This study was to characterise the undigested nutrients present along the gastrointestinal tract of birds offered common wheat- or maize-based diets, with the goal of optimising utilisation of enzymes to enhance digestive efficiency. Wheat- and maize-based diets were offered to 240 mixed-sex broilers (10 birds/pen; n = 12) from 1 to 35 d post–hatch. Digestibility of dry matter, starch, crude protein and non-starch polysaccharides (NSP) were measured in the crop, gizzard, duodenum, jejunum, ileum, caeca and excreta at d 12 and 35 post–hatch. Analysis of nutrient levels in the excreta presented that more than 30% of nutrients provided in the feed was wasted, irrespective of wheat or maize diet type. On average, 92 g/kg crude protein, 92 g/kg insoluble NSP and 14 g/kg oligosaccharides were not utilised by birds at d 12 post–hatch. The quantity of water-insoluble NSP in the small intestine at d 12 was lower in birds offered the wheat-based diet compared to those fed the maize-based diet (P < 0.05), with the reverse being true for water-soluble NSP (P < 0.001). On average, 84 g/kg crude protein, 79 g/kg insoluble NSP and 9 g/kg oligosaccharides remained in the excreta at 35 d of age. At this time period, accumulation of feed in the gizzard was noted for birds offered both diets, but was more pronounced in those offered the maize-based diet (P < 0.001). Birds offered the maize-based diet demonstrated improved utilisation of oligosaccharides compared to those fed the wheat-based diet at both d 12 and 35 (P = 0.087 and P = 0.047, respectively). Protein utilisation in the jejunum and ileum was greater in birds offered the wheat-based diet compared to those fed the maize-based diet (P = 0.004 and P < 0.001, respectively). Thus, while both diets supported standard growth performance of birds, the degree and flow of nutrient disappearance along the gastrointestinal tract was influenced by cereal type and bird age.

本研究旨在表征以普通小麦或玉米为基础饮食的鸟类胃肠道中存在的未消化营养素，目的是优化酶的利用以提高消化效率。向 240 只雌雄混合肉鸡（10 只鸡/围栏；n = 12) 孵化后 1 至 35 天。在孵化后第 12 天和第 35 天测量作物、胼胝、十二指肠、空肠、回肠、盲肠和排泄物中的干物质、淀粉、粗蛋白和非淀粉多糖 (NSP) 的消化率。排泄物中营养水平的分析表明，饲料中提供的营养中有 30% 以上被浪费了，无论小麦或玉米的饮食类型如何。平均而言，在孵化后第 12 天，鸟类未利用 92 g/kg 粗蛋白、92 g/kg 不溶性 NSP 和 14 g/kg 寡糖。与饲喂以玉米为基础的日粮相比，饲喂以小麦为基础的日粮的鸟类在第 12 天时小肠中水不溶性 NSP 的数量较低（P  < 0.05），而水溶性 NSP 的情况正好相反（P < 0.05）。磷 < 0.001)。平均 84 g/kg 粗蛋白、79 g/kg 不溶性 NSP 和 9 g/kg 寡糖在 35 天龄时留在排泄物中。在这个时间段内，两种饲料都喂食的鸡的胼胝中积累了饲料，但在喂以玉米为基础的饲料的鸡中更为明显（P  < 0.001）。在第 12 天和第35 天，与喂食小麦饲料的鸡相比，喂食玉米饲料的鸡对低聚糖的利用有所提高（分别为P = 0.087 和P  = 0.047）。与饲喂以玉米为基础的饲料的鸟类相比，饲喂以小麦为基础的饲料的鸟类在空肠和回肠中的蛋白质利用率更高（P  = 0.004 和P < 0.001，分别）。因此，虽然两种日粮都支持家禽的标准生长性能，但营养物质沿胃肠道消失的程度和流量受谷物类型和家禽年龄的影响。