1 材料与方法
1.1 试验材料
1.2 试验分组设计
1.3 试验饲粮
表1 饲粮组成及营养水平(风干基础)Table 1 Composition and nutrient levels of diets (air-dry basis)% |
| 项目 Items | 饲粮异亮氨酸水平Dietary isoleucine level/% | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.46 | 0.54 | 0.62 | 0.70 | 0.78 | 0.86 | ||||||||
| 原料Ingredients | |||||||||||||
| 玉米Corn | 68.54 | 68.46 | 68.38 | 68.30 | 68.22 | 68.14 | |||||||
| 豆粕Soybean meal | 12.00 | 12.00 | 12.00 | 12.00 | 12.00 | 12.00 | |||||||
| 花生粕Peanut meal | 6.00 | 6.00 | 6.00 | 6.00 | 6.00 | 6.00 | |||||||
| 玉米蛋白粉Corn gluten meal | 5.00 | 5.00 | 5.00 | 5.00 | 5.00 | 5.00 | |||||||
| 小麦Wheat | 4.50 | 4.50 | 4.50 | 4.50 | 4.50 | 4.50 | |||||||
| 石粉Limestone | 1.25 | 1.25 | 1.25 | 1.25 | 1.25 | 1.25 | |||||||
| 磷酸氢钙CaHPO4 | 0.72 | 0.72 | 0.72 | 0.72 | 0.72 | 0.72 | |||||||
| 食盐NaCl | 0.30 | 0.30 | 0.30 | 0.30 | 0.30 | 0.30 | |||||||
| L-赖氨酸盐酸盐L-lysine·HCl (98.5%) | 0.42 | 0.42 | 0.42 | 0.42 | 0.42 | 0.42 | |||||||
| DL-蛋氨酸DL-methionine (99%) | 0.10 | 0.10 | 0.10 | 0.10 | 0.10 | 0.10 | |||||||
| L-苏氨酸L-threonine (98.5%) | 0.11 | 0.11 | 0.11 | 0.11 | 0.11 | 0.11 | |||||||
| L-缬氨酸L-valine (98%) | 0.06 | 0.06 | 0.06 | 0.06 | 0.06 | 0.06 | |||||||
| L-异亮氨酸L-isoleucine | 0.08 | 0.16 | 0.24 | 0.32 | 0.40 | ||||||||
| 预混料Premix1) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | |||||||
| 合计Total | 100.00 | 100.00 | 100.00 | 100.00 | 100.00 | 100.00 | |||||||
| 营养水平Nutrient levels2) | |||||||||||||
| 氮校正表观代谢能AMEn/(MJ/kg) | 12.60 | 12.60 | 12.60 | 12.60 | 12.60 | 12.60 | |||||||
| 粗蛋白质CP | 15.99 | 16.01 | 15.91 | 15.91 | 15.64 | 16.04 | |||||||
| 钙Ca | 0.70 | 0.70 | 0.69 | 0.69 | 0.69 | 0.70 | |||||||
| 可利用磷AP | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | |||||||
| 赖氨酸Lys | 0.81 | 0.84 | 0.82 | 0.80 | 0.83 | 0.82 | |||||||
| 蛋氨酸Met | 0.36 | 0.36 | 0.36 | 0.36 | 0.36 | 0.36 | |||||||
| 蛋氨酸+胱氨酸Met+Cys | 0.65 | 0.65 | 0.65 | 0.65 | 0.65 | 0.65 | |||||||
| 苏氨酸Thr | 0.65 | 0.66 | 0.62 | 0.62 | 0.64 | 0.63 | |||||||
| 色氨酸Trp | 0.16 | 0.16 | 0.16 | 0.16 | 0.16 | 0.16 | |||||||
| 异亮氨酸Ile | 0.44 | 0.56 | 0.61 | 0.68 | 0.79 | 0.87 | |||||||
1)预混料为每千克饲粮提供 The premix provided the following per kg of diets:VA 6 000 IU,VB1 2.1 mg,VB2 3 mg,烟酸 nicotinic acid 15 mg,VB6 3.5 mg,VB12 0.01 mg,VD3 500 IU,VE 20 IU,VK3 0.5 mg,生物素 biotin 0.15 mg,泛酸 pantothenic acid 10 mg,叶酸 folic acid 0.55 mg,氯化胆碱 choline chloride 1 000 mg,Fe 80 mg,Cu 7 mg,Mn 60 mg,Zn 65 mg,I 0.6 mg,Se 0.15 mg。 2)营养水平中粗蛋白质(GB/T 6432—2018)、钙(GB/T 6436—2018)以及赖氨酸、苏氨酸和异亮氨酸(GB/T 18246—2019)为实测值,其余均根据《中国饲料成分及营养价值表(2022年第33版)》中各原料营养成分进行计算。In the nutrient levels, CP (GB/T 6432—2018), Ca (GB/T 6436—2018) as well as Lys, Thr and Ile (GB/T 18246—2019) were measured values, while the rest were calculated according to the values of each raw material in the Tables of Feed Composition and Nutritive Values in China (thirty-third edition, 2022). |
1.4 饲养管理
1.5 样品采集
1.6 指标测定及方法
1.6.1 生长性能
1.6.2 血浆生化指标
1.6.3 胴体性状
1.6.4 肉品质
1.6.5 空肠氨基酸转运和肝脏脂质代谢相关基因表达量
1.7 数据统计与分析
2 结果
2.1 饲粮异亮氨酸水平对61~80日龄黄羽肉鸡生长性能的影响
表2 饲粮异亮氨酸水平对61~80日龄黄羽肉鸡生长性能的影响Table 2 Effects of dietary isoleucine level on growth performance of yellow-feathered chickens aged 61 to 80 days |
| 项目 Items | 饲粮异亮氨酸水平Dietary isoleucine level/% | SEM | P值P-value | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 0.46 | 0.54 | 0.62 | 0.70 | 0.78 | 0.86 | 方差分析 ANOVA | 线性 Linear | 二次 Quadratic | ||
| 初始体重 Initial BW/g | 1 581.67 | 1 581.67 | 1 581.67 | 1 581.67 | 1 581.67 | 1 581.67 | <0.001 | |||
| 终末体重 Final BW/g | 2 138.76 | 2 148.67 | 2 152.67 | 2 158.33 | 2 147.43 | 2 131.75 | 15.483 | 0.877 | ||
| 平均日增重 ADG/g | 27.86 | 28.35 | 28.55 | 28.83 | 28.29 | 27.71 | 0.709 | 0.879 | ||
| 平均日采食量 ADFI/g | 110.35 | 109.95 | 109.00 | 106.06 | 106.05 | 106.20 | 1.794 | 0.083 | ||
| 料重比F/G | 3.97a | 3.90ab | 3.83ab | 3.70b | 3.78ab | 3.80ab | 0.102 | 0.041 | 0.037 | 0.013 |
| 死亡率Mortality/% | 0.56 | 0.00 | 1.11 | 0.00 | 1.11 | 1.67 | 0.300 | 0.090 | ||
2.2 饲粮异亮氨酸水平对80日龄黄羽肉鸡血浆生化指标的影响
表3 饲粮异亮氨酸水平对80日龄黄羽肉鸡血浆生化指标的影响Table 3 Effects of dietary isoleucine level on plasma biochemical indices of 80-day-old yellow-feathered chickens |
| 项目 Items | 饲粮异亮氨酸水平Dietary isoleucine level/% | SEM | P值P-value | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 0.46 | 0.54 | 0.62 | 0.70 | 0.78 | 0.86 | 方差分析 ANOVA | 线性 Linear | 二次 Quadratic | ||
| 尿酸UA/(mg/L) | 90.79 | 80.17 | 85.78 | 91.56 | 81.70 | 77.63 | 2.993 | 0.718 | ||
| 葡萄糖 GLU/(mmol/L) | 12.47c | 13.80a | 12.59c | 13.57ab | 13.23abc | 12.78bc | 0.135 | 0.008 | 0.696 | 0.367 |
| 甘油三酯 TG/(mmol/L) | 0.78ab | 0.79ab | 0.68b | 0.65b | 1.05a | 0.53b | 0.048 | 0.026 | 0.735 | 0.055 |
| 总胆固醇 TC/(mmol/L) | 3.75 | 4.24 | 3.92 | 3.54 | 3.73 | 3.04 | 0.132 | 0.148 | ||
| 谷丙转氨酶 ALT/(U/L) | 2.57b | 4.33ab | 5.89ab | 7.33a | 8.72a | 7.43a | 0.646 | 0.047 | 0.002 | 0.008 |
| 谷草转氨酶 AST/(U/L) | 32.13 | 34.74 | 37.19 | 36.14 | 37.26 | 38.03 | 0.892 | 0.442 | ||
| 肌酸激酶 CK/(U/mL) | 1.56a | 1.44ab | 1.56a | 1.11b | 1.20b | 1.20b | 0.051 | 0.012 | 0.003 | 0.012 |
| 乳酸脱氢酶 LDH/(U/L) | 4 227.87 | 4 067.80 | 4 082.86 | 3 818.27 | 3 940.68 | 3 920.90 | 66.552 | 0.630 | ||
2.3 饲粮异亮氨酸水平对80日龄黄羽肉鸡胴体性状的影响
表4 饲粮异亮氨酸水平对80日龄黄羽肉鸡胴体性状的影响Table 4 Effects of dietary isoleucine level on carcass traits of 80-day-old yellow-feathered chickens% |
| 项目 Items | 饲粮异亮氨酸水平Dietary isoleucine level/% | SEM | P值P-value | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 0.46 | 0.54 | 0.62 | 0.70 | 0.78 | 0.86 | 方差分析 ANOVA | 线性 Linear | 二次 Quadratic | ||
| 屠宰率Dressing rate | 89.85 | 89.69 | 90.14 | 89.67 | 89.98 | 89.48 | 0.120 | 0.665 | ||
| 半净膛率 Half-eviscerated rate | 83.43 | 82.99 | 83.12 | 82.99 | 83.04 | 83.17 | 0.153 | 0.972 | ||
| 全净膛率 Eviscerated rate | 70.27 | 70.18 | 69.05 | 69.38 | 69.37 | 69.29 | 0.212 | 0.425 | ||
| 胸肌率 Breast muscle rate | 18.36 | 17.93 | 18.64 | 18.22 | 18.08 | 18.25 | 0.423 | 0.668 | ||
| 腿肌率 Leg muscle rate | 20.93 | 20.53 | 20.51 | 20.04 | 20.19 | 20.63 | 0.187 | 0.825 | ||
| 腹脂率 Abdominal fat rate | 5.60a | 5.51ab | 5.54ab | 4.82ab | 4.55b | 4.32b | 0.182 | 0.030 | 0.029 | 0.067 |
2.4 饲粮异亮氨酸水平对80日龄黄羽肉鸡肉品质的影响
表5 饲粮异亮氨酸水平对80日龄黄羽肉鸡肉品质的影响Table 5 Effects of dietary isoleucine level on meat quality of 80-day-old yellow-feathered chickens |
| 项目 Items | 饲粮异亮氨酸水平Dietary isoleucine level/% | SEM | P值P-value | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.46 | 0.54 | 0.62 | 0.70 | 0.78 | 0.86 | 方差分析 ANOVA | 线性 Linear | 二次 Quadratic | ||||
肉色 Meat color | 45 min | 亮度 L* | 51.93 | 51.82 | 52.41 | 52.71 | 51.96 | 51.97 | 0.418 | 0.992 | ||
| 红度 a* | 10.86 | 10.49 | 9.51 | 9.83 | 10.43 | 9.67 | 0.157 | 0.087 | ||||
| 黄度 b* | 10.87 | 11.26 | 12.20 | 11.99 | 12.29 | 12.48 | 0.286 | 0.539 | ||||
24 h | 亮度 L* | 64.55a | 63.17ab | 62.64ab | 60.87b | 60.73b | 63.07ab | 0.395 | 0.021 | 0.828 | 0.357 | |
| 红度 a* | 7.93b | 8.56b | 8.77ab | 9.81a | 8.90ab | 8.29b | 0.166 | 0.028 | 0.015 | 0.031 | ||
| 黄度 b* | 19.80 | 21.08 | 21.76 | 20.76 | 20.69 | 21.85 | 0.252 | 0.168 | ||||
pH | 45 min | 5.65 | 5.67 | 5.74 | 5.71 | 5.67 | 5.69 | 0.017 | 0.882 | |||
| 24 h | 5.58 | 5.51 | 5.28 | 5.53 | 5.50 | 5.50 | 0.027 | 0.061 | ||||
| 滴水损失 Drip loss/% | 2.94 | 2.56 | 2.79 | 2.49 | 2.54 | 2.90 | 0.074 | 0.263 | ||||
| 剪切力 Shear force/N | 35.47a | 33.80ab | 29.69abc | 27.30c | 28.96c | 26.19c | 1.128 | 0.034 | 0.001 | 0.369 | ||
2.5 饲粮异亮氨酸水平对80日龄黄羽肉鸡空肠氨基酸转运相关基因表达量的影响
表6 饲粮异亮氨酸水平对80日龄黄羽肉鸡空肠氨基酸转运相关基因表达量的影响Table 6 Effects of dietary isoleucine level on jejunal amino acid transport related gene expression of 80-day-old yellow-feathered chickens |
| 项目 Items | 饲粮异亮氨酸水平Dietary isoleucine level/% | SEM | P值P-value | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 0.46 | 0.54 | 0.62 | 0.70 | 0.78 | 0.86 | 方差分析 ANOVA | 线性 Linear | 二次 Quadratic | ||
| 小肽转运载体1 PepT1 | 1.02 | 1.14 | 1.17 | 0.98 | 0.86 | 0.79 | 0.075 | 0.924 | ||
| B0系统中性氨基 酸转运载体 B0AT | 1.11 | 1.12 | 1.15 | 0.93 | 1.03 | 1.07 | 0.086 | 0.751 | ||
| 兴奋性氨基酸 转运载体3 EAAT3 | 1.06a | 0.86ab | 0.70abc | 0.57bc | 0.71abc | 0.50c | 0.035 | 0.027 | 0.001 | 0.004 |
| 碱性氨基酸 转运载体1 CAT1 | 1.02 | 1.01 | 1.26 | 1.06 | 1.18 | 0.96 | 0.064 | 0.921 | ||
2.6 饲粮异亮氨酸水平对80日龄黄羽肉鸡肝脏脂质代谢相关基因表达量的影响
表7 饲粮异亮氨酸水平对80日龄黄羽肉鸡肝脏脂质代谢相关基因表达量的影响Table 7 Effects of dietary isoleucine level on liver fat metabolism related gene expression of 80-day-old yellow-feathered chickens |
| 项目 Items | 饲粮异亮氨酸水平Dietary isoleucine level/% | SEM | P值P-value | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.46 | 0.54 | 0.62 | 0.70 | 0.78 | 0.86 | 方差分析 ANOVA | 线性 Linear | 二次 Quadratic | |||||||||||||
| 过氧化物酶体增殖 物激活受体γ PPARγ | 1.22 | 1.16 | 1.14 | 1.10 | 1.06 | 1.09 | 0.066 | 0.806 | |||||||||||||
| 3-羟基-3-甲基 戊二酰辅酶A 还原酶 HMGCR | 1.26a | 1.22a | 1.13ab | 0.74b | 0.83b | 0.80b | 0.058 | 0.034 | 0.081 | 0.060 | |||||||||||
| 沉默信息调节因子1 SIRT1 | 1.04b | 0.96b | 1.18ab | 1.62a | 1.41a | 1.28ab | 0.087 | 0.023 | 0.098 | 0.146 | |||||||||||
| 肉碱棕榈酰转移酶1 CPT1 | 1.12 | 1.17 | 1.26 | 1.21 | 1.10 | 1.16 | 0.053 | 0.520 | |||||||||||||
2.7 回归模型估测饲粮异亮氨酸适宜水平
表8 回归模型估测饲粮异亮氨酸适宜水平Table 8 Estimation of optimal level of dietary isoleucine based on regression model |
| 项目 Items | 回归方程 Regression equations | P值 P-value | 决定系数 R2 | 饲粮异亮氨酸适宜水平 Optimal dietary isoleucine level/% |
|---|---|---|---|---|
| 料重比F/G | y=2.930x2-4.346x+5.367 | 0.013 | 0.886 | 0.74 |
| 腹脂率 Abdominal fat rate/% | y=-2.297x2+3.931x+6.108 | 0.067 | 0.724 | 0.86 |
| 24 h亮度L* at 24 h | y=53.902x2-77.324x+88.009 | 0.357 | 0.321 | 0.72 |
| 24 h红度a* at 24 h | y=-30.554x2+41.833x-5.030 | 0.031 | 0.864 | 0.68 |
| 剪切力Shear force/N | y=45.553x2-82.245x+26.893 | 0.369 | 0.296 | 0.90 |

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