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Reproductive biology and endocrinology : RB&E2014; 12; 72; doi: 10.1186/1477-7827-12-72

The influence of nutrition on the insulin-like growth factor system and the concentrations of growth hormone, glucose, insulin, gonadotropins and progesterone in ovarian follicular fluid and plasma from adult female horses (Equus caballus).

Abstract: Feed intake affects the GH-IGF system and may be a key factor in determining the ovarian follicular growth rate. In fat mares, the plasma IGF-1 concentration is high with low GH and a quick follicular growth rate, in contrast to values observed in thin mares. Nothing is known regarding the long-term effects of differential feed intake on the IGF system. The objective of this experiment was to quantify IGFs, IGFBPs, GH, glucose, insulin, gonadotropin and progesterone (P4) in blood and in preovulatory follicular fluid (FF) in relation to feeding levels in mares. Methods: Three years prior to the experiment, Welsh Pony mares were assigned to a restricted diet group (R, n = 10) or a well-fed group (WF, n = 9). All mares were in good health and exhibited differences in body weight and subcutaneous fat thickness. Follicular development was scanned daily and plasma was also collected daily. Preovulatory FF was collected by ultrasound-guided follicular aspiration. Hormone levels were assayed in FF and plasma with a validated RIA. Results: According to scans, the total number of follicles in group R was 53% lower than group WF. Insulin and IGF-1 concentrations were higher in WF than in R mares. GH and IGF-2 concentrations were lower in plasma from WF mares than from R mares, but the difference was not significant in FF. The IGFBP-2/IGFBP-3 ratio in FF was not affected by feeding but was dramatically increased in R mare plasma. No difference in gonadotropin concentration was found with the exception of FSH, which was higher in the plasma of R mares. On the day of puncture, P4 concentrations were not affected by feeding but were higher in preovulatory FF than in plasma. Conclusions: The bioavailability of IGF-1 or IGF-2, represented by the IGFBP2/IGFBP3 ratio, is modified by feed intake in plasma but not in FF. These differences partially explain the variability in follicular growth observed between well-fed mares and mares on restricted diets.
Publication Date: 2014-07-31 PubMed ID: 25078409PubMed Central: PMC4237953DOI: 10.1186/1477-7827-12-72Google Scholar: Lookup
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  • Journal Article
  • Randomized Controlled Trial
  • Research Support
  • Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research paper discusses how feeding patterns may influence hormone and growth factors in horses, affecting their reproductive processes like ovarian follicular growth. Results show a significantly higher insulin and IGF-1 concentration in well-fed mares, while GH and IGF-2 concentrations are lower but not significantly different in preovulatory follicular fluid compared to thin mares.

Research Objectives & Methods

The aim of this study was to measure the various growth and hormone device levels like IGFs, IGFBPs, GH, glucose, insulin, gonadotropin, and progesterone (P4) in the blood and preovulatory follicular fluid (FF) of mares and how these are influenced by their feeding levels.

To achieve this:

  • Two distinct groups of Welsh pony mares were created three years prior to the actual experiment – a restricted diet group and a well-fed group.
  • Follicular development was monitored daily using scans and plasma samples were collected every day for monitoring.
  • Preovulatory FF was collected using ultrasound-guided follicular aspiration. A validated RIA was used to assay hormones in FF and plasma.

Results

The experimental results revealed various significant differences between the two groups:

  • The restricted diet group had 53% fewer follicles compared to the well-fed group.
  • Insulin and IGF-1 concentrations were higher in well-fed mares than in the restricted diet group.
  • GH and IGF-2 concentration were marginally lower in plasma from the well-fed group, but there was no significant difference in the FF.
  • The IGFBP-2/IGFBP-3 ratio in FF did not show any feeding effects but was remarkably increased in the plasma of the restricted diet group.
  • No difference was observed in the gonadotropin concentration except for a higher FSH level in plasma from the restricted diet group, , while progesterone concentration remained constant.

Conclusions

It was found that feed intake modified the bioavailability of IGF-1 or IGF-2 (represented by the IGFBP2/IGFBP3 ratio) in plasma but not in FF. The differences in hormone and growth factor concentrations between the two groups help explain the variability in the ovarian follicular growth patterns between them. Thus, feeding has a significant impact on hormone and growth factor concentrations, affecting the reproductive processes in mares.

Cite This Article

APA
Salazar-Ortiz J, Monget P, Guillaume D. (2014). The influence of nutrition on the insulin-like growth factor system and the concentrations of growth hormone, glucose, insulin, gonadotropins and progesterone in ovarian follicular fluid and plasma from adult female horses (Equus caballus). Reprod Biol Endocrinol, 12, 72. https://doi.org/10.1186/1477-7827-12-72

Publication

ISSN: 1477-7827
NlmUniqueID: 101153627
Country: England
Language: English
Volume: 12
Pages: 72

Researcher Affiliations

Salazar-Ortiz, Juan
    Monget, Philippe
      Guillaume, Daniel
      • INRA, UMR85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France. dguillaume@tours.inra.fr.

      MeSH Terms

      • Animals
      • Blood Glucose / analysis
      • Caloric Restriction / adverse effects
      • Caloric Restriction / veterinary
      • Female
      • Follicular Fluid / chemistry
      • France
      • Glucose / analysis
      • Gonadotropins, Equine / analysis
      • Gonadotropins, Equine / blood
      • Gonadotropins, Equine / metabolism
      • Growth Hormone / analysis
      • Growth Hormone / blood
      • Growth Hormone / metabolism
      • Horses / blood
      • Horses / growth & development
      • Horses / physiology
      • Insulin-Like Growth Factor Binding Protein 3 / analysis
      • Insulin-Like Growth Factor Binding Protein 3 / blood
      • Insulin-Like Growth Factor Binding Protein 3 / metabolism
      • Insulin-Like Growth Factor Binding Proteins / analysis
      • Insulin-Like Growth Factor Binding Proteins / blood
      • Insulin-Like Growth Factor Binding Proteins / metabolism
      • Insulin-Like Growth Factor I / analysis
      • Insulin-Like Growth Factor I / metabolism
      • Insulin-Like Growth Factor II / analysis
      • Insulin-Like Growth Factor II / metabolism
      • Insulins / analysis
      • Insulins / blood
      • Insulins / metabolism
      • Ovarian Follicle / diagnostic imaging
      • Ovarian Follicle / growth & development
      • Ovarian Follicle / metabolism
      • Proestrus
      • Progesterone / analysis
      • Progesterone / blood
      • Progesterone / metabolism
      • Signal Transduction
      • Ultrasonography

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