There is considerable concern that isoflavones,such as genistein in fish feed composed of soybean protein,affects somatic growth in fish.Our previous works demonstrated that 30 and 300 μg/g dietary genistein had no s...There is considerable concern that isoflavones,such as genistein in fish feed composed of soybean protein,affects somatic growth in fish.Our previous works demonstrated that 30 and 300 μg/g dietary genistein had no significant effect on growth performance in Nile tilapia(Oreochromis niloticus),but the higher level of genistein(3 000 μg/g) significantly depressed growth.This study was conducted to further examine the effects of dietary genistein on the endocrine disruption on growth hormone/insulin-like growth factor-I(GH/IGF-I) axis in Nile tilapia(O.niloticus).Juvenile fish were fed by hand twice daily to satiation with one of four isonitrogenous and isoenergetic diets,each containing either 0,30,300 or3 000 μg/g genistein.Following an 8-week feeding period,plasma GH and IGF-I levels were investigated by radioimmunoassay and gene expression levels of gh,ghrelin,gnrhs,ghr,npy,npyrs,pacap,ghrs,igf-I,igf-Ir,and igfbp3 were examined by real-time PCR.The results show that no significant change in plasma GH and IGF-I levels in fish fed with diets containing 30 μg/gand 300 μg/g genistein.mRNA expression of genes along the GH/IGF-I axis remained unaffected,except for igf-Ir,which was stimulated by the 300 μg/g genistein diet.While in fish fed the 3 000 μg/g genistein diet,the plasma GH and IGF-I levels decreased,and mRNA expression of gh,ghr2,npyr1,igf-I,and igf-Ir were also significantly depressed.In contrast,npy and igfbp3 mRNA expression were enhanced.This study provides convincing evidence for growth impediment by genistein by disturbing the GH/IGF-I axis in Nile tilapia O.niloticus.展开更多
The effects of stocking density on the growth and metabolism of Amur sturgeon were assessed. Amur sturgeon were grown for 70 days at three dif ferent stocking densities(low stocking density, LSD: 5.5 kg/m^3; medium st...The effects of stocking density on the growth and metabolism of Amur sturgeon were assessed. Amur sturgeon were grown for 70 days at three dif ferent stocking densities(low stocking density, LSD: 5.5 kg/m^3; medium stocking density, MSD: 8.0 kg/m^3; and high stocking density, HSD: 11.0 kg/m^3), and the biometric index, muscle composition, and serum biochemical parameters were evaluated. In addition, pituitary, liver, and muscle samples were collected for gene cloning and expression analyses. After 70 days of growth, the fish maintained at HSD had significantly lower fi nal body weight and specifi c growth rate, and a higher feed conversion ratio than those of the fish in the MSD and LSD groups. The HSD group had the lowest lipid and protein concentrations in serum and muscle. The serum cortisol concentration increased significantly in the HSD group, indicating that the stress-response system was activated in these fish. There was no change in the concentration of serum insulin-like growth factor 2(IGF-2), while the concentrations of serum growth hormone(GH) and insulin-like growth factor 1(IGF-1) decreased in the HSD group. The full-length cDNAs of G H and IGF-2 genes(995-bp and 1 207-bp long, respectively), were cloned and analyzed. In the HSD group, the expressions of GH in the pituitary and growth hormone receptor( GHR) and IGF-1 in the liver were down-regulated at the end of the 70-day experiment. In the HSD group, the transcript level of IGF-2 significantly decreased in the liver, but did not change in muscle. Overall, our results indicated that a HSD negatively af fects the growth performance and leads to changes in lipid and protein metabolism in Amur sturgeon. The down-regulated expression of genes related to the GH/IGF axis may be responsible for the poor growth performance of Amur sturgeon under crowding stress.展开更多
本研究旨在探讨不同蛋白质水平日粮对绵羊胰岛素样生长因子-1(IGF-1)和生长激素(GH)分泌及基因mRNA表达量的影响,为科学配置肉羊饲料及研究肉羊生长发育提供基础。选择6月龄体重相近的多胎萨福克公羔18只,随机分为3组,分别饲喂不同蛋白...本研究旨在探讨不同蛋白质水平日粮对绵羊胰岛素样生长因子-1(IGF-1)和生长激素(GH)分泌及基因mRNA表达量的影响,为科学配置肉羊饲料及研究肉羊生长发育提供基础。选择6月龄体重相近的多胎萨福克公羔18只,随机分为3组,分别饲喂不同蛋白质水平的日粮(低蛋白日粮、中蛋白日粮和高蛋白日粮)。采用ELISA方法和SYBR Green Real-time PCR方法检测日粮不同蛋白质水平对不同生长发育阶段(30、60、90和120d)羔羊外周血中IGF-1、GH浓度和皮肤组织中基因表达的影响。结果显示,日粮蛋白质水平显著影响绵羊平均日增重、外周血中IGF-1和GH的浓度以及皮肤组织IGF-1基因的表达丰度,而未显著影响GH基因的表达丰度。结果提示,随着日粮蛋白质水平的升高,绵羊生长发育快,外周血中IGF-1浓度增加,GH浓度降低,IGF-1基因表达量增加。展开更多
基金Supported by the National Natural Science Foundation of China(No.31170322)
文摘There is considerable concern that isoflavones,such as genistein in fish feed composed of soybean protein,affects somatic growth in fish.Our previous works demonstrated that 30 and 300 μg/g dietary genistein had no significant effect on growth performance in Nile tilapia(Oreochromis niloticus),but the higher level of genistein(3 000 μg/g) significantly depressed growth.This study was conducted to further examine the effects of dietary genistein on the endocrine disruption on growth hormone/insulin-like growth factor-I(GH/IGF-I) axis in Nile tilapia(O.niloticus).Juvenile fish were fed by hand twice daily to satiation with one of four isonitrogenous and isoenergetic diets,each containing either 0,30,300 or3 000 μg/g genistein.Following an 8-week feeding period,plasma GH and IGF-I levels were investigated by radioimmunoassay and gene expression levels of gh,ghrelin,gnrhs,ghr,npy,npyrs,pacap,ghrs,igf-I,igf-Ir,and igfbp3 were examined by real-time PCR.The results show that no significant change in plasma GH and IGF-I levels in fish fed with diets containing 30 μg/gand 300 μg/g genistein.mRNA expression of genes along the GH/IGF-I axis remained unaffected,except for igf-Ir,which was stimulated by the 300 μg/g genistein diet.While in fish fed the 3 000 μg/g genistein diet,the plasma GH and IGF-I levels decreased,and mRNA expression of gh,ghr2,npyr1,igf-I,and igf-Ir were also significantly depressed.In contrast,npy and igfbp3 mRNA expression were enhanced.This study provides convincing evidence for growth impediment by genistein by disturbing the GH/IGF-I axis in Nile tilapia O.niloticus.
基金Supported by the National Special Research Fund for Non-Profit Sector(Agriculture)(No.201003055)
文摘The effects of stocking density on the growth and metabolism of Amur sturgeon were assessed. Amur sturgeon were grown for 70 days at three dif ferent stocking densities(low stocking density, LSD: 5.5 kg/m^3; medium stocking density, MSD: 8.0 kg/m^3; and high stocking density, HSD: 11.0 kg/m^3), and the biometric index, muscle composition, and serum biochemical parameters were evaluated. In addition, pituitary, liver, and muscle samples were collected for gene cloning and expression analyses. After 70 days of growth, the fish maintained at HSD had significantly lower fi nal body weight and specifi c growth rate, and a higher feed conversion ratio than those of the fish in the MSD and LSD groups. The HSD group had the lowest lipid and protein concentrations in serum and muscle. The serum cortisol concentration increased significantly in the HSD group, indicating that the stress-response system was activated in these fish. There was no change in the concentration of serum insulin-like growth factor 2(IGF-2), while the concentrations of serum growth hormone(GH) and insulin-like growth factor 1(IGF-1) decreased in the HSD group. The full-length cDNAs of G H and IGF-2 genes(995-bp and 1 207-bp long, respectively), were cloned and analyzed. In the HSD group, the expressions of GH in the pituitary and growth hormone receptor( GHR) and IGF-1 in the liver were down-regulated at the end of the 70-day experiment. In the HSD group, the transcript level of IGF-2 significantly decreased in the liver, but did not change in muscle. Overall, our results indicated that a HSD negatively af fects the growth performance and leads to changes in lipid and protein metabolism in Amur sturgeon. The down-regulated expression of genes related to the GH/IGF axis may be responsible for the poor growth performance of Amur sturgeon under crowding stress.
文摘本研究旨在探讨不同蛋白质水平日粮对绵羊胰岛素样生长因子-1(IGF-1)和生长激素(GH)分泌及基因mRNA表达量的影响,为科学配置肉羊饲料及研究肉羊生长发育提供基础。选择6月龄体重相近的多胎萨福克公羔18只,随机分为3组,分别饲喂不同蛋白质水平的日粮(低蛋白日粮、中蛋白日粮和高蛋白日粮)。采用ELISA方法和SYBR Green Real-time PCR方法检测日粮不同蛋白质水平对不同生长发育阶段(30、60、90和120d)羔羊外周血中IGF-1、GH浓度和皮肤组织中基因表达的影响。结果显示,日粮蛋白质水平显著影响绵羊平均日增重、外周血中IGF-1和GH的浓度以及皮肤组织IGF-1基因的表达丰度,而未显著影响GH基因的表达丰度。结果提示,随着日粮蛋白质水平的升高,绵羊生长发育快,外周血中IGF-1浓度增加,GH浓度降低,IGF-1基因表达量增加。
