Exogenous leptin advances puberty in domestic hen.
The present study was undertaken to examine the effect of recombinant chicken leptin administered to fed ad libitum and feed-restricted immature chickens of a layer strain on ovarian development and the timing of sexual maturity. In the first experiment 11-week-old pullets (77 days of age) fed ad libitum were injected daily with leptin at four dose levels (4, 16, 64 and 256 microg/kg body weight) until sexual maturity (lay of the first egg). Leptin treatment at the highest dose significantly (P<0.05) advanced the onset of puberty (day 116.3+/-1.0) in comparison to controls (day 121.3+/-1.2). The rises of luteinizing hormone, estradiol and progesterone in blood plasma were also advanced by leptin treatment. In the second experiment, both full-fed and feed-restricted pullets (79 days of age) were injected daily with leptin (256 microg/kg body weight). In birds fed ad libitum, exogenous leptin again significantly (P<0.05) advanced first ovipostion (day 118.4+/-1.4 versus day 124.4+/-1.7), while abolishing the significant (P<0.05) delay caused by feed restriction (day 131.5+/-1.6) and restoring the normal onset of sexual maturity (day 125.7+/-1.6). Analysis of the ovaries in 106-day-old pullets revealed that leptin injections advanced follicular development, particularly in birds fed ad libitum, and significantly (P<0.01) reduced follicular apoptosis both in full-fed and feed-restricted birds. In conclusion, we have shown that in female chickens exogenous leptin advances the onset of puberty by attenuation of ovarian apoptosis and enhancement of folliculogenesis.
Paczoska-Eliasiewicz
Helena Elzbieta
HE
Department of Animal Physiology, University of Agriculture, Kraków, Poland. rzeliasi@cyf-kr.edu.pl <rzeliasi@cyf-kr.edu.pl>
Proszkowiec-Weglarz
Monika
M
Proudman
John
J
Jacek
Tomasz
T
Mika
Maria
M
Sechman
Andrzej
A
Rzasa
Janusz
J
Gertler
Arieh
A
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D002645:Chickens / Q000502:physiology*; D004958:Estradiol / Q000097:blood; D005260:Female; D005508:Food Deprivation / Q000502:physiology; D020287:In Situ Nick-End Labeling / Q000662:veterinary; D020738:Leptin / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000097:blood; D010053:Ovary / Q000187:drug effects* / Q000502:physiology; D011374:Progesterone / Q000097:blood; D012741:Sexual Maturation / Q000187:drug effects* / Q000502:physiology
D020738:Leptin; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone