Hu Qingyong, Wang Xinpei, Luo Jun, Mu Yuanpan, Yang Min, Usman Muhammad, Loor Juan J, Wang Ping, Gong Ping
Shaanxi Provincial Key Laboratory of Agricultural Molecular Biology, College of Animal Science and Technology, Northwest A & F University, Yangling, 712100, P.R. China.
Department of Animal Sciences, University of Illinois, Urbana, IL, 61801, USA.
J Anim Sci. 2025 Jan 4;103. doi: 10.1093/jas/skaf226.
Starter feeds in pre-ruminant diets help optimize ruminal development before weaning, contributing significantly to lifelong health and performance. This study investigated the effects of varying neutral detergent fiber (NDF) levels in starter diets on growth, serum indices, slaughter performance, nutrient digestibility, gastrointestinal tract (GIT) development, and microbial profiles of dairy goat kids. Sixty 14-d-old Xinong Saanen dairy goat kids were assigned to 3 groups (n = 20/group) with NDF levels of 20%, 25%, or 30%. All kids received milk and starters from day 15 to 84. Body weight (BW) was monitored bi-weekly, and blood was sampled at weeks 2, 6, 10, and 12. At 12 wk, 3 male kids per group were slaughtered for GIT morphology, enzyme activity, microbial profiles, and carcass assessment. The 25N and 30N groups exhibited significantly greater overall BW (P < 0.01) and serum aspartate transaminase (AST; P < 0.01) and β-hydroxybutyric acid (BHBA; P < 0.01). Dressing percentage, duodenum mass, jejunum mass, and total small intestine mass increased linearly (P < 0.05) with higher NDF levels. The ruminal papilla length (P < 0.05) and papilla width (P < 0.05), the villus height/crypt depth (VH/CD) of jejunum (P < 0.01) and the mucosal thickness (P < 0.01) of ileum also increased linearly as dietary NDF levels increased. Enzyme activities, such as cellulase in the rumen (P = 0.071) and small intestine (P = 0.075) tended to increase with increasing NDF content, whereas α-amylase in the rumen (P < 0.05) and small intestine (P < 0.05), pepsin in the rumen (P < 0.01) and trypsin in the small intestine (P < 0.05) decreased. Increasing NDF levels resulted in linear responses (P < 0.05) in ruminal acetate, butyrate, acetate/propionate (A/P) ratio, and total volatile fatty acid concentrations. In the rumen, Lachnospiraceae_UCG-010 and norank_f_UCG-010_o__Oscillospirales, fibrolytic microorganisms were more abundant in the 30N group, while Succinivibrio, a saccharolytic bacterium was enriched in the 20N group. In the jejunum, norank_o__Clostridia_vadinBB60_group and unclassified_f__Lachnospiraceae, were enriched in the 25N and 30N groups. In contrast, Candidatus_Arthromitus, Mitsuokella, and norank_f__F082, involved in host immunity, were significantly enriched in the 20N group. Overall, starters containing 25% and 30% NDF promoted fiber-degrading bacteria and enhanced GIT development, thereby optimizing the growth performance of dairy goat kids.
反刍前日粮中的开食料有助于在断奶前优化瘤胃发育，对终生健康和生产性能有显著贡献。本研究调查了开食料日粮中不同中性洗涤纤维（NDF）水平对奶山羊羔羊生长、血清指标、屠宰性能、养分消化率、胃肠道（GIT）发育和微生物谱的影响。将60只14日龄的西农萨能奶山羊羔羊分为3组（每组n = 20），NDF水平分别为20%、25%或30%。所有羔羊从第15天到第84天均接受牛奶和开食料。每两周监测一次体重（BW），并在第2、6、10和12周采集血液样本。在12周龄时，每组屠宰3只雄性羔羊，用于评估GIT形态、酶活性、微生物谱和胴体。25N组和30N组的总体BW（P < 0.01）、血清天冬氨酸转氨酶（AST；P < 0.01）和β-羟基丁酸（BHBA；P < 0.01）显著更高。随着NDF水平升高，屠宰率、十二指肠质量、空肠质量和小肠总质量呈线性增加（P < 0.05）。随着日粮NDF水平的增加，瘤胃乳头长度（P < 0.05）和乳头宽度（P < 0.05）、空肠绒毛高度/隐窝深度（VH/CD）（P < 0.01）和回肠黏膜厚度（P < 0.01）也呈线性增加。瘤胃和小肠中的纤维素酶活性（瘤胃P = 0.071，小肠P = 0.075）随着NDF含量的增加有增加趋势，而瘤胃（P < 0.05）和小肠（P < 0.05）中的α-淀粉酶、瘤胃中的胃蛋白酶（P < 0.01）和小肠中的胰蛋白酶（P < 0.05）降低。随着NDF水平的增加瘤胃乙酸、丁酸、乙酸/丙酸（A/P）比值和总挥发性脂肪酸浓度呈线性变化（P < 0.05）。在瘤胃中，30N组中纤维分解微生物Lachnospiraceae_UCG - 010和norank_f_UCG - 010_o__Oscillospirales更为丰富，而20N组中糖分解细菌琥珀酸弧菌富集。在空肠中，25N组和30N组中norank_o__Clostridia_vadinBB60_group和未分类的_f__Lachnospiraceae富集。相反，参与宿主免疫的类芽孢杆菌属、 Mitsuokella和norank_f__F082在20N组中显著富集。总体而言，含有25%和30% NDF的开食料促进了纤维降解细菌的生长并增强了GIT发育，从而优化了奶山羊羔羊的生长性能。
