Relationship between faecal microbiota and plasma metabolome in rats fed NK603 and MON810 GM maize from the GMO90+ study

A 7-year feed study on the long-term effects of genetically modified maize containing cry1Ab/cry2Aj and EPSPS genes on gut microbiota and metabolite profiles across two generations of cynomolgus macaques

The health implications of genetically modified (GM) crops remain controversial relative to their non-GM counterparts, particularly regarding long-term dietary exposure. Although the gut microbiome is a key health indicator, studies investigating the impact of GM crop consumption on intestinal microbiota remain limited. This study presents a comprehensive 7-year evaluation of GM maize expressing cry1Ab/cry2Aj and G10evo-EPSPS proteins through metagenomic and metabolomic analyses. We assessed the effects of GM maize consumption on gut microbiota diversity and metabolite profiles in cynomolgus macaques (Macaca fascicularis) compared with non-GM maize. Three diet regimens were implemented: a conventional compound feed (CK group), diet formulation containing 70 % non-GM maize (Corn group), and diet formulation containing 70 % GM maize (Tg group). The results demonstrated that feeding GM maize to the first (F0) and second (F1) generations of monkeys did not substantially affect the composition, community structure, or function of the intestinal microbiome, as indicated by species composition and diversity analyses. Minor differences in intestinal metabolites were observed but were not directly linked to transgenic maize consumption. Collectively, long-term intake of maize with cry1Ab/cry2Aj and g10evo-epsps genes had no adverse effects on macaques or their offspring.

Effects of genetically modified soybean on physiological variables and gut microbiota of Sprague-Dawley rats

Soybean is an important source of food and feed. To keep weeds out of soybean it is often genetically modified. The goal of the current study was to evaluate the effects of a diet containing 70% GM soybean on Sprague-Dawley rats. Two groups of rats were fed GM and non-GM soybeans for a period of 120 days, and their body weight, hematology and serum biochemistry were compared. In addition, the effect of the consumption of GM soybean on identified intestinal microbiota and antibiotic resistance was compared with the effect of the consumption of non-GM soybean. Total bacteria and six types of bacteria shared by humans and rats were detected by q-PCR. The results showed that the consumption of GM soybean did not result in any significant changes in body weight, hematology and serum biochemistry. The results of q-PCR indicated that compared with the consumption of non-GM soybeans, the consumption of GM soybean did not have a comparable effect on the abundance of total bacteria, namely Bifidobacterium group, Clostridium perfringens subgroup, Escherichia coli, Lactobacillus group, and the Bacteroides-Prevotella group. The results of antibiogram showed that the consumption of GM soybean did not change the resistance of E.coli, although it changed the resistance of E. faecalis against erythromycin (the GM group was significantly less resistant than non-GM group). Overall, the study indicated that the consumption of GM soybean did not exhibit adverse effects on physiological variables and gut microbiota of rats. However, the obtained antibiogram results indicated that it is necessary to further investigate the antibiotic resistance of the gut microbiota when GM food is consumed.

Effects of glyphosate exposure on intestinal microbiota, metabolism and microstructure: a systematic review

Glyphosate is the most commercialized herbicide in Brazil and worldwide, and this has become a worrying scenario in recent years. In 2015 glyphosate was classified as potentially carcinogenic by the World Health Organization, which opened avenues for numerous debates about its safe use regarding non-target species' health, including humans. This review aimed to observe the impacts of glyphosate and its formulations on the gut microbiota, as well as on the gut microstructure and animal metabolism. A systematic review was conducted based on the PRISMA recommendations, and the search for original articles was performed in Pubmed/Medline, Scopus and Web of Science databases. The risk of bias in the studies was assessed using the SYRCLE strategy. Our findings revealed that glyphosate and its formulations are able to induce intestinal dysbiosis by altering bacterial metabolism, intestinal permeability, and mucus secretion, as well as causing damage to the microvilli and the intestinal lumen. Additionally, immunological, enzymatic and genetic changes were also observed in the animal models. At the metabolic level, damage was observed in lipid and energy metabolism, the circulatory system, cofactor and vitamin metabolism, and replication, repair, and translation processes. In this context, we pointed out that the studies revealed that these alterations, caused by glyphosate-based herbicides, can lead to intestinal and systemic diseases, such as Crohn's disease and Alzheimer's disease.

Urinary glyphosate concentration in pregnant women in relation to length of gestation

Human exposure to glyphosate-based herbicides (GBH) is increasing rapidly worldwide. Most existing studies on health effects of glyphosate have focused on occupational settings and cancer outcomes and few have examined this common exposure in relation to the health of pregnant women and newborns in the general population. We investigated associations between prenatal glyphosate exposure and length of gestation in The Infant Development and the Environment Study (TIDES), a multi-center US pregnancy cohort. Glyphosate and its primary degradation product [aminomethylphosphonic acid (AMPA)] were measured in urine samples collected during the second trimester from 163 pregnant women: 69 preterm births (<37 weeks) and 94 term births, the latter randomly selected as a subset of TIDES term births. We examined the relationship between exposure and length of gestation using multivariable logistic regression models (dichotomous outcome; term versus preterm) and with weighted time-to-event Cox proportional hazards models (gestational age in days). We conducted these analyses in the overall sample and secondarily, restricted to women with spontaneous deliveries (n = 90). Glyphosate and AMPA were detected in most urine samples (>94 %). A shortened gestational length was associated with maternal glyphosate (hazard ratio (HR): 1.31, 95 % confidence interval (CI) 1.00-1.71) and AMPA (HR: 1.32, 95%CI: 1.00-1.73) only among spontaneous deliveries using adjusted Cox proportional hazards models. In binary analysis, glyphosate and AMPA were not associated with preterm birth risk (<37 weeks). Our results indicate widespread exposure to glyphosate in the general population which may impact reproductive health by shortening length of gestation. Given the increasing exposure to GBHs and the public health burden of preterm delivery, larger confirmatory studies are needed, especially in vulnerable populations such as pregnant women and newborns.

Effects of transgenic Bacillus Thuringiensis maize (2A-7) on the growth and development in rats

This study aimed to determine the effects of genetically modified insect-resistant maize (2A-7) on the growth and development in developing rats. Rats were fed a diet formulated with 2A-7 maize and were compared with rats fed a diet formulated with non-transgenic maize (CK group) and rats fed AIN-93G diet (BC group). 2A-7 maize was formulated into diets at ratios of 82.4% (H group) and 20.6% (L group); non-transgenic maize was formulated into diets at a ratio of 82.4%. From the first day of pregnancy, adult rats were divided into four groups and fed with the above four diets, respectively. Weaning on postnatal day 21, the diets of offspring were consistent with their parents. The results showed that body weight, hematology, serum biochemistry, organ weight, organ coefficients and allergenicity of offspring fed with 2A-7 maize were comparable with those in the CK and BC groups. In physiological and behavioral development experiments, there was no statistically significant difference among groups. Although mCry1Ab proteins were detected in organs and serum, no histopathological changes were observed among groups. In conclusion, A-7 maize cause no treatment-related adverse effects on offspring, indicating that 2A-7 maize is safe for developing rats.

Expression profiling of key pathways in rat liver after a one-year feeding trial with transgenic maize MON810

In a recent one-year feeding study, we observed no adverse effects on tissue level in organs of rats fed with the genetically-modified maize MON810. Here, we assessed RNA expression levels of 86 key genes of the apoptosis-, NF-кB-, DNA-damage response (DDR)-, and unfolded-protein response (UPR) pathways by RT-qPCR in the rat liver. Male and female rats were fed either with 33% MON810 (GMO), isogenic- (ISO), or conventional maize (CONV) and RNAs were quantified from eight rats from each of the six feeding groups. Only Birc2 transcript showed a significant (p ≤ 0.05) consistent difference of ≥1.5-fold between the GMO and ISO groups in both sexes. Unsupervised cluster analysis showed a strong separation of male and female rats, but no clustering of the feeding groups. Individual analysis of the pathways did not show any clustering of the male or female feeding groups either, though transcript levels of UPR pathway-associated genes caused some clustering of the male GMO and CONV feeding group samples. These differences were not seen between the GMO and ISO control or within the female cohort. Our data therefore does not support an adverse effect on rat liver RNA expression through the long-term feeding of MON810 compared to isogenic control maize.