冷藏对米蛾卵液中游离氨基酸变化的影响

Effects of cold storage on the free amino acids in Corcyra cephalonica eggs

赤眼蜂的工厂化繁育常使用米蛾卵作为中间寄主卵,为了满足赤眼蜂生产的需要,需对米蛾卵进行冷藏,但冷藏米蛾卵影响赤眼蜂的生长发育。利用核磁共振技术(NMR)测定了新鲜米蛾卵(U)、新鲜杀胚米蛾卵(CK)、杀胚米蛾卵在4℃条件下冷藏15 d(N15)、30 d(N30)、45 d(N45)和60 d(N60)后,米蛾卵卵液游离氨基酸种类和含量的变化。结果共鉴定到24种游离氨基酸及其衍生物,包括昆虫发育必需的10种氨基酸。U和CK之间的游离氨基酸组分没有显著差异,N15、N30和N45游离氨基酸总量随冷藏时间的延长而显著升高,N60中的氨基酸总量与N45比较没有显著增加。对24种游离氨基酸及其衍生物的含量进行主成分分析,结果表明丙氨酸、谷氨酰胺、鸟氨酸、天冬氨酸、组氨酸、赖氨酸、丝氨酸、焦谷氨酸等8种氨基酸的含量随冷藏时间的增加而有着显著的变化,其中,丙氨酸变化幅度最为明显,随着冷藏时间的增加,含量从0.1624 mmol/L增加到8.6192 mmol/L;组氨酸在N30、N45和N60处理之间显著下降,从0.7553 mmol/L降低到0.2495 mmol/L。因此,冷藏会导致米蛾卵内游离氨基酸含量发生一定变化,这可能是冷藏米蛾卵影响赤眼蜂生长发育的重要原因之一。

Corcyra cephalonica eggs are commonly used as intermediate hosts in Trichogramma mass rearing. Cold storage of C. cephalonica eggs was important to Trichogramma mass rearing,but the growth and development of Trichogramma would be affected by the refrigerated eggs. Free amino acids in the contents of C. cephalonica eggs which was stored at 4℃ for 15（ N15）,30（ N30）,45（ N45）,and 60（ N60） days,respectively,were detected by Nuclear Magnetic Resonance（ NMR） technology,the fresh eggs without（ U） and with（ CK） UV treated were as comparison. The results showed that there were 24 free amino acids and derivatives identified,including 10 essential amino acids for insect development.There was no significant difference in the concentration of total free amino acids between U and CK,there was a significant increase of total amino acids followed by increase of days of cold storage in N15,N30 and N45. However,there was no significant increase in N60 compared with N45. The results of Principal Component Analysis（ PCA） of 24 amino acids and derivatives showed that 8 amino acids such as Alanine,Glutamine,Ornithine, Asparagine, Histidine, Lysine, Serine, and Pyroglutamate were significantly changed with the increase of cold storage days, in which Alanine was significantly increased from0. 1624 mmol / L to 8. 6192 mmol / L. Histidine was significantly declined from 0. 7553 mmol / L to0. 2495 mmol / L. It could be concluded that the cold storage resulted in the change of free amino acids in C. cephalonica eggs,which might be one of the reasons influencing the growth and development of Trichogramma.