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PubMed1999

Control of ovarian follicles activity in the ewe.

During the ovine estrous cycles, three waves of follicular growth, closely associated with the FSH secretion pattern, were observed. The parameters of these follicular waves and the ability of follicles to produce steroids in vitro were studied in various conditions. In vivo, the follicular events were similar between the breeding season and the anestrus, except for the lack of ovulation; but at the end of the breeding season and in anestrus, the follicles lose a big part of their aromatization ability. In ewes carrying the Booroola fecundity gene or Cambridge fecundity gene, the reduction in follicular atresia seems to be one of the main follicular features implicated in the control of high ovulation rate. In vitro, the most relevant difference is an early acquisition of estrogen production ability of small follicles in Booroola fecundity gene barring ewes. Fluoro-gestone-acetate (FGA) pessaries reduced the number of growing follicles; despite this effect disappearing after the sponge withdrawal, the ovulation rate is significantly reduced. But an equine chorionic gonadotrophin (eCG) treatment restores the ovulation rate (OR) by reducing the atresia rate of pre-ovulatory follicles. In similar conditions, a pretreatment of the ewes with melatonin again reduced the atresia rate of large follicles and resulted in an increased ovulation rate. In vitro, FGA blocked aromatization ability, and melatonin inhibited both androstenedione and estradiol production, but a further treatment with eCG partly restores the steroid secretion. Immunization against androstenedione leads to a higher OR, owning to a reduced atresia of large follicles. Daily growth hormone injections for a hole cycle resulted in an increased follicular population and ovulation rate, while FSH plasma levels decreased and the follicle sensitivity to gonadotrophins was reduced.

Androstenedione↗
PubMed2003

Effects of ecdysone agonists on the expression of EcR, USP and other specific proteins in the ovaries of the codling moth (Cydia pomonella L.).

Tebufenozide and methoxyfenozide have been previously shown to significantly reduce fecundity and cause vitellogenin accumulation in hemolymph of the codling moth Cydia pomonella L. In the present study, the effects of these ecdysone agonists, tebufenozide and methoxyfenozide, on the expression of ecdysone receptor (EcR), ultraspiracle protein (USP) and other proteins in the ovaries of C. pomonella L., were investigated at both the translational and/or transcriptional levels with an aim to elucidate the mechanisms by which the fecundity was reduced. Western and Northern blot analyses revealed that the expression of a 65 kDa (p65) EcR, and 60 and 64 kDa (p60 and p64) USP proteins were enhanced by tebufenozide and methoxyfenozide at both transcriptional and translational levels. Northern blot analysis indicated that the p65 EcR protein is encoded by EcRB1 transcript and that the p60 and p64 USP bands were the products of USP-1 transcript. Immunoprecipitation assays demonstrated that both the p60 and p64 USP coprecipitated with the p65 EcR and that p64 was a dominant USP to form complex with EcR. In addition, several other specific proteins were also identified and their expressions affected by the agonists. The data suggest that the ecdysone agonists regulate, via the EcR/USP complex, the expression of these specific proteins that might eventually lead to the inhibition of fecundity in the codling moth.

Animals↗
PubMed2002

Genomic plasticity, energy allocations, and the extended longevity phenotypes of Drosophila.

The antagonistic pleiotropy theory of the evolution of aging is shown to be too simple to fully apply to the situation in which Drosophila are selected directly for delayed female fecundity and indirectly for extended longevity. We re-evaluated our own previously reported selection experiments using previously unreported data, as well as new data from the literature. The facts that led to this re-evaluation were: (1) the recognition that there are at least three different extended longevity phenotypes; (2) the existence of metabolic and mitochondrial differences between normal- and long-lived organisms; and most importantly; (3) the observation that animals selected for extended longevity are both more fecund and longer-lived than their progenitor control animals. This latter observation appears to contradict the theory. A revised interpretation of the events underlying the selection process indicates that there is a two-step change in energy allocations leading to a complex phenotype. Initial selection first allows the up-regulation of the antioxidant defense system genes and a shift to the use of the pentose shunt. This is later followed by alterations in mitochondrial fatty acid composition and other changes necessary to reduce the leakage of H(2)O(2) from the mitochondria into the cytosol. The recaptured energy available from the latter step is diverted from somatic maintenance back into reproduction, resulting in animals that are both long-lived and fecund. Literature review suggests the involvement of mitochondrial and antioxidant changes are likely universal in the Type 1 extended longevity phenotype.

Aging↗
PubMed1995

Slow twin conception at first birth and subsequent maternal twin proneness in a natural fertility population.

To study whether apparently more fecund women having delivered twins at first birth have traits of higher twin-proneness, we performed a retrospective cohort study on population-based historical vital records of the 17-18th century French Canadian immigrants and their descendants under natural fertility conditions. Among 24896 mothers who had at least one child, 248 had twin maternities at their first birth (twinning rate = 1.0%). Among 21508 mothers with a valid marriage-first birth interval, twinning rate was 0.97% among prompt conceptions (7.0-11.0 months), with a particularly high rate at the interval of 7.0-8.0 months (2.2%). Marriages in August-October resulted in a higher twinning rate particularly for the slow conceptions than those in the other seasons. Promptly-conceived mothers of twins at the first delivery may seem to have higher fecundity, but subsequent births from these mothers (n = 88) show a lower twinning rate (1.7%) particularly at younger maternal age than from the other mothers who had slowly conceived twins at their first birth (n = 112). The latter show a 4.5% twinning rate as a whole among their second or later births. So-called twin-proneness of a mother, whether genetic or acquired, was not connected to higher conception rate of twin's mothers immediately after marriage. Reduced fecundity, which may have been imposed by some environmental factors, could raise the chance of twinning.

Adult↗
PubMed1987

Cortisone-sensitive, innate resistance to Hymenolepis nana infection in congenitally athymic nude rats.

The innate resistance of the unnatural rat host to the mouse tapeworm Hymenolepis nana is cortisone sensitive but thymus independent. When congenitally athymic nude rats were orally given eggs, cysticercoids, or adult worms of H. nana, no lumenal adults were established except when they were treated with cortisone acetate during the expected lumenal development. The effect of cortisone to promote adult maturation in the rats was compared in nude and normal rats given eggs of H. nana. The fecundity of the worms (assessed by the fresh worm biomass and the number of infective eggs produced) was much higher in cortisone-treated nude rats than in cortisone-treated normal rats. When the nude rats reconstituted with thymocytes were given eggs and treated with cortisone, the fecundity of H. nana dropped to the same level as in cortisone-treated normal rats. It is strongly suggested that the unnatural rat host has thymus-independent cortisone sensitive resistance to an initial infection (which is the main component of the innate resistance and blocks the lumenal establishment of this parasite) and thymus-dependent resistance (which suppresses the established worms' fecundity and may be ascribed to acquired resistance to the ongoing infection).

Animals↗
PubMed2000

Population growth of Gyrodactylus salaris (Monogenea) on Norwegian and Baltic Atlantic salmon (Salmo salar) stocks.

Reproductive success of Gvrodactylus salaris from River Lierelva was compared experimentally on 3 stocks of salmon (12.5 degrees C +/- 0.2). Isolated fish from 2 susceptible Norwegian stocks (Rivers Lier and Alta) and 1 resistant Baltic stock of salmon (River Neva) were infected with a single gravid worm in order to record the temporal sequence of births and age at death of individual parasites. Establishment success (proportion of worms surviving to give birth) was generally low and mortality high, but significantly fewer worms survived on Neva (45% with mean survival of 3.5 days) compared to Alta and Lier fish (60 % mean survival 7.9 and 5.2 days, respectively). There was a dramatic difference in parasite fecundity between the host stocks: only 2 births occurred on Neva fish compared to third and fourth births on both Alta and Lier hosts. The timing of the first birth was more variable on Neva hosts and was significantly extended (mean 2.3 days) relative to that on Alta and Neva fish (1.8 days). However, timing of the second birth did not vary on any of the 3 salmon stocks. Age-specific mortality and fecundity data are consistent with exponential population growth of G. salaris on Alta and Lier fish but eventual extinction on Neva hosts. This is the first demonstration that gyrodactylids maintained on different host stocks exhibit variations in fecundity, development and mortality, which may in turn account for the variable virulence noted when G. salaris infects different salmonid hosts.

Age Factors↗
PubMed1983

Retarded development of Schistosoma mansoni in immunosuppressed mice.

Previous observations, which showed that treatment of mice with hydrocortisone acetate around the time of their infection with Schistosoma mansoni reduced the mature worm burden, have been confirmed. The number of eggs produced by the surviving worms during early patency was also significantly reduced. Cyclophosphamide and another steroid immunosuppressant, betamethasone, also caused a reduction in fecundity of S. mansoni when given at the time of infection, as did T-cell deprivation of the mice by adult thymectomy and injection of anti-thymocyte serum 1 month before infection. There was no effect of these three treatments on worm numbers. In contrast, injection of mice with anti-thymocyte serum at the time of infection marginally increased the size of the mature worm burden. The deleterious effects of hydrocortisone acetate on S. mansoni worm numbers and fecundity were only apparent if the steroid was given within 1 week of infection. Indomethacin, a compound which inhibits tissue inflammatory reactions by inhibiting prostaglandin synthesis, and which therefore mimics one of the actions of corticosteroids, had no effect on S. mansoni worm maturation and fecundity.

Adrenal Cortex Hormones↗
PubMed1995

Plasmodium yoelii nigeriensis: the effect of high and low intensity of infection upon the egg production and bloodmeal size of Anopheles stephensi during three gonotrophic cycles.

Anopheles stephensi mosquitoes showed a reduction in fecundity over 3 successive gonotrophic cycles, after becoming infected with Plasmodium yoelii nigeriensis. This effect could be observed at high oocyst burdens (> 75) or at low oocyst burdens (mean of 4.36). Mean bloodmeal size of the infected mosquitoes was significantly reduced only when feeding upon a mouse with a high gametocytaemia and the conversion of the bloodmeal into eggs by the infected mosquitoes was disrupted. Patterns of infected mosquito mortality, over the 3 gonotrophic cycles, varied with severity of infection. Although in 1 case increased mortality and decreased bloodmeal size may have affected fecundity, this could not have accounted for all of the observed fecundity reduction. We propose that other, unknown parasite related factors, are involved.

Animals↗
PubMed2004

The effect of the host immune response on the parasitic nematode Strongyloides ratti.

The host immune response has profound effects on parasitic nematode infections. Here we have investigated how a range of infection parameters are affected by host immune responses and by their suppression and enhancement. The infection parameters considered were the number of parasitic females, their size, per capita fecundity and intestinal position. We found that in immunosuppressive treatments worms persist in the gut, sometimes with a greater per capita fecundity, maintain their size and have a more anterior gut position, compared with worms from control animals. In immunization treatments there are fewer worms in the gut, sometimes with a lower per capita fecundity and they are shorter and have a more posterior gut position, compared with worms from control animals. Worms from animals immunosuppressed by corticosteroid treatment reverse their changes in size and gut position. This description of these phenomena pave the way for a molecular biological analysis of how these changes in infection parameters are brought about by the host immune response.

Animals↗
PubMed2003

Lifespan extension of Drosophila melanogaster through hormesis by repeated mild heat stress.

We assessed the impact of repeated episodes of a mild heat stress on lifespan, fecundity, heat stress resistance and Hsp70 expression in Drosophila melanogaster. There was a significant increase in lifespan of females repeatedly exposed to a mild heat stress when measured in both a pair and a group situation. There was no effect on fecundity when the flies were first exposed to the mild heat stress at an age later than 3 days old, but when it did occur on day 3, there was a significant effect on cumulative fecundity levels over 18 days. The negative fitness effect appears to be the result of a direct cessation or reduction of oviposition during the first bout of stress exposure, and is influenced by the age at which this first exposure occurs. The mild heat stress had no impact on egg viability. The mild heat stress exposures increased resistance to potentially lethal heat stress and levels of Hsp70 expression in heat-exposed flies were higher than those in controls.

Adaptation, Physiological↗
PubMed2003

The biology of Oreochromis niloticus in a polluted canal.

In the present investigation, length-weight relationship, condition factor, age, growth, mortality, gonadosomatic index (GSI) and fecundity of tilapias (Bolti in Arabic): Oreochromis niloticus, from Shanawan drainage canal (SDC), Al-Minufiya Province, Egypt, were studied. This was carried out on 162 fish samples collected during the period from April 1992 to May 1993. Oreochromis niloticus was found to attain sexual maturity early (8-9 cm), was more fecund (1,234-3,893) and has high mortality rates (91% for males and 94% for females). A comparison of the various parameters of O. niloticus from SDC with those of other authors in different localities and times in Egypt revealed year-to-year and geographically significant differences in relation to variation in weight with length, condition factor, fecundity, growth and mortality rates. These differences were discussed and were found to be attributed to the effect of eutrophication and pollution on the growth, age and other biological aspects of O. niloticius. Multiple regression analysis showed that only female GSI correlated significantly with pesticides and heavy metals contamination.

Animals↗
PubMed1992

Remating effects on the genetic structure of female life histories in populations of Drosophila mojavensis.

A quantitative genetic analysis of nine adult fitness components was performed in two populations of cactophilic Drosophila mojavensis under natural conditions of fermenting cactus and ethanol vapour. Female progeny from 18 sires and 36 dams were treated to a range of six exposure periods to males to assess effects of remating frequency on female fitness. Lifetime fecundity increased with increasing male exposure, but longevity showed an intermediate optimum with temporary exposure to males of 2-4 days. Narrow-sense heritabilities were significant for egg production traits while broad-sense heritabilities were significant for longevity-related traits. Positive genetic correlations between components of fitness were expressed among functionally related traits, e.g. longevity was positively correlated with lifetime fecundity, the number of clutches laid, clutch size, and the number of eggs laid per day. Negative genetic correlations were detected between early and late life fecundity suggesting genetic tradeoffs among components of adult fitness.

Animal Nutritional Physiological Phenomena↗
PubMed2004

Intergenomic interactions affect female reproduction: evidence from introgression and inbreeding depression in a haplodiploid mite.

Nuclear and cytoplasmic genomes can coevolve antagonistically or harmoniously to affect fitness. One commonly used test for nuclear-cytoplasmic coadaptation relies on the breakup of coadapted gene complexes by introgression, potentially resulting in an increased frequency of nuclear alleles in deleterious interaction with an alien cytoplasm. We investigated the phenotypic effect of such genes on female reproduction in outbred and inbred introgressed lines of the haplodiploid mite Tetranychus urticae. Introgression changed female lifetime fecundity and increased male production, in ways suggesting a control of fecundity by nuclear genes. Conversely introgression reduced the fertilization rate, possibly due to sperm-egg incompatibility or maternal effects. The intensity of inbreeding depression expressed as a reduction in fecundity was more severe in introgressed females than in nonintrogressed ones, giving evidence for recessive interacting alleles contributing to residual nucleo-cytoplasmic incompatibility. Overall, our data suggest recessive negative interactions between nuclear and cytoplasmic genes. This study is the first report of a contribution of nuclear polymorphism within a population to deleterious interactions with an alien cytoplasmic genome.

Animals↗
PubMed1999

Definition and mapping of epitopes recognized by specific monoclonal antibodies to Schistosoma bovis 28 kDa glutathione S-transferase: relation with anti-egg viability immunity.

Monoclonal antibodies to the 28kDa glutathione S-transferase of Schistosoma bovis have been constructed in mice and used to characterize the epitope(s) potentially implied in the induction of anti-fecundity and anti-egg viability immune responses. Among the MoAbs produced three were particularly studied: Sb4-50 (IgG2a) and Sb4-56 (IgG1) which inhibited Sb28GST activity and Sb4-10 (IgG1) which did not. The use of overlapping peptides covering the entire amino acid sequence of Sb28GST, allowed us to define the linear epitopes recognized by these anti-Sb28GST MoAbs. Amino acid residues 202-211 were recognized by both MoAbs Sb4-50 and Sb4-56 and MoAb Sb4-10 recognized amino acid residues 58-67. Their capacity to inhibit GST activity suggested binding to the active site or to neighbouring regions, which include the C-terminal domain (a.a. 190-211) of the protein. When passively transferred into BALB/c mice MoAbs induced a significant reduction in egg hatching and an increase in immature eggs. Effects on worm burdens were, however, variable and no clear-cut association between the inhibition of enzyme activity and anti-fecundity or anti-viability activities was recorded. Our data indicate that beside the anti-fecundity and anti-viability immunity related to the impairment of GST activity, immune response to epitopes located in other regions of the molecule also contribute to the reduction of egg viability.

Amino Acid Sequence↗
PubMed2003

Phenotypic plasticity and the evolution of trade-offs: the quantitative genetics of resource allocation in the wing dimorphic cricket, Gryllus firmus.

In the wing dimorphic sand cricket, Gryllus firmus, there is a pronounced trade-off between flight capability and fecundity. This trade-off is found both between morphs and within the macropterous morph, in which fecundity is negatively correlated with the mass of the principle flight muscles, the dorso-longitudinal muscles (DLM). In this paper, we examine how this trade-off is affected by a reduction in food and its genetic basis. We find that the relative fitness of the two wing morphs is not changed although both fecundity and DLM mass are decreased. A quantitative genetic analysis shows that the trade-off function is genetically variable but that most of the variation occurs in the intercept rather than the slope of the function. Analysis further indicates a very high genetic correlation between environments (food ration) supporting the hypothesis of a strong functional constraint between reproduction and flight capability.

Analysis of Variance↗
PubMed2003

Improving the reproductive efficiency, pregnancy diagnosis and monitoring the resumption of luteal activity in indigenous damascus goats.

Seventy-five female Damascus goats aged between 1.5 and 5.5 years were used to evaluate the effectiveness of the intravaginal sponges and prostaglandin analogue on oestrous synchronization and fecundity; to diagnose pregnancy and to monitor the resumption of the luteal activity. Females were divided randomly, during the breeding season, into three equal groups, S, P and C. Females in group S were fitted with sponges containing 45 mg of flugestone acetate (FGA) for 14 days and injected with pregnant mare serum gonadotrophin (PMSG) at the sponge withdrawal. Females in group P were given two injections of prostaglandin F2alpha analogue at 11-day intervals, whereas females in group C (control) received no treatment. The results showed that there was a significant difference (p < 0.001) in oestrous exhibition between females in group S as compared with those in groups P and C, with means being 30 +/- 10, 172 +/- 115 and 217 +/- 75 h for groups S, P and C, respectively. Kidding rates resulting from the first and all matings were 80 and 88, 52 and 88, and 68 and 80% for groups S, P and C, respectively. Fecundity rates were 215, 175 and 180% for groups S, P and C, respectively, with a significant difference (p < 0.05) between the S and both P and C groups. Using an ultrasound pregnancy detector performed on days 57 +/- 3 after mating, positive pregnancy diagnosis was 93.3% and 100% for non-pregnancy. Females in the control group showed functional corpus luteum starting in September. It is concluded that FGA sponges plus PMSG treatment could be successfully used to synchronize oestrus and improve fecundity; whereas prostaglandin treatment was not effective to synchronize oestrus. It is also concluded that pregnancy can be diagnosed accurately and successfully using an ultrasound pregnancy detector. In addition, ovarian activity in the Damascus goat in Syria resumes in September.

Administration, Intravaginal↗
PubMedDate not supplied

Effects of condensed tannins on established populations and on incoming larvae of Trichostrongylus colubriformis and Teladorsagia circumcincta in goats.

The use of tanniferous plants or tannins represents one alternative approach to the control of gastrointestinal parasites in ruminants but most data have been obtained in sheep. The current study was therefore performed in goats with two objectives: firstly, to investigate the effects of condensed tannins (CT) on adult populations of Trichostrongylus colubriformis and Teladorsagia circumcincta; secondly, to examine their effects on the establishment of infective larvae of these two species. In experiment 1, two groups of kids were infected with 6 000 L3 of T. colubriformis and 6 000 L3 of T. circumcincta. After 7 weeks, quebracho extracts were administered per os for 8 days to one group. A comparable group which did not receive tannins was included as the control. The kids were slaughtered on week 11. Parasitological and pathophysiological parameters were measured weekly. Worm counts were assessed and mast cells, globule leukocytes and eosinophils were counted in the abomasal and intestinal mucosae. Tannin administration was associated with a decrease in egg excretion, and a decrease in female fecundity, but with no changes in worm numbers. These changes were associated with an increased number of intestinal mast cells. In experiment 2, 24 goats were used according to a 2 x 2 factorial design, depending on infection and tannin administration. Two groups were either infected with 6 000 L3 of T. colubriformis or T. circumcincta. Within each group, the goats were either drenched or undrenched with tannin extracts. Pathophysiological parameters were measured weekly. Twelve days after the cessation of tannin administration, the goats were slaughtered. Worm counts and female worm fecundity were determined. Tannin consumption was associated with a significant reduction (P < 0.01) of Trichostrongylus populations and a close to significant reduction for Teladorsagia. No effect on fecundity was observed. Our results (1) confirm the consequences of condensed tannins on nematodes in goats as in sheep and (2) indicate divergent effects depending on the parasitic stage exposed to the condensed tannins.

Abomasum↗
PubMed1997

Laparoscopic surgery in infertile women with minimal or mild endometriosis. Canadian Collaborative Group on Endometriosis.

BACKGROUND: Minimal or mild endometriosis is frequently diagnosed in infertile women. It is often treated by resection or ablation of the lesions, but whether this improves fertility has not been established. We carried out a randomized, controlled trial to determine whether laparoscopic surgery enhanced fecundity in infertile women with minimal or mild endometriosis. METHODS: We studied 341 infertile women 20 to 39 years of age with minimal or mild endometriosis. During diagnostic laparoscopy the women were randomly assigned to undergo resection or ablation of visible endometriosis or diagnostic laparoscopy only. They were followed for 36 weeks after the laparoscopy or, for those who became pregnant during that interval, for up to 20 weeks of pregnancy. RESULTS: Among the 172 women who had resection or ablation of endometriosis, 50 became pregnant and had pregnancies that continued for 20 weeks or longer, as compared with 29 of the 169 women in the diagnostic-laparoscopy group (cumulative probabilities, 30.7 percent and 17.7 percent, respectively; P=0.006 by the log-rank test). The corresponding rates of fecundity were 4.7 and 2.4 per 100 person-months (rate ratio, 1.9; 95 percent confidence interval, 1.2 to 3.1). Fetal losses occurred in 20.6 percent of all the recognized pregnancies in the laparoscopic-surgery group and in 21.6 percent of all those in the diagnostic-laparoscopy group (P=0.91). Four minor operative complications (intestinal contusion, slight tear of the tubal serosa, difficult pneumoperitoneum, and vascular trauma) were reported (three in the surgery group and one in the control group). CONCLUSIONS: Laparoscopic resection or ablation of minimal and mild endometriosis enhances fecundity in infertile women.

Adult↗