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Pre‐pubertal growth, muscle and fat accumulation in male and female sheep—Relationships with metabolic hormone concentrations, timing of puberty and reproductive outcomes
Author(s) -
Rosales Nieto Cesar A.,
Ferguson Mark B.,
Briegel Jan R.,
Hedger Mark P.,
Martin Graeme B.,
Thompson Andrew N.
Publication year - 2019
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/rda.13568
Subject(s) - medicine , endocrinology , biology , nefa , leptin , insulin , testosterone (patch) , hormone , weaning , insulin like growth factor , growth factor , obesity , receptor
Metabolic homeostasis is aligned with changes in growth and body composition, through processes mediated by circulating metabolites and metabolic hormones, and is eventually linked to reproductive success. In the present study with sheep, we determined the relationships among phenotypic and genotypic rates of growth, muscle and fat accumulation, and the circulating concentrations of metabolic and tested for relationships with the timing of puberty and subsequent reproductive outcomes. We used 64 females and 62 males with known phenotypic values for depth of eye muscle (EMD) and fat (FAT) and known Australian Sheep Breeding Values at post‐weaning age for live weight (PWT), depth of eye muscle (PEMD) and depth of fat (PFAT). Blood plasma sampled every 20 min for 8 hr via was assayed for growth hormone (GH), insulin‐like growth factor I (IGF‐I), insulin, leptin, ghrelin, follistatin, glucose and non‐esterified fatty acids (NEFA). In males, PWT was positively related to the concentrations of GH, follistatin and glucose, whereas FAT and PFAT were positively related to IGF‐I concentrations ( p < .01). Testosterone concentration was negatively related to muscle variables ( p < .001) and to PFAT ( p < .05). In females, the only significant relationship detected was the positive link between EMD and insulin concentrations ( p < .05). Reproductive variables were only measured in females. Live weight at first oestrus was related positively to insulin concentration and negatively to GH concentration ( p < .05). No other relationships with reproductive variables were significant. The relationships that were detected suggest subtle differences between the sexes in the way their metabolic homeostasis responds to changes in the rates of growth, and muscle and fat accumulation, perhaps due to interference by testosterone in the males.