Exogenous leptin advances puberty in domestic hen

anglais. 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 μg/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 μg/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. © 2005 Elsevier Inc. All rights reserved.

anglais. Animals; Apoptosis; Body Weight; Chickens; Estradiol; Female; Food Deprivation; In Situ Nick-End Labeling; Leptin; Luteinizing Hormone; Ovary; Progesterone; Sexual Maturation; Aves; Gallus gallus; estradiol; leptin; luteinizing hormone; progesterone; animal; animal disease; apoptosis; article; blood; body weight; chicken; drug effect; female; food deprivation; nick end labeling; ovary; physiology; sexual maturation

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