Title: Effects of genotype and feed allowance on plasma luteinizing hormones, follicle-stimulating hormones, progesterone, estradiol levels, follicle differentiation, and egg production rates of broiler breeder hens
Authors: Onagbesan, OM ×
Metayer, S
Tona, Kokou
Williams, J
Decuypere, Eddy
Bruggeman, Veerle #
Issue Date: Jul-2006
Publisher: Poultry science assoc inc
Series Title: Poultry science vol:85 issue:7 pages:1245-1258
Abstract: The aim of this study was to compare and relate plasma hormone levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone (P-4), estradiol (E-2), and the in vitro P-4 production capacity of the largest yellow (F1) follicle granulosa cells with the laying performance of 2 genotypes ( a standard S line and a dwarf cross-experimental E line) maintained under ad libitum ( SA, EA) or restricted (SR, ER) feeding regimens. Age-related hormone changes were determined from 4 to 50 wk, hormone changes during the ovulatory cycle were determined during lay, and changes in follicle granulosa cell P-4-producing capacity in response to LH with or without growth factors were measured in vitro at different ages. The mean laying rate was similar for SR, EA, and ER but were lower for the SA. Plasma LH and FSH concentrations increased with age in all groups and peaked at puberty. Restricted feeding delayed puberty in both genotypes. Concentrations of E-2 and P-4 increased after puberty in all groups but delayed in restricted hens. Plasma levels of LH, FSH, P-4, and E-2 before and after puberty were not correlated with egg-laying performance, but peak E-2 levels were. Luteinizing hormone and P-4 concentrations during the ovulatory cycle showed differences that may be associated with the different laying performances of the 2 genotypes under ad libitum and restricted feeding. The increase in plasma LH concentration ( from basal) during the preovulatory surge was higher in the SR than in the SA but was similar for EA, ER, and SA. The increase in P-4 was also higher in SR than in the SA with no difference between EA and ER. In vitro P4 production by granulosa cells in response to LH with insulin-like growth factors, and bone morphogenetic protein-7 was different among the SA, SR, EA, and ER; the EA, SR, and ER had greater responses, and the SA had less response. The presence of insulin-like growth factors and bone morphogenetic protein-7 enhanced LH effects depending on the feeding regimen and age of hen. This finding suggests that differences in laying performances among genotypes fed at different nutritional levels may be partly due to differences in processes associated with follicular maturation modulated by gonadotropins and growth factors. It is concluded that the age at puberty is determined mainly by feed allowance, irrespective of genotype, and that differences in laying performance may be due to a combination of factors that include changes in the levels of gonadotropins or ovarian hormones and growth factors, BW, and the condition of the different genotypes under different feeding allowances.
ISSN: 0032-5791
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Division of Livestock-Nutrition-Quality (-)
× corresponding author
# (joint) last author

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