A 90-day safety study of genetically modified rice expressing rhIGF-1 protein in C57BL/6J rats

Food Safety Assessment of Commercial Genetically Modified Soybeans in Rats

Although the safety of commercial genetically modified (GM) soybeans has been well evaluated and GM soybeans are legally sold under government management, some consumers still have concerns about their safety. The objective of this study was to evaluate the safety of commercial GM soybeans sold in markets as a food source. In the present study, two commercial GM (GM-1 and -2) soybeans and one non-GM soybean were randomly purchased and subjected to a whole food toxicity assessment. Rats (SD), male and female, were divided into six groups (10/sex/group). Two dosages of 1 g/kg/day and 5 g/kg/day of soybeans were selected for the low- and high-dose groups. Rats were administered the soybeans via daily oral fed for 90 days. The results indicate that the body weight, organ weight, biochemistry, hematology, and urology showed no biologically adverse effects. At necropsy, no significant differences between organ weights were noted between the non-GM- and GM soybeans-treated groups. Moreover, no gross or histopathological lesions were observed in the high-dosage (5 g/kg/day) fed groups of the non-GM and GM soybean fed rats. In conclusion, this food safety assessment revealed that commercial GM soybeans are substantially equivalent to non-GM soybeans in rats.

A subchronic feeding safety evaluation of transgenic milk containing human β-defensin 3 on reproductive system of C57BL/6J mouse

Bovine mastitis is an infectious disease of the mammary gland which has been generally treated by antibiotic delivery. While the increasing drug-resistant bacteria and the high consumption of the antibiotic had become a noticeable concern. In a previous study, a mammary special vector expressing human β-defensin 3 (hBD3) was transfected into bovine fetal fibroblasts to produce mastitis-resistant bovine. This investigation focused on potential unintended effects of transgenic milk containing hBD3 produced by these mastitis-resistant bovine on the reproductive system of C57BL/6J mice. Mice were fed with diets containing transgenic milk or conventional milk, nutritionally balanced to an AIN93G diet for 90 days, and non-milk diet was selected as the negative group. The reproductive system was given special attention including reproductive organ/body ratios, necropsy and histopathology, serum sex hormone, sperm parameters, estrus cycle and the expression level of some specific genes which could indicate the development and function of reproductive system. No diet-related significant differences were observed among three groups in this 90-day feeding study. The results indicated that hBD3 milk does not appear to exert any effect on the reproductive system in C57BL/6J rats compared with conventional milk or the control diet.

Effects of 60-Week Feeding Diet Containing Bt Rice Expressing the Cry1Ab Protein on the Offspring of Inbred Wuzhishan Pigs Fed the Same Diet

We evaluated the chronic effects of Bt rice carrying the Cry1Ab protein (1.64 mg/kg) on offspring of highly inbred WZSP, fed with Bt rice for 360 days, in a 60-week feeding study. The WZSP offspring (n = 27) were assigned to two groups (Minghui86 group, female n = 6, male n = 5; Bt group, female n = 11, male n = 5). The average obtained Cry1Ab protein dosage for female and male pigs was 1.003 and 1.234 mg/kg body weight after 10 weeks of feeding, respectively. The experimental feed in the study was nutritionally matched in both groups. The average daily gain and feed conversion ratio of the females in week 3 and males from weeks 1 to 10 were different between the Bt and Minghui86 groups (P < 0.05), and the body weight of the male pigs in week 2 was greater in the Minghui86 group than that of the Bt group (P < 0.05). No other differences were observed, and there were no significant differences in the serum sex steroid level, hematology parameters, relative organ weights, or histopathology. Although differences in some serum chemistry parameters (alanine aminotransferase of female pigs and alkaline phosphatase of male pigs) were observed, they were not considered treatment-related. On the basis of these results, long-term intake of transgenic rice carrying Cry1Ab protein exerts no unintended adverse effects on WZSP offspring.

Safety Assessment of Food and Feed from GM Crops in Europe: Evaluating EFSA's Alternative Framework for the Rat 90-day Feeding Study

Regulatory-compliant rodent subchronic feeding studies are compulsory regardless of a hypothesis to test, according to recent EU legislation for the safety assessment of whole food/feed produced from genetically modified (GM) crops containing a single genetic transformation event (European Union Commission Implementing Regulation No. 503/2013). The Implementing Regulation refers to guidelines set forth by the European Food Safety Authority (EFSA) for the design, conduct, and analysis of rodent subchronic feeding studies. The set of EFSA recommendations was rigorously applied to a 90-day feeding study in Sprague-Dawley rats. After study completion, the appropriateness and applicability of these recommendations were assessed using a battery of statistical analysis approaches including both retrospective and prospective statistical power analyses as well as variance-covariance decomposition. In the interest of animal welfare considerations, alternative experimental designs were investigated and evaluated in the context of informing the health risk assessment of food/feed from GM crops.

A 90-day toxicity study of GmTMT transgenic maize in Sprague-Dawley rats

GmTMT transgenic maize is a genetically modified maize plant that overexpresses the γ-tocopherol methyltransferase (γ-TMT) from Glycine max (Gm). The γ-TMT gene was introduced into maize line Zhen58 to encode the GmTMT2a protein which can convert γ-tocopherol into α-tocopherol. Overexpression of GmTMT2a significantly increased the α-tocopherol content in transgenic maize. The present study was designed to investigate any potential effects of GmTMT maize grain in a 90-day subchronic rodent feeding study. Maize grains from GmTMT or Zhen58 were incorporated into rodent diets at low (12.5%), medium (25%) or high (50%) concentrations and administered to Sprague-Dawley rats (n = 10/sex/group) for 90 days. The negative control group of rats (n = 10/sex/group) were fed with common maize diets. Results from body weights, feed consumption, clinical chemistry, hematology, absolute and relative organ weights indicated no treatment-related side effects of GmTMT maize grain on rats in comparison with rats consuming diets containing Zhen58 maize grain. In addition, no treatment-related changes were found in necropsy and histopathology examinations. Altogether, our data indicates that GmTMT transgenic maize is as safe and nutritious as its conventional non-transgenic maize.

Genetically modified rice Bt-Shanyou63 expressing Cry1Ab/c protein does not harm Daphnia magna

The genetically modified (GM) rice Bt-ShanYou63 (Bt-SY63) received an official biosafety certificate while its safety remained in dispute. In a lifelong study, Daphnia magna were experimentally fed a basal diet of rice flours from Bt-SY63 or its parental rice ShanYou63 (SY63) at concentrations of 0.2mg, 0.3mg, or 0.4mgC (per individual per day). Overall the survival, body size, and reproduction of the animals were comparable between Bt-SY63 and ShanYou63.. The results showed that no significant differences were observed in growth and reproduction parameters between D. magna fed GM and non-GM flour and no dose-related changes occurred in all the values. Based on the different parameters assessed, the GM rice Bt-SY63 is a safe food source for D. magna that does not differ in quality from non-GM rice.

Effects of Genetically Modified Milk Containing Human Beta-Defensin-3 on Gastrointestinal Health of Mice

This study was performed to investigate the effects of genetically modified (GM) milk containing human beta-defensin-3 (HBD3) on mice by a 90-day feeding study. The examined parameters included the digestibility of GM milk, general physical examination, gastric emptying function, intestinal permeability, intestinal microflora composition of mice, and the possibility of horizontal gene transfer (HGT). The emphasis was placed on the effects on gastrointestinal (GI) tract due to the fact that GI tract was the first site contacting with food and played crucial roles in metabolic reactions, nutrition absorption and immunity regulation in the host. However, the traditional methods for analyzing the potential toxicological risk of GM product pay little attention on GI health. In this study, the results showed GM milk was easy to be digested in simulated gastric fluid, and it did not have adverse effects on general and GI health compared to conventional milk. And there is little possibility of HGT. This study may enrich the safety assessment of GM product on GI health.

Safety assessment of Maillard reaction products of chicken bone hydrolysate using Sprague-Dawley rats

Background

The Maillard reaction products of chicken bone hydrolysate (MRPB) containing 38% protein, which is a derived product from chicken bone, is usually used as a flavor enhancer or food ingredient. In the face of a paucity of reported data regarding the safety profile of controversial Maillard reaction products, the potential health effects of MRPB were evaluated in a subchronic rodent feeding study.

Methods

Sprague–Dawley rats (SD, 5/sex/group) were administered diets containing 9, 3, 1, or 0% of MRPB derived from chicken bone for 13 weeks.

Results

During the 13-week treatment period, no mortality occurred, and no remarkable changes in general condition and behavior were observed. The consumption of MRPB did not have any effect on body weight or feed and water consumption. At the same time, there was no significant increase in the weights of the heart, liver, lung, kidney, spleen, small intestine, and thymus in groups for both sexes. Serological examination showed serum alanine aminotransferase in both sexes was decreased significantly, indicating liver cell protection. No treatment-related histopathological differences were observed between the control and test groups.

Conclusion

Based on the results of this study, the addition of 9% MRPB in the diet had no adverse effect on both male and female SD rats during the 90-day observation. Those results would provide useful information on the safety of a meaty flavor enhancer from bone residue as a byproduct of meat industry.

Effects of 90-Day Feeding of Transgenic Maize BT799 on the Reproductive System in Male Wistar Rats

BT799 is a genetically modified (GM) maize plant that expresses the Cry1Ac gene from Bacillus thuringiensis (Bt). The Cry1Ac gene was introduced into maize line Zhen58 to encode the Bt crystal protein and thus produce insect-resistant maize BT799. Expression of Bt protein in planta confers resistance to Lepidopteran pests and corn rootworms. The present study was designed to investigate any potential effects of BT799 on the reproductive system of male rats and evaluate the nutritional value of diets containing BT799 maize grain in a 90-day subchronic rodent feeding study. Male Wistar rats were fed with diets containing BT799 maize flours or made from its near isogenic control (Zhen58) at a concentration of 84.7%, nutritionally equal to the standard AIN-93G diet. Another blank control group of male rats were treated with commercial AIN-93G diet. No significant differences in body weight, hematology and serum chemistry results were observed between rats fed with the diets containing transgenic BT799, Zhen58 and the control in this 13-week feeding study. Results of serum hormone levels, sperm parameters and relative organ/body weights indicated no treatment-related side effects on the reproductive system of male rats. In addition, no diet-related changes were found in necropsy and histopathology examinations. Based on results of the current study, we did not find any differences in the parameters tested in our study of the reproductive system of male rats between BT799 and Zhen58 or the control.

A 90-day toxicology study of meat from genetically modified sheep overexpressing TLR4 in Sprague-Dawley rats

Genetic modification offers alternative strategies to traditional animal breeding. However, the food safety of genetically modified (GM) animals has attracted increasing levels of concern. In this study, we produced GM sheep overexpressing TLR4, and the transgene-positive offsprings (F1) were confirmed using the polymerase chain reaction (PCR) and Southern blot. The expression of TLR4 was 2.5-fold compared with that of the wild-type (WT) sheep samples. During the 90-day safety study, Sprague-Dawley rats were fed with three different dietary concentrations (3.75%, 7.5%, and 15% wt/wt) of GM sheep meat, WT sheep meat or a commercial diet (CD). Blood samples from the rats were collected and analyzed for hematological and biochemical parameters, and then compared with hematological and biochemical reference ranges. Despite a few significant differences among the three groups in some parameters, all other values remained within the normal reference intervals and thus were not considered to be affected by the treatment. No adverse diet-related differences in body weights or relative organ weights were observed. Furthermore, no differences were observed in the gross necropsy findings or microscopic pathology of the rats whose diets contained the GM sheep meat compared with rats whose diets contained the WT sheep meat. Therefore, the present 90-day rat feeding study suggested that the meat of GM sheep overexpressing TLR4 had no adverse effect on Sprague-Dawley rats in comparison with WT sheep meat. These results provide valuable information regarding the safety assessment of meat derived from GM animals.

GM crops and the rat digestive tract: a critical review

The aim of this review is to examine the relationship between genetically modified (GM) crops and health, based on histopathological investigations of the digestive tract in rats. We reviewed published long-term feeding studies of crops containing one or more of three specific traits: herbicide tolerance via the EPSPS gene and insect resistance via cry1Ab or cry3Bb1 genes. These genes are commonly found in commercialised GM crops. Our search found 21 studies for nine (19%) out of the 47 crops approved for human and/or animal consumption. We could find no studies on the other 38 (81%) approved crops. Fourteen out of the 21 studies (67%) were general health assessments of the GM crop on rat health. Most of these studies (76%) were performed after the crop had been approved for human and/or animal consumption, with half of these being published at least nine years after approval. Our review also discovered an inconsistency in methodology and a lack of defined criteria for outcomes that would be considered toxicologically or pathologically significant. In addition, there was a lack of transparency in the methods and results, which made comparisons between the studies difficult. The evidence reviewed here demonstrates an incomplete picture regarding the toxicity (and safety) of GM products consumed by humans and animals. Therefore, each GM product should be assessed on merit, with appropriate studies performed to indicate the level of safety associated with them. Detailed guidelines should be developed which will allow for the generation of comparable and reproducible studies. This will establish a foundation for evidence-based guidelines, to better determine if GM food is safe for human and animal consumption.

A two-generation reproduction study with transgenic Bt rice TT51 in Wistar rats

TT51 is a transgenic Bt rice created by fusion a synthetic CryAb/CryAc gene into rice MingHui63. A significant number of animal feeding studies with transgenic crops have been carried out with the rapid development of transgenic crops. However, the evidence is far from identifying whether certain novel transgenic crops possess potential danger for human or animal health after long-term consumption. Rice-based diets, containing 60% ordinary grocery rice, MingHui63 rice or TT51 rice by weight, were fed to two generations of male and female rats in order to determine the potential reproductive effects of TT51. In this study, both clinical performance variables and histopathological responses were examined and compared between groups. There were no significant differences between groups on body weights, food consumption, reproductive data and relative organ/body weights. There were some statistically significant differences in hematology and serum chemistry parameters, but no histological abnormalities were seen in the brain, heart, liver, spleen, kidneys, stomach, small intestine, thymus, ovaries, uterus, testes and epididymides. Based on the results, under the circumstance of this study TT51 show no significant differences on reproduction performance of rats compared with MingHui63 and the control.

The use of whole food animal studies in the safety assessment of genetically modified crops: limitations and recommendations

There is disagreement internationally across major regulatory jurisdictions on the relevance and utility of whole food (WF) toxicity studies on GM crops, with no harmonization of data or regulatory requirements. The scientific value, and therefore animal ethics, of WF studies on GM crops is a matter addressable from the wealth of data available on commercialized GM crops and WF studies on irradiated foods. We reviewed available GM crop WF studies and considered the extent to which they add to the information from agronomic and compositional analyses. No WF toxicity study was identified that convincingly demonstrated toxicological concern or that called into question the adequacy, sufficiency, and reliability of safety assessments based on crop molecular characterization, transgene source, agronomic characteristics, and/or compositional analysis of the GM crop and its near-isogenic line. Predictions of safety based on crop genetics and compositional analyses have provided complete concordance with the results of well-conducted animal testing. However, this concordance is primarily due to the improbability of de novo generation of toxic substances in crop plants using genetic engineering practices and due to the weakness of WF toxicity studies in general. Thus, based on the comparative robustness and reliability of compositional and agronomic considerations and on the absence of any scientific basis for a significant potential for de novo generation of toxicologically significant compositional alterations as a sole result of transgene insertion, the conclusion of this review is that WF animal toxicity studies are unnecessary and scientifically unjustifiable.

Effects of 90-day feeding of transgenic Bt rice TT51 on the reproductive system in male rats

Rice is a staple food crop; however, the threat of pests leads to a serious decline in its output and quality. The CryAb/CryAc gene, encodes a synthetic fusion Bacillus thuringiensis (Bt) crystal protein, was introduced into rice MingHui63 to produce insect-resistant rice TT51. This study was undertaken to investigate potential unintended effects of TT51 on the reproductive system in male rats. Male rats were treated with diets containing 60% of either TT51 or MingHui63 by weight, nutritionally balanced to an AIN93G diet, for 90days. An additional negative control group of rats were fed with a rice-based AIN93G diet. Body weights, food intake, hematology, serum chemistry, serum hormone levels, sperm parameters and relative organ/body weights were measured, and gross as well as microscopic pathology were examined. No diet-related significant differences in the values of response variables were observed between rats that were fed with diet containing transgenic TT51, MingHui63 and the control in this 90-day feeding study. In addition, necropsy and histopathology examination indicated no treatment-related changes. The results from the present study indicated that TT51 does not appear to exert any effect on the reproductive system in male rats compared with MingHui63 or the control.

Plurality of opinion, scientific discourse and pseudoscience: an in depth analysis of the Séralini et al. study claiming that Roundup™ Ready corn or the herbicide Roundup™ cause cancer in rats

A recent paper published in the journal Food and Chemical Toxicology presents the results of a long-term toxicity study related to a widely-used commercial herbicide (Roundup™) and a Roundup-tolerant genetically modified variety of maize, concluding that both the herbicide and the maize varieties are toxic. Here we discuss the many errors and inaccuracies in the published article resulting in highly misleading conclusions, whose publication in the scientific literature and in the wider media has caused damage to the credibility of science and researchers in the field. We and many others have criticized the study, and in particular the manner in which the experiments were planned, implemented, analyzed, interpreted and communicated. The study appeared to sweep aside all known benchmarks of scientific good practice and, more importantly, to ignore the minimal standards of scientific and ethical conduct in particular concerning the humane treatment of experimental animals.

Subchronic feeding study of stacked trait genetically-modified soybean (3Ø5423 × 40-3-2) in Sprague-Dawley rats

The genetically-modified (GM) soybean 3Ø5423 × 40-3-2 expresses siRNA for the fatty acid desaturase-2 enzyme which results in higher concentrations of oleic acid (18:1) relative to linoleic acid (18:2) compared with non-GM soybeans. It also expresses the CP4 EPSPS protein for tolerance to glyphosate. In this study, three different dietary concentrations (7.5%, 15% and 30% wt/wt) of 3Ø5423 × 40-3-2 or non-GM soybeans were fed to Sprague-Dawley rats for 90 days during which in-life nutritional and growth performance variables were evaluated followed by analysis of standard clinical chemistry, hematology and organ variables. Compared with rats fed the non-GM control diet, some statistically significant differences were observed in rats fed the 3Ø5423 × 40-3-2 diet. However the differences were not considered treatment-related and commonly fell within the normal ranges of the control group consuming the commercial diet. These results demonstrated that the GM soybean 3Ø5423 × 40-3-2 is as safe as non-GM soybeans.