本文旨在研究微生态制剂对幼兔生长和下丘脑-垂体-肾上腺(HPA)轴5-羟色胺(5-HT)免疫反应细胞的影响。选用108只雄性幼兔随机分为4组：对照组饲喂基础日粮，益生素组在日粮中添加0.1%蜡样芽孢杆菌PAS38制剂，益生元组在日粮中添加0.2%甘露聚糖制剂，合生元组在日粮中添加0.1%蜡样芽孢杆菌PAS38制剂和0.2%甘露聚糖制剂。其中48只兔(每组12只，每4只为1个重复)用于全程观察生长性能，其余60只家兔饲喂至60、75和90日龄时每组宰杀5只，采用免疫组化法检测HPA轴5-HT阳性细胞数量和表达。结果表明，益生素组和合生元组日增重极显著高于对照组(P<0.01)，益生元组显著高于对照组(P<0.05)。益生素、益生元、合生元组的料重比分别比对照组下降了13.8%、10.9%、14.9%(P>0.05)。微生态制剂对HPA轴5-HT阳性细胞数量变化不显著(P>0.05)；75日龄和90日龄时，益生素和合生元组HPA轴5-HT阳性细胞的表达显著(P<0.05)或极显著(P<0.01)高于对照组，益生元组90日龄时HPA轴5-HT阳性细胞的表达显著高于对照组(P<0.05)。结果提示，微生态制剂能促进幼兔生长，增强HPA轴中5-HT阳性细胞的表达。

The paper focused on the effect of microecological preparation on the growth performance and immunoreactive cells of 5-HT in hypothalamus-pituitary-adrenal (HPA) axis of rabbits. One hundred and eight male weaned rabbits were randomly divided into 4 groups. Control group was fed the basal diet. Probiotics group was fed the diet supplemented with 0.1% Bacillus cereus PAS38. Prebiotics group was fed the diet with 0.2% mannan. Synbiotics group was fed the diet supplemented with 0.1% B.cereus PAS38 and 0.2% mannan. Forty eight rabbits (12 rabbits in each group with 3 replicates and 4 rabbits in each replicate) were selected to observe the growth performance. In the other 60 rabbits, 5 rabbits from each group were slaughtered at 60 d, 75 d and 90 d of age, respectively. Immunohistochemistry SABC was used to measure 5-HT of immunoreactive cells and the expression in HPA axis of rabbits. The results showed that the weight and average daily weight gain in probiotics group and synbiotics group were strongly significantly higher than those of the control group (P<0.01). The prebiotics group was significantly higher than that of the control group (P<0.05). F/G of probiotics, prebiotics and synbiotics group decreased 13.8%, 10.9%, 14.9% compared with the control group, respectively (P>0.05). The probiotics and prebiotics could not significantly change the number of immunoreactive cells of 5-HT in HPA axis of rabbits (P>0.05). At the 75 d and 90 d of age, the expression of 5-HT in HPA axis of the probiotics group and the synbiotics group were significantly (P<0.05) or strongly significantly (P<0.01) higher than that of the control group. The expression of 5-HT in HPA axis of the prebiotics group was significantly (P<0.05) higher than that of the control group at the 90 d of age. The results indicated that the microecological preparation could promote the growth and enhance the expression of 5-HT in HPA axis of rabbits.［Chinese Journal of Animal Nutrition, 2009，21(6):945-952］