1 材料与方法
1.1 试验材料
1.2 试验设计与饲养管理
表1 基础饲粮组成及营养水平(干物质基础)Table 1 Composition and nutrient levels of the basal diet (DM basis)% |
| 项目 Items | 含量 Content | ||
|---|---|---|---|
| 原料 Ingredients | |||
| 青贮玉米 Corn silage | 36.35 | ||
| 压片玉米 Flaked corn | 3.64 | ||
| 全棉籽 Whole cottonseed | 5.54 | ||
| 苜蓿干草 Alfalfa hay | 3.27 | ||
| 苜蓿青贮 Alfalfa silage | 6.70 | ||
| 玉米 Corn | 16.02 | ||
| 豆粕 Soybean meal | 12.46 | ||
| 棉籽粕 Cottonseed meal | 2.23 | ||
| 菜籽粕 Rapeseed meal | 2.45 | ||
| 麦麸 Wheat bran | 1.56 | ||
| 碳酸氢钠 NaHCO3 | 1.02 | ||
| 脂肪酸钙 Fatty acid calcium | 0.98 | ||
| 湿玉米酒糟 Wet corn distiller’s grains | 4.45 | ||
| 膨化大豆 Extruded soybean | 1.33 | ||
| 预混料 Premix1) | 2.00 | ||
| 合计 Total | 100.00 | ||
| 营养水平 Nutrient levels2) | |||
| 粗蛋白质 CP | 17.13 | ||
| 粗脂肪 EE | 5.56 | ||
| 中性洗涤纤维 NDF | 31.36 | ||
| 酸性洗涤纤维 ADF | 20.98 | ||
| 粗灰分 Ash | 7.59 | ||
| 钙 Ca | 0.94 | ||
| 磷 P | 0.39 | ||
| 泌乳净能 NEL/(MJ/kg) | 6.53 |
1)预混料为每千克饲粮提供The premix provided the following per kg of the diet:VA 100 000 IU,VD3 20 000 IU,VE≥1 000 mg,Cu 300 mg,Zn 1 000 mg,Mn 600 mg,I 10 mg,Se 5 mg,Co 5 mg。 |
1.3 样品采集与指标测定
1.3.1 饲粮营养成分测定
1.3.2 干物质采食量(DMI)、产奶量及乳成分的测定
1.3.3 血液采集与指标的测定
1.3.4 瘤胃液采集与指标的测定
1.3.5 瘤胃菌群结构的测定
1.3.6 瘤胃液代谢组的测定
1.4 数据统计与分析
2 结果与分析
2.1 YC对奶牛生产性能的影响
表2 YC对奶牛生产性能的影响Table 2 Effects of YC on performance of dairy cows |
| 项目 Items | 组别 Groups | SEM | P值 P-value | |
|---|---|---|---|---|
| CON | YC | |||
| 干物质采食量 DMI/(kg/d) | 25.80 | 25.78 | 0.076 | 0.900 |
| 产奶量 Milk yield/(kg/d) | 42.24 | 43.00 | 0.179 | 0.035 |
| 4%乳脂校正乳产量 4% FCM yield/(kg/d) | 39.96 | 40.87 | 0.170 | 0.008 |
| 乳脂率 Milk fat rate/% | 3.64 | 3.67 | 0.075 | 0.826 |
| 乳脂产量 Milk fat yield/kg | 1.54 | 1.58 | 0.007 | 0.002 |
| 乳蛋白率 Milk protein rate/% | 3.38 | 3.38 | 0.037 | 0.977 |
| 乳蛋白产量 Milk protein yield/kg | 1.43 | 1.45 | 0.006 | 0.035 |
| 乳糖率 Lactose/% | 4.63 | 4.64 | 0.041 | 0.911 |
| 乳糖产量 Lactose yield/kg | 1.96 | 2.00 | 0.008 | 0.018 |
| 非脂乳固体 Non-fat solids/% | 8.73 | 8.66 | 0.087 | 0.726 |
| 总固形物 Total solids/% | 12.56 | 12.57 | 0.099 | 0.948 |
| 乳尿素氮 MUN/(mg/dL) | 13.89 | 13.35 | 0.283 | 0.347 |
| 体细胞数 SCC/(×103个/mL) | 184.21 | 72.38 | 23.122 | 0.016 |
| 饲料效率 FE | 1.64 | 1.67 | 0.006 | 0.028 |
2.2 YC对奶牛血清生化指标的影响
表3 YC对奶牛血清生化指标的影响Table 3 Effects of YC on serum biochemical indexes of dairy cows |
| 项目 Items | 组别 Groups | SEM | P值 P-value | |
|---|---|---|---|---|
| CON | YC | |||
| 白蛋白 ALB/(g/L) | 38.59 | 41.76 | 0.629 | 0.011 |
| 球蛋白 GLB/(g/L) | 26.45 | 32.53 | 0.937 | 0.001 |
| 白球比 A/G | 1.57 | 1.33 | 0.059 | 0.041 |
| 钙 Ca/(mmol/L) | 2.06 | 2.15 | 0.023 | 0.048 |
| 总胆固醇 TCHO/(mmol/L) | 5.94 | 6.55 | 0.138 | 0.028 |
| 葡萄糖 GLU/(mmol/L) | 2.31 | 2.23 | 0.082 | 0.636 |
| 低密度脂蛋白 LDL/(mmol/L) | 3.86 | 4.28 | 0.095 | 0.026 |
| 甘油三酯 TG/(mmol/L) | 0.17 | 0.18 | 0.006 | 0.556 |
| 总蛋白 TP/(g/L) | 65.05 | 74.29 | 1.276 | <0.001 |
| 肌酐 CREA/(μmol/L) | 86.46 | 83.40 | 1.216 | 0.220 |
2.3 YC对奶牛血清抗氧化指标的影响
表4 YC对奶牛血清抗氧化指标的影响Table 4 Effects of YC on serum antioxidant indexes of dairy cows |
| 项目 Items | 组别 Groups | SEM | P值 P-value | |
|---|---|---|---|---|
| CON | YC | |||
| 过氧化氢酶 CAT/(U/mL) | 6.06 | 7.88 | 0.255 | <0.001 |
| 谷胱甘肽过氧化物酶 GHS-Px/(U/mL) | 65.31 | 65.14 | 1.997 | 0.972 |
| 谷胱甘肽-S转移酶 GST/(U/mL) | 13.03 | 13.22 | 0.638 | 0.882 |
| 丙二醛 MDA/(nmol/mL) | 4.26 | 4.96 | 0.241 | 0.155 |
| 超氧化物歧化酶 SOD/(U/mL) | 27.58 | 31.10 | 0.523 | 0.001 |
2.4 YC对奶牛瘤胃发酵参数的影响
表5 YC对奶牛瘤胃发酵参数的影响Table 5 Effects of YC on rumen fermentation parameters of dairy cows |
| 项目 Items | 组别 Groups | SEM | P值 P-value | |
|---|---|---|---|---|
| CON | YC | |||
| pH | 6.16 | 5.90 | 0.088 | 0.154 |
| 氨态氮 NH3-N/(mg/dL) | 8.76 | 14.03 | 1.144 | 0.020 |
| 微生物蛋白 MCP/(mg/dL) | 2.52 | 3.13 | 0.106 | <0.001 |
| 乙酸 Acetate/(mmol/L) | 67.44 | 79.72 | 2.933 | 0.038 |
| 丙酸 Propionate/(mmol/L) | 28.18 | 30.97 | 1.150 | 0.254 |
| 异丁酸 Isobutyrate/(mmol/L) | 1.32 | 1.66 | 0.048 | 0.013 |
| 丁酸 Butyrate/(mmol/L) | 9.82 | 11.16 | 0.473 | 0.178 |
| 异戊酸 Isovalerate/(mmol/L) | 1.32 | 1.66 | 0.077 | 0.023 |
| 戊酸 Valerate/(mmol/L) | 1.49 | 1.81 | 0.071 | 0.025 |
| 乙丙比 A/P | 2.41 | 2.60 | 0.069 | 0.198 |
| 总挥发性脂肪酸 TVFA/(mmol/L) | 109.18 | 126.47 | 4.369 | 0.051 |
2.5 YC对奶牛瘤胃菌群的影响
2.5.1 α多样性分析
表6 YC对奶牛瘤胃微生物α多样性的影响Table 6 Effects of YC on α-diversity of rumen microorganisms of dairy cows |
| 项目 Items | 组别 Groups | SEM | P值 P-value | |
|---|---|---|---|---|
| CON | YC | |||
| ACE指数 ACE index | 1 585.22 | 1 754.19 | 157.207 | 0.301 |
| Chao指数 Chao index | 1 554.42 | 1 715.23 | 146.813 | 0.292 |
| Shannon指数 Shannon index | 5.95 | 6.12 | 0.151 | 0.279 |
| Simpson指数 Simpson index | 0.01 | 0.01 | 0.002 | 0.441 |
| Coverage指数 Coverage index | 1.00 | 0.99 | 0.002 | 0.504 |
| Sobs指数 Sobs index | 1 523.38 | 1 668.63 | 131.608 | 0.288 |
2.5.2 YC对瘤胃菌群结构的影响
图1 瘤胃菌群在门(A)和属水平(B)的群落分布Bacteroidota:拟杆菌门;Firmicutes:厚壁菌门;Proteobacteria:变形菌门;Patescibacteria:髌骨菌门;Actinobacteriota:放线菌门;Spirochaetota:螺旋体菌门;Cyanobacteria:蓝藻菌门;Verrucomicrobiota:疣微菌门;Desulfobacterota:脱硫杆菌门;Prevotella:普雷沃氏菌属;Succiniclasticum:解琥珀酸菌属;Rikenellaceae_RC9_gut_group:理研菌科RC9_肠道群;Ruminococcus:瘤胃球菌属;Acinetobacter:不动杆菌属;NK4A214_group:NK4A214群;norank_f_Muribaculaceae:未分类拟杆菌目;unclassified_f_Prevotellaceae:未分类普雷沃氏菌科;norank_f_norank_o_Clostridia_UCG-014:未分类梭菌纲UCG-014;Other:其他。 Fig.1 Community distribution of rumen bacteria at phylum (A) and genus (B) levels |
2.5.3 YC对瘤胃菌群在属水平上差异的影响
图2 CON组和YC组差异菌属Lachnospiraceae_UCG-004:毛螺菌科UCG-004;Enterococcus:肠球菌属;unclassified_o_Enterobacterales:未分类肠杆菌目;unclassified_f_Selenomonadaceae:未分类硒单胞菌科;norank_f_norank_o_Rhodospirillales:未分类红螺菌目;norank_f_norank_o_Bradymonadales:未分类慢生单胞菌目。 Fig.2 Differential bacterial genus between CON group and YC group |
2.5.4 瘤胃发酵参数与差异菌属之间的相关性
图3 瘤胃发酵参数与差异菌属相关性分析Lachnospiraceae_UCG-004:毛螺菌科UCG-004;norank_f_norank_o_Rhodospirillales:未分类红螺菌目;unclassified_f_Selenomonadaceae:未分类硒单胞菌科;unclassified_o_Enterobacterales:未分类肠杆菌目;Enterococcus:肠球菌属;norank_f_norank_o_Bradymonadales:未分类慢生单胞菌目;Acetate:乙酸;Propionate:丙酸;Isobutyrate:异丁酸;Butyrate:丁酸;Isovalerate:异戊酸;Valerate:戊酸;TVFA:总挥发性脂肪酸 total volatile fatty acids;AA/PA:乙丙比 acetate/valerate;MCP:微生物蛋白 microprotein;NH3-N:氨态氮 ammoniacal nitrogen。 *表示显著相关(P<0.05),**表示极显著相关(P<0.01),***表示极显著相关(P<0.001)。图7同。 Fig.3 Correlation analysis between rumen fermentation parameters and differential bacteria genus * indicates significant correlation (P<0.05), ** indicates extremely significant correlation (P<0.01), and *** indicates extremely significant correlation (P<0.001). The same as Fig.7. |
2.6 YC对瘤胃液代谢组的影响
2.6.1 瘤胃液代谢组主成分分析(PCA)结果
2.6.2 瘤胃差异代谢物
图5 瘤胃液代谢物火山图横坐标代表组间差异的倍数,纵坐标是代谢物表达量变化差异的统计学检验值,值越大差异越显著。每个点代表1个代谢物,点的大小代表重要变量投影值。红色点是显著上调的代谢物,蓝色点是显著下调的代谢物,灰色点则代表差异不显著的代谢物。 Fig.5 Volcano plot of rumen fluid metabolites The abscissa represents the multiple of the difference between the groups, and the ordinate is the statistical test value of the difference in the expression of metabolites. The larger the value, the more significant the difference. Each point represents a metabolite, and the size of the point represents the VIP value. Red dots are significantly up-regulated metabolites, blue dots are significantly down-regulated metabolites, and gray dots represent metabolites with no significant difference. |
表7 2组瘤胃液显著差异代谢物Table 7 Significantly different metabolites in rumen fluid between two groups |
| 差异代谢物 Differential metabolites | 重要变量投影值 VIP value | 调节 Regulate | P值 P-value |
|---|---|---|---|
| 3-甲基吲哚 3-methylindole | 3.90 | 上调 | <0.001 |
| (S)-2,3,4,5-四氢二吡啶甲酸盐 (S)-2,3,4,5-tetrahydrodipicolinate | 1.77 | 上调 | 0.022 |
| 羟基苯乙酰甘氨酸 Hydroxyphenylacetylglycine | 1.64 | 上调 | 0.026 |
| 1-丁醇 1-butanol | 1.54 | 上调 | 0.040 |
| N-羟基色胺 N-hydroxyl-tryptamine | 1.46 | 上调 | 0.010 |
| 4-吡啶氧酸 4-pyridoxic acid | 1.43 | 上调 | 0.024 |
| 2-甲基-3-羟基-5-甲酰吡啶-4-羧酸盐 2-methyl-3-hydroxy-5-formylpyridine-4-carboxylate | 1.41 | 上调 | 0.028 |
| (3Z,6Z)-3,6-壬二烯醛 (3Z,6Z)-3,6-nonadienal | 1.13 | 上调 | 0.036 |
| 4-(2-氨基苯基)-2,4-二氧丁酸 4-(2-aminophenyl)-2,4-dioxobutanoic acid | 1.06 | 上调 | 0.020 |
| 9(S)-HOTrE | 1.88 | 下调 | 0.005 |
| 吲哚-3-乙醛 Indole-3-acetaldehyde | 1.84 | 下调 | 0.006 |
| 9-hpode | 1.73 | 下调 | 0.009 |
| 8-甲氧基犬尿氨酸盐 8-methoxykynurenate | 1.70 | 下调 | 0.016 |
| 9,10-DiHOME | 1.56 | 下调 | 0.020 |
| 甲基咪唑乙醛 Methylimidazole acetaldehyde | 1.54 | 下调 | 0.009 |
| 9(S)-HpODE | 1.48 | 下调 | 0.017 |
| (9Z,11E,13S,15Z)-13-羟基十八碳-9,11,15-三油酸 (9Z,11E,13S,15Z)-13-hydroxyoctadeca-9,11,15-trienoic acid | 1.27 | 下调 | 0.029 |
2.6.3 差异代谢物的通路分析
表8 2组瘤胃液KEGG代谢通路Table 8 KEGG metabolic pathways of rumen fluid in two groups |
| KEGG通路 KEGG pathways | P值 P-value | 上调的代谢物 Up-regulated metabolites | 下调的代谢物 Down-regulated metabolites |
|---|---|---|---|
| 维生素B6代谢 Vitamin B6 metabolism | 0.012 | 4-吡啶氧酸、2-甲基-3-羟基-5- 甲酰吡啶-4-羧酸盐 | |
| 初级胆汁酸生物合成 Primary bile acid biosynthesis | 0.040 | 3α,7α,12α-三羟基-5β- 胆甾酸酯、胆酸 | |
| 色氨酸代谢 Tryptophan metabolism | 0.007 | 3-甲基吲哚、4-(2-氨基 苯基)-2,4-二氧丁酸, | 吲哚-3-乙醛 |
| α-亚麻酸代谢 Alpha-linolenic acid metabolism | 0.019 | (3Z,6Z)-3,6-壬二烯醛、 (-)-茉莉酸 |
图6 瘤胃液差异代谢物通路分析Vitamin B6 metabolism:维生素B6代谢;Primary bile acid biosynthesis:初级胆汁酸生物合成;Tryptophan metabolism:色氨酸代谢;Alpha-linolenic acid metabolism:α-亚麻酸代谢。 图中每个气泡代表1个代谢通路;横轴表示通路中代谢物相对重要性;纵轴表示代谢物参与通路的富集显著性;气泡大小代表通路的重要性;气泡越大,通路重要性越大。 Fig.6 Pathway analysis of differential metabolites in rumen fluid Each bubble in the figure represents a metabolic pathway; the transverse axis indicates the relative importance of metabolites in the pathway; the longitudinal axis indicates the enrichment significance of metabolites involved in the pathway ; the bubble size represents the importance of the pathway ; the larger the bubble, the greater the importance of the pathway. |
2.7 瘤胃差异菌属与瘤胃液差异代谢物的相关分析
图7 差异代谢物与差异菌属相关性分析g_Enterococcus:肠球菌属;unclassified_o_Enterobacterales:未分类肠杆菌目;unclassified_f_Selenomonadaceae:未分类硒单胞菌科;norank_f_norank_o_Bradymonadales:未分类慢生单胞菌目;Lachnospiraceae_UCG-004:毛螺菌科UCG-004;norank_f_norank_o_Rhodospirillales:未分类红螺菌目;8-methoxykynurenate:8-甲氧基犬尿氨酸盐;Indole-3-acetaldehyde:吲哚-3-乙醛;(9Z,11E,13S,15Z)-13-hydroxyoctadeca-9,11,15-trienoic acid:(9Z,11E,13S,15Z)-13-羟基十八碳-9,11,15-三油酸;Methylimidazole acetaldehyde:甲基咪唑乙醛;(S)-2,3,4,5-tetrahydrodipicolinate:(S)-2,3,4,5-四氢二吡啶甲酸盐;3-methylindole:3-甲基吲哚;4-pyridoxic acid:4-吡啶氧酸;Hydroxyphenylacetylglycine:羟基苯乙酰甘氨酸;N-hydroxyl-tryptamine:N-羟基色胺;(3Z,6Z)-3,6-nonadienal:(3Z,6Z)-3,6-壬二烯醛;4-(2-aminophenyl)-2,4-dioxobutanoic acid:4-(2-氨基苯基)-2,4-二氧丁酸;1-butanol:1-丁醇;2-methyl-3-hydroxy-5-formylpyridine-4-carboxylate:2-甲基-3-羟基-5-甲酰吡啶-4-羧酸盐。 Fig.7 Correlation analysis between differential metabolites and differential bacteria |
