鸡体内小肠液和模拟小肠液对饲料蛋白质消化的比较研究

Comparative Study on Endogenous and Simulated Small Intestinal Fluid to Digest Protein in Feed for Chicken

本试验旨在比较鸡体内小肠液(ESIF)和模拟小肠液(SSIF)对饲料蛋白质进行仿生消化后残渣中蛋白质分解产物片段分布的差异。采用两样本比较试验设计,其中小肠液分别为ESIF和SSIF,以豆粕、棉籽粕、菜籽粕、玉米蛋白粉和酪蛋白为蛋白质饲料原料的代表性底物。在单胃动物仿生消化系统中,以2种小肠液对每个饲料原料进行仿生消化,每个处理5个重复,每个重复1根消化管。以生理盐水提取残渣的蛋白质,然后进行十二烷基硫酸钠聚丙烯酰胺凝胶电泳(SDS-PAGE)分析,使用GS-900成像系统搭配Image Lab进行蛋白质分子量分布计算及采用Quantity One软件进行相似性分析。结果表明:ESIF和SSIF对豆粕、棉籽粕、菜籽粕、玉米蛋白粉和酪蛋白的消化残渣蛋白质分子量分布的相似性分别为69.9%、30.8%、90.1%、77.7%和74.2%(P<0.01)。ESIF消化残渣在13~74 ku低分子量蛋白质的分布上显著高于SSIF(P<0.05),而在104~132 ku高分子量蛋白质的分布上显著低于SSIF(P<0.05),这一差异在棉籽粕上更加明显。由此可见,ESIF与SSIF水解饲料后残渣中蛋白质分子量分布的相似性因饲料来源的不同而呈现较大的差异;ESIF水解饲料后残渣中分子量相对低的蛋白质占比高,而SSIF水解残渣中分子量相对高的蛋白质占比高。

This experiment was conducted to compare the fragment distribution of protein decomposition products in residues of feed protein biomimetic digestion with endogenous small intestinal fluid(ESIF)and simulated small intestinal fluid(SSIF)in chicken. A two-sample experiment design was adopted to compare small intestine fluid of ESIF and SSIF. Soybean meal,cottonseed meal,rapeseed meal,corn gluten meal and casein were used as the representative substrates of protein feed. In the simulated digestion system for monogastric animal,each feed ingredient was digested with 2 kinds of small intestinal fluids. Each treatment contained 5 replicates with 1 digestive tube per replicate. Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE)was performed for proteins extracted with physiological saline in residues. GS-900 imaging system with Image Lab and Quantity One software were used to calculate the molecular weight distribution and perform similarity analysis for proteins. The results showed that the similarity of molecular weight distribution of proteins in residues from soybean meal,cottonseed meal,rapeseed meal,corn gluten meal and casein digested with ESIF and SSIF were 69.9%,30.8%,90.1%,77.7% and 74.2%(P<0.01),respectively. The distribution of low molecular weight of 13 to 74 ku proteins in residues digested with ESIF was significantly higher than that with SSIF(P<0.05),the distribution of high molecular weight of 104 to 132 ku proteins in residues digested with ESIF was significantly lower than that with SSIF group(P<0.05),and this difference was more obvious in cottonseed meal. In conclusion,the similarity of molecular weight distribution of proteins in residues from feed ingredients digested with ESIF and SSIF was a great difference in different sources of feed;in proteins in residues from feed ingredients digested by small intestinal fluid,a greater proportion of relatively low molecular weight was observed in ESIF,whereas a greater proportion of relatively high molecular weight was observed in SSIF.[Chinese Journal of Animal Nutrition,2022,34(2):1325-1333]