融合表达抗菌肽和IL基因的重组酵母制剂对仔猪生长和免疫的调节效应

Effect of recombinant yeasts co-expressing antimicrobial peptide and IL genes on growth performance and immunity of piglets

试验发酵制备融合表达猪IL-2基因与IL-4、6基因、融合表达猪IL-4/6基因和牛源抗菌肽的两种重组毕赤酵母,分别用以饲喂仔猪,每2 d饲喂1次,连续饲喂4周。在试验的第0、14、28和42天,测定各组仔猪的总体重及饲料消耗量,在试验的第0、7、14、28和42天,采取仔猪前腔静脉血,测定外周血免疫细胞数量变化、Th和Tc细胞数量变化、特异性抗体变化以及免疫应答相关基因表达水平的变化,以探讨2种免疫制剂对仔猪生长与免疫方面的调节效应。结果发现,在试验后第42天,A1、A2试验组仔猪平均增重量分别高于对照组C组3.47 kg和1.66 kg(P<0.05)。试验组血样中白细胞、CD8+T细胞、CSF特异性抗体和PRRS特异性抗体含量相比于对照组C明显增加(P<0.05)。此外,A1、A2组的免疫相关基因(TLR2、TLR4、TLR7、TLR9、STAT1、STAT3、NF-k B、IFN-γ、CD45和CD62L)的表达水平较C组显著升高(P<0.05)。总的来说,A1和A2两种免疫制剂,既能有效促进仔猪生长和发育,又能增强仔猪免疫应答水平,可进一步开发为免疫调节剂。

In the experiment, two recombinant Pichia pastoris, which co-express the fused gene of porcine IL-2 and IL-4/6 and the fusion gene of porcine IL-4/6 and bovine antibacterial peptide respectively, were fermented and used to feed piglets once in two days for 4 weeks. On 0, 14; 28 and 42 days of the experiment, body weight of each group was measured in the same condition, and feed consumption of each group was recorded. On O, 7, 14, 28 and 42 days of the experiment, ante- rior vena cava blood of piglets were collected respectively and used to assay the changes of im- mune cells, hemoglobin, Th and Tc cells, specific antibody and immune genes for evaluating its ef- fects on immunity and growth of piglets. The results were found that the weight gain of A1 and A2 groups piglets were higher than the control group C by 3.47 kg and 1.66 kg（P（O. 05） on 42 days. The leukocytes, CD8~ T cells and the specific antibodies to CSF and PRRS increased significantly in the blood of treated piglets in comparison with those of the control（P（O. 05）. Moreover, the ex- pression levels of the selected genes（TLR2, TLR4, TLR7, TLR9, STAT1, STAT3, NF-kB, IFN- y, CD45 and CD62L） significantly elevated in group A1 and A2 in comparison with those of group C. These suggested that A1 and A2 immune products can effectively promote the growth of piglets and en- hance immune response level of piglets, which can be further developed as promising immunopotenti- ator.