| 摘要: |
| 以蛋氨酸作为惟一氮源和碳源，设添加L-蛋氨酸（Met）组（试验组）和不添加L-蛋氨酸组（对照组），在体外培养条件下研究了这2组的瘤胃微生物谷草转氨酶（AST）和谷丙转氨酶（ALT）活性及各氨基酸含量的变化规律。结果表明，添加Met对AST和ALT活性无明显影响，添加Met后产物中游离甘氨酸（Gly）含量和蛋氨酸（Met）含量较对照极显著增加，培养液中游离半胱氨酸（Cys-s）和丝氨酸（Set）含量随培养时间的增加而减少（P<0.05），培养16h培养液中的游离组氨酸（His）含量较培养8h显著提高（P<0.05），缬氨酸（Val）迅速消耗，不能检出。本结果提示，Val，Cys-s，Ser和His可能对以Met为惟一氮源和碳源的瘤胃微生物是十分重要的氨基酸。 |
| 关键词: 瘤胃微生物 蛋氨酸 谷草转氨酶(AST) 谷丙转氨酶(ALT) 游离氨基酸 |
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| 基金项目:合肥市重点农业科研项目（2005-1011） |
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| Effect of methionine as N and C sources on amino acids metabolism of rumen microorganism in vitro |
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| Abstract: |
| In vitro studies were conducted to examine the effect of methionine used as sole nitrogen and carbon sources on the aspartate aminotransferase (AST)，alanine aminotransferase (ALT) and amino acids metabolism of rumen microorganisms.Rumen microorganisms were collected from fistulated goats fed with alfalfa hay and a concentrate mixture twice a day.Six serum bottles,each containing 100 mL mineral and vitamin media,taken and injected into the rumen fluid (off feed granules) 5 mL from every bottle,were randomly divided into two groups,with three bottles in each group.One group was injected 0.1 mmol/L L Met as trial group1;the other three bottles were injected without L Met,as a control group.Then they were anaerobically incubated at 39 ℃ for 16 h.Free amino acids and transaminase (AST,ALT) in the supernatants of the incubation were analyzed by HPLC and an automatic biochemistry analyzer respectively.When Met was used as a unique source of N and C of rumen microorganisms,the contents of free valine (Val) and histidine (His) were highly significantly (P<0.01) and significantly (P<0.05) reduced respectively;but glycine (Gly) was highly increased (P<0.01).No significant differences in the other free amino acids were found,as well as for GOT and GPT activities.The results indicate that Val and cysteine (Cys) are probably the most important essential amino acids of rumen microorganisms when Met serves as a unique source of nitrogen and carbon. |
| Key words: rumen microorganism methionine AST ALT free amino acid |
