| In the batch management and production of sows in large-scale pig farms,the current timed artificial insemination program has some problems,such as synchronous development of sow follicles induced by reproductive hormones,low concentration of synchronous ovulation,and large fluctuation of timed artificial insemination and breeding rate.In addition,there are a lot stress factors in large-scale pig farms,which enhance the incidence of ovarian cysts and affect the smooth implementation of batch production.The purpose of this test is to verify the effect of KP-10,and to explore the influence on the reproductive performance of regularly fertilized sows,so as to provide technical basis for optimizing and improving the existing procedures of sow cysts,so as to reduce the occurrence of ovarian cysts.Experiment 1: KP-10 Study on follicle development in timing insemination sows.A total of 202 weaned sows were selected and randomly divide into 3 groups,PMSGGn RH group(n=102),1-KP-Gn RH group(n=50)and 2-KP-Gn RH group(n=50).1 000 IU PMSG,0.5 mg KP-10 and 1.0 mg KP-10 were injected intramuscularly 24 h after weaning;100 μg Gn RH was injected intramuscularly 96 h after weaning,with 16 h and40 h intervals for breeding,respectively.The results showed that the mean follicle diameter(0 h to 96 h),weaning-estrus interval,estrus rate,parturition rate,total litter size and live litter size were not significantly different between the groups,but the pregnancy rate in the 1-KP-Gn RH group was 96%,which was significantly higher than the other two groups(P < 0.05).Experiment 2: Study on the effect of KP-10 treatment on ovulation in timed artificial insemination sows.A total of 198 weaned sows were selected and randomly divided into 3 groups,PMSG-Gn RH group(n=98),1-PMSG-KP group(n=50)and 2-PMSG-KP group(n=50),with 1 000 IU PMSG injected intramuscularly 24 h after weaning.100 μg Gn RH,0.5 mg KP-10 and 1.0 mg KP-10 were injected intramuscularly96 h after weaning,with 16 h and 40 h intervals between breeding,respectively.The results showed that LH peaked at 0.5 h with concentrations of 7.49 m IU/m L and 7.07 m IU/m L in the 1-PMSG-KP and PMSG-Gn RH groups,respectively,while LH peaked at 0.75 h with a concentration of 8.30 m IU/m L in the 2-PMSG-KP group;mean follicle diameter(96-120 h),estrus rate,weaning-estrus interval,Mean follicle diameter(96-120 h),oestrus rate,weaning-estrus interval,pregnancy rate,total litter size and litter live births were not significantly different among the groups,and the farrowing rate of sows in the 2-PMSG-KP group was significantly higher than that in the PMSG-Gn RH group(P < 0.05).Experiment 3: To investigate the effect of KP-10 on hormone secretion in cultured granulose cells in vitro.The results showed that KP-10 significantly elevated the expression levels of steroid hormone synthase 3β-HSD,CYP11A1 m RNA and gonadotropin receptor FSHR and LHCGR in porcine granulose cells(P < 0.05).Experiment 4: To compare the morphological differences between cysts and normal follicles,as well as to detect changes in hormone levels within the follicular fluid and differences in the expression of stereotypic enzymes and gonadotropic receptor genes.The results showed that the diameter of cystic follicles was significantly larger than that of normal follicles(P<0.05);the levels of E2,P4 and COR in cystic follicular fluid were significantly higher than that of normal follicles(P<0.05),while the levels of MT were significantly lower than that of normal follicles(P<0.05);the expression levels of GR and 11β-HSD1/2 m RNA in cystic follicular membrane were significantly higher than that of normal follicles(P<0.05),while MT1/2 m RNA expression was significantly lower than that of normal follicles(P<0.05).MT1/2m RNA expression was significantly lower than that of normal follicles(P<0.05).The expression levels of St AR,CYP11A1 and 3β-HSD m RNA were significantly higher in cystic follicles than in normal follicles(P < 0.01);the expression levels of LHCGR m RNA were significantly lower in cystic follicles than in normal follicles(P < 0.01).Conclusions: KP-10 has potential for application in timed vasectomy procedures;follicular cysts are associated with disrupted hormone secretion and abnormal expression of key enzymes for hormone synthesis. |
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