Qingyun Li，Eric R Burrough，Nicholas K Gabler，Crystal L Loving，Orhan Sahin，Stacie A Gould，John F Patience
翻译：朱滔 

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本试验目的在于研究可溶性纤维和不可溶性纤维，以及碳水化合物酶（木聚糖，β葡聚糖和果胶酶）对被产肠毒素大肠杆菌（ETEC）攻毒仔猪腹泻率、免疫反应和生长性能的影响。

试验选用60头断奶仔猪（6.9±0.1kg体重，23d），根据体重分为6组，单栏饲养，每组10个重复。试验处理包括：1个阴性对照组（无攻毒），1个攻毒对照组、甜菜渣组（攻毒+10%甜菜渣）、甜菜渣+酶组（攻毒+10%甜菜渣+碳水化合物酶） 、DDGS组（攻毒+15%DDGS）、DDGS+酶组（攻毒+15%DDGS+碳水化合物酶）。对照组日粮主要为玉米-豆粕型，添加13.5%小麦粉。这两种纤维以替代日粮中的淀粉添加。断奶后第7d口服6ml溶血性 F18 ETEC（约3.5×109 cfu/ml）或者6ml生理盐水。所有ETEC攻毒仔猪均为F18 ETEC易感基因型。14d试验期间所有仔猪自由采食和饮水。记录断奶后第0、7、14或15d的体重和采食量。攻毒第-7、0、1、2、3、5、7或8d收集仔猪粪便，评估溶血性大肠杆菌。攻毒后每天记录粪便评分，评估腹泻率。攻毒第-1、3、7或8d解剖时收集血液样品和肠道组织。

试验数据显示，攻毒组猪攻毒后1-7d日增重和采食量显著低于对照组（P＜0.05）。与攻毒组相比，甜菜渣+酶组攻毒前和攻毒后日增重显著升高（P＜0.05）。DDGS组攻毒后腹泻率显著高于攻毒组（P＜0.05）。甜菜渣组回肠大肠杆菌粘附程度显著低于攻毒组（P＜0.05）。与攻毒组相比，甜菜渣+酶组攻毒后第三天触珠蛋白明显降低，DDGS+酶组C-反应蛋白显著降低（P＜0.05）。与攻毒组相比，甜菜渣+酶组猪有较低的回肠肿瘤坏死因子α和较大的回肠阻塞素（ocln）mRNa（（P＜0.10），结肠ocln mRNa水平较高（P＜0.05）。

总之，DDGS提高了腹泻率和粪便中大肠杆菌脱落数。甜菜渣+酶改善仔猪攻毒后的生长性能，可能是由于降低了炎症因子。

A soluble and highly fermentable dietary fiber with carbohydrases improved gut barrier integrity markers and growth performance in F18 ETEC challenged pigs

This study aimed to evaluate the effects of a source of dietary soluble (SF) and insoluble fiber (IF) without or with exogenous carbohydrases (xylanase, β-glucanase, and pectinase) on diarrhea incidence, selected immune responses, and growth performance in enterotoxigenic Escherichia coli (ETEC)-challenged pigs. Sixty weaned pigs (6.9 ± 0.1 kg BW, ~23 d of age) were blocked by initial BW and placed in individual pens. Pens were randomly assigned to one of six treatments (n = 10 per treatment), including a nonchallenged control (NC), a positive challenge control (PC), the PC + a soluble fiber diet (10% sugar beet pulp) without (SF?) or with carbohydrases (SF+), and PC + an IF diet (15% corn distillers dried grains with solubles) without (IF?) or with carbohydrases (IF+). The control diet was primarily based on corn and soybean meal with 13.5% whey powder. The two sources of fiber were added at the expense of cornstarch in the control diet. Pigs were orally inoculated with 6 mL hemolytic F18 ETEC (~3.5 × 109 cfu/mL) or sham infected with 6 mL phosphate-buffered saline on day 7 (0 d postinoculation, dpi) postweaning. All ETEC challenged pigs were confirmed to be genetically susceptible to F18 ETEC. Pigs had free access to feed and water throughout the 14-d trial. Pig BW and feed intake were recorded on dpi ?7, 0, and 7 or 8. Fecal swabs were collected on dpi ?7, 0, 1, 2, 3, 5, and 7 or 8 to evaluate hemolytic E. coli shedding. Fecal score was visually ranked daily postchallenge to evaluate diarrhea incidence. Blood samples were collected on dpi ?1, 3, and 7 or 8 at necropsy and intestinal tissues were collected at necropsy. Pigs on PC had lower dpi 1 to 7 ADG and ADFI than those on NC (P < 0.05). Compared with PC pigs, SF+ pigs had greater ADG during both pre- and postchallenge period (P < 0.05). The IF? increased postchallenge diarrhea incidence compared with PC (P < 0.05). Pigs on SF? had lower ileal E. coli attachment than PC (P < 0.05). The SF+ reduced haptoglobin and IF+ reduced C-reactive protein on dpi 3 compared with PC (P < 0.05). Compared with PC pigs, SF+ pigs tended to have lower ileal tumor necrosis factor alpha and greater ileal occludin (OCLN) mRNA (P < 0.10) and had greater (P < 0.05) colonic OCLN mRNA levels. Collectively, IF? increased incidence of diarrhea and fecal E. coli shedding compared with PC. The SF+ pigs had improved growth compared with PC pigs, likely due in part to a reduction in inflammatory intermediates.

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