Papers by Sylvaine Camous
Reproduction Nutrition Développement, 1983
Background: Since the first success in sheep, the production of viable cloned offspring by somati... more Background: Since the first success in sheep, the production of viable cloned offspring by somatic cell nuclear transfer (SCNT) in various mammals has increased significantly. The incidence of pregnancy failure and fetal death, however, is still very high, whatever the species, and impairs the commercial development of this technology, even in the bovine species where the success rates are highest compared to other species. Review: In cattle, most gestation losses are initially due to abnormal implantation and poor placental development leading to fetal demise during the early post-implantation period (30 to 70 days of pregnancy). Thereafter, in continuing pregnancies, los ses usually occur in the last third of gestation and affect about 25% of the on-going pregnancies, with very large differences according to phenotype. These are currently referred to as the Large Offspring Syndrome (LOS), Large Placenta Syndrome or Abnormal Offspring Syndrome. In all cases, the placenta appears to...
Theriogenology, 1984
Early bovine embryos (1to 8-cell stages) were recovered from superovulated heifers at slaughter o... more Early bovine embryos (1to 8-cell stages) were recovered from superovulated heifers at slaughter on Days 2 or 3. Embryos were cultured for 3\p=n-\4 days in Medium B2 supplemented with 15% (v/v) fetal calf serum in the absence (B2SS, 106 embryos) or presence of trophoblastic vesicles (B2SS + TV, 190 embryos).
Animal Production Science, 2014
There is ample evidence on the importance of maternal nutrition during pregnancy on fetal and off... more There is ample evidence on the importance of maternal nutrition during pregnancy on fetal and offspring development. In ruminant females, the pool of oocytes is complete and definitive before birth, based on the resting reserve of primordial follicles established during fetal life, which represent the lifespan supply for the female's fertilisable oocytes, whereas in males, although the production of spermatozoa is a continuous process throughout post-pubertal life. Sertoli cells, which play a central role in the development of a functional testis, proliferate during pre-and post-natal life, coordinating testicular development. Both male and female fertility may, therefore, be affected by the maternal environment, but studies on the effects of developmental nutritional conditions on reproductive function and fertility, both in males and females, are relatively scarce. In humans, intrauterine growth retardation has been associated with abnormal ovarian development, characterised by a decreased volume of primordial follicles in the ovarian cortical tissue in girls, and a higher incidence of cryptorchidism in boys, with subsequent low sperm counts in adulthood. Age at puberty and gonadotropin and inhibin B plasma concentrations are also affected. Animal studies suggest both in males and females that maternal undernutrition during pregnancy may affect pituitary response to GnRH and gonadal development and function, depending on the timing and magnitude of the undernutrition. Excess nutrition, which is often associated with intrauterine growth retardation in domestic species, induces effects on the onset of puberty and both testicular and ovarian function, maybe through the observed reduction in fetal growth. This review addresses the influence of maternal nutrition on offspring reproductive function using examples in humans and animals, with particular focus on ruminants.
PLOS ONE, 2015
In stud management, broodmares are commonly fed concentrates in late pregnancy. This practice, ho... more In stud management, broodmares are commonly fed concentrates in late pregnancy. This practice, however, was shown to correlate with an increased incidence of osteochondrosis in foals, which may be related to insulin sensitivity. We hypothesized that supplementation of the mare with barley in the last trimester of pregnancy alters the pre-weaning foal growth, glucose metabolism and osteoarticular status. Here, pregnant multiparous saddlebred mares were fed forage only (group F, n=13) or both forage and cracked barley (group B, n=12) from the 7 th month of pregnancy until term, as calculated to cover nutritional needs of broodmares. Diets were given in two daily meals. All mares and foals returned to pasture after parturition. Post-natal growth, glucose metabolism and osteoarticular status were investigated in pre-weaning foals. B mares maintained an optimal body condition score (>3.5), whereas that of F mares decreased and remained low (<2.5) up to 3 months of lactation, with a significantly lower bodyweight (-7%) than B mares throughout the last 2 months of pregnancy. B mares had increased plasma glucose and insulin after the first meal and after the second meal to a lesser extent, which was not observed in F mares. B mares also had increased insulin secretion during an intravenous glucose tolerance test (IVGTT). Plasma NEFA and leptin were only temporarily affected by diet in mares during pregnancy or in early lactation. Neonatal B foals had increased serum osteocalcin and slightly increased glucose increments and clearance after glucose injection, but these effects had vanished at weaning. Body measurements, plasma IGF-1, T 4 , T 3 , NEFA and leptin concentrations, insulin secretion during IVGTT, as well as glucose metabolism rate during euglycemic hyperinsulinemic clamps after weaning, did not differ between groups. Radiographic examination of joints indicated increased osteochondrosis relative risk in B foals, but this was not significant. These PLOS ONE |
Veterinary parasitology, Jan 31, 2013
The objective of this study was to compare the effects of the type of Haemonchus contortus experi... more The objective of this study was to compare the effects of the type of Haemonchus contortus experimental infection (trickle infection, TI versus single infection, SI) on feed intake, nutrients digestibility, parasitological and haematological measures, and plasma leptin in Creole kids. The animals were infected over 2 periods (challenge 1 and challenge 2) of 6 weeks each, corresponding respectively to the primary and the secondary infection. Periods prior infection (1 week each) were considered as controls. The primary infection was realized with 35 Creole kids (18.40±3.76 kg BW) housed in individual boxes and fed a hay-based diet. The secondary infection continued with 29 kids (21.90±3.40 kg BW) from the initial 35. A total of 6 kids and 8 kids were slaughtered for measuring nematode burden at the end of the primary and the secondary infection, respectively. Measurements of nutrients digestibility were made at 0, 3 and 5 weeks post-infection for both challenges. Faecal egg count (FE...
Reproduction, nutrition, development, 1993
In order to have a specific marker for studying pregnancy in cattle we examined the characteristi... more In order to have a specific marker for studying pregnancy in cattle we examined the characteristics of a pregnancy serum protein produced by the placenta (PSP60). Its profile in peripheral blood was determined by radioimmunoassay in pregnant cows of 3 breeds after artificial insemination (AI): Charolais (n = 24), Normande (n = 24) and Holstein (n = 26). From 27 d post-AI to the end of pregnancy the plasma PSP60 concentration increased, especially during the last 2 wk, to reach a peak a few d before calving, which was higher (P < 0.001) in the Charolais (1,238 +/- 422 ng/ml) than in the other breeds (528 +/- 458 and 444 +/- 204 ng/ml). With an apparent half-life of approximately 8 d, this protein was still detectable in the maternal blood from 105, 85 and 87 d post-partum in the Charolais, Normande and Holstein breeds, respectively. Fertility results on 1,102 inseminations in the Charolais breed showed that the PSP60 concentration dropped then disappeared after embryonic mortality...
Reproduction Nutrition Development, 1994
― The accuracy and efficiency of pregnancy diagnoses in cattle by pregnancy serum protein ... more ― The accuracy and efficiency of pregnancy diagnoses in cattle by pregnancy serum protein (PSP60) radioimmunoassay, a progesterone radioimmunoassay or oestrus detection were compared. Blood samples were taken from 349 suckling heifers and cows (1 191 inseminations) at 28, 35, 50 and 90 d post-insemination for PSP60 determination and at 22-23 d for progesterone. Females were declared nonpregnant when plasma PSP60 concentration was lower than 0.2 ng/ml at 28, 35 and 50 d and 0.5 ng/mi at 90 d. When compared with rectal palpation at 90 d, the accuracy of positive (negative) diagnoses by progesterone assay was 80% (100%) in heifers and 75% (99%) in cows. The accuracy of positive diagnoses by PSP60 assay increased with gestation stage from 90% on d 28 in heifers (74% in cows) to 100% (99% in cows) at the time of rectal palpation. This accuracy was 84% on d 28 in cows when the interval from calving to blood sampling was higher than 115 5 d. Whatever the stage, the accuracy of negative diagnoses was higher than 90%. Efficiency in detecting pregnant or nonpregnant females on d 28 was equivalent to the progesterone assay. The method for detecting oestrus applied in this experiment was as efficient as the PSP60 or progesterone test at any stage of gestation. The PSP60 test is very flexible, which makes its use particularly interesting in naturally mated suckling herds because of the uncertainty regarding the date of fertili-
Domestic Animal Endocrinology, 2015
Effects of parity (primiparous, PRIM vs multiparous, MULT) and litter size (singletons, SING vs t... more Effects of parity (primiparous, PRIM vs multiparous, MULT) and litter size (singletons, SING vs twins, TWIN) on metabolic profiles from 1 wk before lambing to the end of lactation were studied in 48 Lacaune dairy ewes reared in confinement during most of the year and grazed on improved pastures at the end of lactation (summer). Another group of 48 ewes was incorporated during the milking period (ie, from 1 wk after weaning), to measure the effects of milking frequency (1 vs 2 milkings per day) on intake, milk production and composition, and body energy usage. Thus, in a 2 Â 2 Â 2 factorial design, ewes (n ¼ 96) were allocated to homogeneous groups according to body weight (BW) and body condition score (BCS) and were monitored from late pregnancy to late lactation as a function of parity (PRIM, n ¼ 48; MULT, n ¼ 48), litter size (LSi) (SING, n ¼ 40; TWIN, n ¼ 56) and daily milking frequency (FREQ; milked once, ONE; n ¼ 48; or twice, TWO; n ¼ 48). Individual BW, BCS, plasma metabolites, and metabolic hormones were measured regularly (ie, 9 consecutive sampling dates). The BW was higher in MULT but no differences because of LSi or FREQ were detected at the intra-parity group level. The BCS was higher in MULT and in ewes with SING throughout the experiment. The latter was related to the demands for body reserves mobilization, as expressed by higher nonesterified fatty acids and bhydroxybutyrate concentrations in ewes with TWIN from late pregnancy to weaning (35 d postpartum) in both PRIM and MULT ewes. This was consistent with higher insulin in MULT and higher triiodothyronine, leptin and insulin-like growth factor 1 in ewes with SING during this period. Differences in energy balance because of FREQ were evident after interpretation of plasma nonesterified fatty acids, glucose, insulin, and leptin concentration during the milking period. At similar feed intakes, ewes in ONE were in positive balance with regard to TWO. Overall, clear effects of parity, LSi, physiological states, and FREQ on metabolic profiles were found because of differences in nutrient partitioning when combining these experimental factors. Without considering FREQ, changes in metabolic measures in milking period were marginal compared with the periparturient adjustments performed until weaning to compensate energy deficiencies.
Canadian Journal of Physiology and Pharmacology, 2003
Aspirin consumption has been reported to be able to reduce colorectal cancer risk in humans and i... more Aspirin consumption has been reported to be able to reduce colorectal cancer risk in humans and in animal models of colon carcinogenesis. Although the mechanism involved in such an effect is not yet clear, both prostaglandin-dependent and -independent effects have been proposed. Using HT-29 Glc(-/+)cells, which originate from a human colon adenocarcinoma, we demonstrated in this study a dose-dependent effect of millimolar concentration of aspirin on cell growth that was concomitant with a rapid accumulation of the cells in the G0/G1 phase, followed by an accumulation in the G2/M phase and by a minor increase in the proportion of cells undergoing nuclear condensation. Cell membrane integrity and cell release into the culture medium were not affected by this treatment. The aspirin effects were apparently unrelated to prostaglandin biosynthesis inhibition, since although these cells were found to express high levels of cyclooxygenase 1 (COX-1) and low levels of COX-2 proteins, they did not produce any measurable net amounts of prostaglandins, based on both utilization of radiolabelled arachidonic acid and the radioimmunoassay of prostaglandins E2 and F2 alpha. In contrast, we identified polyamine biosynthesis as a cellular target of aspirin, since the treatment of HT-29 Glc(-/+) cells with aspirin reduced the flux of L-ornithine through ornithine decarboxylase, an effect that could not be explained by an acute action of the drug on the ornithine decarboxylase catalytic activity. Since polyamine biosynthesis is strictly necessary for HT-29 cell growth, our data suggest that reduced flux through ornithine decarboxylase may participate in the antiproliferative activity of aspirin towards colonic tumoral cells. It is concluded that in HT-29 Glc(-/+) cells that are not functional for prostaglandin production, aspirin can affect cell growth, cell cycle, and polyamine biosynthesis without affecting cell membrane integrity.
Reproduction Nutrition Développement, 1988
Theriogenology, 2006
Somatic cloning in the bovine species leads to high levels of fetal losses which occur throughout... more Somatic cloning in the bovine species leads to high levels of fetal losses which occur throughout pregnancy. These losses are most often associated with fetal overgrowth, a syndrome known as large offspring syndrome (LOS), and excessive maternal plasma pregnancy serum protein 60 (PSP60), a protein similar to a pregnancy-associated glycoprotein of 67 kDa (PAG I67) produced by the bovine placenta. Predicting the outcome of pregnancies initiated from cloned embryos has become an important issue both to prevent potential harm to the mother because of excessive fetal size at birth and also to get a better understanding of the relationships between growth, differentiation and placental functions in developing cloned fetuses. Here, we report on a systematic analysis of fetal and placental development in the first trimester of pregnancy performed by ultrasonographic imaging and by measurement of the maternal concentrations of pregnancy associated glycoproteins (PAGS), using four different radioimmunoassays (RIA) (two homologous RIA systems with PSP60 and PAG I67; two heterologous RIA systems with PAG I67 as standard and tracer, and antisera anti-caprine PAGs). We showed that crown-rump length (CRL) in clones appeared smaller than controls at 35, 50 and 62 days (P < 0.05). At 62 days of pregnancy, CRL in cloned fetuses that died before 90 days was smaller compared to the other cloned fetuses (P < 0.05) whereas the width of the fetal sack and the biparietal diameter (BPD) was larger in fetuses that developed LOS in late gestation (P < 0.05). Maternal PAGs concentrations were statistically different between controls and all clone recipients as early as Day 34, suggesting early abnormal placental glycoprotein synthesis for clone pregnancies regardless of pregnancy outcome. This work provides a practical, non-invasive tool to follow up clone pregnancies and suggests that primary growth retardation and abnormal placental function precedes excessive fetal and placental growth at later stages of pregnancy. #
Theriogenology, 2011
Somatic nuclear transfer (NT) in cattle is often accompanied by severe placental anomalies, hyper... more Somatic nuclear transfer (NT) in cattle is often accompanied by severe placental anomalies, hypertrophy, and hydrallantois, which induce a high rate of pregnancy losses throughout gestation. These placental deficits are associated with an abnormal increase of the maternal plasma levels of pregnancy-associated glycoprotein (PAG), produced by the trophoblastic binucleate cells (BNC) of the placenta. The objective of this study was to analyze the origin of the abnormally elevated PAG concentrations in the peripheral circulation of NT recipients during pathological pregnancies. Concentrations of PAG were measured both in maternal blood, in chorionic and cotyledonary tissular extracts from control recipients (after artificial insemination, AI, or in vitro fertilization, IVF) and clone recipients on Day 32, Day 62, and during the third trimester of gestation. Three different radioimmunoassay (RIA) systems were used. One homologous RIA for PSP60, similar to bovine PAG-1 (PAG 67kDa ), and two heterologous RIA with PAG 67kDa as standard and tracer, and antisera anti-caprine PAG (AS#706 and AS#708). Circulating and tissular concentrations of bovine placental lactogen (bPL), a glycoprotein also produced by BNC, were determined by RIA at the same stages. The number of BNC in the placental tissues was determined by cell counting after immunostaining with anti PSP60 antibody on tissue sections from control and NT pregnancies. Maternal plasma PAG concentrations were not different among groups on Day 32, but they were significantly higher in NT than in control pregnancies on Day 62 with all three RIA and during the third trimester with two RIA (RIA-PSP60 and RIA with AS#708). Circulating bPL concentrations were undetectable on Days 32 and 62 and were not different in the third trimester between NT and control pregnancies. Tissular amounts of PAG on total proteins were not different between the two groups at all stages studied. No difference was determined in the percentage of PSP60-positive BNC in placental tissues between controls and NT on Day 62 and during the third trimester of pregnancy. Western blots of tissular extracts from placenta showed no major molecular weight changes of PAG in NT pregnancies compared to controls. No differences in maternal circulation concentrations or tissular content of bPL were observed between control and NT pregnancies. In conclusion, the specific increase of PAG in maternal plasma concentrations during abnormal NT pregnancies do not result from a higher proportion of BNC, or an increased protein expression of PAG and could be due to changes in the composition of terminal glycosylation which result into a clearance decrease of PAG from the circulation.
PloS one, 2014
In equids, placentation is diffuse and nutrient supply to the fetus is determined by uterine size... more In equids, placentation is diffuse and nutrient supply to the fetus is determined by uterine size. This correlates with maternal size and affects intra-uterine development and subsequent post-natal growth, as well as insulin sensitivity in the newborn. Long-term effects remain to be described. In this study, fetal growth was enhanced or restricted through ET using pony (P), saddlebred (S) and draft (D) horses. Control P-P (n = 21) and S-S (n = 28) pregnancies were obtained by AI. Enhanced and restricted pregnancies were obtained by transferring P or S embryos into D mares (P-D, n = 6 and S-D, n = 8) or S embryos into P mares (S-P, n = 6), respectively. Control and experimental foals were raised by their dams and recipient mothers, respectively. Weight gain, growth hormones and glucose homeostasis were investigated in the foals from birth to weaning. Fetal growth was enhanced in P-D and these foals remained consistently heavier, with reduced T3 concentrations until weaning compared t...
Theriogenology, 2012
Maternal undernutrition during gestation can condition offspring adult health, with the periconce... more Maternal undernutrition during gestation can condition offspring adult health, with the periconceptional period pointed out as a key period. The aim of this study was to evaluate the effects of maternal periconceptional undernutrition on pregnancy and offspring growth performance in sheep.
Theriogenology, 1988
The accuracy and efficiency of progesterone (P4 ) and bovine pregnancy-specific protein B (bPSPB)... more The accuracy and efficiency of progesterone (P4 ) and bovine pregnancy-specific protein B (bPSPB) radioimmunoassays (RIA) in detectirq pregnant and nonpregnant dairy cows were compared at different stages of pregnancy. The study included 145 French Friesian heifers and cows from a single herd. A total of 175 artificial insemination (A.1.) and blood sampling procedures were performed. Animals were bled 24 d post AI for P4 RIA. They were bled at 24,26,30 to 35, and 70 f 9 after AI for bPSPB RIA. Females were declared nonpregnant when plasma P4 concentrations were lower than 1.5 ng/ml. With the bPSPB RIA, cows were nonpregnant when at least one of the B/Be x 100 replicates was higher than 95% in the RIA.
Research in Veterinary Science, 1998
This study characterised the peripheral plasma concentration of PSP-60 throughout gestation, and ... more This study characterised the peripheral plasma concentration of PSP-60 throughout gestation, and examined the effect of stage of gestation and foetal number on this protein in Holstein cows after non-surgical embryo transfer. Cows (n=12) were divided into
Reproductive Biology and Endocrinology, 2011
Background: Mares have an annual reproductive rhythm, with a phase of inactivity in midwinter. Th... more Background: Mares have an annual reproductive rhythm, with a phase of inactivity in midwinter. The aim of this study was to determine the impact of food restriction on physiological and metabolic hallmarks of this rhythm. Methods: Over three successive years, 3 groups of 10 mares were kept under natural photoperiod. A 'well-fed' group was fed to maintain the mares in good body condition; a 'restricted' group received a diet calculated to keep the mares thin and a 'variable' group was fed during some periods like the 'restricted' group and during some other periods like the 'well-fed' group, with the aim of mimicking the natural seasonal variation of pasture availability, but a few months in advance of this natural rhythm. Results: Winter ovarian inactivity always occurred and was long in the restricted group. In contrast, in the 'well-fed' group, 40% of mares showed this inactivity, which was shorter than in the other groups. Re-feeding the 'variable' group in autumn and winter did not advance the first ovulation in spring, compared with the 'restricted' group. Measurements of glucose and insulin concentrations in mares from the 'restricted' group during two 24 h periods of blood sampling, revealed no post-prandial peaks. For GH (Growth hormone), IGF-1 and leptin levels, large differences were found between the 'well-fed' group and the other groups. The glucose, insulin, GH and leptin levels but not melatonin level are highly correlated with the duration of ovulatory activity. Conclusions: The annual rhythm driven by melatonin secretion is only responsible for the timing of the breeding season. The occurrence and length of winter ovarian inactivity is defined by metabolic hormones.
Reproduction, Fertility and Development, 2011
ABSTRACT Epidemiological studies in humans, as well as animal models, have shown that maternal en... more ABSTRACT Epidemiological studies in humans, as well as animal models, have shown that maternal environment at critical periods of fetal development can condition offspring adult health. Previous studies have shown effects of maternal undernutrition during early to mid gestation on Sertoli cell proliferation and seminiferous tubule diameter in male lambs of 10 months of age. Delayed follicular maturation and meiosis in female fetuses have been reported after maternal undernutrition from mating. The aim of this project was to evaluate the long-term effects of maternal periconceptional undernutrition on offspring physiology and reproductive function. Postnatal development of male offspring is presented here. Fifty-two control females of Merinos d&#39;Arles breed (R100) were fed a normal diet adapted to their needs, and 64 restricted females (R50) received 50% of their dietary needs from 15 days before until 30 days after synchronized breeding. Thereafter, both groups were fed to meet their nutritional requirements. Males were weighed at birth and every week. Blood samples were collected monthly to monitor plasma leptin and cortisol concentrations. Organ weights were recorded at commercial slaughter (35kg) and histological analysis was performed on testicles and adrenals. Data were analysed by ANOVA or Student&#39;s test. Twenty-two live R100 and 34 live R50 male lambs were obtained. Gestation was significantly longer in the restricted group (P&lt;0.01). Growth rate, live weight, and age at slaughter were not significantly different between groups. Plasma leptin concentrations were significantly lower at birth (P&lt;0.001) and tended to be higher at 4 months of age (P=0.09) in R50. There was a significant interaction between group, age, and litter size for basal cortisol concentrations: in singletons (n=15 R50 and n=8 R100), cortisol was significantly lower in R50 at 3 months of age (P&lt;0.05) and tended to be higher at 4 months whereas in twins (n=17 R50 and n=10 R100), cortisol was significantly lower at birth (P&lt;0.05) but not thereafter (triplets were not considered here because of low numbers). There was no statistical difference for carcass, testicle, or kidney weight. In contrast, carcass to live weight ratio and perirenal fat to live weight ratio were increased in all R50 (P&lt;0.05). Adrenal to live weight ratio tended to be increased in R50 lambs (P=0.06). Histological examination revealed no statistical difference between groups for adrenal corticomedullary ratio, zona glomerulosa to medulla ratio, and zona fasciculata to medulla ratio. There was no significant difference for the analysis of testicular tissue (diameter and surface of seminiferous tubules). The expression of genes involved in testicular differentiation (SRY, 3β-HSD, OCT3/4, VASA, stra8, SOX9) is currently being studied by quantitative PCR and will be presented. These results confirm the effects of periconceptional undernutrition on metabolic function but so far, no effect has been demonstrated on testicular histology. Litter size seems to play an important role, because effects were different between singletons and twins.
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Papers by Sylvaine Camous