Virginia Tech, Blacksburg, VA, USA.
Iowa State University, Ames, IA, USA.
Poult Sci. 2022 Apr;101(4):101705. doi: 10.1016/j.psj.2022.101705. Epub 2022 Jan 10.
Two consecutive 35 d experiments were conducted to investigate the effects of a multistrain DFM fed continuously to broiler chickens exposed to HS from 28 to 35 d on broiler performance, body composition, ileal digestibility, and intestinal permeability using serum Fluorescein Isothiocyanate Dextran (FITC-d) concentration. The treatments were arranged as a 2 × 2 factorial with temperature: Elevated (HS: 33 ± 2°C for 6 h and 27.7°C for the remaining 18 h from 28 to 35 days of age) and Thermoneutral (TN: 22 to 24°C over the entire 24-h day from 28 to 35 days of age) and diet: corn-soybean meal based with and without DFM (3-strain Bacillus; Enviva PRO) fed over the entire 35-d period as the two factors. Experimental diets were formulated to meet all nutrient recommendations based on breed standards using a starter (0-10 d), grower (10-21 d), and finisher (21-35 d) period. For each of the 2 experiments, 648 Ross 708 broiler chicks were allotted among the treatments with 9 replicate pens of 18 broilers. Data were analyzed as a 2 × 2 factorial within each experiment in JMP 14. In both experiments, cloacal temperatures were increased (P ≤ 0.05) in the broilers subjected to the HS treatment at both 28 d (acute) and 35 d (chronic). Supplementing birds with DFM reduced cloacal temperatures in the Experiment 1 at 28 d, but not at the other time periods. The HS treatment reduced body weight gain and lean tissue accretion from 0 to 35 d in both experiments (P ≤ 0.05). In Experiment 2, when the litter was reused BWG was increased by 36 g/bird with supplementation of DFM (P ≤ 0.05). Ileal digestibility at 28 d (2 h post HS) was improved with DFM supplementation in both experiments (P ≤ 0.05). Serum FITC-d increased with HS at both 28 and 35 d. Serum FITC-d was generally decreased with DFM at 28 d but the response was inconsistent at 35 d. Overall, the results suggest that HS reduced broiler performance and DFM treatment improved intestinal permeability and nutrient digestibility responses to HS in both experiments but did not improve performance until built up litter was used in Experiment 2.
进行了两项连续 35 天的试验，以研究从 28 日龄到 35 日龄连续给肉鸡饲喂多菌株 DFM 对肉鸡生产性能、体组成、回肠消化率和肠道通透性的影响，使用血清荧光素异硫氰酸酯葡聚糖（FITC-d）浓度。处理方法采用 2×2 因子设计，温度：高温（HS：33±2°C，持续 6 小时，27.7°C，其余 18 小时，从 28 日龄到 35 日龄）和常温（TN：22 到 24°C，整个 24 小时，从 28 日龄到 35 日龄），日粮：基于玉米-豆粕的日粮，有无 DFM（3 菌株芽孢杆菌；Enviva PRO），在整个 35 天内饲喂。试验日粮根据品种标准，使用起始（0-10 天）、生长（10-21 天）和育肥（21-35 天）期，用一种配方进行配制，以满足所有营养需求。在每个试验中，648 只罗斯 708 肉鸡被分配到处理组中，每组 9 个重复，每个重复 18 只肉鸡。在 JMP 14 中，每个试验内均以 2×2 因子进行数据分析。在两个试验中，在 28 天（急性）和 35 天（慢性），暴露于 HS 的肉鸡的泄殖腔温度升高（P≤0.05）。在试验 1 中，在 28 天给鸡补充 DFM 降低了泄殖腔温度，但在其他时间点没有。在两个试验中，HS 处理从 0 到 35 天都降低了体重增加和瘦肉组织增加（P≤0.05）。在试验 2 中，当重复使用垫料时，DFM 的补充增加了 36 克/只鸡的体重增加（P≤0.05）。在两个试验中，28 天（HS 后 2 小时）时，DFM 的补充提高了回肠消化率（P≤0.05）。在两个试验中，28 天和 35 天，HS 后血清 FITC-d 增加。在 28 天，血清 FITC-d 通常随着 DFM 的添加而降低，但在 35 天的反应不一致。总的来说，结果表明，HS 降低了肉鸡的生产性能，DFM 处理改善了肠道通透性和对 HS 的养分消化率反应，但在试验 2 中，只有当使用旧垫料时，性能才有所提高。
