Trouw Nutrition Agresearch, Guelph, Ontario, Canada.
Department of Human Health and Nutritional Sciences, University of Guelph, Canada.
Poult Sci. 2019 Oct 1;98(10):4901-4908. doi: 10.3382/ps/pez241.
Feed additives that promote gastrointestinal health may complement coccidiosis vaccination programs in antibiotic-free broiler production systems. This study examined the effects of a commercial feed additive blend (FA) on intestinal histomorphology and inflammatory biomarkers in vaccinated Ross 708 cockerels (N = 2,160). The study was a randomized complete block design (12 blocks) with 3 dietary treatments: CON (negative control), AGP (positive control: 55 ppm of bacitracin methylene disalicylate), and FA (1.5 kg/MT in starter; 1.0 kg/MT in grower; and 0.5 kg/MT in finisher). Birds were reared on re-used litter and fed a 3-phase feeding program (starter, 0 to 14 D; grower, 15 to 28 D; finisher, 29 to 36 D). One master batch of basal feed for each feeding phase was prepared and final experimental diets were manufactured by mixing the basal feed with the respective test ingredient prior to pelleting. Growth measurements, including pen body weight and feed intakes, and fresh fecal samples were taken throughout the study. On day 20, samples of intestinal tissue were collected from a subset of birds (n = 72, 1 block) for histomorphology and mRNA expression of tight junction and inflammatory genes. In the duodenum, the ratio of villi length to crypt depth was significantly lower in FA (and AGP) fed birds than those consuming the CON diet. Relative mRNA expressions of iNOS, IFNƔ, and claudin-1 were upregulated in the jejunum of FA and AGP treatment groups compared to those in the CON group; the response in the FA was of lesser magnitude than AGP. Together, these results demonstrated that the FA treatment altered the microstructure of the duodenum and affected the expression of inflammatory genes in the jejunum. The timing of these changes coincided with peak oocyte shedding in feces and an observed reduction in feed efficiency in all dietary treatment groups.
促进胃肠道健康的饲料添加剂可以补充肉鸡生产系统中无抗生素条件下球虫病疫苗接种计划。本研究检查了一种商业饲料添加剂混合物（FA）对接种 Ross 708 公鸡肠道组织形态和炎症生物标志物的影响（N = 2160）。该研究是一个随机完全区组设计（12 个区组），有 3 种日粮处理：CON（阴性对照）、AGP（阳性对照：55 ppm 杆菌肽甲烯二水杨酸酯）和 FA（起始料中添加 1.5 kg/MT、生长料中添加 1.0 kg/MT、育肥料中添加 0.5 kg/MT）。鸡在重复使用的垫料上饲养，并采用 3 阶段饲养方案（起始料，0-14 天；生长料，15-28 天；育肥料，29-36 天）。每个饲养阶段都准备了一个基础饲料的母料，并在制粒前将基础饲料与相应的试验成分混合制成最终的实验日粮。在整个研究过程中，进行了生长测量，包括栏体重和采食量，以及采集新鲜粪便样本。在第 20 天，从一部分鸡（n = 72，1 个区组）中采集肠道组织样本，进行组织形态学和紧密连接及炎症基因的 mRNA 表达分析。在十二指肠中，与 CON 组相比，FA（和 AGP）组鸡的绒毛长度与隐窝深度比值显著降低。FA 和 AGP 处理组空肠的 iNOS、IFNƔ 和 Claudin-1 的相对 mRNA 表达均高于 CON 组；FA 的反应幅度小于 AGP。这些结果表明，FA 处理改变了十二指肠的微观结构，并影响了空肠中炎症基因的表达。这些变化的时间与粪便中卵母细胞脱落高峰期以及所有日粮处理组采食量效率降低相吻合。
