In this paper, we studied the structure, expression and function of black carp insulin gene. The complete Mylopharyngodon piceus insulin (Mp-Ins) gene is 1,965 bp long and includes a 1,499 bp 5ʹ-untranslated region (UTR), a 139 bp 3′-UTR with a poly(A) tail, and an open reading frame (ORF) of 327 bp. The predicted molecular weight of the recombinant Mp-Ins(rMp-Ins) protein is 11.87 kDa. The mRNA expression of Mp-Ins is upregulated in the brain and liver. After the injection of rMp-Ins, Mp-Ins mRNA transcript abundance was significantly upregulated in the liver. The rMp-Ins protein could inhibit the concentration of glycogen phosphorylase (GP), growth hormone (GH), fatty acid synthase (FAS), and insulin-like growth factors-1 (IGF-1), and it also significantly increased the concentration of PI3K. Additionally, the injection of rMp-Ins did not have a significant impact on the glucose-6-phosphatase (G6Pase) content in blood. In situ hybridization results showed that the positive signal of the Mp-Ins gene was mainly concentrated in the cell nucleus of brain tissue and the cell membrane of liver tissue and muscle tissue. Together, these results demonstrated that Mp-Ins plays an important role in growth and metabolism in M. piceus.

为了解长江水系青鱼不同地理群体肌肉营养品质的差异,用国标生化法测定了湖南湘江群体(XJ)、湖北石首群体(SS)、江苏邗江群体(HJ)青鱼肌肉的常规营养成分、氨基酸和脂肪酸的含量,并按FAO/WHO建议的标准进行了营养品质评价.结果显示:3个群体青鱼肌肉的水分质量分数为81.08％～82.20％,粗蛋白质质量分数为16.86％～17.94％,粗脂肪质量分数为0.46％～0.52％,粗灰分质量分数为1.26％～1.34％,3个群体间常规营养成分无显著性差异(P>0.05);在3个群体青鱼的肌肉中均检测出16种氨基酸,其中人体必需氨基酸7种,半必需氨基酸2种,非必需氨基酸7种,必需氨基酸占总氨基酸的39.24％～40.22％,鲜味氨基酸占总氨基酸的38.54％～39.37％;在脂肪酸组成和含量上,石首群体、邗江群体中均检测到18种脂肪酸,其中饱和脂肪酸9种,单不饱和脂肪酸3种,多不饱和脂肪酸6种,以上两个群体的脂肪酸组成种类均多于湘江群体,邗江群体在饱和脂肪酸总量和多不饱和脂肪酸总量上均显著高于石首群体和湘江群体(P<0.05),而在单不饱和脂肪酸总量上,3个群体间差异不显著(P>0.05),3个群体都含有高水平的DHA+EPA.结果表明,青鱼3个群体的蛋白质含量均较高,氨基酸组成合理,富含多种不饱和脂肪酸,均具有较高的营养价值,其中邗江群体营养价值最高,可作为青鱼良种选育的主要对象.

为了评估青鱼(Mylopharyngodon piceus)不同群体的生长性能,对湖南湘江(XJ)、湖北石首(SS)、江苏邗江(HJ)的青鱼采用PIT标记和网箱同池混养法,比较三个不同地理群体生长差异性.通过单因素方差分析、相关性分析、多重比较分析不同青鱼群体间生长差异性和性状间的相关性.结果显示:三个群体中,HJ群体在增重率、增长率、生长指数等表现良好.XJ群体体重增重率以及生长指数都较低,表明XJ群体生长较为缓慢.SS群体在体重增重率上与HJ群体不具有显著性差异,但在体宽和体高上SS群体生长离散程度最大.性状相关性分析中,体长、体宽、体高与体重的相关系数也均达到极显著水平.综合以上研究,HJ群体的生长性能最好,可以作为良种选育的主要对象.

The black carp (Mylopharyngodon piceus) is an important carnivorous freshwater-cultured species. To understand the molecular basis underlying the response of black carp to fasting, we used RNA-Seq to analyze the liver and brain transcriptome of fasting fish. Annotation to the NCBI database identified 66,609 unigenes, of which 22,841 were classified into the Gene Ontology database and 15,925 were identified in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Comparative analysis of the expression profile between fasting and normal feeding fish revealed 13,737 differentially expressed genes (P < 0.05), of which 12,480 were found in liver tissue and 1257 were found in brain tissue. The KEGG pathway analysis showed significant differences in expression of genes involved in metabolic and immune pathways, such as the insulin signaling pathway, PI3K-Akt signaling pathway, cAMP signaling pathway, FoxO signaling pathway, AMPK signaling pathway, endocytosis, and apoptosis. Quantitative real-time PCR analysis confirmed that expression of the genes encoding the factors involved in those pathways differed between fasting and feeding fish. These results provide valuable information about the molecular response mechanism of black carp under fasting conditions.

The black carp (Mylopharyngodon piceus), native to eastern Asian, is a large, commercially valuable fish, and has been widely introduced to other countries. In this study, the mitochondrial gene sequence of gray black carp (M. piceus MT084757) in Foshan, Guangdong Province was first determined using the Sanger sequencing method. The mitochondrial DNA genome was 16,616 bp in length, including 13 protein-coding genes (PCGs), two rRNA genes, 22 transfer RNA genes, and a non-coding control region (D-loop). The overall nucleotide composition of the mitochondrial DNA is 32.04% A, 24.52% T, 15.68% C, 27.76% G, with 56.56% AT, respectively. Phylogenetic tree analysis suggests that the gray black carp (M. piceus MT 084757) is closely related to Elopichthys bambus and Squaliobarbus curriculus. The complete mitochondrial genome of the gray black carp (M. piceus MT 084757) would be useful for researching the causes of changes in body color.