五肽胃泌素调节瘤胃微生物代谢的体外研究

Effect of pentagastrin on ruminal microbial metabolism in vitro

研究了五肽胃泌素对体外培养瘤胃微生物挥发性脂肪酸代谢和蛋白质合成 ,以及CCK2 /gastrin特异性受体阻断剂丙谷胺对其作用的影响。实验分两系列 :Ⅰ 经瘤胃瘘管从采食粗料的绵羊、山羊收集瘤胃液 ,分别加入 0、 1× 1 0 -1 2 、1× 1 0 -1 0 和 5× 1 0 -1 0 mol·L-1 的五肽胃泌素 ,厌氧培养 8h ,测定挥发性脂肪酸和微生物蛋白质 ;Ⅱ 经瘤胃瘘管收集采食粗料添加部分精料的水牛瘤胃液 ,分别加入含有丙谷胺 (1 0 -1 0 mol·L-1 )、五肽胃泌素 (1 0 -1 0 mol·L-1 )、丙谷胺 (1 0 -1 0mol·L-1 ) +五肽胃泌素 (1 0 -1 0 mol·L-1 )的培养基中 ,厌氧培养 6h ,样品测定同系列I。结果显示 ,经五肽胃泌素(1 0 -1 0 mol·L-1 )处理 ,瘤胃微生物总挥发性脂肪酸浓度提高 5 %～ 2 0 % (P <0 0 5 ) ,微生物蛋白增加 7%～ 1 5 % (P <0 0 5 ) ,水牛乙酸 /丙酸 (C2 /C3 )值 (3 4vs 2 9)呈升高的趋势。五肽胃泌素对瘤胃微生物代谢的促进作用可被丙谷胺阻断。上述结果表明 ,胃泌素有促进瘤胃微生物挥发性脂肪酸代谢 ,提高微生物蛋白合成的作用 ;

Two series of in vitro experiments were conducted to study the effects of pentagastrin(PG)on metabolism of rumen volatile fatty acids(VFA)and synthesis of microbial protein(MCP).In Series Ⅰ the rumen microbes,obtained from sheep and goats consumed hay,were treated with 3 doses of PG(1×10 -12 ,1×10 -10 and 5×10 -10 mol· L -1 ,EXP)or without PG(Control).In Series Ⅱ the rumen microbes obtained from water buffalo consumed hay and concentrate,were divided into 4 groups.Each group received one of the following treatments:1)Basic medium(BM);2)Proglumide(10 -10 mol·L -1 ),a specific CCK2/gastrin receptor blocker;3)PG(10 -10 mol·L -1 );4)Proglumide(10 -10 mol·L -1 )and PG(10 -10 mol·L -1 ).In Series Ⅰ and Ⅱ the total volatile fatty acids(TVFA)increased by 5%20%( P <0 05)and MCP increased by 7% 15%( P <0 05)with PG treatment.In Series Ⅱ the acetic acid/propionic acid(C 2/C 3)tended to increase(3 4 vs 2 9).But these stimulating effects of PG were inhibited by proglumide.In conclusion,PG promoted ruminal VFA metabolism and enhanced MCP synthesis.The effects of PG on rumen microbes could be mediated by CCK2/gastrin receptor located on the plasma membrane of rumen bacteria.