促肾上腺皮质激素释放因子在肉仔鸡食欲调控中的作用

Effects of Corticotropin-Releasing Factor on Appetite Regulation of Broilers

本试验以活体肉仔鸡为研究对象,以静脉注射方式外源导入促肾上腺皮质激素释放因子(CRF),分析肉仔鸡采食量的变化和下丘脑、肠道中食欲调控相关基因的表达情况,对CRF在肉仔鸡食欲调控中的作用进行探究。选取体重相近的1日龄雄性爱拔益加(AA)肉仔鸡20只,7日龄时随机分为2个组,每组10只鸡,单笼单饲。试验组肉仔鸡于10日龄08:00翅静脉注射1 000.0μg/kg BW的CRF,对照组同时注射等量的生理盐水。注射2 h后,统计采食量,10日龄10:00进行屠宰取样,利用实时荧光定量PCR(RT-PCR)检测下丘脑、十二指肠、空肠和回肠中与食欲相关基因胃饥饿素、促肾上腺皮质激素释放因子受体(CRFR) 1、CRFR2、生长激素促分泌素受体-1α(GHSR-1α) mRNA相对表达量。结果表明:与对照组相比,静脉注射CRF显著降低了肉仔鸡采食量(P<0.05);显著提高了肉仔鸡下丘脑中胃饥饿素和CRFR1 mRNA相对表达量(P<0.05),而下丘脑中CRFR2和GHSR-1αmRNA相对表达量无显著变化(P>0.05);显著提高了肉仔鸡十二指肠、空肠和回肠中CRFR1、CRFR2和GHSR-1αmRNA相对表达量(P <0.05),显著降低了十二指肠胃饥饿素mRNA相对表达量(P <0.05),而在空肠和回肠中胃饥饿素mRNA相对表达量无显著变化(P>0.05)。由此可见,静脉注射CRF能降低肉仔鸡采食量,诱导中枢胃饥饿素的基因表达,下丘脑CRFR1、胃饥饿素以及肠道CRFR1、CRFR2、GHSR-1α基因表达上调导致的食欲抑制可能是造成采食量下降的原因。

This experiment used the live broilers as the object of study,intravenous injection of exogenous corticotropin-releasing factor(CFR),the changes of feed intake and the expression of appetite regulation related genes in the hypothalamus and intestine were analyzed,and the effects of CFR on the appetite regulation of broilers were investigated.Twenty 1-day-old male Arbor Acres(AA)broilers with similar body weight were randomly divided into 2 groups at 7 days of age with 10 broilers per group(one cage per broiler).At 10 days of age,broilers in the experimental group were injected 1 000.0μg/kg BW CRF through wing intravenous and broilers in the control group were injected the same dose of saline at 08:00.After 2 h injection,the feed intake was recorded,and the mRNA relative expression level of appetite related genes in the hypothalamus,duodenum,jejunum and ileum were measured by RT-PCR,such as ghrelin,corticotropin releasing factor receptor(CRFR)1,CRFR2 and growth hormone secretagogues receptor-1α(GHSR-1α).The results showed that compared with the control group,intravenous injection of CRF significantly decreased the feed intake of broilers(P<0.05);significantly increased the mRNA relative expression levels of ghrelin and CRFR1 in hypothalamus of broilers(P<0.05),but did not affect the mRNA relative expression levels of CRFR2 and GHSR-1αin hypothalamus(P >0.05);significantly increased the mRNA relative expression levels of CRFR1,CRFR2 and GHSR-1αin duodenum,jejunum and ileum of broilers(P<0.05),significantly decreased the mRNA relative expression level of ghrelin in duodenum(P<0.05),but did not affect the mRNA relative expression level of ghrelin in jejunum and ileum(P >0.05).In conclusion,intravenous injection of CRF can decrease the feed intake of broilers,induce the central ghrelin gene expression,the inhibition of appetite suppression mediated by the up-regulated expression of CRFR1,ghrelin in the hypothalamus and CRFR1,CRFR2 and GHSR-1αgenes in the intestinal tract may be the cause of the decrease of feed intake.