Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon SK S7N 5A8, Canada.
Agriculture and Agri-Food Canada, Winnipeg, R3T 2E1 Manitoba, Canada.
Poult Sci. 2021 Mar;100(3):100967. doi: 10.1016/j.psj.2020.12.064. Epub 2020 Dec 29.
The reduced use of antibiotics in poultry feed has led to the investigation of alternatives to antibiotics, and one such substitution is fermentable carbohydrates. Exogenous β-glucanase (BGase) is commonly used in poultry fed barley-based diets to reduce digesta viscosity. The effects of hulless barley (HB) and BGase levels on ileal digesta soluble β-glucan molecular weight, digestive tract characteristics, and performance of broiler chickens were determined. A total of 360 day-old broilers were housed in battery cages (4 birds per cage) and fed graded levels of high β-glucan HB (CDC Fibar; 0, 30, and 60% replacing wheat) and BGase (Econase GT 200 P; 0, 0.01, and 0.1%) in a 3 × 3 factorial arrangement. Beta-glucan peak molecular weight in the ileal digesta was lower with 30 and 60 than 0% HB, whereas the peak decreased with increasing BGase. The weight average molecular weight was lower at 0.1 than 0% BGase in wheat diets, whereas in HB diets, it was lower at 0.01 and 0.1 than 0% BGase. The maximum molecular weight was lower with 0.01 and 0.1 than 0% BGase regardless of the HB level. The maximum molecular weight was lower with HB than wheat at 0 or 0.01% BGase. Overall, empty weights and lengths of digestive tract sections increased with increasing HB, but there was no BGase effect. Hulless barley decreased the duodenum and jejunum contents, whereas increasing the gizzard (diets with BGase), ileum, and colon contents. The jejunum and small intestine contents decreased with increasing BGase. Ileal and colon pH increased with increasing HB, but there was no BGase effect. Treatment effects were minor on short-chain fatty acids levels and performance. In conclusion, exogenous BGase depolymerized the ileal digesta soluble β-glucan in broiler chickens in a dose-dependent manner. Overall, feed efficiency was impaired by increasing HB levels. However, HB and BGase did not affect carbohydrate fermentation in the ileum and ceca, although BGase decreased ileal viscosity and improved feed efficiency at the 0.1% dietary level.
抗生素在禽类饲料中的使用减少，促使人们开始研究抗生素替代品，其中一种替代品是可发酵碳水化合物。外源性β-葡聚糖酶（BGase）常用于以大麦为基础的禽类日粮中，以降低食糜的黏度。本试验旨在研究裸大麦（HB）和 BGase 水平对肉鸡回肠食糜中可溶性β-葡聚糖分子量、消化道特性和生产性能的影响。将 360 只 1 日龄肉鸡饲养在笼养（每个笼 4 只鸡）中，日粮中添加不同水平的高β-葡聚糖 HB（CDC Fibar；0、30 和 60%替代小麦）和 BGase（Econase GT 200 P；0、0.01 和 0.1%），采用 3×3 析因设计。与 0%HB 相比，30%和 60%HB 组回肠食糜中β-葡聚糖的峰值分子量较低，而随着 BGase 添加量的增加，峰值分子量降低。在小麦日粮中，0.1%BGase 组的重均分子量低于 0%BGase 组，而在 HB 日粮中，0.01%和 0.1%BGase 组的重均分子量低于 0%BGase 组。无论 HB 水平如何，0.01%和 0.1%BGase 组的最大分子量均低于 0%BGase 组。与小麦相比，0 或 0.01%BGase 组 HB 组的最大分子量较低。总体而言，随着 HB 的增加，空肠和回肠的重量和长度增加，但 BGase 没有影响。裸大麦降低了十二指肠和空肠的内容物，而增加了肌胃（添加 BGase 的日粮）、回肠和盲肠的内容物。随着 BGase 添加量的增加，空肠和回肠的内容物减少。随着 HB 的增加，回肠和盲肠的 pH 值增加，但 BGase 没有影响。处理组对短链脂肪酸水平和生产性能的影响较小。综上所述，外源性 BGase 以剂量依赖的方式在肉鸡中对回肠食糜中的可溶性β-葡聚糖进行了解聚。总的来说，随着 HB 水平的增加，饲料效率受到损害。然而，HB 和 BGase 并没有影响回肠和盲肠中的碳水化合物发酵，尽管 BGase 降低了回肠的黏度，在 0.1%日粮水平上提高了饲料效率。
Zotero 插件