ABSTRACT

• 1. A total of 864 d old (male) Ross × Ross 708 broiler chicks were allocated to 48 floor pens (12 pens/treatment and 18 birds/pen) to investigate dose-response of a blend of seaweeds (SB) on growth performance, breast yield, jejunal histomorphology, microbial metabolites and community and plasma biochemical profile.

• 2. A maize-soybean meal diet was formulated with 0, 5, 10 or 20 g/kg of SB. Diets were formulated for a three-phase feeding programme (starter: d 0–10, grower: d 11–24, and finisher: d 25–42) and met or exceeded Aviagen nutrient specifications. Diets were allocated to pens (n = 12) balanced for body weight (BW). Birds had free access to feed and water, BW and feed intake (FI) were monitored by phase. One bird per pen was randomly selected on d 42, bled for plasma, and samples for intestinal tissue and caecal digesta were taken. Microbial DNA was extracted and submitted for microbial community profile using the Illumina Miseq® platform.

• 3. In the starter phase, SB linearly (P ≤ 0.01) improved BW, body weight gain (BWG), and FCR. However, the improvement was quadratic, such that there was no further improvement beyond 5 g/kg SB inclusion. Growth performance response to SB in the grower phase was similar to the starter phase, with the exception of FCR (P > 0.05). Overall, from d 0–42, a linear and quadratic (P < 0.01) response was observed for final BW (d 42), whereby birds fed 5, 10 and 20 g/kg SB were heavier than control by 166, 183 and 180 g, respectively. A quadratic (P = 0.03) effect was observed for breast yield in response to SB. There was a quadratic reduction (P < 0.05) in gamma-glutamyl transferase (GGT) and a linear increase in glutamate dehydrogenase (GDH) in response to SB. Supplemental SB linearly reduced (P ≤ 0.04) the relative abundance of phylum Bacteroidetes and Proteobacteria, and increased the abundance of phylum Firmicutes (linearly; P = 0.02) and Actinobacteria (quadratically; P = 0.03).

• 4. The data indicated that the optimal inclusion for SB was between 5 and 10 g/kg for improved growth performance and breast yield. However, increased abundance of Firmicutes and actinobacteria in the caecal digesta suggested that the higher doses enhanced prebiotic effects of seaweed components.

摘要

• 1.将总共864 d（雄性）Ross×Ross 708肉鸡雏鸡分配到48楼围栏（12只围栏/处理和18只鸟/围栏）中，研究海藻混合物（SB）对生长性能的剂量反应，乳房产量，空肠组织形态，微生物代谢产物以及群落和血浆生化特征。

• 2.以0、5、10或20g / kg的SB配制玉米-大豆粉饮食。制定了三个阶段的饲喂计划（起始：d 0-10，生长者：d 11-24，最终：d 25-42），并且达到或超过了Aviagen的营养标准。饮食分配到体重（BW）平衡的围栏（n = 12）。禽类可以自由获取饲料和水，并按阶段监测体重和饲料摄入量（FI）。在第42天，每只笔随机选择一只鸟，取血浆，取肠道组织和盲肠消化液的样品。使用IlluminaMiseq®平台提取微生物DNA并提交微生物群落图。

• 3.在起动阶段，SB线性（P ≤0.01）提高BW，体重增加（BWG），和FCR。但是，改进是二次的，因此没有超过5 g / kg SB夹杂物的进一步改进。在生长阶段，对SB的生长性能响应与启动阶段相似，但FCR除外（P > 0.05）。总体而言，从d 0-42开始，观察到最终体重的线性和二次响应（P <0.01）（d 42），饲喂5、10和20 g / kg SB的家禽比对照组重166、183和180 g，分别。观察到对SB的乳房产量具有二次效应（P = 0.03）。出现了二次减少（Pγ-谷氨酰转移酶（GGT）中的<0.05）和响应SB的谷氨酸脱氢酶（GDH）线性增加。补充SB线性减少（P ≤0.04）门的相对丰度拟杆菌和变形菌门，和增加门的丰度厚壁菌门（线性; P = 0.02）和放线菌（二次曲线; P = 0.03）。

• 4.数据表明，SB的最佳夹杂物在5至10 g / kg之间，以改善生长性能和乳房产量。然而，盲肠消化道中Firmicutes和放线菌的丰度增加表明，较高剂量可增强海藻成分的益生元作用。