Tropical and subtropical regions were quite short of high-quality protein forage. Ramie (Boehmeria nivea L. Gaud) leaves as crop by products, are rich in protein and widely cultivated in tropical and subtropical regions. Thence, the development and utilization of ramie is of great significance to animal production in these regions. But it contained high level of tannins and total phenols, which may produce potentially adverse effect. It is very essential to evaluate the safety of ramie leaves before they are used as feed supplements. To evaluate potential toxic level of ramie leaf, control group, low dose and high dose (0, 1, 2 g/kg·BW) groups of ramie leaf were conducted orally in Sprague-Dawley rats (SD rats). Body weight, hematology, and histopathology was assessed during 28 d of treatment and 14 d of recovery period. The results showed that there were no toxic symptoms appeared in the treated and control groups. There were a few individual indicators showed abnormal, but most indices of body weight, organ weight ratios and hematology were normal. And compared to control group, it showed no significant differences (P>0.05). Histopathological examination of the high dose group and control group showed that there was no lesions related to ramie administration. The pathological changes appeared in the liver, and lungs of rats in individual rat of both groups were common and spontaneous, and had no significant differences (P>0.05). These results suggest that under this experimental condition, up to 2 g/kg·BW intragastric administration of ramie leaf did not produce adverse effect to SD rats. These findings would provide available information for ramie leaf to utilize as a feed supplement, particularly in P.R. China.
Keywords: Hematology; Protein feed; Ramie; Safety; Toxicity.