过瘤胃烟酰胺对育肥羊肠道形态、屏障和转运功能以及挥发性脂肪酸含量的影响

Effects of Rumen Protected Nicotinamide on Intestinal Morphology,Barrier and Transport Function,and Volatile Fatty Acid Contents of Fattening Hu Sheep

本试验旨在研究在育肥湖羊基础饲粮中添加过瘤胃烟酰胺(RPN)对其肠道形态、屏障和转运功能以及后肠道内容物挥发性脂肪酸含量的影响。选取16只年龄(2月龄)、体重相近的健康育肥公湖羊为研究对象,试验分为对照组(饲喂基础饲粮)和试验组(额外添加1 g/d RPN),预试期为7 d,正试期为90 d。结果表明:与对照组相比,1)添加1 g/d RPN显著提高湖羊空肠的绒毛高度与肌层厚度(P<0.05);2)添加1 g/d RPN显著增加空肠黏膜中封闭蛋白-2(Claudin-2)与闭合蛋白(Occludin)的蛋白表达水平(P<0.05);3)添加1 g/d RPN后,空肠葡萄糖转运蛋白2(GLUT2)、钠-葡萄糖共同转运体1(SGLT1)的基因相对表达量显著升高(P<0.05),回肠GLUT2、氨基酸转运蛋白2(SLC38A2)和溶质载体家族1成员5(SLC1A5)的基因相对表达量显著升高(P<0.05),SGLT1的基因相对表达量显著升高(P<0.05);4)添加1 g/d RPN能显著提高湖羊空肠的异戊酸含量(P<0.05),有提高乙酸(P=0.058)和总挥发性脂肪酸(P=0.077)含量的趋势。综上所述,在基础饲粮中额外添加1 g/d RPN可促进育肥湖羊肠道发育,改善肠道屏障功能,提高肠道葡萄糖、氨基酸转运载体基因的表达,并促进湖羊后肠道发酵。

The purpose of this experiment was to study the effects of rumen protected nicotinamide(RPN)on intestinal morphology,barrier and transport function and volatile fatty acid contents in hindgut contents of fatte-ning Hu sheep.Sixteen healthy fattening male Hu sheep with similar age(2-month-old)and weight were se-lected and allocated to 2 groups:CON group(fed a basal diet only)and RPN group(adding 1 g/d RPN).The pre-test lasted for 7 days and the experiment lasted for 90 days.The results showed as follows:compared with the CON group,1)adding 1 g/d RPN significantly increased the villus height and muscle thickness of the jejunum of Hu sheep(P<0.05);2)adding 1 g/d RPN significantly increased the protein expression levels of Claudin-2 and Occludin in jejunal mucosa(P<0.05);3)the relative expression levels of glucose transporter 2(GLUT2)and sodium-glucose cotransporter 1(SGLT1)genes in jejunum of RPN group were significantly in-creased(P<0.05),the relative expression levels of GLUT2,amino acid transporter 2(SLC38A2)and solute carrier family 1 member 5(SLC1A5)genes in ileum of RPN group were significantly increased(P<0.05),and the relative expression level of SGLT1 gene of RPN group was significantly increased(P<0.05);4)sup-plementing 1 g/d RPN significantly increased the content of isovaleric acid(P<0.05),and tended to increase acetic acid(P=0.058)and total volatile fatty acids contents(P=0.077).In conclusion,supplementing 1 g/d RPN to the diet promotes the intestinal development,improves the intestinal barrier and expression of amino acid transporter,and promotes the post-intestinal fermentation of Hu sheep.