{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,2]],"date-time":"2026-10-02T16:17:42Z","timestamp":1790957862483,"version":"4.1.0"},"reference-count":34,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2021,2,8]],"date-time":"2021-02-08T00:00:00Z","timestamp":1612742400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>Gonadotropin-releasing hormone (GnRH)\u2013loaded chitosan nanoparticles (GnRH\u2013ChNPs) were used at different doses and routes of administration to induce ovulation in rabbits as an attempt to improve artificial insemination (AI) procedures and outcomes. In this study, the characteristics (size, polydispersity, loading efficiency, and zeta-potential) of GnRH\u2013ChNPs and the GnRH release pattern were determined in an in vitro study. A first in vivo study assessed the pituitary and ovarian response to different GnRH\u2013ChNPs doses and routes of administration (two i.m. doses, Group HM = 0.4 \u00b5g and Group QM = 0.2 \u00b5g, and two intravaginal doses, Group HV = 4 \u00b5g and Group QV = 2 \u00b5g) against a control group (C) receiving bare GnRH (0.8 \u00b5g). The HM, QM, and HV treatments induced an earlier LH-surge (90 min) than that observed in group C (120 min), whilst the QV treatment failed to induce such LH surge. The number of ovulation points was similar among treatments, except for the QV treatment (no ovulation points). A second in vivo study was consequently developed to determine the hormonal (progesterone, P4, and estradiol, E2) profile and pregnancy outcomes of both HM and HV treatments against group C. The treatment HM, but not the treatment HV, showed adequate P4 and E2 concentrations, conception and parturition rates, litter size, litter weight, and viability rate at birth. Overall, the use of GnRH\u2013ChNPs allows for a reduction in the conventional intramuscular GnRH dose to half without compromising fertility. However, the addition of GnRH\u2013ChNPs to semen extenders, although successfully inducing ovulation, has negative impacts on fertility. Thus, more studies are needed to explore this point and allow further adjustments.<\/jats:p>","DOI":"10.3390\/ani11020440","type":"journal-article","created":{"date-parts":[[2021,2,9]],"date-time":"2021-02-09T04:18:50Z","timestamp":1612844330000},"page":"440","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":45,"title":["Efficiency of GnRH\u2013Loaded Chitosan Nanoparticles for Inducing LH Secretion and Fertile Ovulations in Protocols for Artificial Insemination in Rabbit Does"],"prefix":"10.3390","volume":"11","author":[{"given":"Eman M.","family":"Hassanein","sequence":"first","affiliation":[{"name":"Animal and Fish Production Department, Faculty of Agriculture, Alexandria University, Alexandria 21545, Egypt"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0058-9671","authenticated-orcid":false,"given":"Nesrein M.","family":"Hashem","sequence":"additional","affiliation":[{"name":"Animal and Fish Production Department, Faculty of Agriculture, Alexandria University, Alexandria 21545, Egypt"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kheir El-Din M.","family":"El-Azrak","sequence":"additional","affiliation":[{"name":"Animal and Fish Production Department, Faculty of Agriculture, Alexandria University, Alexandria 21545, Egypt"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Antonio","family":"Gonzalez-Bulnes","sequence":"additional","affiliation":[{"name":"Departamento de Reproduccion Animal, INIA, Avda. Puerta de Hierro s\/n., 28040 Madrid, Spain"},{"name":"Departamento de Produccion y Sanidad Animal, Facultad de Veterinaria, Universidad Cardenal Herrera-CEU, CEU Universities, C\/ Tirant lo Blanc, 7, 46115 Alfara del Patriarca, Valencia, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gamal A.","family":"Hassan","sequence":"additional","affiliation":[{"name":"Animal and Fish Production Department, Faculty of Agriculture, Alexandria University, Alexandria 21545, Egypt"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohamed H.","family":"Salem","sequence":"additional","affiliation":[{"name":"Animal and Fish Production Department, Faculty of Agriculture, Alexandria University, Alexandria 21545, Egypt"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,2,8]]},"reference":[{"key":"ref_1","unstructured":"Boiti, C. (2004, January 7\u201310). 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