Department of Animal Sciences, University of Illinois, Urbana, IL 61801, USA.
J Anim Sci. 2012 Jan;90(1):345-60. doi: 10.2527/jas.2010-3662. Epub 2011 Sep 9.
Two experiments were conducted to determine whether 3 different clays in the nursery diet reduce diarrhea of weaned pigs experimentally infected with a pathogenic Escherichia coli. Weaned pigs (21 d old) were housed in individual pens of disease containment chambers for 16 d [4 d before and 12 d after the first challenge (d 0)]. The treatments were in a factorial arrangement: 1) with or without an E. coli challenge (F-18 E. coli strain; heat-labile, heat-stable, and Shiga-like toxins; 10(10) cfu/3 mL oral dose daily for 3 d from d 0) and 2) dietary treatments. The ADG, ADFI, and G:F were measured for each interval (d 0 to 6, 6 to 12, and 0 to 12). Diarrhea score (DS; 1 = normal; 5 = watery diarrhea) was recorded for each pig daily. Feces were collected on d 0, 3, 6, 9, and 12 and plated on blood agar to differentiate β-hemolytic coliforms (HC) from total coliforms (TC) and on MacConkey agar to verify E. coli. Their populations on blood agar were assessed visually using a score (0 = no growth; 8 = very heavy bacterial growth) and expressed as a ratio of HC to TC scores (RHT). Blood was collected on d 0, 6, and 12 to measure total and differential white blood cell (WBC) counts, packed cell volume (PCV), and total protein (TP). In Exp. 1 (8 treatments; 6 replicates), 48 pigs (6.9 ± 1.0 kg of BW) and 4 diets [a nursery control diet (CON), CON + 0.3% smectite (SM), CON + 0.6% SM, and CON until d 0 and then CON + 0.3% SM] were used. The SM treatments did not affect growth rate of the pigs for the overall period. In the E. coli challenged group, the SM treatments reduced DS for the overall period (1.77 vs. 2.01; P < 0.05) and RHT on d 6 (0.60 vs. 0.87; P < 0.05) and d 9 (0.14 vs. 0.28; P = 0.083), and altered differential WBC on d 6 (neutrophils, 48 vs. 39%, P = 0.092; lymphocytes, 49 vs. 58%, P = 0.082) compared with the CON treatment. In Exp. 2 (16 treatments; 8 replicates), 128 pigs (6.7 ± 0.8 kg of BW) and 8 diets [CON and 7 clay treatments (CON + 0.3% SM, kaolinite, and zeolite individually and all possible combinations to total 0.3% of the diet)] were used. The clay treatments did not affect growth rate of the pigs. In the E. coli challenged group, the clay treatments reduced DS for the overall period (1.63 vs. 3.00; P < 0.05), RHT on d 9 (0.32 vs. 0.76; P < 0.05) and d 12 (0.13 vs. 0.39; P = 0.094), and total WBC on d 6 (15.2 vs. 17.7 × 10(3)/μL; P = 0.069) compared with the control treatment. In conclusion, dietary clays alleviated diarrhea of weaned pigs.
进行了两项实验，以确定在育肥日粮中添加 3 种不同的粘土是否可以减少人工感染致病性大肠杆菌的断奶仔猪的腹泻。断奶仔猪（21 日龄）在疾病隔离室的单独栏中饲养 16 天[第 4 天之前和第 1 次攻毒（d0）后的 12 天]。处理采用析因设计：1）有无大肠杆菌攻毒（F-18 大肠杆菌株；不耐热、耐热和志贺样毒素；每日口服 3 毫升 10(10)cfu/剂量，连续 3 天，从 d0 开始）和 2）日粮处理。在每个间隔（d0 到 6、6 到 12 和 0 到 12）测量 ADG、ADFI 和 G:F。每天为每头猪记录腹泻评分（DS；1=正常；5=水样腹泻）。在 d0、3、6、9 和 12 时收集粪便，并在血琼脂上进行平板计数，以区分β-溶血性大肠菌（HC）和总大肠菌（TC），并在麦康凯琼脂上验证大肠杆菌。使用评分（0=无生长；8=细菌生长非常重）评估血琼脂上的细菌种群，并表示为 HC 与 TC 评分的比值（RHT）。在 d0、6 和 12 时采集血液，以测量总白细胞（WBC）计数和差异、红细胞压积（PCV）和总蛋白（TP）。在实验 1（8 种处理；6 个重复）中，使用 48 头仔猪（体重 6.9±1.0 公斤）和 4 种日粮[育肥期对照日粮（CON）、CON+0.3%蒙脱石（SM）、CON+0.6% SM 和 CON 直至 d0，然后 CON+0.3% SM]。SM 处理对整个时期的仔猪生长速度没有影响。在大肠杆菌攻毒组中，SM 处理降低了整个时期的 DS（1.77 对 2.01；P<0.05）和第 6 天的 RHT（0.60 对 0.87；P<0.05）和第 9 天（0.14 对 0.28；P=0.083），以及第 6 天的白细胞差异（中性粒细胞，48%对 39%，P=0.092；淋巴细胞，49%对 58%，P=0.082）与 CON 处理相比。在实验 2（16 种处理；8 个重复）中，使用 128 头仔猪（体重 6.7±0.8 公斤）和 8 种日粮[CON 和 7 种粘土处理（CON+0.3%SM、高岭土和沸石单独以及所有可能的组合，共计日粮的 0.3%）]。粘土处理对仔猪的生长速度没有影响。在大肠杆菌攻毒组中，粘土处理降低了整个时期的 DS（1.63 对 3.00；P<0.05）、第 9 天和第 12 天的 RHT（0.32 对 0.76；P<0.05）和 0.13 对 0.39；P=0.094），以及第 6 天的总 WBC（15.2 对 17.7×10(3)/μL；P=0.069）与对照处理相比。总之，日粮中的粘土减轻了断奶仔猪的腹泻。
