Feed Research Institute of Chinese Academy of Agricultural Sciences, Key Laboratory of Feed Biotechnology of the Ministry of Agriculture and rural affairs, Beijing, China.
College of Animal Science and Veterinary, Shanxi Agricultural University, Taigu, China.
J Anim Sci. 2020 Apr 1;98(4). doi: 10.1093/jas/skaa093.
Neutral detergent fiber (NDF), as the main component of structural carbohydrate in forage, is a vital factor impacting the performance of young ruminants. The objective of this study was to evaluate the effect of starter NDF level on the rumen fermentation and morphometrics of lambs fed isocaloric and isonitrogenous diets. One hundred Hu sheep lambs (18 days of age and 6.1 ± 0.1 kg body weight [BW]) were randomly assigned to one of the four starter diets differing in their NDF levels on a dry matter (DM) basis: 1) diet with 14% NDF (NDF14), 2) diet with 18% NDF (NDF18), 3) diet with 22% NDF (NDF22), and 4) diet with 26% NDF (NDF26). Lambs were fed milk replacer with designed starters from 21 to 60 d of age and then transitioned to the same starter feed until 90 d of age. Six lambs from each treatment (close to the average BW of the corresponding treatment) were selected and slaughtered at 90 d of age for measuring rumen fermentation, anatomical development, and morphometric characteristics. Lambs receiving NDF22 and NDF26 starter diets had greater (P < 0.05) intake of starter and total DM, and average daily gain during the overall period, thereby heavier (P < 0.05) final weights at 90 d of age compared with those fed NDF14 starter diet. At 90 d of age, lambs fed NDF22 and NDF26 starters had higher rumen pH, followed by lower propionate, higher acetate concentrations (P < 0.05), and a higher acetate-to-propionate ratio compared with those fed NDF14 and NDF18 starters (P < 0.05). No significant differences of the full and empty weight of reticulorumen were observed among treatments; however, the reticulorumen weight expressed as a percentage of the complex stomach weight was lower (P < 0.05) in lambs fed NDF22 and NDF26 starters compared with those fed NDF14 starter. Furthermore, NDF14 lambs had the thickest keratin layer and epithelium compared with those in the other treatments but showed the thinnest muscle layer (P < 0.05). These results suggest that increasing starter NDF levels can ameliorate the rumen fermentation environment and alleviate hyperkeratosis and plaque formation in the rumen epithelium. In summary, including 22% and 26% NDF in the pelleted starter can improve the performance of lambs.
中性洗涤纤维（NDF）作为饲料中结构性碳水化合物的主要成分，是影响幼反刍动物性能的重要因素。本研究旨在评估基础饲粮中不同中性洗涤纤维（NDF）水平对羔羊瘤胃发酵和形态计量学的影响。将 100 只湖羊羔羊（18 日龄，体重 6.1±0.1kg）随机分为 4 种不同 NDF 水平的基础饲粮（干物质基础）处理组：1）NDF14 组，饲粮 NDF 水平为 14%；2）NDF18 组，饲粮 NDF 水平为 18%；3）NDF22 组，饲粮 NDF 水平为 22%；4）NDF26 组，饲粮 NDF 水平为 26%。羔羊在 21~60 日龄期间饲喂含设计的基础饲粮的代乳料，然后过渡到相同的基础饲粮，直到 90 日龄。每个处理组选择 6 只羔羊（接近相应处理组的平均 BW），在 90 日龄时屠宰，用于测量瘤胃发酵、解剖发育和形态计量学特征。与饲喂 NDF14 基础饲粮的羔羊相比，饲喂 NDF22 和 NDF26 基础饲粮的羔羊摄入更多的基础饲粮和总 DM，整个阶段的平均日增重更大（P＜0.05），因此在 90 日龄时体重更重（P＜0.05）。在 90 日龄时，饲喂 NDF22 和 NDF26 基础饲粮的羔羊的瘤胃 pH 较高，随后丙酸、乙酸浓度较低（P＜0.05），乙酸与丙酸的比值较高（P＜0.05），而饲喂 NDF14 和 NDF18 基础饲粮的羔羊则较低。各处理组间皱胃的全重和空重无显著差异；然而，以皱胃总重的百分比表示的皱胃重较低（P＜0.05），与饲喂 NDF14 基础饲粮的羔羊相比，饲喂 NDF22 和 NDF26 基础饲粮的羔羊较低。此外，与其他处理组相比，NDF14 组羔羊的角蛋白层和上皮最厚，但肌肉层最薄（P＜0.05）。这些结果表明，增加基础饲粮 NDF 水平可以改善瘤胃发酵环境，减轻瘤胃上皮的过度角化和斑块形成。总之，在颗粒化基础饲粮中添加 22%和 26%的 NDF 可以提高羔羊的生产性能。
