Hormonal changes associated with ageing and induced moulting of domestic hens.
1. The effect of age on ovarian function was studied in 245-, 350-, 500-, 700- and 800-d-old Lohmann hens. The effect of three different methods for moult induction on ovarian function and corticosterone concentration was studied in 500-d-old hens. 2. No significant reductions in ovarian weight or in number of follicles before the age of 700 d were found. The ability to produce progesterone and oestradiol-17beta was unchanged up to the age of 700 d and the circadian secretion of these two steroids was identical in young (225 d) and old hens (600 d). 3. The effects of induced moulting by feed withdrawal (FW) and a high Zn (HZn) diet on body weight and ovarian function were very similar; those of a moderate Zn with low Ca (MZn/LCa) diet were smaller. 4. The first significant effect of moulting was a decrease in oestradiol-17beta plasma concentration (d 2). Plasma progesterone decreased more gradually than oestradiol-17beta, and reached a nadir on d 6 in FW- and HZn-treated hens and on d 9 in MZn/LCa-treated ones. 5. Hens treated with either FW or the MZn/LCa, but not those with the HZn diet, showed a very sharp rise in corticosterone concentration on d 2 of treatment. Thus the MZn/LCa diet was less efficient than the other treatments in induction of ovarian involution, but had a similar effect on stress induction, as indicated by increases in plasma corticosterone.
Braw-Tal
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R
Institute of Animal Science, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. brawtal@agri.huji.ac.il
Yossefi
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S
Pen
S
S
Shinder
D
D
Bar
A
A
D000375:Aging / Q000097:blood / Q000502:physiology*; D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000097:blood / Q000502:physiology*; D003345:Corticosterone / Q000097:blood; D004958:Estradiol / Q000097:blood; D005241:Feathers; D005260:Female; D005508:Food Deprivation / Q000502:physiology; D018978:Molting / Q000502:physiology*; D009929:Organ Size; D010053:Ovary / Q000502:physiology; D011374:Progesterone / Q000097:blood; D012098:Reproduction / Q000502:physiology*
D011374:Progesterone; D004958:Estradiol; D003345:Corticosterone