1 材料与方法
1.1 试验设计和饲养管理
表1 基础饲粮组成及营养水平(风干基础)Table 1 Composition and nutrient levels of the basal diet (air-dry basis) % |
| 项目Items | 含量Content |
|---|---|
| 原料Ingredients | |
| 青贮玉米秸秆Silage corn straw | 31.00 |
| 燕麦干草Oaten hay | 13.00 |
| 鲜玉米酒糟Fresh corn distiller’s grains | 16.00 |
| 玉米Corn | 24.00 |
| 豆粕Soybean meal | 4.23 |
| 发酵酒糟Fermented distiller’s grains | 10.56 |
| 食盐NaCl | 0.48 |
| 碳酸钙CaCO3 | 0.32 |
| 小苏打NaHCO3 | 0.32 |
| 氯化胆碱Choline chloride | 0.08 |
| 预混料Premix1) | 0.01 |
| 合计Total | 100.00 |
| 营养水平Nutrient levels2) | |
| 增重净能NEg/(MJ/kg) | 4.28 |
| 干物质DM | 58.50 |
| 粗蛋白质CP | 14.67 |
| 酸性洗涤纤维ADF | 21.60 |
| 中性洗涤纤维NDF | 40.15 |
| 钙Ca | 0.53 |
| 总磷TP | 0.45 |
1)预混料为每千克饲粮提供 The premix provided the following for per kg of the diet: Fe 20 mg,I 0.5 mg,Co 0.2 mg,Mn 40 mg,Se 0.3 mg,Zn 30 mg,VA 1 500 IU,VD 550 IU,VE 10 IU。 | |
2)增重净能为计算值,其余均为实测值。NEg was a calculated value, while the others were measured values. |
1.2 样品采集及指标测定
1.2.1 饲粮营养成分
1.2.2 生长性能
1.2.3 屠宰性能
1.2.4 肌肉品质
1.2.5 肌肉挥发性风味物质组成
1.2.6 瘤胃微生物多样性
1.2.7 瘤胃挥发性脂肪酸(VFA)含量
1.2.8 肌肉中脂肪酸合成酶(FAS)和心脏型脂肪酸结合蛋白(H-FABP)mRNA表达
表2 引物序列Table 2 Primer sequence |
| 基因 Genes | 引物序列 Primer sequence (5'→3') | 退火温度 Annealing temperature/℃ |
|---|---|---|
| 甘油醛-3-磷酸脱氢酶 GAPDH | F:GAGAAACCTGCCAAGTATGA R:CGAAGGTAGAAGAGTGAGTG | 57 |
| 脂肪酸合成酶 FAS | F:ATGCACACCAACGAGCAACA R:GAGGCTGCAGAGTTGCAATA | 57 |
| 心脏型脂肪酸结合蛋白 H-FABP | F:ACTCGGTGTCGGTTTTGCTA R:ACTTTCCTGTCATCTGCTGTGG | 60 |
1.3 数据统计分析
2 结果
2.1 饲粮中添加酵母培养物对牦牛生长性能和屠宰性能的影响
表3 饲粮中添加酵母培养物对牦牛生长性能和屠宰性能的影响Table 3 Effects of dietary yeast culture on growth performance and slaughter performance of yaks |
| 项目 Items | 组别Groups | P值 P-value | ||
|---|---|---|---|---|
| 对照Control | 0.4%YC | 0.8%YC | ||
| 平均干物质采食量ADMI/(kg/d) | 9.08±0.15a | 8.87±0.20b | 8.81±0.20b | 0.008 |
| 平均日增重ADG/(kg/d) | 1.20±0.30 | 1.10±0.20 | 1.22±0.21 | 0.558 |
| 料重比F/G | 8.45±2.27 | 8.89±1.76 | 7.64±1.46 | 0.318 |
| 宰前活重SBW/kg | 321.20±58.58 | 289.60±25.05 | 313.00±40.99 | 0.703 |
| 胴体重Carcass weight/kg | 156.83±29.16 | 137.87±17.43 | 152.21±18.18 | 0.401 |
| 净肉重Net meat weight/kg | 131.51±27.77 | 115.68±15.68 | 129.01±16.17 | 0.452 |
| 净肉率Net meat percentage/% | 40.80±2.17 | 41.93±2.80 | 44.11±6.20 | 0.484 |
| 屠宰率Slaughter percentage/% | 48.84±1.80 | 49.85±3.30 | 51.99±7.49 | 0.607 |
| 肉骨比Meat/bone | 5.22±1.11 | 5.20±0.35 | 5.56±0.40 | 0.678 |
同行数据肩标不同小写字母表示差异显著(P<0.05),相同或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), while with the same or no letter superscripts mean no significant difference (P>0.05). The same as below. |
2.2 饲粮中添加酵母培养物对牦牛肉品质的影响
表4 饲粮中添加酵母培养物对牦牛肉品质的影响Table 4 Effects of dietary yeast culture on meat quality of yaks |
| 项目 Items | 组别Groups | P值 P-value | |||
|---|---|---|---|---|---|
| 对照Control | 0.4%YC | 0.8%YC | |||
| 水分Moisture/% | 74.56±0.48 | 74.75±0.36 | 73.47±1.13 | 0.405 | |
| 粗蛋白质CP/% | 23.71±0.57 | 23.37±0.35 | 24.30±1.19 | 0.210 | |
| 粗灰分Ash/% | 5.23±0.59 | 5.16±0.53 | 5.34±0.59 | 0.905 | |
| 肌内脂肪IMF/% | 1.28±0.09b | 1.52±0.34ab | 1.79±0.39a | 0.021 | |
| 滴水损失Drip loss/% | 4.31±0.56 | 3.94±0.75 | 3.78±0.83 | 0.078 | |
| 蒸煮损失Cooking loss/% | 34.96±2.11a | 33.61±1.83ab | 30.73±2.58b | 0.045 | |
| pH45 min | 6.28±0.27 | 6.44±0.19 | 6.58±0.05 | 0.125 | |
| pH24 h | 5.89±0.19 | 5.84±0.04 | 5.81±0.08 | 0.787 | |
| pH下降率Decline rate of pH/% | 6.24±2.32b | 9.18±2.83ab | 11.34±1.21a | 0.007 | |
肉色Muscle color | 亮度L* | 29.98±1.28 | 30.36±1.95 | 30.34±3.24 | 0.652 |
| 红度a* | 8.06±1.18 | 8.33±1.46 | 8.77±1.15 | 0.721 | |
| 黄度b* | 2.51±0.51b | 2.81±0.40ab | 3.46±0.75a | 0.027 | |
剪切力Shear force/N | 生肉Uncooked meat | 80.08±6.84a | 66.94±5.70ab | 61.71±16.34b | 0.035 |
| 熟肉Cooked meat | 125.07±20.45 | 152.38±38.58 | 114.89±31.40 | 0.297 | |
2.3 饲粮中添加酵母培养物对牦牛肌肉中脂肪酸组成的影响
表5 饲粮中添加酵母培养物对牦牛肌肉中脂肪酸组成的影响Table 5 Effects of dietary yeast culture on muscle fatty acid composition of yaks |
| 项目 Items | 组别Groups | P值 P-value | ||
|---|---|---|---|---|
| 对照Control | 0.4%YC | 0.8%YC | ||
| 饱和脂肪酸Saturated fatty acids/% | 50.42±7.27 | 52.51±2.70 | 49.33±5.35 | 0.653 |
| 癸酸Capric acid(C10∶0)/% | 0.10±0.06 | 0.08±0.01 | 0.09±0.01 | 0.884 |
| 月桂酸Lauric acid(C12∶0)/% | 0.06±0.01 | 0.06±0.01 | 0.07±0.01 | 0.463 |
| 肉豆蔻酸Myristic acid(C14∶0)/% | 2.15±0.46 | 2.33±0.19 | 2.35±0.64 | 0.756 |
| 十五烷酸Pentadecanoic acid(C15∶0)/% | 0.32±0.10 | 0.36±0.06 | 0.29±0.05 | 0.298 |
| 棕榈酸Palmitic acid(C16∶0)/% | 25.68±1.6 | 26.20±0.34 | 26.96±3.00 | 0.601 |
| 十七烷酸Margaric acid(C17∶0)/% | 0.86±0.26 | 0.94±0.13 | 0.76±0.13 | 0.333 |
| 硬脂酸Stearic acid(C18∶0)/% | 23.93±3.49a | 21.88±2.88ab | 18.16±1.92b | 0.015 |
| 花生酸Arachidonic acid(C20∶0)/% | 0.23±0.02a | 0.19±0.04a | 0.13±0.03b | 0.013 |
| 二十一烷酸Heneicosoic acid(C21∶0)/% | 0.23±0.09 | 0.26±0.10 | 0.20±0.05 | 0.622 |
| 二十二烷酸Docosanoic acid(C22∶0)/% | 0.09±0.03 | 0.05±0.00 | ND | 0.363 |
| 二十四烷酸Tetracosanoic acid(C24∶0)/% | 0.32±0.33 | 0.25±1.56 | 0.47±0.51 | 0.628 |
| 不饱和脂肪酸Unsaturated fatty acids/% | 47.03±5.67 | 46.57±2.69 | 49.49±5.21 | 0.565 |
| 单不饱和脂肪酸Monounsaturated fatty acids/% | 40.81±2.96 | 42.00±2.74 | 42.38±3.58 | 0.715 |
| 十四烯酸Tetradecenic acid(C14∶1)/% | 0.23±0.05 | 0.22±0.06 | 0.28±0.06 | 0.291 |
| 棕榈油酸Palmitic acid(C16∶1)/% | 4.19±0.49b | 4.30±0.60b | 4.99±0.24a | 0.039 |
| 银杏酸Ginkgoic acid(C17∶1)/% | 0.55±0.06 | 0.59±0.08 | 0.58±0.04 | 0.515 |
| 反式油酸Elaidic acid(C18∶1n9t)/% | 1.52±0.71 | ND | ND | |
| 顺式油酸Oleic acid(C18∶1n9c)/% | 34.82±2.47 | 36.80±2.22 | 36.44±3.63 | 0.521 |
| 花生一烯酸Arachidonic acid(C20∶1)/% | 0.11±0.03 | 0.11±0.02 | 0.12±0.04 | 0.918 |
| 多不饱和脂肪酸Polyunsaturated fatty acids/% | 3.93±1.89 | 4.57±1.51 | 4.78±1.36 | 0.772 |
| 亚油酸Linoleic acid(C18∶2n6c)/% | 2.52±1.15 | 2.86±0.80 | 3.33±0.48 | 0.522 |
| γ-亚麻酸Gamma linolenic acid(C18∶3n6)/% | 0.09±0.04 | 0.10±0.01 | 0.07±0.00 | 0.563 |
| α-亚麻酸Alpha linolenic acid(C18∶3n3)/% | 0.31±0.10 | 0.31±0.11 | 0.42±0.25 | 0.525 |
| 二十碳二烯酸Eicosadienoic acid(C20∶2)/% | 0.05±0.00 | 0.05±0.00 | ND | 1.000 |
| 二十碳三烯酸Eicosatrienoic acid(C20∶3n6)/% | 0.25±0.19 | 0.18±0.09 | 0.26±0.22 | 0.744 |
| 花生四烯酸Arachidonic acid(C20∶4n6)/% | 1.84±1.33 | 1.16±0.69 | 2.08±1.79 | 0.555 |
| 多不饱和脂肪酸/饱和脂肪酸PUFA/SFA | 0.11±0.08 | 0.08±0.03 | 0.11±0.02 | 0.541 |
| 不饱和脂肪酸/饱和脂肪酸UFA/SFA | 0.96±0.25 | 0.89±0.10 | 1.03±0.22 | 0.584 |
| 单不饱和脂肪酸Monounsaturated fatty acids/% | 41.91±3.50 | 42.39±2.77 | 42.84±3.54 | 0.890 |
ND为未检出。下表同。 | |
ND was not detected. The same as below. |
2.4 饲粮中添加酵母培养物对牦牛肉中挥发性风味物质组成的影响
2.5 饲粮中添加酵母培养物对牦牛瘤胃微生物多样性的影响
2.5.1 操作分类单元(operational taxonomic unit,OTU)和Alpha多样性结果
表6 饲粮中添加酵母培养物对牦牛肌肉中挥发性风味物质组成的影响Table 6 Effects of dietary yeast culture on muscle volatile flavor compounds composition of yaks % |
| 项目 Items | 化合物名称 Compound names | 组别Groups | P值 P-value | ||
|---|---|---|---|---|---|
| 对照Control | 0.4%YC | 0.8%YC | |||
醛类 Aldehyde | 乙醛Acetaldehyde | 3.20±1.86 | 3.38±0.73 | 4.33±1.78 | 0.517 |
| 己醛Hexanal | 14.96±7.45 | 11.25±0.60 | 15.17±1.95 | 0.712 | |
| 庚醛Heptanal | 2.51±1.21 | 2.22±0.35 | 2.30±0.29 | 0.131 | |
| 辛醛Octanal | 1.82±0.70 | 1.36±0.17 | 2.16±0.46 | 0.112 | |
| (e)-2-辛烯醛(e)-2-octenal | ND | ND | 0.84±0.16 | ||
| 癸醛Decanal | ND | ND | 1.39±0.52 | ||
| 苯甲醛Benzaldehyde | 4.39±1.68 | 5.65±1.03 | 5.96±2.10 | 0.397 | |
| (e)-2-壬烯醛(e)-2-nonenal | 1.33±0.28 | ND | ND | ||
| 3-乙基苯甲醛3-ethyl-benzaldehyde | 0.77±0.01 | 0.86±0.23 | 0.94±0.09 | 0.490 | |
| 十四醛Tetradecanal | ND | 3.40±1.89 | 2.68±3.10 | 0.706 | |
| 十五醛Pentadecanal | ND | ND | 1.60±0.08 | ||
| 十六醛Hexadecanal | 4.58±5.04 | 6.56±2.00 | 4.41±1.96 | 0.695 | |
| 十八醛Octadecanal | ND | 2.39±0.96 | 1.42±0.87 | 0.314 | |
醇类 Alcohols | 乙醇Ethanol | 2.06±1.46 | 1.38±0.37 | 1.44±0.94 | 0.573 |
| 1-戊烯-3-醇1-pentene-3-ol | 0.70±0.03 | 0.91±0.14 | 0.61±0.16 | 0.128 | |
| 1-戊醇1-pentanol | 5.00±1.29a | 5.92±0.89a | 3.46±0.51b | 0.007 | |
| 1-己醇1-hexanol | 2.09±0.34 | 2.19±0.27 | 1.67±0.34 | 0.083 | |
| 1-辛烯-3-醇1-octen-3-ol | 17.87±6.17 | 16.65±3.22 | 14.40±3.50 | 0.563 | |
| 1-庚醇1-heptanol | 2.16±0.16b | 3.14±0.82a | 2.11±0.49b | 0.027 | |
| 2-乙基-1-己醇 2-ethyl-1-hexanol | 1.68±1.17 | 1.04±0.77 | 1.95±1.35 | 0.525 | |
| (e)-2-辛烯-1-醇 (e)-2-octen-1-ol | 2.29±1.19 | 2.32±0.55 | 1.85±0.53 | 0.107 | |
酮类 Ketone | 丙酮Acetone | 1.50±1.45 | 1.71±0.73 | 1.52±0.24 | 0.949 |
| 2-丁酮2-butanone | 0.70±0.30 | 0.81±0.13 | 0.96±0.15 | 0.271 | |
| 2-庚酮2-heptanone | 1.10±0.33 | 1.46±0.35 | 1.08±0.19 | 0.154 | |
| 3-羟基-2-丁酮Acetoin | 5.96±4.47 | 6.80±2.36 | 8.42±4.77 | 0.644 | |
酯类Esters | 乙酸乙烯酯 Acetic acid ethenyl ester | 1.58±0.68b | 2.74±0.97ab | 4.05±1.92a | 0.045 |
| N-己酸乙烯酯 N-caproic acid vinyl ester | 9.65±1.35 | 7.17±2.26 | 8.32±3.59 | 0.532 | |
| 酸类Acids | 4-羟基丁酸 4-hydroxy-butanoic acid | 0.72±0.31 | 0.86±0.45 | 1.38±0.57 | 0.278 |
| 烷烃类Alkanes | 戊基环丙烷 Pentyl-cyclopropane | 3.24±0.56ab | 4.02±0.68a | 2.41±0.61b | 0.012 |
含氮含硫及其他 杂环化合物 Nitrogen, sulfur and other heterocyclic compounds | 丙氨酰甘氨酸二肽Ala-Gly | 4.79±2.47 | 4.90±1.01 | 4.96±1.20 | 0.984 |
| 2-乙基呋喃2-ethyl-furan | 0.69±0.34b | 1.19±0.17a | 0.77±0.15b | 0.020 | |
| 2-戊基呋喃2-pentyl-furan | 2.34±0.85 | 2.71±0.56 | 1.92±0.42 | 0.208 | |
表7 OTU和Alpha多样性结果Table 7 Results of OTU and alpha diversity |
| 项目 Items | 组别Groups | P值 P-value | ||
|---|---|---|---|---|
| 对照Control | 0.4%YC | 0.8%YC | ||
| 操作分类单元OTU | 1 611.33±105.24b | 1 889.50±135.28a | 1 788.20±144.08b | 0.023 |
| Ace指数Ace index | 1 982.05±95.77b | 2 304.86±151.95a | 2 198.22±110.29a | 0.022 |
| Chao1指数Chao1 index | 2 042.58±120.33b | 2 383.33±166.65a | 2 259.54±81.12a | 0.018 |
| 覆盖率Coverage | 0.99±0.00 | 0.99±0.00 | 0.99±0.00 | 0.999 |
| Simpson指数Simpson index | 0.97±0.02 | 0.99±0.01 | 0.99±0.00 | 0.989 |
| Shannon指数Shannon index | 7.57±0.20b | 8.25±0.29a | 8.35±0.24a | 0.006 |
2.5.2 瘤胃微生物组成
2.6 饲粮中添加酵母培养物对牦牛瘤胃VFA含量的影响
表8 饲粮中添加酵母培养物对牦牛瘤胃VFA含量的影响Table 8 Effects of dietary yeast culture on rumen VFA contents of yaks |
| 项目 Items | 组别Groups | P值 P-value | ||
|---|---|---|---|---|
| 对照Control | 0.4%YC | 0.8%YC | ||
| 乙酸Acetic acid/% | 68.86±1.89b | 70.47±0.65ab | 70.98±0.86a | 0.033 |
| 丙酸Propionic acid/% | 18.14±1.16 | 17.10±0.37 | 17.93±0.71 | 0.309 |
| 丁酸Butyric acid/% | 6.56±1.30 | 7.48±2.21 | 7.41±0.64 | 0.672 |
| 戊酸Pentanoic acid/% | 0.73±0.20 | 0.70±0.10 | 0.76±0.01 | 0.797 |
| 异丁酸Isobutyric acid/% | 2.28±0.44 | 2.47±0.44 | 2.05±0.36 | 0.318 |
| 异戊酸Isopentanoic acid/% | 2.98±0.68 | 3.43±1.25 | 2.69±0.55 | 0.428 |
| 乙酸/丙酸Acetic acid/propionic acid | 3.81±0.31b | 4.33±0.26a | 4.11±0.18ab | 0.013 |
2.7 饲粮中添加酵母培养物对牦牛脂肪代谢相关基因mRNA表达的影响
图3 饲粮中添加酵母培养物对牦牛脂肪代谢相关基因mRNA表达的影响数据柱标相同小写字母表示差异不显著(P>0.05),不同小写字母表示差异显著(P<0.05)。 Fig.3 Effects of dietary yeast culture on mRNA expression of lipid metabolism related genes of yaks Value columns with the same small letter mean no significant difference (P>0.05), while with different small letters mean significant difference (P<0.05). |
