1 材料与方法
1.1 酵母培养物的制备
1.2 试验设计
1.3 试验方法
1.3.1 酵母培养物中营养活性物质含量的测定
1.3.2 酵母培养物理化指标的测定
1.3.3 酵母培养物中益生菌数量的测定
表1 引物序列、片段大小以及退火温度Table 1 Primer sequences, fragment size, and annealing temperature |
| 项目 Items | 引物序列 Primer sequences (5'—3') | 扩增长度 Amplification length/bp | 退火温度 Tm/℃ |
|---|---|---|---|
酿酒酵母BC Saccharomyces cerevisiae BC | F:CGAGAGACCGATAGCGAACAAG | 144 | 61.70 |
| R:CCCTACCCACAAGGAGCAGA | 59.80 | ||
马克斯克鲁维酵母XR4 Kluyveromyces marxianus XR4 | F:CCTTTGGGTTTGGTAGTGAGTGATA | 200 | 61.80 |
| R:GAGACAAACACCAGCGAGTCTTTAT | 61.30 |
1.3.4 瘤胃体外发酵试验
表2 基础饲粮组成及营养水平(风干基础)Table 2 Composition and nutrient levels of the basal diet (air-dry basis) % |
| 项目Items | 含量Content |
|---|---|
| 原料Ingredients | |
| 玉米Corn | 47.48 |
| 豆粕Soybean meal | 15.82 |
| 玉米秸秆Corn stalk | 17.00 |
| 燕麦干草Oat hay | 17.00 |
| 磷酸氢钙CaHPO4 | 0.90 |
| 食盐NaCl | 0.50 |
| 石粉Limestone | 0.80 |
| 预混料Premix1) | 0.50 |
| 合计Total | 100.00 |
| 营养水平Nutrient levels2) | |
| 干物质DM | 83.42 |
| 总能GE/(MJ/kg) | 16.14 |
| 粗蛋白质CP | 15.31 |
| 粗脂肪EE | 5.22 |
| 粗纤维CF | 11.09 |
| 钙Ca | 0.69 |
| 磷P | 0.46 |
1)预混料为每千克饲粮提供 The premix provided the following per kg of the diet:Zn (as zinc sulfate) 50 mg,Mn (as manganese sulfate) 25 mg,Cu (as copper sulfate) 2.5 mg,Fe (as ferrous sulfate) 40 mg,I (as potassium iodide) 0.70 mg,VA 3 000 IU,VD 3 290 IU,VE 3.2 mg。 2)营养水平均为实测值。Nutrient levels were all measured values. |
1.3.4.1 体外营养物质降解率的测定
1.3.4.2 体外发酵参数的测定
1.4 数据统计分析
2 结果与分析
2.1 不同发酵工艺对酵母培养物中营养活性物质含量的影响
表3 不同发酵工艺对酵母培养物中营养活性物质含量的影响Table 3 Effects of different fermentation processes on contents of nutritional active substances in yeast cultures |
| 项目 Items | 组别Groups | P值 P-value | |||
|---|---|---|---|---|---|
| CON | AF | BF | TF | ||
| β-葡聚糖β-glucan/% | 0.05±0.00b | 0.81±0.10a | 0.81±0.08a | 0.88±0.04a | 0.038 |
| 甘露聚糖Mannan/% | 0.29±0.02c | 0.62±0.02a | 0.56±0.02b | 0.64±0.01a | <0.001 |
| 牛磺酸Taurine/(mg/kg) | 0.00±0.00c | 234.80±3.07b | 231.74±1.61b | 249.73±3.52a | <0.001 |
| N-乙酰谷氨酸N-acetylglutamic acid/(mg/kg) | 12.23±3.60b | 233.20±5.16a | 225.38±9.27a | 227.96±4.76a | 0.001 |
| 花生四烯酸Arachidonic acid/(mg/kg) | 0.00±0.00d | 15.56±0.13a | 13.40±0.16c | 15.21±0.15b | <0.001 |
2.2 不同发酵工艺对酵母培养物理化指标的影响
表4 不同发酵工艺对酵母培养物理化指标的影响Table 4 Effects of different fermentation processes on physicochemical indices in yeast cultures |
| 项目 Items | 组别Groups | P值 P-value | |||
|---|---|---|---|---|---|
| CON | AF | BF | TF | ||
| pH | 6.33±0.02a | 5.79±0.03b | 5.74±0.03c | 5.78±0.01bc | <0.001 |
| 粗蛋白质CP/% | 16.63±0.98b | 17.38±0.36b | 17.25±0.74b | 18.52±0.30a | 0.011 |
| 三氯乙酸可溶蛋白TCA-SP/% | 5.74±0.26c | 6.58±0.08b | 6.66±0.08ab | 6.91±0.16a | 0.001 |
| 有机酸Organic acids/(mg/100 g) | |||||
| 酒石酸Tartaric acid | 216.56±7.70b | 270.26±17.12a | 236.79±22.17b | 238.12±9.94b | 0.017 |
| 苹果酸Malic acid | 465.66±43.02b | 919.05±15.99a | 801.83±109.47a | 877.48±109.39a | 0.001 |
| 乳酸Lactic acid | 1 570.35±21.88d | 1 795.98±16.78c | 2 249.44±78.70a | 2 009.49±48.42b | <0.001 |
| 乙酸Acetic acid | 192.03±26.83c | 500.68±19.80a | 426.10±49.49b | 444.14±9.51ab | <0.001 |
| 柠檬酸Citric acid | 418.43±27.43c | 561.53±8.39a | 552.27±43.27ab | 508.44±7.77b | 0.001 |
| 琥珀酸Succinic acid | 188.59±53.68b | 1 034.53±23.29a | 1 100.85±100.60a | 1 017.22±11.95a | <0.001 |
| 丙酸Propanoic acid | 2 361.46±145.56b | 2 409.79±277.74b | 3 052.42±205.22a | 2 933.09±89.36a | 0.004 |
| 总有机酸Total organic acid | 5 413.08±50.10c | 7 491.82±257.85b | 8 419.70±308.76a | 8 027.99±239.42a | <0.001 |
2.3 不同发酵工艺对酵母培养物中益生菌数量的影响
表5 不同发酵工艺对酵母培养物中益生菌数量的影响Table 5 Effects of different fermentation processes on quantity of probiotics in yeast cultures lg(拷贝数/g) |
| 项目 Items | 组别Groups | P值 P-value | |||
|---|---|---|---|---|---|
| CON | AF | BF | TF | ||
| 酿酒酵母BC Saccharomyces cerevisiae BC | 3.11±0.34b | 7.52±0.08a | 7.49±0.02a | 7.49±0.03a | <0.001 |
| 马克斯克鲁维酵母XR4 Kluyveromyces marxianus XR4 | 3.52±0.56c | 7.41±0.05a | 6.21±0.06b | 6.98±0.08a | <0.001 |
2.4 不同发酵工艺酵母培养物对肉牛瘤胃体外营养物质降解率的影响
表6 不同发酵工艺酵母培养物对肉牛瘤胃体外营养物质降解率的影响Table 6 Effects of yeast cultures with different fermentation processes on degradation rates of nutrients in rumen of beef cattle in vitro % |
| 项目 Items | 组别Groups | P值 P-value | |||
|---|---|---|---|---|---|
| CON | AF | BF | TF | ||
| 体外干物质降解率IVDMD | 64.13±0.58d | 68.00±0.49b | 66.14±0.40c | 68.98±0.26a | <0.001 |
| 体外粗蛋白质降解率IVCPD | 65.00±0.76b | 68.02±1.51a | 68.02±0.97a | 69.00±1.07a | 0.011 |
| 体外中性洗涤纤维降解率IVNDFD | 32.08±0.31b | 36.42±0.77a | 35.50±0.63a | 36.98±1.32a | 0.001 |
| 体外酸性洗涤纤维降解率IVADFD | 26.29±0.76b | 27.99±1.51ab | 27.22±1.21b | 29.74±1.15a | 0.039 |
2.5 不同发酵工艺酵母培养物对肉牛瘤胃体外发酵参数的影响
表7 不同发酵工艺酵母培养物对肉牛瘤胃体外发酵参数的影响Table 7 Effects of yeast cultures with different fermentation processes on rumen fermentation parameters of beef cattle in vitro |
| 项目 Items | 组别Groups | P值 P-value | |||
|---|---|---|---|---|---|
| CON | AF | BF | TF | ||
| pH | 5.85±0.02b | 5.91±0.02a | 5.89±0.01a | 5.91±0.01a | 0.002 |
| 产气量Gas production/mL | 263.65±5.26b | 279.88±5.50a | 266.20±5.79b | 279.99±6.63a | 0.014 |
| 氨态氮NH3-N/(mg/dL) | 10.20±1.21c | 12.84±1.14ab | 11.11±0.51bc | 13.93±0.81a | 0.006 |
| 菌体蛋白BCP/(mg/dL) | 38.49±1.15c | 47.67±0.60b | 48.50±0.34ab | 50.63±2.30a | <0.001 |
| 挥发性脂肪酸VFA/(mmol/L) | |||||
| 乙酸Acetate | 51.59±3.89c | 59.87±0.31ab | 57.23±1.05b | 62.40±2.02a | 0.002 |
| 丙酸Propionate | 22.04±1.84 | 24.55±0.87 | 23.70±1.25 | 24.10±1.07 | 0.177 |
| 异丁酸Isobutyrate | 0.78±0.03 | 0.84±0.02 | 0.81±0.03 | 0.88±0.05 | 0.051 |
| 异戊酸Isovalerate | 1.50±0.10 | 1.57±0.06 | 1.53±0.01 | 1.70±0.14 | 0.113 |
| 丁酸Butyrate | 12.63±0.62 | 12.78±0.12 | 12.64±0.38 | 13.84±1.25 | 0.201 |
| 戊酸Valerate | 1.58±0.07b | 1.66±0.04ab | 1.63±0.05b | 1.74±0.04a | 0.028 |
| 总挥发性脂肪酸TVFA | 90.11±5.73c | 101.27±0.38ab | 97.54±2.01b | 104.49±2.68a | 0.004 |
| 乙酸/丙酸Acetate/propionate | 2.34±0.14 | 2.44±0.10 | 2.42±0.09 | 2.59±0.19 | 0.220 |
2.6 TOPSIS综合分析
表8 TOPSIS法综合分析结果Table 8 Results of comprehensive analysis by TOPSIS method |
| 项目 Items | 组别Groups | |||
|---|---|---|---|---|
| CON | AF | BF | TF | |
| 最优解D+ | 16.432 | 7.348 | 10.583 | 6.164 |
| 最劣解D- | 5.568 | 12.923 | 8.544 | 14.248 |
| 置信区间CI | 0.253 | 0.637 | 0.447 | 0.698 |
| 排序Ranking | 4 | 2 | 3 | 1 |

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