[1] TUMMARUK P,TANTASUPARUK W,TECHAKUMPHU M,et al.Age,body weight and backfat thickness at first observed oestrus in crossbred Landrace×Yorkshire gilts,seasonal variations and their influence on subsequence reproductive performance[J].Animal Reproduction Science,2007,99(1/2):167-181.
[2] LE COZLER Y,DAGORN J,LINDBERG J E,et al.Effect of age at first farrowing and herd management on long-term productivity of sows[J].Livestock Production Science,1998,53(2):135-142.

[3] TUMMARUK P,LUNDEHEIM N,EINARSSON S,et al.Effect of birth litter size,birth parity number,growth rate,backfat thickness and age at first mating of gilts on their reproductive performance as sows[J].Animal Reproduction Science,2001,66(3/4):225-237.
[4] ROONGSITTHICHAI A,CHEUCHUCHART P,CHATWIJITKUL S,et al.Influence of age at first estrus,bodyweight,and average daily gain of replacement gilts on their subsequent reproductive performance as sows[J].Livestock Science,2013,151(2/3):238-245.
[5] PINILLA L,AGUILAR E,DIEGUEZ C,et al.Kisspeptins and reproduction:physiological roles and regulatory mechanisms[J].Physiological Reviews,2012,92(3):1235-1316.

[6] GOTTSCH M L,CLIFTON D K,STEINER R A.Kisspepeptin-GPR54 signaling in the neuroendocrine reproductive axis[J].Molecular and Cellular Endocrinology,2006,254/255:91-96.
[7] PLANT T M,BARKER-GIBB M L.Neurobiological mechanisms of puberty in higher primates[J].Human Reproduction Update,2004,10(1):67-77.

[8] TENA-SEMPERE M.GPR54 and kisspeptin in reproduction[J].Human Reproduction Update,2006,12(5):631-639.

[9] OHTAKI T,SHINTANI Y,HONDA S,et al.Metastasis suppressor gene
KiSS-1 encodes peptide ligand of a G-protein-coupled receptor[J].Nature,2001,411(6837):613-617.

[10] LEE J H,MIELE M E,HICKS D J,et al.
KiSS-1,a novel human malignant melanoma metastasis-suppressor gene[J].Journal of the National Cancer Institute,1996,88(23):1731-1737.

[11] KOTANI M,DETHEUX M,VANDENBOGAERDE A,et al.The metastasis suppressor gene
KiSS-1 encodes kisspeptins,the natural ligands of the orphan G protein-coupled receptor GPR54[J].The Journal of Biological Chemistry,2001,276:34631-34636.
[12] SEMINARA S B,MESSAGER S,CHATZIDAKI E E,et al.The
GPR54 gene as a regulator of puberty[J].The New England Journal of Medicine,2003,349:1614-1627.
[13] DE ROUX N,GENIN E,CAREL J C,et al.Hypogonadotropichypogonadism due to loss of function of the
KiSS1-derived peptide receptor GPR54[J].The Proceedings of the National Academy of Sciences of the United States of America,2003,100(19):10972-10976.

[14] KINOSHITA M,TSUKAMURA H,ADACHI S,et al.Involvement of central metastin in the regulation of preovulatory luteinizing hormone surge and estrous cyclicity in female rats[J].Endocrinology,2005,146(10):4431-4436.

[15] DHILLO W S,CHAUDHRI O B,PATTERSON M,et al.Kisspeptin-54 stimulates the hypothalamic-pituitarygonadal axis in human males[J].The Journal of Clinical Endocrinology and Metabolism,2005,90(12):6609-6615.

[16] NAVARRO V M,CASTELLANO J M,FERNNDEZ-FERNÁNDEZ R,et al.Effects of KiSS-1 peptide,the natural ligand of GPR54,on follicle-stimulating hormone secretion in the rat[J].Endocrinology,2005,146(4):1689-1697.

[17] NAVARRO V M,CASTELLANO J M,FERNÁNDEZ-FERNÁNDEZ R,et al.Characterization of the potent luteinizing hormone-releasing activity of KiSS-1 peptide,the natural ligand of GPR54[J].Endocrinology,2005,146 (1):156-163.
[18] SHAHAB M,MASTRONARDI C,SEMINARA S B,et al.Increased hypothalamic GPR54 signaling:a potential mechanism for initiation of puberty in primates[J].The Proceedings of the National Academy of Sciences of the United States of America,2005,102(6):2129-2134.

[19] GREIVES T J,MASON A O,SCOTTI M A L,et al.Environmental control of kisspeptin:implications for seasonal reproduction[J].Endocrinology,2007,148(3):1158-1166.

[20] KAUFFMAN A S,PARK J H,MCPHIE-LALMANSINGH A A,et al.The kisspeptin receptor GPR54 is required for sexual differentiation of the brain and behavior[J].The Journal of Neuroscience:the Official Journal of the Society for Neuroscience,2007,27(33):8826-8835.

[21] XU S Y,LINHER-MELVILLE K,YANG B B,et al.Micro-RNA378 (miR-378) regulates ovarian estradiol production by targeting aromatase[J].Endocrinology,2011,152(10):3941-3951.

[22] IRWIG M S,FRALEY G S,SMITH J T,et al.Kisspeptin activation of gonadotropin releasing hormone neurons and regulation of
KiSS-1 mRNA in the male rat[J].Neuroendocrinology,2004,80(4):264-272.

[23] HAN S K,GOTTSCH M L,LEE K J,et al.Activation of gonadotropin-releasing hormone neurons by kisspeptin as a neuroendocrine switch for the onset of puberty[J].The Journal of Neuroscience,2005,25(49):11349-11356.

[24] PIELECHA-FORTUNNA J,CHU Z G,MOENTER S M.Kisspeptin acts directly and indirectly to increase gonadotropin-releasing hormone neuron activity and its effects are modulated by estradiol[J].Endocrinology,2008,149(4):1979-1986.

[25] CLARKSON J,HERBISON A E.Postnatal development of kisspeptin neurons in mouse hypothalamus;sexual dimorphism and projections to gonadotropin-releasing hormone neurons[J].Endocrinology,2006,147(12):5817-5825.

[26] DECOURT C,TILLET Y,CARATY A,et al.Kisspeptinimmunoreactive neurons in the equine hypothalamus interactions with GnRH neuronal system[J].Journal of Chemical Neuroanatomy,2008,36(3/4):131-137.
[27] RAMASWAMY S,GUERRIERO K A,GIBBS R B,et al.Structural interactions between kisspeptin and GnRH neurons in the mediobasal hypothalamus of the male rhesus monkey (
Macaca mulatta) as revealed by double immunofluorescence and confocal microscopy[J].Endocrinology,2008,149(9):4387-4395.

[28] NAVARROV M,TENA-SEMPERE M.Neuroendocrine control by kisspeptins:role in metabolic regulation of fertility[J].Nature Reviews Endocrinology,2012,8(1):40-53.
[29] LENTS C A,HEIDORN N L,BARB C R,et al.Central andperipheral administration of kisspeptin activates gonadotropinbut not somatotropin secretion in prepubertal gilts[J].Reproduction,2008,135:879-887.
[30] ADACHI S,YAMADA S,TAKATSU Y,et al.Involvement of anteroventral periventricular metastin/kisspeptin neurons in estrogen positive feedback action on luteinizing hormonerelease in female rats[J].The Journal of Reproduction and Development,2007,53(2):367-378.

[31] TOMIKAWA J,HOMMA T,TAJIMA S,et al.Molecular characterization and estrogen regulation of hypothalamic
KISS1 gene in the pig[J].Biology of Reproduction,2010,82(2):313-319.

[32] IEDA N,UENOYAMA Y,TAJIMA Y,et al.
KISS1 gene expression in the developing brain of female pigs in pre- and peripubertal periods[J].The Jounal of Reproduction and Development,2014,60(4):312-316.

[33] SMITH J T,CUNNINGHAM M J,RISSMAN E F,et al.Regulation of
Kiss1 gene expression in the brain of the female mouse[J].Endocrinology,2005,146(9):3686-3692.

[34] FRISH R E.Body fat,menarche,fitness and fertility[J].Human Reproduction,1987,2(6):521-533.
[35] ARMSTRONG J D,BRITT J H.Nutritionally-induced anestrus in gilts:metabolic and endocrine changes associated with cessation and resumption of estrous cycles[J].Journal of Animal Science,1987,65(2):508-523.
[36] ROZEBOOM D W,MOSER R L,CORNELIUS S G,et al.Body composition of postpubertal gilts at nutritionally induced anestrus[J].Journal of Animal Science,1993,71(2):426-435.
[37] LENTS C A,REMPEL L A,KLINDT J,et al.The relationship of plasma urea nitrogen with growth traits and age at first estrus in gilts[J].Journal of Animal Science,2013,91(7):3137-3142.

[38] OURY F,SUMARA G,SUMARA O,et al.Endocrine regulationof male fertility by the skeleton[J].Cell,2011,144(5):796-809.

[39] MAYER C,ACOSTA-MARTINEZ M,DUBOIS S L,et al.Timing and completion of puberty in female mice depend on estrogen receptor α-signaling in kisspeptin neurons[J].The Proceedings of the National Academy of Sciences of the United States of America,2010,107(52):22693-22698.

[40] ZHOU D,ZHUO Y,CHE L.Nutrient restriction induces failure of reproductive functionand molecular changes in hypothalamus-pituitary-gonadal axisin postpubertal gilts[J].Molecular Biology Reprots,2014,41(7):4733-4742.

[41] CASTELLANO J M,NAVARRO V M R,FERNANDEZ-FERNANDEZ R,et al.Changes in hypothalamic KiSS-1 system and restoration of pubertal activation of the reproductive axis by kisspeptin in undernutrition[J].Endocrinology,2005,146(9):3917-3925.

[42] OWEN B M,BOOKOUT A L,DING X S,et al.FGF21 contributes to neuroendocrine control of female reproduction[J].Nature Medicine,2013,19(9):1153-1156.

[43] POTTHOFF M J,INAGAKI T,SATAPATI S,et al.FGF21 induces PGC-1alpha and regulates carbohydrate and fatty acid metabolism during the adaptive starvation response[J].The Proceedings of the National Academy of Sciences of the United States of America,2009,106(26):10853-10858.

[44] SONIGO C,BOUILLY J,CARRN,et al.Hyperprolactinemia-induced ovarian acyclicity is reversed by kisspeptin administration[J].The Journal of Clinical Investigation,2012,122(10):3791-3795.

[45] XU J,KIRIGITI M A,GROVE K L,et al.Regulation of food intake and gonadotropin-releasing hormone/luteinizing hormone during lactation:role of insulin and leptin[J].Endocrinology,2009,150(9):4231-4240.

[46] TRUE C,KIRIGITI M A,KIEVIT P,et al.Leptin is not the critical signal for kisspeptin or luteinising hormone restoration during exit from negative energy balance[J].Journal of Neuroendocrinology,2011,23(11):1099-1112.

[47] ROLAND A V,MOENTER S M.Glucosensing by GnRH neurons:inhibition by androgens and involvement of AMP-activated protein kinase[J].Molecular Endocrinology,2011,25(5):847-858.

[48] ZHANG C G,BOSCH M A,LEVINE J E,et al.Gonadotropin-releasing hormone neurons express KATP channels that are regulatedby estrogen and responsive to glucose and metabolic inhibition[J].The Journal of Neuroscience,2007,27(38):10153-10164.

[49] ROA J,GARCIA-GALIANO D,VARELA L,et al.The mammalian target of rapamycin as novel central regulator of puberty onset via modulation of hypothalamic Kiss1 system[J].Endocrinology,2009,150(11):5016-5026.

[50] ALTAREJOS J Y,GOEBEL N,CONKRIGHT M D,et al.The Creb1 coactivator Crtc1 is required for energybalance and fertility[J].Nature Medicine,2008,14(10):1112-1117.

[51] ZHUO Y,ZHOU D S,CHE L Q,et al.Feeding prepubescent gilts a high-fat diet induces molecularchanges in the hypothalamus-pituitary-gonadal axis and predictsearly timing of puberty[J].Nutrition,2014,30(7/8):890-896.
[52] BARB C R,HAUSMAN G J,LENTS C A.Energy metabolism and leptin:effects on neuroendocrine regulation of reproduction in the gilt and sow[J].Reproduction in Domestic Animals,2008,43(Suppl.2):324-330.
[53] 李方方.日粮能量来源对大鼠初情启动的影响及调控机理研究[D].博士学位论文.雅安:四川农业大学,2012.
[54] SMITH J T,ACOHIDO B V,CLIFTON D K,et al.KiSS-1 neurones are direct targets for leptin in the
ob/ob mouse[J].Journal of Neuroendocrinology,2006,18(4):298-303.

[55] QUENNELL J H,HOWELL C S,ROA J,et al.Leptindeficiency and diet-induced obesity reduce hypothalamic kisspeptinexpression in mice[J].Endocrinology,2011,152(4):1541-1550.

[56] CUNNINGHAM P J,NABER C H,ZIMMERMAN D R,et al.Influence of nutritional regime on age at puberty in gilts[J].Journal of Animal Science,1974,39(1):63-67.
[57] PATTERSON J L,BALL R O,WILLIS H J,et al.The effect of lean growth rate on puberty attainment in gilts[J].Journal of Animal Science,2002,80(5):1299-1310.
[58] TORRE S D,RANDO G,MEDA C,et al.Amino acid-dependent activation of liver estrogen receptor alpha integrates metabolic and reproductive functions via IGF-1[J].Cell Metabolism,2011,13(2):205-214.

[59] NARITA K,NAGAO K,BANNAI M,et al.Dietary deficiency of essential amino acids rapidly induces cessation of the rat estrous cycle[J].PLoS One,2011,6(11):e28136.
[60] ROLDAN M B,WHITE C,WITCHEL S F.Association of the GAA1013→GAG polymorphism of the insulin-like growth factor-1 receptor (
IGF1
R) gene with premature pubarche[J].Fertility and Sterility,2007,88(2):410-417.

[61] ROONGSITTHICHAI A,KOONJAENAK S,TUMMARUK P.Association among serum insulin-like growth factor-Ⅰ,backfat thickness,and age at first observed estrus in gilts[J].Thai Journal of Veterinary Medicine,2013,43(1):41-48.
[62] JOHNSTON D J,BARWICK S A,CORBET N J,et al.Genetics of heifer puberty in two tropical beef genotypes in northern Australia and associations with heifer- and steer-production traits[J].Animal Production Science,2009,49(6):399-412.

[63] FORTES M R S,LI Y T,COLLIS E,et al.The IGF1 pathway genes and their association with age of puberty in cattle[J].Animal Genetics,2013,44(1):91-95.

[64] HINEY J K,SRIVASTAVA V K,PINE M D,et al.Insulin-like growth factor-Ⅰactivates
KiSS-1 gene expression in the brain of the prepubertal female rat[J].Endocrinology,2009,150(1):376-384.

[65] TODD B J,MERHI Z O,SHU J,et al.Hypothalamic insulin-like growth factor-Ⅰ receptors are necessary for hormone-dependent luteinizing hormone surges:implications for female reproductive aging[J].Endocrinology,2010,151(3):1356-1366.

[66] SUN Y,TODD B J,THORNTON K,et al.Differential effects of hypothalamic IGF-Ⅰ on gonadotropin releasing hormone neuronal activation during steroid-induced LH surges in young and middle-aged female rats[J].Endocrinology,2011,152(11):4276-4287.

[67] OZKAN S,JINDAL S,GREENSEID K,et al.Replete vitamin D stores predict reproductive success following
in vitro fertilization[J].Fertility and Sterility,2009,94(5):1314-1319.
[68] SUN W,XIE H,JI J,et al.Defective female reproductive function in 1, 25(OH)
2D-deficient mice results from indirect effect mediated by extracellular calcium and/or phosphorus[J].American Journal of Physiology:Endocrinology and Metabolism,2011,299(6):E928-E935.
[69] DICKEN C L,ISRAEL D D,DAVIS J B,et al.Peripubertalvitamin D
3 deficiency delays puberty and disrupts the estrous cycle in adult female mice[J].Biology of Reproduction,2012,87(2):51.
[70] PATTERSON J L,BELTRANENA E,FOXCROFT G R.The effect of gilt age at first estrus and breeding on third estruson sow body weight changes and long-term reproductive performance[J].Journal of Animal Science,2010,88(7):2500-2513.

[71] PINE M,LEE B,DEARTH R,et al.Manganese acts centrally to stimulate luteinizing hormonesecretion:a potential influence on female pubertaldevelopment[J].Toxicological Science,2005,85(2):880-885.

[72] LEE B,HINEY J K,PINE M D,et al.Manganese stimulates luteinizing hormone releasing hormone secretion in prepubertal female rats:hypothalamic site and mechanism of action[J].Journal of Physiology,2007,578:765-772.
[73] HINEY J K,SRIVASTAVA V K,DEES W L.Manganese induces
IGF-1 and cyclooxygenase-2 gene expressionsin the basal hypothalamus during prepubertalfemale development[J].Toxicological Science,2011,121(2):389-396.

[74] SRIVASTAVA V K,HINEY J K,DEES W L.Early life manganese exposure upregulatestumor-associated genes in the hypothalamus of female rats:relationship to manganese-induced precocious puberty[J].Toxicological Science,2013,136(2):373-381.

[75] TOMIKAWAA J,YOSHIHISA U,OZAWAA M,et al.Epigenetic regulation of
Kiss1 gene expression mediating estrogen-positive feedback action in the mouse brain[J].The Proceedings of the National Academy of Sciences of the United States of America,2012,109(20):E1294-E1301.
[76] LOMNICZI A,LOCHE A,CASTELLANO J M,et al.Epigenetic control of female puberty[J].Nature Neuroscience,2013,16(3):281-289.

[77] LOSA-WARD S M,TODD K L,MCCAFFREY K A,et al.Disrupted organization of Rfami depathways in the hypothalamus is associated with advanced puberty in female rats neonatallyexposed to bisphenol A[J].Biology of Reproduction,2012,87(2):28.
[78] GORE A C,WALKER D M,ZAMA A M,et al.Early life exposure to endocrine-disrupting chemicals causes lifelong molecular reprogramming of the hypothalamus and premature reproductive aging[J].Molecular Endocrinology,2011,25(12):2157-2168.