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)

Reproductive Biology and Endocrinology

Research

Sylvaine Camous¹  Juan Salazar-Ortiz²  Christine Briant²  Lionel Lardic²  Daniel Guillaume²  Didier Chesneau² 

[1] INRA, UMR1198 Biologie du Développement et Reproduction, F-78352, Jouy-en-Josas, France;ENVA, F-94704, Maisons Alfort, France;INRA, UMR85 Physiologie de la Reproduction et des Comportements, F-37380, Nouzilly, France;CNRS, UMR6175 Physiologie de la Reproduction et des Comportements, F-37380, Nouzilly, France;Université François Rabelais de Tours, F-37041, Tours, France;IFCE, F-37380, Nouzilly, France;

关键词: Growth Hormone;    Melatonin;    Versus Group;    Feed Intake;    Body Condition Score;   

DOI  :  10.1186/1477-7827-9-130

 received in 2011-06-08, accepted in 2011-09-29,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundMares 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.MethodsOver 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.ResultsWinter 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.ConclusionsThe 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.

【 授权许可】

Unknown   
© Salazar-Ortiz et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.