Iron is an essential trace element in both animal and human nutrition. It plays vital important roles in various biological processes. However, a deficiency in iron would induce anaemia, while an overload would result in toxic effects. Therefore, how to safely use this chemical draw scentists' attention.

In order to improve the iron deficiency problems in new born piglets, the researcher group in Institute of Subtropical Agriculture, Chinese Academy of Sciences (ISA) had designed a new iron chelate ferrous N-carbamylglycinate as an iron fortifier (patent No: 201310142525.4), which aimed to improve iron bioavailability and reduce extra digestion.

Scientists believed that toxicological evaluation, which includes acute toxicity, sub-acute toxicity and mutagenicity studies, can give an overall assessment and is the essential process for the new feed additives development. Then, the subject chemical can be classified according to the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) or the Chinese chemical classification system. The classification levels of the target chemical will give vital information for the decision making: not recommend as a feed addictive, recommend as a feed addictive at a low dosage or short period, or recommend as a feed addictive for long term usage.

Through a series of experiments in Sprague-Dawley (SD) rats (8 weeks, 180-20 g) and Kunming mice, scientists in ISA found that the median lethal dose (LD50) of the ferrous N-carbamylglycinate in SD rat was 3.02 g/kg, according to the improved Karber's method. The 95% confidence intervals were between 2.78 and 3.31 g/kg. No significant differences were observed in body weights, feed consumption, clinical signs, organ weights, histopathology, ophthalmology, hematology, and clinical chemistry parameters in any of the treatment groups of ferrous N-carbamylglycinate at target concentrations 150, 300, and 600 mg/kg/day for 28 days. Then, the no observed adverse effect level (NOAEL) for ferrous N-carbamylglycinate was recommended at least 600 mg/kg b.w. per day in SD rats. In addition, no evidence of mutagenicity was found in the study, either in bacterial reverse mutation assay in vitro or in mice bone marrow micronucleus assay and sperm shape abnormality assay in vivo. The ferrous N-carbamylglycinate has little toxic and no genotoxicity. It can be recommended as long-term use."said WAN Dan, an assistant researcher in ISA ,"We're really looking forward to its good performance in preventing iron deficiency in the future."

This research was granted by National Science Foundation of China (31330075, 31110103909), National Key Technology Research and Development Program of the Ministry of Science and Technology of China (2012BAD39B00), the Chinese Academy of Sciences comprehensive strategic cooperation project of Guangdong Province (2013B091500095, 2013B090900007), Science and Technology Planning Project of Guangdong Province (2013B091500095, 2013B090900007, 2013B070704081) and Guangzhou Industry Research Collaborative innovation major special (201508020048).

The study entitled "Toxicological evaluation of ferrous N-carbamylglycinate chelate: Acute, Sub-acute toxicity and mutagenicity"can be found online at http://dx.doi.org/10.1016/j.yrtph.2015.09.013.

Contact: YIN Yulong

E-mail: yinyulong@isa.ac.cn

Institute of Subtropical Agriculture, Chinese Academy of Sciences