Evaluation Of Enhanced Antibiotic Resistance And Unintended Effects On Gut Microbiota In Neo Transgenic Pigs

Neo gene is widely used as a selection marker in studies related to transgenic animals and plants. Recent attention has been focused on the potential impact of neo expression and its subsequent safety concerns by the publics.In this study, two litters of F1 half sibs piglets(neo transgenic and non-transgenic) were randomly assigned into two groups. Group A pigs were fed with standard diet supplemented with antibiotic neomycin sulfate for seven days to evaluate antibiotic resistance of gut microbiota. Group B pigs were fed with only standard diet to evacuate unintended effect on gut microbiota. Fecal samples collected from different time points(0D,8D,23 D and 45D)post antibiotic feeding in Group A and from various intestinal sections from Group B were analyzed by high throughput sequencing. The multiple PCR results in this study demonstrated that there is no horizontal gene transfer from porcine tissues/cells to gut microbiota.These results of group A indicated that the expression product of neo transgene, NPT II, which was leaked from dead epithelial tissues or cells of intestinal tract, or has been accumulated inside bacteria, can indeed have an enhanced effect on antibiotic resistance of gut microbiota in transgenic pigs. Therefore, it can be concluded that neo transgene could, to a certain degree, enhance antibiotic resistance in gut microbiota in transgenic pigs. The above different patterns and/or magnitudes in changes of bacteria at other phylum and genus levels between transgenic and non-transgenic pigs post neomycin feeding also suggest that the low level of NPT II in gut microbiota in transgenic pigs may have on antibiotic resistance, although the mechanism needs further investigation in the future.In group B,the significant different patterns and/or magnitudes of dynamic changes in gut microbiota at phylum and genus levels observed between transgenic and non-transgenic pigs indicate that neo transgene produced unintended effects on gut microbiota. In 1.5M to 3M, group A and group B the significant different patterns and/or magnitudes of dynamic changes in gut microbiota,at phylum and genus levels observed between transgenic and non-transgenic pigs indicate that following the time,the major gut microbiota’s rate have the different. The above different patterns and/or magnitudes in changes of bacteria at other phylum and genus levels between transgenic and non-transgenic pigs suggest that the low level of NPT II in gut microbiota in transgenic pigs may have on antibiotic resistance, although the mechanism needs further investigation in the future.In short, antibiotic resistanceand unintended effects on some bacterial species in gut microbiota was observed in transgenic pigs along with some impact on transgenic animal’s health. It is thus notable that wide use of neo transgene in transgenic animals and plants should be carefully considered. At the same time this research through the high-throughput sequencing technology has accumulated valuable raw data for each pig intestine microbial distribution and dynamic changes in time and space.