仿生法评定抗草甘膦玉米和转Bt基因玉米的酶水解物能值的研究

摘要

本试验旨在分析抗草甘膦玉米和转Bt基因玉米原料及饲粮与同源非转基因玉米原料及饲粮体外总能消化率以及酶水解物能值,为转基因玉米的营养实质等同性仿生评定方法的研究提供参考. 试验采用单因素完全随机设计,使用单胃动物仿生消化系统模拟饲料原料和饲粮在鸡胃肠道的消化过程,分析同源非转基因玉米、抗草甘膦玉米和转Bt基因玉米以及对应的3种玉米-豆粕饲粮在不同体外模拟消化阶段的干物质消化率、总能消化率和酶水解物能值的差异. 结果表明:同源非转基因玉米、抗草甘膦玉米和转Bt基因玉米以及对应饲粮在常规概率成分含量上是相似的. 抗草甘膦玉米及饲粮与同源非转基因玉米及饲粮相比,在干物质和能量胃消化率、全消化道消化率及酶水解物能值上均没有显著差异( P>0.05). 转Bt基因玉米全消化道总能消化率低于同源非转基因玉米(P=0.03,变异系数=0.50%),对应玉米饲粮的酶水解物能值则高于同源非转基因玉米饲粮(P=0.02,变异系数=1.12%),但均处于仿生消化系统测试的误差范围内(变异系数≤1.64%). 由此可见,抗草甘膦玉米的酶水解物能值与同源对照玉米没有差异,而转Bt基因玉米存在统计学意义上的差异,但所有的测值均处于仿生消化系统的测试误差之内. 仿生法发现的差异是否具有生物学意义有待体内试验验证. 仿生法可为转基因饲料营养等同性研究提供一种新方法.%The objective of the present study was to evaluate the energy value of the glyphosate?tolerant corn and transgenic Bt corn or the glyphosate?tolerant corn diet and transgenic Bt corn diet comparing to the isogenic non?transgenic corn or diet using an in vitro digestion method with computer?controlled simulated digestion sys?tem ( SDS) . It would provide a reference to develop in vitro method for evaluating the nutritional substantial e?quivalence of genetically modified crops using the SDS. A single factorial completely randomized design with 3 corn ingredients ( isogenic non?transgenic corn, glyphosate?tolerant corn, and transgenic Bt corn) and corre?sponding 3 corn diets ( isogenic non?transgenic corn diet, glyphosate?tolerant corn diet, and transgenic Bt corn diet) was adapted. The digestion in the stomach and total tract were simulated respectively. The in vitro dry matter digestibility ( DMD) , in vitro gross energy digestibility ( GED) , and enzymatic hydrolysate gross ener?gy ( EHGE) were determined of corn ingredients and diets. The results showed that the nutrient concentration was similar between the corn ingredients and diets. As a whole, the gastric and total tract DMD, the gastric and total tract GED and the EHGH were not affected by the corn ingredient treatments (P>0.05). However, the GED of transgenic Bt corn were lower than the GED of isogenic non?transgenic corn ( P=0.03, coefficient of variation=0.50%) , when the EHGE of transgenic Bt corn diet were greater than the EHGE of isogenic non?transgenic corn diet ( P=0.02, coefficient of variation=1.12%) . But, above two coefficient of variations were all less than the coefficient of variation of feed ingredients using the SDS (coefficient of variation≤1.64%). These results suggest that in vitro gastric and total tract digestibility of dry matter and gross energy for glypho?sate?tolerant corn is similar to that for isogenic non?transgenic corn, with transgenic Bt corn has some statistical differences. These differences are all within the test error of the SDS, via next animal testing test and verify. The SDS may supply a new method for evaluating the nutritional substantial equivalence of genetically modified crops.