scholarly journals Effects of increased ambient temperature and supplemental altrenogest prior to pregnancy establishment in gilts

Author(s):  
Matthew R Romoser ◽  
Katie L Bidne ◽  
Lance H Baumgard ◽  
Aileen F Keating ◽  
Jason W Ross

Abstract Heat stress (HS) mitigation strategies are critically needed to combat the substantial economic effects on animal agriculture. The manifestations of seasonal infertility include delayed puberty onset, reduced conception rates, decreased litter size, and increased wean to estrus interval. To assess the effects of HS during early gestation and evaluate a benefit of supplemental altrenogest (ALT) as a mitigation strategy, thirty crossbred post-pubertal gilts (157 ± 11 kg) were subjected to estrous synchronization via 14 d oral administration of ALT. Artificial insemination during estrus was performed and gilts were then placed into one of four treatment groups; heat stress (HS; 35 ± 1 οC for 12h/31.60 ± 1 οC for 12h) with (HSALT, n = 7) or without (HSCON, n = 7) 15 mg/d ALT supplementation or thermal neutral (TN; 20 ± 1 οC) conditions with (TNALT, n = 8) or without (TNCON, n = 8) 15 mg/d ALT supplementation until 12 d post-estrus (dpe). Administrating ALT occurred at 0600 h from 3-12 dpe and rectal temperatures (TR) and respiration rates (RR) were recorded. Blood was collected via jugular venipuncture on 0, 4, 8 and 12 dpe. Gilts were euthanized humanely at 12 dpe followed by collection of ovarian tissue, and uterine flushing for conceptus collection. In HS compared to TN gilts, RR and TR were increased (P < 0.01) but unaffected by ALT supplementation. Feed intake (FI) was reduced (P < 0.01) by HS but unaltered by ALT treatment. Corpora lutea (CL) weight was reduced (P < 0.01) in HSCON gilts when compared to TNCON and HSALT gilts despite progesterone (P4) concentrations in serum and luteal tissue not being affected by treatment (P ≥ 0.10). CL diameter was reduced (P ≤ 0.05) in HSALT gilts compared to other treatments. Interleukin-1β (IL1B) uterine flush concentration was not affected (P > 0.20) by environment or ALT supplementation, although moderate (P = 0.06) interaction between environment and ALT existed, as IL1B concentration in TNALT was increased (P = 0.03) compared to TNCON gilts. While environment did not affect conceptus development (P = 0.90), ALT supplementation advanced conceptus elongation (P < 0.01). Collectively, these data demonstrate that HS may affect luteal development prior to pregnancy establishment, and ALT increases conceptus elongation by12 dpe.

1972 ◽  
Vol 52 (1) ◽  
pp. 37-50 ◽  
Author(s):  
W. H. TAM

SUMMARY The ovarian tissue components of the pregnant chinchilla were incubated with equimolar amounts of [7α-3H]pregnenolone and [4-14C]progesterone. The greater contribution by [7α-3H]pregnenolone than by [4-14C]progesterone towards the formation of 17α-hydroxyprogesterone and androstenedione, and the relatively high yields of 17α-hydroxypregnenolone and dehydroepiandrosterone showed that both the 4-ene and 5-ene pathways of steroid metabolism were used in the interstitial tissue. No significant amount of 17α-hydroxylation was observed in the primary and accessory corpora lutea. The results of kinetic investigations using [7α-3H]pregnenolone as substrate also demonstrated a precursor—product relationship between dehydroepiandrosterone and androstenedione in the interstitial tissue, but this was not apparent in the luteal tissue. The results indicated that the interstitial tissue was capable of synthesizing progesterone and oestrogens as major products, and that the lack of 17α-hydroxylation in the luteal tissue was a controlling factor ensuring the synthesis of progesterone as its principal hormonal product. A small amount of [4-14C]dehydroepiandrosterone was always isolated with a much larger amount of the tritiated compound. This implied the conversion of 14C-labelled 4-en-3-oxosteroids into 5-ene-3β-hydroxysteroids which has generally been regarded as impossible. The isolation of this product, which may be an artifact, and the possibility that progesterone and oestrogens may be synthesized by different cells (granulosa and theca lutein cells) in the corpus luteum, or that there may be a third pathway for oestrogen synthesis, as suggested by the results of the kinetic experiments, are discussed.


2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 120-120
Author(s):  
Jason W Ross ◽  
Benjamin J Hale ◽  
Jacob T Seibert ◽  
Matthew R Romoser ◽  
Malavika K Adur ◽  
...  

Abstract Seasonal variations in environmental temperatures impose added stress on domestic species bred for economically important production traits. These heat-mediated stressors vary on a seasonal, daily, or spatial scale, and negatively impact behavior and reduce feed intake and growth rate, which inevitably leads to reduced herd productivity. The seasonal infertility observed in domestic swine is primarily characterized by depressed reproductive performance manifesting as delayed puberty onset, reduced farrowing rates, and extended weaning-to-estrus intervals. Understanding the effects of heat stress at the organismal, cellular, and molecular level is a prerequisite to identifying mitigation strategies that could reduce the economic burden of compromised reproduction. Additionally, hyperthermia experienced in utero influences industry-relevant postnatal phenotypes. Understanding tissue-specific molecular mechanisms through which heat stress confers suppressed reproductive ability is essential to the development of mitigation focused hypothesis driven solutions. This work was supported by the National Pork Board and the Iowa Pork Producers Association.


1961 ◽  
Vol 36 (2) ◽  
pp. 180-184 ◽  
Author(s):  
Béla Flerkó ◽  
Vera Bárdos

ABSTRACT Absence of compensatory ovarian hypertrophy in »constant oestrus rats« from lesions in the anterior hypothalamic area suggests that nervous elements localized in this region play an essential role in the stimulation of gonadotrophin output by diminution of the blood oestrogen level. The constant vaginal oestrus after unilateral ovariectomy in the majority of animals was, however, repeatedly interrupted by vaginal smears of a dioestrous type. The appearance of a dioestrous vaginal smear in the »hypothalamic constant oestrus rats« is often associated with some luteinisation. It is assumed that diminution of the blood oestrogen level by reduction of ovarian tissue in these animals may bring about a release of LH sufficient to cause formation of corpora lutea.


1986 ◽  
Vol 113 (4) ◽  
pp. 570-575 ◽  
Author(s):  
Firyal S. Khan-Dawood

Abstract. Immunoreactive oxytocin is detectable in the corpora lutea of women and cynomolgus monkeys by radioimmunoassay. To localize the presence of oxytocin and neurophysin I in ovarian tissues of subhuman primates, three corpora lutea and ovarian stromal tissues and two Fallopian tubes obtained during the menstrual cycle of the baboon and decidua from two pregnant baboons were examined using highly specific antisera against either oxytocin or neurophysin I and preoxidase-antiperoxidase light microscopy immunohistochemistry. Oxytocin-like as well as neurophysin I-like immunoreactivities were found in some cells of all the corpora lutea only, but could not be demonstrated in ovarian stromal tissues, Fallopian tubes and decidua. Specificity of the immunocytochemical reaction was further confirmed by immunoabsorption of the antiserum with excess oxytocin or neurophysin, after which the immunoreactivities for both oxytocin and neurophysin in the luteal tissue were negative. Similar controls using normal rabbit serum gave no positive staining for either oxytocin or neurophysin. Counterstaining of the positive immunoreactivities for oxytocin and neurophysin I with Mayer's haematoxylin and eosin demonstrated clearly that the oxytocin and neurophysin I appeared as granular material mainly within the cytoplasm of the luteal cells. The localization of immunoreactive oxytocin and neurophysin I in the corpus luteum of the baboon demonstrates directly the presence of these two neurohypophysial peptides within primate luteal cells and suggests their local production.


2018 ◽  
Vol 96 (suppl_2) ◽  
pp. 76-76
Author(s):  
E D Grusenmeyer ◽  
T J Safranski ◽  
M C Lucy ◽  
K Kerns ◽  
P Sutovsky ◽  
...  

2022 ◽  
pp. 1256-1277
Author(s):  
Vishakha Shrimali ◽  
Nibedita Naha ◽  
Sukanta Mondal

Climate change is a global threat to livestock sector to so many species and ecosystem in different parts of the world. Climate change, heat stress, and nutritional stress are the major intriguing factors responsible for reduced fertility in farm animals in tropical countries. Heat and nutritional stresses affect the reproductive performance by decreasing the expression of estrous behavior, altering ovarian follicular development and hormonal profiles, compromising oocyte competence, and inhibiting embryonic development in livestock. Climate is changed by greenhouse gases that released into atmosphere through man-made activities. Livestock contribute 18% of the production of greenhouse gases itself and causes climate change including heat stress, which has direct and indirect impact on fertility of the animals as well as reduce milk production. Adaptation to climate change and lowering its negative effect by alteration of animal micro-environment using different essential technologies are the main mitigation strategies to recover heat stress damage in this respect.


2019 ◽  
Vol 97 (10) ◽  
pp. 4314-4322 ◽  
Author(s):  
Katie L Bidne ◽  
Matthew R Romoser ◽  
Jason W Ross ◽  
Lance H Baumgard ◽  
Aileen F Keating

Abstract Heat stress (HS) occurs when heat dissipation mechanisms are insufficient to maintain euthermia, and it is associated with seasonal infertility (SI), which manifests as smaller litters, longer wean-to-estrus interval, increased abortions, and reduced conception rates. To understand HS-induced mechanisms underlying SI, crossbred post-pubertal gilts (167 ± 10 kg; n = 14) experienced either thermal neutral (TN, 20 ± 1 °C, n = 7) or cyclical HS (35 ± 1 °C for 12 h and 31.6 °C for 12 h, n = 7) conditions from 2 to 12 d post-estrus (dpe). Estrous cycles were synchronized via altrenogest administration for 14 d, phenotypic manifestation of estrus was observed and gilts were assigned to experimental treatment. Gilts were limit fed 2.7 kg daily with ad libitum water access. Blood was collected at 0, 4, 8, and 12 dpe via jugular venipuncture and animals were humanely euthanized at 12 dpe. The corpora lutea (CL) width were measured via digital calipers on both ovaries, and CL from one ovary were excised, weighed, and protein and steroid abundance analyzed via western blotting and ELISA, respectively. Relative to TN, HS increased (P < 0.01) rectal temperature and respiration rates and reduced (P < 0.01) feed intake. The CL from HS ovaries were reduced in diameter (P < 0.05) and weight (P < 0.01) relative to those from TN animals. No difference (P = 0.38) in CL or serum progesterone concentrations between groups was observed at any time point, though at 12 dpe the serum progesterone:CL weight was increased (P < 0.10) by HS. No treatment differences (P = 0.84) in circulating insulin were observed. Luteal protein abundance of steroid acute regulatory protein, 3 beta-hydroxysteroid, or prostaglandin F2α receptor were not different between treatments (P = 0.73). Taken together, these data demonstrate that the CL mass is HS sensitive, but this phenotype does not appear to be explained by the metrics evaluated herein. Regardless, HS-induced decreased CL size may have important implications to pig SI and warrants additional attention.


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