多菌种联合发酵饲料对肉鸡抗沙门氏菌感染能力的影响

旨在探明发酵饲料对肉鸡抗沙门氏菌感染的影响。将50只1日龄中速黄羽肉鸡随机分为5个处理组,对照组、模型对照组饲喂基础饲粮(基础日粮+10%未发酵饲料),抗生素对照组在基础饲粮中添加20 mg·kg^-1硫酸粘杆菌素,5%发酵组、10%发酵组分别用5%、10%发酵饲料替代基础饲粮中的未发酵饲料。肉鸡13日龄时,对照组连续2 d口腔灌服400 μL无菌水,其他组连续2 d口腔灌服400 μL沙门氏菌液(1×10⁹ CFU·mL^-1)。肉鸡15日龄时进行屠宰,取血清测定促炎因子(IL-1β、IL-6、TNF-α)、内毒素(LPS)、D-乳酸(D-LA)水平,取结肠进行HE染色观察结肠形态,取结肠黏膜测定TLR4路径关键信号分子的基因表达量。结果表明,沙门氏菌感染导致肉鸡血清促炎因子(IL-1β、IL-6、TNF-α)水平显著上升,TLR4信号通路中的关键信号分子(TLR4、MyD88、TRAF6、NF-κB)mRNA相对表达量显著上升,血清LPS、D-LA水平显著上升,而抗生素组、5%发酵组、10%发酵组的这些指标均有不同程度的改善,表明多菌种联合发酵饲料能够改善沙门氏菌感染导致的炎症反应和肠道屏障受损,效果接近20 mg·kg^-1硫酸粘杆菌素。

Effect of multi-strain co-fermented feed on anti-Salmonella infection in broilers

To investigate the effect of multi-strain co-fermented feed on resisting Salmonella infection in broilers, 50 one-day-old broilers were randomly divided into 5 groups and were fed with different feeds: control group (basal diet+10% unfermented feed), model control group (basal diet+10% unfermented feed), antibiotic control group (basal diet+10% unfermented feed+20 mg·kg^-1 colistin sulfate), 5% fermented group (basal diet+5% unfermented feed+5% fermented feed), 10% fermented feed (basal diet+10% fermented feed). Oral administration of 400 μL Salmonella(1 × 10⁹ CFU·mL^-1) for two days except the control group when the broilers were 13 days old, the control group was given equal volume of sterile water. The broilers were slaughtered at the age of 15 days. Serum levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α), endotoxins (LPS) and D-lactic acid (D-LA) were measured. Got colon for HE staining was to observe the shape of colon and got cecum mucosa was to determine the mRNA expression of TLR4 pathway key signaling molecules. The results showed that salmonella infection resulted in a significantly increase level of serum pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α).The mRNA expression of TLR4 signal pathway key signaling molecules (TLR4, MyD88, TRAF6, NF-κB) increased significantly. The level of serum LPS and D-LA increased significantly. While the indexes of antibiotic control group, 5% fermented group, and 10% fermented group were improved to some extent, indicating that the multi-strain co-fermented feed can ameliorate the intestinal inflammation and intestinal barrier destruction that caused by Salmonella infection. The effect was close to 20 mg·kg^-1 colistin sulfate.