scholarly journals Gestational nutrition 1: alterations to gestational nutrition can increase indicators of fertility in sheep

Reproduction ◽  
2019 ◽  
Vol 157 (3) ◽  
pp. 199-213 ◽  
Author(s):  
Peter Smith ◽  
Jo-Ann L Stanton ◽  
Laurel Quirke ◽  
Jennifer L Juengel
Keyword(s):  
Germ Cell ◽  
Ovarian Development ◽  
Plasma Concentrations ◽  
Antral Follicle ◽  
Female Offspring ◽  
Maternal Plasma ◽  
Metabolic Factors ◽  
Fetal Plasma ◽  
Female Sheep ◽  
Antral Follicle Counts

The aim of this study was to examine the relationships between gestational nutrition, fetal ovarian development and offspring fertility in female sheep and to highlight the potential mechanisms underlying these relationships. Adult sheep (n = 79) were fed either a maintenance or 0.6 of maintenance plane of nutrition for the first 55 days of gestation and thereafter fed ad libitum. Fetuses were collected for analysis at days 55 and 75 of gestation. Female offspring were monitored from birth until 19 months of age. Effects of restricted nutrition were observed on maternal plasma concentrations of progesterone, creatinine, albumin and Ca2+ at day 55 and creatinine at day 75. Concentrations of metabolic factors and steroid hormones in day 75 fetal plasma were not affected by the restricted maternal plane of nutrition. At day 55 of gestation, fetal ovarian germ cell development was not affected by maternal plane of nutrition. At day 75 of gestation ovaries from fetuses whose dams were exposed to restricted nutrition contained more germ cells but had lower germ cell proliferation rates than controls. For female offspring at 8 months of age, the dams gestational plane of nutrition did not affect the onset of puberty, ovulation rate (OR) and antral follicle counts (AFC). At 19 months of age, ewes from dams exposed to the restricted plane of gestational nutrition had higher OR, AFC and progesterone concentrations while concentrations of FSH were lower. In conclusion, while effects on fertility per se are yet to be determined, a reduced maternal plane of gestational nutrition can improve indicators of fertility in female offspring.

Premature birth of live lambs induced by pulsatile infusion of ACTH

1990 ◽  
Vol 124 (1) ◽  
pp. 99-107 ◽  
Author(s):  
R. J. MacIsaac ◽  
R. S. Carson ◽  
A. P. Horvath ◽  
E. M. Wintour
Keyword(s):  
Plasma Concentrations ◽  
Maternal Plasma ◽  
Sampling Time ◽  
Plasma Acth ◽  
Fetal Plasma ◽  
A Value ◽  
Normal Term ◽  
Acth Treatment ◽  
Normal Gestation ◽  
Pulsatile Infusion

ABSTRACT This study was designed to investigate the effects of pulsatile infusion of ACTH into ovine fetuses on the endocrine changes that precede parturition, the timing of birth and the subsequent survival of the lamb. Where appropriate, these parameters were compared with fetuses infused with pulses of saline and uninfused normal term fetuses. Ten fetuses received a 15-min infusion of synthetic ACTH(1–24) (79 ng/min) from day 125 (n=9) or day 126 (n=1) of gestation. Seven fetuses were born prematurely within 174±14 h (mean ± s.e.m.) after the commencement of the infusion, i.e. at 132 ± 0·6 days, whilst three died in utero at 130–131 days. When born all lambs could breath, walk and suckle. Of the seven premature lambs, four died 2–10 days after parturition but three survived for at least 12 months after birth. Fetuses infused with pulses of ACTH exhibited intermittent but very large increases in plasma ACTH values, with the first pulse, on day 1, increasing ACTH values from 5·1 ± 1·1 to 140 ± 31·3 pmol/l (P<0·001). At the next sampling time, ACTH values were not significantly different from preinfusion values. A similar plasma ACTH profile was observed on each subsequent day of ACTH treatment. In contrast, fetuses (n=4) infused with pulses of saline between 125 and 131 days exhibited fetal plasma concentrations of ACTH which ranged between 2 and 12 pmol/l for the majority of the time. Of the uninfused fetuses (n=8) that were studied during the last week of normal gestation, seven were born alive at 148·9± 1·0 days of gestation, whilst one lamb was stillborn at 146 days. In these fetuses, plasma concentrations of ACTH increased slowly to 35·6 ±2·4 pmol/l on the day before delivery with a further increase to 76·4± 3·9 pmol/l occurring on the day of delivery. In fetuses infused with pulses of ACTH there was also a significant (P< 0·001) increase in the fetal cortisol to corticosterone ratio from a value of 2·9 before the commencement of the infusion to 69·1 just before birth. In ewes bearing uninfused fetuses born at normal term, maternal plasma concentrations of progesterone on day 4 before delivery were significantly (P<0·05) lower than on day 5 before delivery. In comparison, in ewes bearing fetuses infused with pulses of ACTH, a significant (P<0·05) decrease from maternal plasma concentrations of progesterone on day 5 before delivery did not occur until day 1 before delivery. In ewes bearing uninfused or prematurely delivered fetuses infused with pulses of ACTH, maternal plasma concentrations of oestrogen did not significantly (P<0·01) increase until the day of parturition. It is concluded that a minimum of 6–7 days of ACTH treatment is required by the fetal adrenal for the induction of cortisol synthesis sufficient to produce the birth of viable lambs. However, premature lambs have a 57% mortality rate in the 2- to 10-day period after birth. Journal of Endocrinology (1990) 124, 99–107

Thyroid and parathyroid-independent increase in plasma 1,25-dihydroxyvitamin D during late pregnancy in the rat

1988 ◽  
Vol 116 (3) ◽  
pp. 381-385 ◽  
Author(s):  
T. M. Nguyen ◽  
A. Halhali ◽  
H. Guillozo ◽  
M. Garabedian ◽  
S. Balsan
Keyword(s):  
Vitamin D ◽  
Placental Transfer ◽  
Plasma Concentrations ◽  
Late Pregnancy ◽  
Maternal Plasma ◽  
Vitamin D Metabolites ◽  
Pregnant Rats ◽  
Dihydroxyvitamin D ◽  
Fetal Plasma ◽  
And Control

ABSTRACT The effect of thyroparathyroidectomy (TPTX) on the plasma concentrations of the vitamin D metabolites (25-(OH)D, 24,25-(OH)2D and 1,25-(OH)2D) has been studied in pregnant rats and their fetuses during the last quarter of gestation. Maternal and fetal vitamin D metabolites were not significantly affected by TPTX. A significant increase in plasma 1,25-(OH)2D concentrations was observed in both TPTX and control mothers and fetuses from days 19 to 21. Fetal and maternal plasma 25-(OH)D were positively correlated in both control and TPTX groups. Such a correlation was also found for 24,25-(OH)2D in the two groups. In contrast, a positive correlation between maternal and fetal plasma concentrations of 1,25-(OH)2D was found in TPTX but not in control rats. These data suggest that major alterations in calcium metabolism, such as that produced by maternal TPTX, are insufficient to affect the changes in maternal and fetal plasma 1,25-(OH)2D during late pregnancy significantly. They also suggest that parathyroid hormone, thyroxine, and/or calcitonin may control a possible placental transfer of 1,25-(OH)2D in the rat. J. Endocr. (1988) 116, 381–385

Effect of alteration of maternal plasma progesterone concentrations on fetal behavioural state during late gestation

1997 ◽  
Vol 152 (3) ◽  
pp. 379-386 ◽  
Author(s):  
M B Nicol ◽  
J J Hirst ◽  
D Walker ◽  
G D Thorburn
Keyword(s):  
Plasma Concentrations ◽  
Maternal Plasma ◽  
Late Gestation ◽  
Emg Activity ◽  
Fetal Sheep ◽  
Plasma Progesterone ◽  
Fetal Plasma ◽  
Progesterone Synthesis ◽  
Progesterone Metabolites ◽  
Vascular Catheters

Placental progesterone synthesis exposes the fetus to high levels of progesterone and progesterone metabolites during late gestation which may influence fetal behaviour. To determine the role of maternal progesterone synthesis in the control of fetal arousal state and fetal breathing movements (FBM), the effect of raising and lowering maternal progesterone concentrations was examined in chronically catheterised fetal sheep. Fetal and maternal vascular catheters, fetal tracheal and amniotic fluid catheters as well as electrodes for recording fetal electrocortical (ECoG), electro-ocular (EOG) and nuchal muscle electromyographic (EMG) activity were implanted between 118 and 122 days gestational age (GA). Progesterone, 100 mg, administered twice daily i.m. for 3 days (130–133 days GA) resulted in a marked elevation in maternal plasma progesterone concentrations (370 ± 121%, n=5, P<0·05), but had no effect on fetal plasma concentrations. Fetal EOG episodes and the duration of fetal behavioural arousal were significantly suppressed throughout the progesterone treatment period (74·4–81·1% and 58–65% respectively, P<0·05, n=5). Four ewes received Trilostane (25 mg i.v.), a 3β-hydroxysteroid dehydrogenase inhibitor, between 136 and 140 days GA. Maternal and fetal progesterone concentrations were significantly lowered by 60 min after treatment (19·8 ± 8·0% and 39·5 ± 24·3% respectively, P<0·05). The incidence of fetal EOG activity increased from a pretreatment level of 26·8 ± 1·5 min/h to 30·3 ± 2·8 min/h at 1–6 h and to 35·0 ± 1·7 min/h (P<0·05) during the 7–12 h after Trilostane treatment. The duration of FBM episodes was significantly higher at 1–6 h and 7–12 h after Trilostane treatment (19·5 ± 3·0 and 23·6 ± 5·5 min/h respectively, P<0·05) compared with pretreatment levels (11·2 ± 1·2 min/h). We conclude that increasing maternal progesterone levels suppresses fetal EOG activity and behavioural arousal, whereas reducing maternal progesterone synthesis leads to an elevation of EOG activity and FBM. Journal of Endocrinology (1997) 152, 379–386

RELATIONSHIP BETWEEN LAMB BIRTH WEIGHTS AND FETAL PLASMA GROWTH HORMONE AND INSULIN CONCENTRATIONS

1986 ◽  
Vol 66 (4) ◽  
pp. 995-1001
Author(s):  
G. J. MEARS
Keyword(s):  
Growth Hormone ◽  
Fetal Growth ◽  
Plasma Insulin ◽  
Plasma Concentrations ◽  
Maternal Plasma ◽  
Metabolic Clearance ◽  
Plasma Growth Hormone ◽  
Fetal Plasma ◽  
Plasma Gh ◽  
Ovine Fetal

Plasma concentrations of growth hormone (GH) and insulin were monitored in 11 chronically cannulated ovine fetuses and their mothers during the last month of gestation to obtain information on the role that these hormones have in determining fetal growth rate. Maternal plasma GH and insulin concentrations were independent of stage of gestation and lamb birth weights. Fetal plasma insulin concentrations were episodic in nature, independent of stage of gestation, and tended to be higher in fetuses that were heavier at birth. Fetal plasma GH concentrations were only slightly episodic in nature, were tenfold higher than maternal levels at 116–124 d gestation and increased by approximately another 25% prior to parturition. Fetal plasma GH concentrations were negtively correlated with lamb birth weights. In twin preparations, fetal plasma GH concentrations were significantly lower in the twin that was heaviest at birth. The lower GH concentrations found in faster growing fetuses are suggestive of a more rapid metabolic clearance of GH by the tissues of these animals. The results indicate that circulating fetal GH and, possibly, insulin are involved in determining the rate of ovine-fetal growth. Key words: Ovine birth weights, fetal GH, fetal insulin, fetal growth

Genotype and fetal size affect maternal­–fetal amino acid status and fetal endocrinology in Large White×Landrace and Meishan pigs

2013 ◽  
Vol 25 (2) ◽  
pp. 439 ◽  
Author(s):  
Cheryl J. Ashworth ◽  
Margaret O. Nwagwu ◽  
Harry J. McArdle
Keyword(s):  
Amino Acid ◽  
Plasma Concentrations ◽  
Placental Tissue ◽  
Maternal Plasma ◽  
Plasma Amino Acid ◽  
Large White ◽  
Fetal Plasma ◽  
Acid Status ◽  
Fetal Size

This study compared maternal plasma amino acid concentrations, placental protein secretion in vitro and fetal body composition and plasma amino acid and hormone concentrations in feto–placental units from the smallest and a normally-sized fetus carried by Large White × Landrace or Meishan gilts on Day 100 of pregnancy. Compared with Large White × Landrace, Meishan placental tissue secreted more protein and Meishan fetuses contained relatively more fat and protein, but less moisture. Fetal plasma concentrations of insulin, triiodothryonine, thyroxine and insulin-like growth factor (IGF)-II were higher in Meishan than Large White × Landrace fetuses. In both breeds, fetal cortisol concentrations were inversely related to fetal size, whereas concentrations of IGF-I were higher in average-sized fetuses. Concentrations of 10 amino acids were higher in Large White × Landrace than Meishan gilts, while glutamine concentrations were higher in Meishan gilts. Concentrations of alanine, aspartic acid, glutamic acid and threonine were higher in Meishan than Large White × Landrace fetuses. Average-sized fetuses had higher concentrations of asparagine, leucine, lysine, phenylalanine, threonine, tyrosine and valine than the smallest fetus. This study revealed novel genotype and fetal size differences in porcine maternal–fetal amino acid status and fetal hormone and metabolite concentrations.

Distribution of ionic sulfate, lithium, and bromide across the sheep placenta

1979 ◽  
Vol 236 (1) ◽  
pp. C58-C65 ◽  
Author(s):  
K. L. Thornburg ◽  
N. D. Binder ◽  
J. J. Faber
Keyword(s):  
Steady State ◽  
Continuous Infusion ◽  
Plasma Concentrations ◽  
Maternal Plasma ◽  
Potential Difference ◽  
Nernst Equation ◽  
Indwelling Catheters ◽  
Fetal Plasma ◽  
Total Potential ◽  
Fetal Lamb

Salts of sulfate, lithium, and bromine were injected or infused intravenously into ewes in the last trimester of gestation. Ewes and fetuses had indwelling catheters; most fetuses were nephrectomized. Concentrations were measured in paired maternal and fetal samples over periods of 4--14 days. Maternal excretion of sulfate was too rapid to permit near equilibration of fetal and maternal plasma concentrations; the results, however, did not support the existence of a large potential difference across the exchange barrier. The concentrations of Li+ (given by continuous infusion) and 82Br- in maternal plasma did not change rapidly. The concentrations of these tracers in fetal plasma rose until they were nearly equal to the maternal plasma concentrations. Steady-state transplacental potentials, calculated by use of the Nernst equation, were 5.2 +/- 2.0 (SEM) mV (n = 26) for Li+ and -2.2 +/- 0.8 (SEM) mV (n = 10) for Br-. Nernst potentials calculated from previously measured maternal and fetal plasma concentrations of Na+, K+, Mg2+, and Cl- were +0.4, +3.6, +0.5, and -1.4 mV. We concluded that, of the total potential difference of about -50 mV (fetus negative) between the fetal lamb and the ewe, only a few mV are dropped across the placental exchange barrier.

scholarly journals Treatment of underfed pigs with GH throughout the second quarter of pregnancy increases fetal growth

2000 ◽  
Vol 166 (1) ◽  
pp. 227-234 ◽  
Author(s):  
KL Gatford ◽  
JA Owens ◽  
RG Campbell ◽  
JM Boyce ◽  
PA Grant ◽  
...  
Keyword(s):  
Fetal Growth ◽  
Plasma Glucose ◽  
Plasma Concentrations ◽  
Amino Nitrogen ◽  
Live Weight ◽  
Maternal Plasma ◽  
Gh Treatment ◽  
Fetal Plasma ◽  
Nitrogen Concentrations ◽  
Ad Libitum Intake

Circulating growth hormone (GH) concentrations increase in pregnancy and administration of GH during early-mid pregnancy increases fetal growth in well-fed pigs. To determine whether increased maternal GH could promote fetal growth when feed availability is restricted, fifteen cross-bred primiparous sows (gilts) were fed at approximately 30% of ad libitum intake, from mating onwards and were injected daily i.m. with recombinant porcine GH (pGH) at doses of 0, 13.4+/-0.3 and 25.6+/-0.5 microg/kg live weight from day 25 to day 51 of pregnancy (term approximately 115 days). Treatment with pGH increased maternal backfat loss between day 25 and day 51 of pregnancy, and increased maternal plasma IGF-I concentrations measured at day 51 of pregnancy. Fetal body weight, length and skull width at day 51 of pregnancy were increased by maternal treatment with pGH. Fetal plasma glucose concentrations were increased and maternal/fetal plasma glucose concentration gradients were decreased by maternal pGH treatment at 13.4, but not 25.6 microg/kg.day. Fetal plasma concentrations of urea were decreased by both levels of pGH treatment. Overall, fetal weight was negatively correlated with fetal plasma concentrations of urea, positively correlated with maternal plasma alpha-amino nitrogen concentrations and unrelated to glucose concentrations in either maternal or fetal plasma. This suggests that the availability of amino acids, not glucose, limits fetal growth in the first half of pregnancy in underfed gilts, and that maternal GH treatment may improve amino acid delivery to the fetus.

Effect of long-term infusion of ovine corticotrophin-releasing factor in the immature ovine fetus

1986 ◽  
Vol 111 (3) ◽  
pp. 469-475 ◽  
Author(s):  
E. M. Wintour ◽  
R. J. Bell ◽  
R. S. Carson ◽  
R. J. MacIsaac ◽  
G. W. Tregear ◽  
...  
Keyword(s):  
Plasma Concentrations ◽  
Maternal Plasma ◽  
In Utero ◽  
Premature Delivery ◽  
Jugular Veins ◽  
Plasma Progesterone ◽  
Fetal Plasma ◽  
Corticotrophin Releasing Factor ◽  
Ovine Fetus

ABSTRACT Synthetic ovine corticotrophin-releasing factor (oCRF) was infused continuously into the jugular veins of six ovine fetuses for 5–11 days. Two fetuses receiving 0·1 and 1·0 μg oCRF/h from gestational days 134 and 135 respectively, lambed prematurely on days 141 and 140 respectively. Three out of four fetuses receiving oCRF at 2·4 μg/h, from 125 days of gestation, delivered spontaneously at 131, 131 and 136 days, whilst one died in utero at 132 days. Two fetuses receiving vehicle only or oCRF intra-amniotically, were born at 148 and 145 days respectively, whilst six fetuses chronically cannulated but not infused were born at 149·8 ±2·1 (s.d.) days. In ewes lambing at term, maternal plasma progesterone concentrations were 41·4±11·4 (s.e.m.; n = 5), 28·8±7·8 (n = 6), 17·1 ±4·8 (n = 5) and 7·9± 1·1 (n = 4) nmol/l on 3, 2, 1 and 0 days respectively before the lambs were born. No such decrease in maternal plasma progesterone concentrations was seen in the oCRF-infused fetuses. Fetal plasma concentrations of immunoreactive ACTH were maintained above normal in oCRF-infused fetuses, but some desensitization to bolus oCRF injections occurred in these fetuses. Four of the five fetuses born prematurely were sufficiently mature to survive, being able to stand, breathe and suckle. It is concluded that continuous oCRF infusions into immature fetuses can accelerate maturation of a number of organs and systems culminating in the premature delivery of viable lambs. J. Endocr. (1986) 111, 469–475

Are fetal adrenocorticotropic hormone and renin secretion suppressed by maternal cortisol secretion?

1988 ◽  
Vol 255 (3) ◽  
pp. R412-R417 ◽  
Author(s):  
C. E. Wood
Keyword(s):  
Plasma Cortisol ◽  
Adrenocorticotropic Hormone ◽  
Plasma Concentrations ◽  
Plasma Renin ◽  
Maternal Plasma ◽  
Renin Secretion ◽  
Plasma Acth ◽  
Fetal Sheep ◽  
Fetal Plasma ◽  
Adrenal Secretion

Previous studies from this laboratory have demonstrated that intravenous infusions of hydrocortisone (cortisol) into fetal sheep at rates that produce plasma concentrations achieved during fetal stress inhibit fetal adrenocorticotropic hormone (ACTH) and renin secretion. The present study was designed to test for inhibition of fetal renin and ACTH after maternal adrenal secretion of cortisol. ACTH-(1-24) or saline infusion into 12 pregnant ewes (120-132 days gestation) at rates of 0, 1, 5, or 20 ng ACTH.kg-1.min-1 for 5 h produced dose-related increases in maternal plasma ACTH and cortisol concentrations and fetal plasma cortisol concentration. In the 20-ng.kg-1.min-1 group, increases in fetal plasma cortisol of 8.0 ng/ml (to 24.3 +/- 3.7 ng/ml) did not suppress basal fetal plasma renin activity. One hour after the end of the maternal vehicle or ACTH infusion, fetal ACTH secretion was stimulated by fetal intravenous infusion of sodium nitroprusside. In the 0-, 1-, and 5-ng.kg-1.min-1 groups, fetal ACTH responses to nitroprusside were suppressed in animals infused with ACTH. Together, these results indicate that the maternal adrenal secretion of cortisol inhibits stimulated secretion of ACTH but not renin in 120- to 132-day-gestation fetal sheep.

Corticotropin-releasing factor in the ovine fetus and pregnant ewe: role of placenta

1991 ◽  
Vol 261 (4) ◽  
pp. R995-R1002 ◽  
Author(s):  
M. Keller-Wood ◽  
C. E. Wood
Keyword(s):  
Adrenocorticotropic Hormone ◽  
Plasma Concentrations ◽  
Late Pregnancy ◽  
Maternal Plasma ◽  
Corticotropin Releasing Factor ◽  
Late Gestation ◽  
Fetal Plasma ◽  
Ovine Fetus ◽  
Arterial Plasma ◽  
Pregnant Ewe

In the sheep, maternal plasma adrenocorticotropic hormone and cortisol are increased in late pregnancy, and fetal plasma cortisol and adrenocorticotropic hormone rise precipitously in late gestation. To test whether the ovine placenta secretes corticotropin-releasing factor (CRF) into either the maternal or fetal circulation, pregnant ewes and their fetuses were prepared with femoral arterial catheters and uterine and umbilical venous catheters. Samples were taken from all sites before and during hypoxia. There was no difference in CRF concentration across the placenta in the mothers or the fetuses under resting or hypoxemic conditions, but maternal and fetal arterial plasma CRF concentrations increased between 128 and 145 days. In a second study, maternal and fetal femoral venous plasma CRF concentrations were measured 1-19 days before spontaneous parturition. The mean concentration increased 8.6 +/- 0.6 pg/ml 11-19 days before parturition to 13.0 +/- 1.0 and 13.2 +/- 1.4 pg/ml in fetuses 4-8 and 1-3 days before parturition, respectively. Maternal plasma concentrations did not significantly increase in the days closer to parturition. These studies demonstrate that there are low but measurable CRF concentrations in fetal and maternal sheep plasma but that these are not the result of tonic placental secretion of CRF.

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