玉米赤霉烯酮对青年母猪子宫发育、生长激素分泌及其受体分布与表达的影响

Effects of Zearalenone on Uterus Development,Growth Hormone Secretion and Its Receptor Distribution and Expression in Prepubertal gilts

本试验旨在研究玉米赤霉烯酮(ZEA)对青年母猪子宫发育、生长激素(GH)分泌及其受体(GHR)分布与表达的影响。选择胎次和体重[(23.20±0.68)kg]相近的长×大二元青年母猪48头,将其随机分为4组,每组12个重复,每个重复1头。对照组(CON组)饲喂基础饲粮,试验组(T1、T2、T3组)饲喂在基础饲粮中分别添加200、800、1600μg/kg ZEA的试验饲粮。预试期7 d,正试期40 d。结果表明:1)各组间血清及子宫组织中GH含量均无显著差异(P>0.05)。2)各组间子宫组织中ZEA含量均无显著差异(P>0.05)。3)各组间始重、末重、平均日增重(ADG)、平均日采食量(ADFI)及料重比(F/G)均无显著差异(P>0.05);但与CON组相比,T2组子宫指数显著升高(P<0.05),T3组极显著升高(P<0.01)。4)与CON组相比,试验组子宫肌层和内膜增厚,子宫腺数量增多,毛细血管增多,T2和T3组还出现炎性反应及上皮细胞坏死。5)与CON组相比,T2组GHR和Janus蛋白酪氨酸激酶2(JAK2)mRNA相对表达量及T3组GHR mRNA相对表达量显著上调(P<0.05),信号转导与转录激活因子3(STAT3)mRNA相对表达量各组间无显著差异(P>0.05)。6)ZEA对GHR在青年母猪子宫中的分布与定位无明显影响,但与CON组相比,试验组GHR免疫阳性物质分布增多,免疫阳性强度增大。7)各组间子宫GHR蛋白表达量没有显著差异(P>0.05);但与CON组相比,T2组灰度值有升高的趋势(P=0.09)。综上所述,ZEA对青年母猪的生长性能以及血液和子宫中GH和ZEA的含量均无显著影响,但可通过升高GHR、JAK2和STAT3的mRNA相对表达量、增强GHR免疫阳性及升高蛋白表达量来增强GH的生物效应,使子宫发育异常,导致子宫指数出现极显著升高,子宫肌层和内膜增厚,子宫腺和毛细血管数量增多。

The purpose of this experiment was to investigate the effects of zearalenone on uterus development,growth hormone secretion and its receptor distribution and expression in prepubertal gilts.A total of 48 Landrace×Yorkshire prepubertal gilts with similar litter times,breeds and weight of(23.20±0.68)kg were randomly divided into 4 groups(12 replicates per group,1 gilt per replicate).Prepubertal gilts in control group(CON group)were fed a basal diet and those in test groups(T1,T2 and T3 groups)were fed the basal diet supplemented with 200,800,1600μg/kg ZEA,respectively.Pretest lasted for 7 d,and test lasted for 40 d.The results showed as follows:1)there were no significant differences in the contents of GH in serum and uterine tissues of prepubertal gilts in all groups(P>0.05).2)There were no significant differences in the contents of ZEA in uterine tissues of prepubertal gilts in all groups(P>0.05).3)There were no significant differences in the initial weight,final weight,average daily gain,average daily feed intake and feed/gain of each group of prepubertal gilts(P>0.05),but compared with the CON group,the uterine index of the gilts in the T2 group was significantly increased(P<0.05),and the T3 group was extremely significantly increased(P<0.01).4)Compared with the CON group,the myometrium and endometrium of prepubertal gilts in the test groups were thickened,and the number of uterine glands and capillaries were increased.The T2 and T3 groups also showed inflammatory responses and epithelial cell necrosis.5)Compared with the CON group,the relative expression levels of GHR and Janus activated kinase 2 mRNA in the T2 group and GHR mRNA in the T3 group were significantly increased(P<0.05),and the relative expression levels of signal transducer and activator of transcriptions 3 mRNA were not significantly different among the groups(P>0.05).6)ZEA had no obvious effect on the distribution and localization of GHR in the uterus of prepubertal gilts.However,compared with the CON group,the distribution of GHR immunopositive substances increased in the experimental groups,and the immunopositive intensity increased.7)There was no significant difference in the expression level of GHR protein in the uterus among groups(P>0.05),but the gray value in T2 group showed an increasing trend compared with CON group(P=0.09).In conclusion,ZEA has no significant effect on the growth performance and the levels of serum and uterus GH and ZEA of prepubertal gilts.However,ZEA can increase the relative expression levels of GHR,JAK 2 and STAT3 mRNA,and enhance the immunopositive of GHR,and increase the protein expression level,which enhance the biological effect of GH and make the uterus abnormal development.ZEA significantly increase uterine index,thicken myometrium and endometrium,and increase uterine glands and capillaries.