The effect of Ghrelin on development of chicken prehierarchical follicles was evaluated in this study. The expression of growth hormone secretagogue receptor (GHSR) was determined by RTPCR, and effects of Ghrelin and follicle stimulating hormone (FSH) on morphology of prehierarchical follicles and laminin and connexin43 labeling indexes in granulosa cells were estimated by histological and immunohistochemical methods. The results showed that GHSR mRNA was expressed in both granulosa and theca layers, and the expression level reached the peak in large white follicle (LWF) and small yellow follicle (SYF), and then decreased thereafter. After treatment with Ghrelin and FSH for 24 h, the thicknesses of granulosa and theca layers and density of granulosa cells were significantly increased in both LWF and SYF in suspension culture (P<0.05). In addition, the labeling indexes of laminin and connexin43 were remarkably elevated in granulosa cells (P<0.05). An additive effect of FSH with ghrelin was demonstrated. In conclusion, the above results indicate that Ghrelin promotes the expression of laminin and connexin43 in granulosa cells to enhance cell to cell interactions, subsequently stimulates the proliferation of granulosa cells, and cooperates with FSH to regulate chicken prehierarchical follicle development.

The objective of the study was to provide a reliable evidence for artificial insemination and multiple ovulation by the knowledge of characteristic of ovarian follicular waves and by determining whether the dynamic change existed in ovarian follicule (including recruitment, selection, dominance, atresia or ovulation) during the interovulatory interval (IOI). The ovarian follicles of 5 Dezhou donkeys with ten continuous estrous cycles were examined daily using rectal ultrasonography during the breeding season. Blood samples were drawn daily to measure serum concentrations of estradiol17β, LH, FSH and IGF1 by RIA for ten estrous cycles. The results of the research indicated that:（1）IOI in donkeys was (23.22±0.28)d .In the 10 estrous cycles evaluated, donkeys with two follicle waves exhibited a six minormajor waves and four majormajor waves pattern of follicle development. （2）The recruitment occurring of wave1 and wave2 began on the first and (10.2±1.4) days after ovulation，the numbers of follicles recruited were (5.2±1.2) and (4.0±0.3)，and the numbers of follicles selected were (2.3±0.5) and (2.5±0.4). The dominance of follicles at wave1 and 2 began on (5.8±0.6) and (18.1±1.4)days after ovulation. The mean days of the largest follicle occurred at (7.67±0.24) and (23.22±0.28)days and were (26.44±2.37) and (40.7±2.45)mm,with daily growth rate of (2.01±0.5) and (3.15±0.6) mm·d-1,respectively.（3）The average diameter of the biggest CL was (37.61±1.58)mm and the life length of CL was (17.30±1.62)d.（4）The high concentration of E2 ((46.47±9.53) pg·mL-1) lasted at from 3 d before to 2 d after ovulation ,and it reached the crest value((62.84±4.89) pg·mL-1) at 2 d befor ovulation. （5）The concentration of FSH declined significantly during the stage of the largest follicle at wave 1（7 d after ovulation）and wave 2（23 or 24 d after ovulation）with the negative feedback of E2.（6）The concentration of LH rose suddenly at several days before ovulation,and it reached the peak value((4.69±0.43) mIU·mL-1) at 2 d after ovulation. （7）The change in concentration of IGF1 was similar to E2, and it reached the crest value((47.9±3.91) ng·mL-1) at 1 d before ovulation. In conclusion, the results indicate that the follicular waves patterns exist in follicular development,and the occurrence of 2 follicular waves per cycle is a more common phenomena in Dezhou donkey ; and the ovulation occurr at 2 d before estrus ceased; E2, FSH, LH and IGF1 play important role in the change of folliculae wave, the recuitment and selection of small follicles, estrus and ovulation at wave 1 and wave 2.