Department of Animal and Poultry Health and Nutrition, Faculty of Veterinary Medicine, University of Tehran, PO Box 14155-6453, Tehran, Iran.
Vet Parasitol. 2012 Jun 8;187(1-2):119-22. doi: 10.1016/j.vetpar.2011.12.016. Epub 2012 Jan 4.
An experiment was carried out to assess the influence of tannic acid (TA) on integrity of the intestine in broiler chicks vaccinated against coccidiosis and challenged with the disease. In a 2 × 2 factorial design, the trial had five groups of 10 chickens each, including positive (group 2) and negative (group 1) controls. The chickens were kept on wood shavings and fed a commercial maize and soybean-based starter-grower diet. From day 1, groups 3 and 5 received TA (10 g kg(-1)) in their diet. On day 4, birds of groups 4 and 5 were vaccinated orally against coccidiosis with anti-coccidial vaccine, Livacox T™. Each dose of the vaccine contained 300-500 sporulated oocysts of each of Eimeria acervulina, Eimeria maxima and Eimeria tenella. On day 18, all experimental groups except for the negative (group 1) were challenged with 10-fold dose of Livacox T™ to produce a mild coccidiosis infection. Faecal samples of individual birds were collected on day 23, and the number of faecal oocysts was determined. d-Xylose absorption test was also carried out on all birds on day 23. Immediately after d-xylose absorption test, all birds were killed humanely and the intestinal tract was removed, weighed and examined for gross lesions. Results showed that negative (group 1) and positive controls (group 2) had the highest and lowest levels of plasma d-xylose post-ingestion of the substrate, respectively. Vaccination and/or feeding TA raised the level of plasma d-xylose in infected birds, although this was not significant for TA-fed birds. Vaccination reduced but TA increased the total number of oocysts per gram of faeces. Birds of groups 2-5 had distinct intestinal lesions when compared with group 1. However, vaccination prevented intestinal lesions. Relative weights of intestinal parts were the lowest in group 1 and the highest in group 2. Vaccination but not TA reduced the relative weights of intestinal parts in infected birds. It was concluded that dietary tannins may reduce the efficacy of anticoccidial vaccines and alter the proper development of immunity against the disease.
进行了一项实验，以评估单宁酸（TA）对接种抗球虫病疫苗并受到疾病挑战的肉鸡肠道完整性的影响。在 2×2 析因设计中，试验有五组，每组 10 只鸡，包括阳性（第 2 组）和阴性（第 1 组）对照组。鸡被饲养在刨花上，并喂食商业玉米和大豆基础的开食料。从第 1 天开始，第 3 组和第 5 组在饮食中添加 TA（10 g kg(-1)）。第 4 天，第 4 组和第 5 组的鸡口服接种抗球虫疫苗 Livacox T™进行抗球虫病免疫。疫苗的每个剂量含有 300-500 个每个柔嫩艾美耳球虫、巨型艾美耳球虫和堆形艾美耳球虫的孢子化卵囊。第 18 天，除阴性（第 1 组）对照组外，所有实验组均用 Livacox T™ 进行 10 倍剂量攻毒，以产生轻度球虫感染。第 23 天，收集每只鸡的粪便样本，并确定粪便卵囊数量。第 23 天，还对所有鸡进行了 d-木糖吸收试验。d-木糖吸收试验后，立即将所有鸡人道处死，取出肠道，称重并检查肉眼病变。结果表明，阴性（第 1 组）和阳性对照组（第 2 组）在摄入底物后血液中 d-木糖水平最高和最低。接种和/或饲喂 TA 提高了感染鸡血液中 d-木糖的水平，尽管对饲喂 TA 的鸡而言这并不显著。接种减少了粪便中的卵囊总数，但 TA 增加了粪便中的卵囊总数。与第 1 组相比，第 2-5 组的鸡有明显的肠道病变。然而，接种可预防肠道病变。第 1 组肠道各部分的相对重量最低，第 2 组最高。接种但不是 TA 降低了感染鸡肠道各部分的相对重量。结论是，日粮单宁可能降低抗球虫疫苗的效力，并改变对疾病的适当免疫发展。
