1. Effects of nutritional cues on the duration of the winter anovulatory phase and on associated hormone levels in adult female Welsh pony horses (Equus caballus)
- Author
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Daniel Guillaume, Lionel Lardic, Didier Chesneau, Christine Briant, Sylvaine Camous, Juan Salazar-Ortiz, Physiologie de la reproduction et des comportements [Nouzilly] (PRC), Institut National de la Recherche Agronomique (INRA)-Institut Français du Cheval et de l'Equitation [Saumur]-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Biologie du développement et reproduction (BDR), Centre National de la Recherche Scientifique (CNRS)-École nationale vétérinaire d'Alfort (ENVA)-Institut National de la Recherche Agronomique (INRA), French National Stud, French 'Region Centre', CONACYT (Mexico), Centre National de la Recherche Scientifique (CNRS)-Université de Tours-Institut Français du Cheval et de l'Equitation [Saumur]-Institut National de la Recherche Agronomique (INRA), Biologie du Développement et Reproduction (BDR), Institut National de la Recherche Agronomique (INRA), Institut National de la Recherche Agronomique (INRA)-Institut Français du Cheval et de l'Equitation [Saumur]-Université de Tours-Centre National de la Recherche Scientifique (CNRS), and Guillaume, Daniel
- Subjects
hiver ,mélatonine ,Blood Glucose ,Leptin ,Time Factors ,hormone animale ,reproduction animale ,Physiology ,0403 veterinary science ,Endocrinology ,lcsh:Reproduction ,Insulin ,Insulin-Like Growth Factor I ,media_common ,Adiposity ,Melatonin ,2. Zero hunger ,biology ,Obstetrics and Gynecology ,04 agricultural and veterinary sciences ,[SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,Circadian Rhythm ,Endocrinologie et métabolisme ,Female ,France ,Seasons ,inactivité ovarienne ,medicine.drug ,équin ,Anovulation ,Ovulation ,medicine.medical_specialty ,endocrine system ,lcsh:QH471-489 ,040301 veterinary sciences ,media_common.quotation_subject ,Photoperiod ,Reproductive medicine ,lcsh:Gynecology and obstetrics ,Rhythm ,femelle ,biology.animal ,Internal medicine ,poney ,medicine ,Animals ,Circadian rhythm ,nutrition animale ,Horses ,lcsh:RG1-991 ,Caloric Restriction ,Endocrinology and metabolism ,Pony ,Research ,Body Weight ,0402 animal and dairy science ,biology.organism_classification ,medicine.disease ,photopériode ,040201 dairy & animal science ,Equus ,Subcutaneous Fat, Abdominal ,Reproductive Medicine ,Growth Hormone ,Developmental Biology - Abstract
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.
- Published
- 2011
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