ABSTRACT

1. The hypothesis behind the study was that a high dietary starch level (HS) would lead to impaired gut health compared to a low-starch diet (LS) in Eimeria-challenged broilers. The effects of two diets with different starch to fat ratios on intestinal histomorphometry, Clostridium perfringens counts and toxin profile, necrotic enteritis prevalence and abundance of short-chain fatty acids (SCFAs) were examined.

2. A total of 1,920 one-day-old Ross 308 broiler chickens were fed one of two isocaloric diets formulated either with high (32:1) or low (2:1) starch to fat ratios from d 10 to 29 of age. Each treatment group had 12 pen replicates containing 80 broilers each. On d 17, the chickens were challenged with Eimeria vaccine strains. Samples were collected on d 16, 21–23 and 29.

3. Whereas villus length increased gradually throughout the study in the HS group, a peak level was reached on d 21–23 in the LS group. On d 29, the HS group had significantly longer villi than the LS group.

4. Caecal SCFA concentrations were higher in the HS group compared to the LS group on d 16. In both groups, the SCFA level peaked on d 21–23, with the most pronounced increase seen in the LS group.

5. The C. perfringens netB:cpa ratio increased from d 16 to 29 in the HS group. C. perfringens counts and necrotic enteritis prevalence were similar between the two groups.

6. Diet affected the dynamics of small intestinal villus length and caecal SCFA abundance. These findings suggest that structural remodelling of the small intestine is an adaptation to different dietary starch levels, and that caecal SCFA abundance is associated with the availability of substrate for the microbiota in the posterior intestinal segments. Chickens adapted to higher levels of dietary starch might be more robust against Eimeria infections due to increased mucosal surface area. Studies with other dietary starch sources are required to clarify the impact of dietary starch levels on intestinal health in Eimeria–challenged broilers.

摘要

1.该研究背后的假设是，与艾美瑞氏菌感染的肉鸡相比，低淀粉饮食（LS）相比，高淀粉饮食（HS）会导致肠道健康受损。考察了两种淀粉/脂肪比例不同的饮食对肠道组织形态学，产气荚膜梭菌计数和毒素谱，坏死性肠炎的流行以及短链脂肪酸（SCFA）含量的影响。

2.总共给1,920只一天大的Ross 308肉鸡饲喂了两种等热量日粮之一，这些日粮在d 10到29岁时采用高（32：1）或低（2：1）的淀粉与脂肪比率。每个处理组有12个笔重复，每个重复包含80只肉鸡。在第17天，用艾美球虫疫苗株对鸡进行攻击。在第16、21-23和29天收集了样品。

3.在整个研究中，HS组的绒毛长度逐渐增加，而LS组在第21–23天达到峰值。在第29天，HS组的绒毛明显长于LS组。

4.在第16天，HS组的盲肠SCFA浓度高于LS组。在两组中，SCFA浓度均在第21-23天达到峰值，其中LS组最明显。

5. HS组中产气荚膜梭菌netB：cpa的比例从d 16增加到29。两组之间的产气荚膜梭菌计数和坏死性肠炎患病率相似。

6.饮食影响小肠绒毛长度和盲肠SCFA丰度的变化。这些发现表明，小肠的结构重塑是对不同饮食淀粉水平的适应，并且盲肠SCFA的丰度与后肠段中微生物群的底物的可用性有关。适应较高饮食淀粉水平的鸡由于粘膜表面积增加，可能更能抵抗艾美球虫感染。需要对其他膳食淀粉来源进行研究，以阐明膳食淀粉水平对艾美球虫感染的肉鸡肠道健康的影响。