Abstract

Optimum™GAT™ ¹ soybean is a genetically modified (GM) soybean containing event DP-356Ø43-5 (356043) that was produced by integration of the coding sequences of the GAT4601 and GM–HRA proteins. In planta expression of these proteins confers tolerance to glyphosate and sulfonylurea/imidazolinone herbicides, respectively. This paper reports the results from a subchronic rat feeding study conducted with 356043 soybeans. Dehulled/defatted toasted meal and toasted ground hulls were prepared from soybeans from untreated plants (356043), herbicide-treated plants (356043 + Gly/SU), non-transgenic isoline control (091), and three commercial non-transgenic reference varieties (93B86, 93B15, and 93M40). Individual diets conforming to standard certified rodent chow formulation (Purina Rodent LabDiet^® 5002) were prepared with 20% meal (w/w) and 1.5% hulls (w/w). Diets were fed to young adult Sprague–Dawley rats (12/sex/group) for at least 93 days. Compared with rats fed the isoline control or conventional reference diets, no biologically-relevant, adverse effects were observed in rats fed diets containing 356043 or 356043 + Gly/SU soybean with respect to body weight/gain, food consumption/efficiency, clinical signs, mortality, ophthalmology, neurobehavioral assessments (sensory response, grip strength, motor activity), clinical pathology (hematology, coagulation, serum chemistry, urinalysis), organ weights, and gross and microscopic pathology. The results from this study indicate that 356043 soybeans are as safe and nutritious as conventional non-GM soybeans.

Keywords: Biotechnology; Genetically modified; Glyphosate acetyltransferase; Rat; Soybean; Subchronic

Abbreviations: DNA, deoxyribonucleic acid; EC, European commission; EFSA, European food safety authority; EPA, environmental protection agency; FAO, food and agricultural organisation; FDA, food and drug administration; h, hour; ILSI, international life sciences institute; LLOQ, lower limit of quantitation; LOD, limit of detection; OECD, organisation for economic cooperation and development; PMI, Purina mills international; ppm, part-per-million; SD, standard deviation; WHO, world health organisation; US, United States

Article Outline

1. Introduction

2. Materials and methods

2.1. Test, control, and reference substances

2.2. Soybean processing and compositional analysis

2.3. Experimental diet formulation, composition, and molecular characterization

2.4. Animal care and management

2.5. Study design and diet administration

2.6. Clinical observations

2.7. Ophthalmology

2.8. Neurobehavioral evaluation

2.9. Clinical pathology

2.9.1. Hematology and coagulation

2.9.2. Serum chemistry

2.9.3. Urinalysis

2.10. Anatomic pathology

2.11. Statistical analysis

3. Results

3.1. Composition of soybeans and processed soybeans fractions

3.2. Composition of experimental diets

3.3. In-life toxicology

3.3.1. Body weight/gain and food consumption/efficiency

3.3.2. Clinical observations and ophthalmology

3.3.3. Neurobehavioral evaluation

3.4. Clinical pathology

3.4.1. Hematology and coagulation

3.4.2. Serum chemistry

3.4.3. Urinalysis

3.5. Organ weights/ratios

3.6. Gross and microscopic anatomic pathology

4. Discussion

5. Conclusion

Conflict of interest statement

Acknowledgements

References