饲粮营养水平对绒山羊小肠感应因子mRNA相对表达量、血液理化指标及激素含量的影响

本试验旨在适当降低饲粮氮水平条件下,通过饲粮添加N-氨甲酰谷氨酸(NCG)及小肠灌注葡萄糖,研究其对绒山羊小肠感应因子mRNA相对表达量、血液理化指标及激素含量的影响。选用27只体况良好、装有永久性瘤胃和十二指肠瘘管的内蒙古白绒山羊羯羊,按年龄和体重相近原则随机分成9组,每组3只。饲粮分为3个处理:低氮粗蛋白质(CP)10.5%]、低氮+NCG(0.20 g/d)和高氮(CP 13.5%);每个处理的山羊分别进行3个水平的十二指肠葡萄糖灌注:0、20和40 g/d。饲养试验(15 d预试期、15 d正试期)结束后,屠宰取空肠和十二指肠组织,通过实时定量PCR法测定营养感应因子mRNA相对表达量,测定血液理化指标、血清和空肠相关激素含量。结果表明:1)在基础饲粮条件(无葡萄糖灌注)下,随着饲粮氮水平的下降,空肠和十二指肠钠-葡萄糖共转运载体1(SGLT1)的mRNA相对表达量,血浆尿素氮、葡萄糖含量,血清瓜氨酸、胰岛素含量,血清和空肠胰高血糖素样肽1(GLP-1)、胰高血糖素样肽2(GLP-2)和促胰岛素肽(GIP)含量减少,而空肠和十二指肠溶质载体家族7成员9(SLC7A9)、溶质载体家族7成员1(SLC7A1)的mRNA相对表达量增加。2)增加适宜过瘤胃葡萄糖后,随着饲粮氮水平的下降,SGLT1、味觉受体1型1、味觉受体1型2、味觉受体1型3 mRNA相对表达量呈增加趋势。3)低氮饲粮条件下灌注20 g/d葡萄糖,额外饲喂NCG能够缓解饲粮氮水平降低引起的空肠和十二指肠SGLT1 mRNA相对表达量,血浆尿素氮、葡萄糖含量,血清瓜氨酸含量,血清和空肠GLP-1、GLP-2和GIP含量的下降。结果提示,适当降低饲粮氮水平,补饲NCG和增加过瘤胃葡萄糖(十二指肠灌注20 g/d)对绒山羊机体代谢及肠道营养物质感应均有促进作用。

Effects of Dietary Nutrient Level on mRNA Relative Expression Levels of Nutrient Sensing Factors,Blood Physiochemical Indexes and Hormone Contents of Cashmere Goats

To study the effects of N?carbamylglutamic acid ( NCG) supplementation and intestinal infusion of glucose on mRNA relative expression levels of nutrient sensing factors, blood physiochemical indexes and hor?mone contents of cashmere goats under the condition of decreasing dietary nitrogen level. Twenty seven healthy Inner Mongolia cashmere wethers with permanent rumen fistula and duodenal cannulas were used. In accord?ance with the principle of similar age and body weight, twenty seven goats were divided into nine groups with three goats per group. There were 3 dietary treatments, which were low nitrogen crude protein ( CP ) 10.5%], low nitrogen +NCG (0.20 g/d) and high nitrogen (CP 13.5%); meanwhile, goats in each treat?ment were infused glucose at 3 levels, which were 0, 20 and 40g/d. After feeding experiment (15 d of pre?ex?periment and 15 d of formal experiment) , goats were slaughtered to collect jejunum and duodenum tissues, the mRNA relative expression levels of intestinal nutrient sensing factor were determined by real?time PCR method, and blood physiochemical indexes, and serum and jejunal hormone contents were determined. The results showed as follows:1) under the condition of basal diet ( without glucose infusion) , with the decrease of dieta?ry nitrogen level, the mRNA relative expression level of sodium?glucose cotransporter 1 ( SGLT1 ) in jejunum and duodenum, plasma urea nitrogen ( UN) and glucose contents, serum citrulline and insulin contents, and serum and jejunal contents of glucagon?likepeptide 1 ( GLP?1) , glucagon?likepeptide 2 ( GLP?2) and glucose insulinotropic peptide ( GIP) were declined, but the mRNA relative expression levels of solute carrier family 7 member 9 ( SLC7A9) and solute carrier family 7 member 1 ( SLC7A1) were increased. 2) After increase prop?er amount glucose, with the decease of dietary nitrogen level, the mRNA relative expression levels of SGLT1, taste 1 receptor member 1 ( T1R1) , taste 1 receptor member 2 ( T1R2) and taste 1 receptor member 3 ( T1R3) tended to be increased. 3) Under the condition of low dietary nitrogen level and 20 g/d glucose infusion, extra supplementation of NCG could help relieve the decrease of the mRNA relative expression level of SGLT1 in je?junum and duodenum, plasma UN and glucose contents, serum citrulline content, and serum and jejunal con?tents of GLP?1, GLP?2 and GIP induced by the decreasing dietary nitrogen level. The results indicate that under the condition of decreasing dietary nitrogen level at proper extent, NCG supplementation and increasing rumen?passed glucose ( duodenal infusion 20 g/d glucose) can improve metabolism and intestinal nutrient sensing of cashmere goats.