VB_6对家蚕氮代谢的影响

Effects of Vitamin B_6 on Nitrogen Metabolism in the Silkworm, Bombyx mori

用人工饲料无菌饲育方式 ,分析维生素B6(VB6)对家蚕丝腺生长、血淋巴蛋白质浓度、血淋巴游离氨基酸组成变化及氮代谢终产物尿酸形成的影响。结果表明 :5龄期家蚕在缺乏VB6条件下 ,丝腺生长严重受阻碍 ,血淋巴蛋白质不能正常合成 ,使体内氨基酸转化利用率下降 ,氮代谢终产物尿酸的排泄量增加 ,血淋巴中部分游离氨基酸浓度下降 ,特别是合成丝蛋白质主要成分的Ala、Ser和Tyr等蚕体非必需氨基酸的组成比率显著减少 ,而Gly、Orn和Cysta等的浓度增加异常 ,导致血淋巴中游离氨基酸组成动态平衡破坏 ,显示蚕体内因VB6缺乏引起氨基酸代谢失调。

The effects of Vitamin B 6 deficiency on silkglands growth,protein content,free amino acid composition and their changes in haemolymph and uric acid excretion were determined using the 5th instar silkworm reared with disinfected artificial diet.Under Vitamin B 6 deficient conditions,the growth of silkglands was retarded,the protein biosynthesis in haemolymph was abnormal ,and the rate of amino acid transformation dropped due to abnormal protein synthesis.Uric acid excretion was increased while the free amino acid composition in haemolymph was reduced.The ratio of non necessary amino acid such as Ala,Ser and Tyr chiefly composed of silk protein was remarkably reduced whereas the content of Gly,Orn and Cysta was abnormally increased, which indicated that the dynamic balance of free amino acid composition in haemolymph was destroyed.These results suggested that amino acid metabolism could not be regulated with Vitamin B 6 deficiency in the silkworm, Bombyx mori .