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Montevideo, Uruguay

Meikle A.,Laboratorio Of Tecnicas Nucleares
Biological Rhythm Research | Year: 2013

Metabolic status is an important factor modulating reproductive function in ruminants. Evidence from our group has led to the concept that reproductive hormones, in turn, were capable of modulating metabolic responses. In the present study, cortisol plasma concentrations have been determined in the peri-oestrus of cyclic ewes fed half or all of their maintenance requirements, and related to concentrations of insulin, insulin-like growth factor 1 (IGF-1), leptin, glucose and non-esterified fatty acids (NEFA). Cortisol concentrations experienced a six-fold rise at oestrus, independently of the level of nutrition. Moreover, they were positively correlated with glucose and IGF-1 concentrations. It is suggested that the cortisol increase at oestrus could be due to oestrogenic action in the adrenal cortex, and that it could explain some of the metabolic fluctuations observed before. © 2013 Copyright Taylor and Francis Group, LLC. Source

Fernandez-Foren A.,Laboratorio Of Tecnicas Nucleares | Abecia J.,University of Zaragoza | Vazquez M.,University of Zaragoza | Forcada F.,University of Zaragoza | And 4 more authors.
ITEA Informacion Tecnica Economica Agraria | Year: 2011

The metabolic responses to changes in metabolic status could depend on recent (feeding level) or more ancient (body reserves) metabolic history, a concept termed "metabolic memory". The aim of this work was to study the metabolic response to food restriction in ewes with different body condition score at the beginning of the experiment (CCi). During the breeding season, 36 Rasa Aragonesa ewes were divided into 2 groups with different BCS: BCS > 2.75 (fat ewes, A, mean ± standard error: 2.9 ± 0.04) and BCS < 2.25 (lean ewes, B, 2.1 ± 0.04). During 20 days, both groups received a diet to supply energy and protein maintain requirements, each group was divided into 2 groups and were fed to provide either 1.5 or 0.5 times the daily maintenance requirements; therefore, the 4 groups were: fat control (AC, n = 9), fat undernourished (AS, n = 10), lean control (BC, n = 9) and lean undernourished (BS, n = 8) ewes. Body weight (BW), glucose, non-esterified fatty acids (NEFA), ß-hydroxybutyrate (BHB), insulin, leptin, and insulin-like growth factor (IGF-I) were determined. BS and AS groups lost weight, BC group gained weight, and ACewes maintained their BW. Plasma glucose concentration and insulin were higher and NEFA was lower in control ewes. Ewes with high BCS had higher concentrations of insulin and IGF-I, and leptin tended to be higher in these animals. Insulin concentrations were higher in control ewes, while other hormones remained unchanged. Glucose, BHB, insulin and IGF-I profiles were affected by initial BCS and nutritional treatment, as is demonstrated by the significant interaction between these factors and days. Metabolites (glucose and BHB) and metabolic hormones (insulin and IGF-I) concentrations showed a peak at estrus time. In conclusion, it was found that glucose, BHB, insulin and IGF-I profiles respond to undernutrition according to the level of body reserves of the animals at the onset of the nutritional restriction. Source

de Brun V.,Laboratorio Of Tecnicas Nucleares | Abecia J.A.,University of Zaragoza | Fernandez-Foren A.,Laboratorio Of Tecnicas Nucleares | Carriquiry M.,Avda. Garzon | And 5 more authors.
Spanish Journal of Agricultural Research | Year: 2013

The effect of undernutrition on gene expression of progesterone and oestrogen receptors (PGR and ESR1), and insulin-like growth factors 1 and 2 (IGF1 and IGF2) in the uterus and oviducts of ewes on day 5 after oestrus was investigated. The effect of the side of the uterus/oviduct regarding the ovary bearing a corpus luteum (CL) (ipsi vs. contralateral) was also analyzed. Fourteen oestrous synchronized ewes were fed either 1.5 (C, n = 7) or 0.5 (L, n = 7) times their maintenance requirements from the onset of the hormonal treatment (day -14), till slaughter on day 5 postoestrus. Oviducts and samples of uterus were collected and their gene expression studied by real time RT-PCR. Undernourished ewes had greater PGR expression in the oviduct than control ewes, but lower expression of IGF1 in uterus and of IGF2 in oviducts. The ipsilateral oviduct presented lower expression of PGR, ESR1 and IGF2 mRNA than the contralateral one, but this did not occur in the uterus. In conclusion, there is an effect of undernutrition on gene expression that is transcript and organ dependent (uterus/oviduct). This work reports for the first time that growth factors and sex steroid receptor expression on day 5 after oestrus vary depending on the side of the CL-bearing ovary and the region of the reproductive tract. Source

de Brun V.,Laboratorio Of Tecnicas Nucleares | de Brun V.,University of Zaragoza | Meikle A.,Laboratorio Of Tecnicas Nucleares | Sequeira M.,Laboratorio Of Tecnicas Nucleares | And 4 more authors.
Journal of Animal Physiology and Animal Nutrition | Year: 2015

Summary: This study investigated whether a 22-day period of undernutrition (half maintenance) could affect maternal endocrine responses and liver gene expression during early pregnancy (day 7). Thirty-five ewes were fed 1.5 (n = 15) or 0.5 (n = 20) their maintenance requirements and slaughtered on day 7 of the oestrus cycle or pregnancy (oestrus = day 0). Insulin, IGF, leptin and non-esterified fatty acids (NEFA) were determined on days -14, 0 and 7. Transcripts of the IGF family and adipokines receptors were determined in the liver by real-time RT-PCR. Underfed animals presented lower body weight and body condition, greater plasma concentration of NEFA, and lower plasma concentrations of leptin, insulin and IGF1 compared to adequately fed animals. Underfed ewes presented greater hepatic expression of IGFBP2 than well-fed ewes, but tended to have lesser expression of IGFBP5. While no effect of undernutrition on IGFBP4 and ADIPOR2 mRNA expressions was observed, they were increased by pregnancy in underfed animals. This study shows that undernutrition modifies endocrine profiles and hepatic gene expression of IGFBP2 and 5. The pregnancy status increased hepatic gene expression of IGFBP4 and ADIPOR2 mRNA in undernourished ewes. © 2015 Blackwell Verlag GmbH. Source

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