十二指肠灌注不同水平大豆小肽对奶山羊小肠小肽吸收的影响

Effects of Intraduodenal Infusion of Soybean Small Peptide on Absorption of Small Peptide and Free Amino Acids in Dairy Goats

本试验旨在研究十二指肠灌注大豆小肽对奶山羊小肠小肽和游离氨基酸吸收的影响。选择7只体况良好、体质量相近的奶山羊((37.88±3.03)kg),安装永久性十二指肠近端瘘管和门静脉、肠系膜静脉近端和远端以及颈动脉慢性血插管进行4×4拉丁方试验,分别从十二指肠灌注生理盐水、60、120、180g.d-1大豆小肽。结果表明,随着十二指肠大豆小肽灌注水平的提高,奶山羊肠系膜排流组织(MDV)总肽结合氨基酸净流量显著增加(P<0.05或P<0.01);60、120、180g.d-1组门静脉排流组织(PDV)总肽结合氨基酸净流量均显著高于对照组(P<0.05),但3个大豆小肽灌注组间无显著性差异(P>0.05)。奶山羊小肠对小肽的吸收率随小肠中肽量的增加而下降。随着大豆小肽灌注水平的增加,奶山羊MDV和PDV组织游离氨基酸净流量显著增加(P<0.05)。随十二指肠大豆小肽灌注水平的提高,试验羊颈静脉血浆尿素氮浓度显著增加(P<0.05),对血浆葡萄糖、胰岛素、生长激素、胰高血糖素和IGF-1浓度没有显著影响(P>0.05)。研究结果表明,大豆小肽灌注增加奶山羊小肠中肽结合氨基酸的流量,提高了MDV肽结合氨基酸的净流量,但因肽结合氨基酸吸收率降低或/和肽结合氨基酸吸收细胞降解率提高,降低了进入肠系膜静脉的肽结合氨基酸的比率。

This experiment was conducted to study the effects of intraduodenally infusion of soybean small peptide（SSP）on absorption of small peptide and free amino acids in dairy goats.Seven dairy goats（（37.88±3.03）kg）were used in a 4×4 Latin square design.Goats were fitted with duodenal cannulas and implanted with indwelling catheters in carotid artery,mesenteric vein and portal vein.Each goat received four treatments respectively：infusion of normal saline,60,120 and 180 g·d-1 SSP into duodenum.Increased SSP duodenal infusion elevated the net fluxes of peptide bound amino acids（PAA）across mesenteric-drained viscera（MDV）（P0.05）,but decreased the net appearance rates of PAA in mesenteric vein blood flow.SSP infusion increased net fluxed of PAA across portal-drained viscera（PDV）compared with that of the control（P0.05）,but there was no significant difference among those of three SSP infusion treatments（P0.05）.SSP infusion did not change concentrations of glucose,insulin,growth hormone and IGF-1（P0.05）,but increased the concentration of urea nitrogen（P0.05）in the plasma of jugular vein.The results indicated that SSP infusion increased the net fluxes of PAA and free amino acid（FAA）across the MDV and PDV,but decreased the net appearances of PAA in the MDV,which may be a result of decreased absorption,increased degradation of PAA in the absorptive cell,or both.