桑叶对大鼠血液生化指标和组织病理学的影响

Effects of mulberry leaves on blood biochemical parameters and histopathology in rats

桑(Morus alba)是一种潜力较大的蛋白饲料资源,但其含有多种抗营养因子和天然活性物质,具有一定饲喂风险性,因此需注重饲用安全性及饲喂剂量研究。本研究以SD大鼠(Sprague-Dawley rats)为试验动物,通过长期经口灌胃桑叶受试物,观察可能产生的不利影响,判定其毒性反应,以期为桑叶的饲用潜力开发提供理论依据。选择60只SD大鼠,按照完全随机区组设计,分别设置T_1溶媒对照组和T_2低剂量组(1 g·kg^(-1))、T_3高剂量组(2 g·kg^(-1))进行灌胃试验。每组20只,雌雄各半,连续经口灌胃桑叶受试物28 d,恢复期14 d,于灌胃期和恢复期结束时分别测定其血液生化、组织器官及其病理学指标。结果表明,与T_1溶媒对照组相比,各剂量组大鼠的血液生化、组织器官系数和病理学指标,虽有个别指标异常,但属正常生理现象或不具毒理意义,大部分指标均无显著性差异(P>0.05)。初步验证了桑叶具有一定的饲用安全性。本试验条件下,其无毒性反应剂量(NOAEL)为2.00 g·kg^(-1)。

Mulberry (Morus alba) is a high-quality protein resource, which contains various anti-nutritional factors and biological active substances that could pose certain risks when present in animal feed. Therefore, the safety of mulberry for use in feed and the appropriate allowable concentration in feed requires investigation. This study aimed to observe the possible toxic responses in Sprague-Dawley rats (SD) rats administered a long-term gavage of mulberry leaves and thus evaluate its safety in addition to providing a basis for the development and utilization of mulberry leaves. Sixty SD rats were selected and divided according to the randomized complete block design. Doses of 1 and 2 g·kg^–1 of mulberry leaf extract were administered, as the low and high dose, respectively, in addition to a solvent control group. There were ten male and ten female SD rats in each group. The gavage treatment and recovery periods were 28 days and 14 days, respectively. When the gavage treatment and recovery period ended, the rats were collected to determine the biochemical, organ coefficient, and histopathology indexes. The results showed that most indicators of the physical symptoms in SD rats showed no significant difference compared with those in the control group (P > 0.05). Factors that remained unchanged in each dose group were the biochemical, organ coefficient, and histopathology indexes. However, a few individual indicators were observed to be abnormal, but these were due to normal physiological phenomena and had no toxicological significance. Thus, it was preliminarily verified that mulberry leaves are safe for use in feed. Under the conditions of this experiment, the NOAEL (noobserved- adverse-effect-level) of the mulberry leaf was found to be 2.00 g·kg^–1.