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本试验旨在研究冷季补饲精料或尿素-糖蜜型舔砖对藏羊小肠组织形态发育及营养物质转运载体基因表达量的影响。选择1.5岁、体重((29.4±1.79)kg)相近的健康藏系绵羊母羊18头,随机分为对照组(CON组)、尿素-糖蜜型舔砖补饲组(BS组)和精料补饲组(CS组)。CON组自由采食燕麦干草,BS组在CON组基础上自由舔食尿素-糖蜜型舔砖,CS组在CON组基础上补饲精料200g·只-1·d-1。进行60d的饲养试验后,对全部试验藏羊进行屠宰,采集小肠各段组织,通过制作组织切片及荧光定量PCR,测定小肠组织形态发育和营养物质转运载体基因表达量。结果表明:(1)补饲精料或舔砖均显著提高了藏羊消化能和粗蛋白质摄入量(P<0.05),且CS组显著高于BS组(P<0.05);(2)补饲精料或舔砖均显著提高了藏羊十二指肠、空肠及回肠绒毛宽度(P<0.05),且CS组均显著大于BS组(P<0.05),补饲精料还显著提高了十二指肠和回肠绒毛高度(P<0.05),显著降低了空肠和回肠隐窝深度(P<0.05);(3)胰岛素样生长因子结合蛋白5(Insulin-like growth factor binding protein,IGFBP5)mRNA表达量在十二指肠和空肠黏膜中CS和BS组均显著高于CON组(P<0.05),且CS组显著高于BS组(P<0.05),在回肠黏膜中CS组显著高于BS和CON组(P<0.05);(4)十二指肠黏膜中L型氨基酸转运载体1(L-type amino acid transporter 1,LAT1)、阳离子氨基酸转运载体1(Cationic amino acid transporters 1,CAT1)、小肽转运载体1(Peptides transporter 1,pepT1)、钠依赖型葡萄糖转运载体1(Na+-dependent glucose co-transporter 1,SGLT1)及促葡萄糖转运载体2(Facilitative glucose transporter 2,GLUT2)mRNA表达量CS组显著高于BS和CON组(P<0.05),空肠黏膜中CAT1、pepT1mRNA表达量和回肠黏膜中CAT1、LAT1、SGLT1及GLUT2mRNA表达量,BS组显著高于CS和CON组(P<0.05)。以上结果表明,冷季补饲精料或尿素-糖蜜型舔砖均增加了藏羊对能量和蛋白质等营养物质的摄入量,促进了小肠组织形态发育,补饲精料提高了十二指肠黏膜中氨基酸、小肽及葡萄糖转运载体基因mRNA的表达量,而补饲尿素-糖蜜型舔砖提高了其在空肠和回肠黏膜中的表达量。
The aim of this study was to investigate the effect of cold-season supplement concentrate or urea-molasses-licking brick on the morphological development of small intestine and the gene expression of nutrient transporter in Tibetan sheep. Eighteen healthy Tibetan sheep ewes aged 1.5 years and weighing (29.4 ± 1.79) kg were randomly divided into control group (CON group), urea-molasses lick-brick supplement group (BS group) and concentrate Feed group (CS group). In CON group, oat hay was fed freely. BS group was licked with urea-molasses lick brick freely on the basis of CON group. CS group was given 200 g · only -1 · d-1 of concentrate on the basis of CON group. After feeding for 60 days, all the Tibetan sheep were slaughtered, and the tissues of small intestine were collected. The histological sections of small intestine and the quantitative expression of small intestine were determined by fluorescence quantitative PCR. The results showed that: (1) Supplementation concentrate or lick bricks significantly increased digestibility and crude protein intake of Tibetan sheep (P <0.05), and significantly higher in CS group than in BS group (P <0.05); (2) Supplement concentrate or lick bricks significantly increased the width of duodenum, jejunum and ileum of Tibetan sheep (P <0.05), and significantly increased in CS group compared with BS group (P <0.05) (P <0.05), significantly reduced the depth of jejunum and ileum crypts (P <0.05); (3) Insulin-like growth factor binding protein 5 (IGFBP5 ) mRNA expression in CS and BS groups in duodenum and jejunum mucosa were significantly higher than those in CON group (P <0.05), and CS group was significantly higher than that in BS group (P <0.05). CS group in ileum mucosa was significantly (P <0.05); (4) L-type amino acid transporter 1 (LAT1), Cationic amino acid transporters 1 , CAT1), Peptides transporter 1 (pepT1), Na + -dependent glucose co-transporter 1 (SGLT1) and Facilitativ (P <0.05). The expression of CAT1 and pepT1 mRNA in jejunum mucosa and CAT1, LAT1, SGLT1 and GLUT2 mRNA expression in ileum mucosa were significantly higher in group BS than those in group BS Higher than the CS and CON groups (P <0.05). The above results show that supplemental concentrate in the cold season or urea-molasses lick bricks increased energy and protein intake of Tibetan sheep and other nutrients, and promote the morphological development of small intestine, feeding concentrate to improve the twelve fingers Intestinal mucosa amino acids, small peptides and glucose transporter mRNA expression, while feeding urea - molasses lick brick increased its expression in jejunum and ileum mucosa.