Sexual dimorphism for growth in Muscovy ducks and changes in insulin-like growth factor I (IGF-I), growth hormone (GH) and triiodothyronine (T3) plasma levels

Citation
E. Baeza et al., Sexual dimorphism for growth in Muscovy ducks and changes in insulin-like growth factor I (IGF-I), growth hormone (GH) and triiodothyronine (T3) plasma levels, REPROD NUTR, 41(2), 2001, pp. 173-179
Citations number
23
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences
Journal title
REPRODUCTION NUTRITION DEVELOPMENT
ISSN journal
0926-5287 → ACNP
Volume
41
Issue
2
Year of publication
2001
Pages
173 - 179
Database
ISI
SICI code
0926-5287(200103/04)41:2<173:SDFGIM>2.0.ZU;2-R
Abstract
Muscovy ducks display marked sexual dimorphism for body weight. The aim of our study was to analyse the possible relationships between this dimorphism and plasma levels of T3, GH and IGF-I from hatch to 15 weeks of age. We fo und no significant effect of sex or age on plasma T3 which remained relativ ely stable about 6 nM.L-1. Plasma GH levels were highest (14-24 ng.mL(-1)) but highly variable during the first four weeks in females and during the f irst seven weeks in males. Then, they decreased and remained low (3-4 ng.mL (-1)) until the age of 15 weeks. A trend for higher GH concentrations in ma les compared to females was observed across the experimental period. The di fference was maximum around 6-7 weeks of age. Plasma IGF-I levels rose shar ply between 2 and 3 weeks of age and remained high until 6-7 weeks of age f or the females and 13 weeks of age for the males then started to decrease. For the whole experimental period, significantly higher IGF-I levels were m easured in males. The differences between sexes were significant between 7 and 12 weeks of age and at 14 weeks of age. The differences in circulating GH and IGF-I levels between sexes suggest that the somatotrophic axis is im plicated in Muscovy duck sexual dimorphism.