Degradation Of Transgenic Ingredients Of Genetically Modified Soybean During Feed Processing

With the increasing presence of transgenic plant for feedstuffs, the safety of genetically modified feeds was focused. This paper was conducted to study the degradation of endogenous gene and exogenous gene during different manufacturing processes from genetically modified soybeans, soybean meal and its derivative feedstuffs, to provide the scientifically basement for the estimation of GMO feed.Analyzed the exogenous gene and exogenous protein of genetically modified soybeans, and selected the PCR technology to detect endogenous gene and exogenous gene; Real-time quantitative PCR method was developed, the standard curve was established with 0.9959 of R2 value and had good reproducibility and sensitivity; Selected Western to detect cp4 epsps protein in the genetically modified soybeans and soybean meal.Soybean meal as raw materials was dry-heated, moist-heated and extrusion processed, and collected feed products for the test. The soybean meal at 7 different temperature gradients, respectively heated 3 min, 5 min, 10 min. The different lengths of soybean endogenous gene were amplified, which studied the change of endogenous gene fragment after dry-heating treatment, the results showed that the high temperature less affected endogenous gene; Soybean meal at 121℃, 0.1 MPa respectively heated 1min, 3min, 5min, the degradation of endogenous gene was deteriorated; Extruded soybean meal was degraded through high temperature and pressure; The endogenous gene of pellet and extruded pellet degraded to 1060bp that explained the degradation took place.Soybean meal as a kind of by-product whose gene had been destroyed, the cp4 epsps gene of soybean meal had been degraded to 1512 bp, exogenous gene fragment degraded to 408bp after 120℃heating 10 min; The effect of moist-heating about cp4 epsps gene was significantly greater than dry-heated, the 807 bp fragment of exogenous gene could not detected after 1min; Extruding had little effect on the exogenous gene, the exogenous gene fragment was degraded to 1512bp. The degradation of feedstuff gene was similar with dry extruding.The use of real-time fluorescence quantitative PCR technology to detect genetically modified content for dry-heating and moist-heating soybean meal so as to research of genetically modified content during processing. The genetically modified content dropped to 2.49% after heating at 120℃, moist-heating had great influence on gene content, it quickly declined to 0.99% after 3 min.The security of exogenous protein has always been concern, The content of exogenous protein was reduced with the temperature increased, particularly after heating at 120℃, the content was decreased significantly; There wasn't hybridization signal after 1 min of moist-heating processing, which explained the rapid decline in protein content; The exogenous protein of extruded soybean, extruded soybean meal, extruded pellet and pellet were degraded.