopy demonstrated its ability to predict cortisol and progesterone concentrations with certain accuracy (R2 = 0.90 for cortisol and R2 = 0.87 for progesterone). Although NIRS is far from being a complete alternative to current methodologies, the proposed equations can offer screening capability. Considering the advantages of both fields, our results open the possibility for future work on the combination of hair steroid measurement and NIRS methodology.