摘要Energy is a crucial component for maintaining egg production in layers.The hypothalamic-pituitary-ovarian(HPO)axis is an energy-sensitive functional axis for follicle development,synthesis,and secre-tion of reproductive hormones,and plays a key role in modulating sustained ovulation in layers.To investigate the mechanism of integrated network regulation of the HPO axis under energy fluctuation,ninety Hy-line brown layers(265-day-old,1.92±0.02 kg)were randomly divided into three groups for a 17-day experiment:a control group(Con group)fed ad libitum from days 1 to 17,an energy-deprived group(ED group)that was fed ad libitum from days 1 to 12 and then underwent a fasting period from days 13 to 17 to induce a pause in laying,and a re-fed group(Rf group)that fasted for seven days(specifically,days 1 to 5,day 7,and day 9),had ad libitum access to feed on days 6 and 8,and was continuously fed from days 10 to 17.Each treatment consisted of 10 replicates with 3 birds per replicate.The study found that energy deprivation significantly decreased reproductive performance such as egg laying rate,ovarian index,number of small yellow follicles(SYF),and normal hierarchical follicles(NHIE)(P＜0.05),which recovered after refeeding,indicating the importance of energy availability for sustained ovulation in layers.In addition,estradiol(E2),estradiol to progesterone(E2/P4)ratio,and luteinizing hormone(LH)displayed changes similar to follicle number,whereas follicle-stimulating hormone(FSH)exhibited a contrasting pattern.Transcriptome analysis revealed that energy deprivation downregulated genes related to energy and appetite-regulated neurotransmitter receptors and neuropeptides in the hypothalamus.These signals combined to inhibit gonadotropin-releasing hormone(GnRH)secretion and subsequently downregulated the crucial genes responsible for synthesizing gonadotropins,gonado-tropin-releasing hormone receptor(GnRHR),and glycoprotein hormones alpha chain(CGA).Conse-quently,this suppression of the hypothalamus and pituitary affected ovarian function through ovarian steroidogenesis and the extracellular matrix(ECM)-receptor interaction.These findings suggest that energy deprivation inhibits the function of the HPO axis,leading to impaired follicle development and reduced egg production,and that refeeding can partially restore these indicators.