1 材料与方法
1.1 试验设计
表1 开食料、苜蓿干草和代乳粉的营养水平(干物质基础)Table 1 Nutrient levels of starter, alfalfa hay and milk replacer (DM basis) % |
| 营养水平Nutrient levels | 代乳粉Milk replacer | 开食料Starter | 苜蓿干草Alfalfa hay |
|---|---|---|---|
| 粗蛋白质CP | 26.24 | 21.34 | 13.68 |
| 粗脂肪EE | 27.79 | 7.01 | 5.79 |
| 中性洗涤纤维NDF | 15.55 | 43.00 | |
| 酸性洗涤纤维ADF | 4.90 | 29.39 | |
| 钙Ca | 2.50 | 0.80 | 1.45 |
| 磷P | 1.40 | 0.55 | 0.34 |
1.2 饲养管理
1.3 样品采集
1.4 指标测定及方法
1.4.1 生长性能
1.4.2 瘤胃发酵参数
1.4.3 瘤胃消化酶活性
1.4.4 瘤胃微生物区系
1.4.5 瘤胃代谢组学
1.5 数据处理与统计分析
2 结果与分析
2.1 代乳粉饲喂量对牦牛犊牛生长性能的影响
表2 代乳粉饲喂量对牦牛犊牛生长性能的影响Table 2 Effects of milk replacer feeding amount on growth performance of yak calves |
| 项目Items | 组别Groups | P值P-value | |
|---|---|---|---|
| dC | dH | ||
| 初始体重Initial body weight/kg | 35.00±1.14 | 37.60±1.03 | 0.129 |
| 终末体重Final body weight/kg | 69.00±0.99b | 76.80±2.14a | 0.011 |
| 平均日增重Average daily gain/(g/d) | 323.81±14.21b | 373.33±15.25a | 0.045 |
| 净增重Net weight gain/kg | 39.20±1.56b | 45.10±1.47a | 0.025 |
| 体斜长Body oblique length/cm | 85.90±0.24b | 87.90±0.71a | 0.029 |
| 体高Body height/cm | 82.40±1.21 | 86.20±1.15 | 0.052 |
| 胸围Chest circumference/cm | 102.50±1.58B | 109.30±1.11A | 0.008 |
| 管围Cannon circumference/cm | 11.50±0.00b | 12.10±0.24a | 0.040 |
同行数据肩标不同小写字母表示差异显著(P<0.05),不同大写字母表示差异极显著(P<0.01),无字母表示差异不显著(P>0.05)。下表同。 | |
In the same row, values with different small letter superscripts mean significant difference (P<0.05), and with different capital letter superscripts mean significant difference (P<0.01), while with no letter superscript mean no significant difference (P>0.05). The same as below. |
2.2 代乳粉饲喂量对牦牛犊牛瘤胃发酵参数的影响
表3 代乳粉饲喂量对牦牛犊牛瘤胃发酵参数的影响Table 3 Effects of milk replacer feeding amount on rumen fermentation parameters of yak calves |
| 项目Items | 组别Groups | P值P-value | |
|---|---|---|---|
| dC | dH | ||
| pH | 5.87±0.18 | 5.92±0.79 | 0.823 |
| 氨态氮NH3-N/(mg/dL) | 5.39±0.31 | 5.43±0.31 | 0.932 |
| 微生物蛋白MCP/(mg/dL) | 11.12±0.51 | 11.11±0.61 | 0.991 |
| 乙酸Acetate/(mmol/L) | 14.62±2.62 | 27.89±5.86 | 0.732 |
| 丙酸Propionate/(mmol/L) | 3.40±0.60 | 6.71±1.50 | 0.134 |
| 丁酸Butyrate/(mmol/L) | 2.35±0.42 | 4.01±0.74 | 0.082 |
| 总挥发性脂肪酸TVFA/(mmol/L) | 22.33±3.81 | 40.89±8.40 | 0.074 |
| 乙酸/丙酸Acetate/propionate | 3.66±0.30 | 4.16±0.10 | 0.143 |
2.3 代乳粉饲喂量对牦牛犊牛瘤胃消化酶活性的影响
表4 代乳粉饲喂量对牦牛犊牛瘤胃消化酶活性的影响Table 4 Effects of milk replacer feeding amount on rumen digestive enzyme activities of yak calves |
| 项目Items | 组别Groups | P值P-value | |
|---|---|---|---|
| dC | dH | ||
| 纤维素酶Cellulase/(U/mL) | 245.21±18.49b | 346.21±16.60a | 0.015 |
| 淀粉酶Amylase/(U/L) | 483.03±50.77 | 510.89±52.02 | 0.712 |
| 木聚糖酶Xylanase/(U/mL) | 382.12±16.29b | 459.00±15.50a | 0.027 |
| 内切葡聚糖酶Endoglucanase/(U/L) | 90.52±11.54 | 89.61±7.81 | 0.950 |
2.4 代乳粉饲喂量对牦牛犊牛瘤胃微生物区系的影响
2.4.1 操作分类单元(OTU)聚类及基础分析结果
2.4.2 牦牛犊牛瘤胃微生物OTU Venn图
2.4.3 瘤胃微生物Alpha多样性指数
表5 牦牛犊牛瘤胃微生物Alpha多样性指数Table 5 Alpha diversity index of rumen microorganisms of yak calves |
| 项目Items | 组别Groups | P值P-value | |
|---|---|---|---|
| dC | dH | ||
| Chao1指数Chao1 index | 656.64±51.11 | 731.40±44.88 | 0.304 |
| ACE指数ACE index | 655.89±50.53 | 730.66±44.37 | 0.298 |
| 覆盖率Good's coverage | 0.99±0.00A | 1.00±0.00B | 0.008 |
| Shannon指数Shannon index | 7.08±0.36 | 7.40±0.31 | 0.513 |
| Simpson指数Simpson index | 0.97±0.01 | 0.97±0.01 | 0.592 |
2.4.4 瘤胃微生物优势菌门和菌属相对丰度
表6 代乳粉饲喂量对牦牛犊牛瘤胃微生物优势菌门和菌属相对丰度的影响Table 6 Effects of milk replacer feeding amount on relative abundances of dominant phylum and genus of rumen microorganism of yak calves |
| 项目Items | 组别Groups | P值P-value | ||
|---|---|---|---|---|
| dC | dH | |||
| 门水平Phylum level | 拟杆菌门Bacteroidota | 84.88±1.37 | 82.39±0.81 | 0.156 |
| 厚壁菌门Firmicutes | 12.19±1.30b | 15.75±0.82a | 0.049 | |
| 变形菌门Proteobacteria | 1.24±0.28 | 0.75±0.11 | 0.147 | |
| 螺旋体门Spirochaetota | 0.90±0.24 | 0.37±0.08 | 0.065 | |
| 纤维杆菌门Fibrobacterota | 0.30±0.13 | 0.11±0.03 | 0.199 | |
| 脱硫细菌门Desulfobacterota | 0.34±0.08 | 0.31±0.09 | 0.801 | |
| 弯曲杆菌门Campilobacterota | 0.05±0.01 | 0.10±0.03 | 0.172 | |
| 浮游菌门Planctomycetota | 0.08±0.04 | 0.01±0.01 | 0.110 | |
| 髌骨细菌门Patescibacteria | 0.05±0.03 | 0.02±0.01 | 0.374 | |
| 迷踪菌门Elusimicrobiota | 0.04±0.01 | 0.02±0.01 | 0.337 | |
| 属水平Genus level | F082 | 25.29±6.86 | 22.91±5.22 | 0.789 |
| 普雷沃氏菌属Prevotella | 33.93±4.30 | 30.74±6.32 | 0.687 | |
| 理研菌科RC9肠道群Rikenellaceae-RC9-gut-group | 9.21±1.41 | 8.32±0.91 | 0.609 | |
| 拟杆菌属Bacteroides | 6.30±0.96 | 6.56±1.95 | 0.911 | |
| 普雷沃氏菌科-UCG-003 Prevotellaceae-UCG-003 | 2.40±0.40 | 4.63±1.51 | 0.192 | |
| 普雷沃氏菌科-UCG-001 Prevotellaceae-UCG-001 | 2.14±0.51 | 2.60±0.57 | 0.560 | |
| 毛螺菌科-ND3007群Lachnospiraceae_ND3007_group | 0.64±0.28b | 3.33±0.96a | 0.028 | |
| 拟杆菌目-RF16群Bacteroidales_RF16_group | 1.62±0.54 | 1.22±0.28 | 0.518 | |
| 梭状芽孢杆菌属-UCG-014 Clostridium_UCG-014 | 1.05±0.37 | 1.47±0.39 | 0.462 | |
| 拟杆菌目-BS11-肠道群Bacteroidales-BS11-gut-group | 1.04±0.58 | 2.61±1.57 | 0.124 | |
2.5 牦牛犊牛瘤胃代谢组学分析
2.5.1 主成分分析(PCA)
2.5.2 正交偏最小二乘判别分析(OPLS-DA)
2.5.3 瘤胃微生物差异代谢产物
表7 42日龄牦牛犊牛瘤胃差异代谢产物(dC组vs dH组)Table 7 Differential metabolites in rumen of 42-day-old yak calves (dC group vs dH group) |
| 代谢通路Metabolic pathways | 代谢产物Metabolites | 质荷比m/z | 保留时间Retention time/min | log2(差异倍数)log2(FC) | P值P-value | 变量投影重要性VIP | 上调/下调Up-regulated/down-regulated |
|---|---|---|---|---|---|---|---|
| 嘌呤代谢Purine metabolism | 腺嘌呤核苷酸Adenosine | 268.104 | 1.276 | 2.587 | 0.037 | 19.157 | 上调 |
| 次黄嘌呤Hypoxanthine | 137.046 | 1.074 | -0.743 | 0.009 | 10.535 | 下调 | |
| 腺嘌呤Adenine | 136.062 | 1.067 | 2.584 | 0.026 | 7.992 | 上调 | |
| 脱氧肌苷二磷酸Deoxyinosine diphosphate | 411.012 | 1.260 | 2.872 | 0.038 | 2.083 | 上调 | |
| 硫胺素代谢Thiamine metabolism | 4-氨基-5-羟甲基-2-甲基嘧啶4-amino-5-hydroxymethyl-2-methylpyrimidine | 140.082 | 14.066 | -0.318 | 0.024 | 17.086 | 下调 |
| 甘油磷脂代谢Glycerophospholipid metabolism | [(2R)-3-十七碳酰氧基-2-羟基丙基]2-(三甲基铵基)乙基磷酸酯[(2R)-3-heptadecanoyloxy-2-hydroxypropyl] 2-(trimethylazaniumyl)ethyl phosphate | 554.346 | 10.924 | 1.492 | <0.001 | 2.176 | 上调 |
| 天冬氨酸代谢Aspartate metabolism | L-天冬氨酸L-asparagine | 115.051 | 14.650 | -0.222 | 0.042 | 1.893 | 下调 |
| 色氨酸代谢Tryptophan metabolism | 5-羟基-N-甲酰基犬尿氨酸5-hydroxy-N-formylkynurenine | 270.109 | 1.276 | 2.753 | 0.041 | 1.863 | 上调 |
| 维生素B6代谢Vitamin B6 metabolism | 4α-甲基苄醇-4-羧酸4α-methylzymosterol-4-carboxylic acid | 460.378 | 12.958 | 0.567 | 0.029 | 1.617 | 上调 |
| 鞘脂代谢Sphingolipid metabolism | 磷酸鞘氨醇Sphinganine phosphate | 362.247 | 9.345 | 1.064 | 0.016 | 1.067 | 上调 |
2.5.4 KEGG富集分析
图6 牦牛犊牛差异代谢物KEGG富集分析气泡图Purine metabolism:嘌呤代谢;Parkinson disease:帕金森病;cAMP signaling pathway:cAMP信号通路;Sphingolipid signaling pathway:鞘脂信号途径;Regulation of lipolysis in adipocytes:脂肪细胞的脂肪分解调节;Vascular smooth muscle contraction:血管平滑肌收缩;Choline metabolism in cancer:癌症中的胆碱代谢;MAPK signaling pathway:MAPK信号通路;Rap1 signaling pathway:Rap1信号通路;EGFR tyrosine kinase inhibitor resistance:表皮生长因子受体酪氨酸激酶抑制剂的抗药性;ErbB signaling pathway:ErbB信号通路;Natural killer cell mediated cytotoxicity:自然杀伤细胞介导的细胞毒性;Th17 cell differentiation:Th17细胞分化;T cell receptor signaling pathway:T细胞受体信号通路;B cell receptor signaling pathway:B细胞受体信号通路;Growth hormone synthesis, secretion and action:生长激素的合成、分泌和作用;Glioma:胶质瘤;PD-L1 expression and PD-1 checkpoint pathway in cancer:癌症中的PD-L1表达和PD-1检查点通路;NF-kappa B signaling pathway:NF-kappa B信号通路;Th1 and Th2 cell differentiation:Th1和Th2细胞分化。 Fig.6 KEGG enrichment analysis bubble diagram of differential metabolites of yak calves |

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