1 材料与方法
1.1 试验设计与动物分组
1.2 试验饲粮
表1 5~8周龄怀乡鸡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 for Huaixiang chickens at 5 to 8 weeks of age (air-dry basis)% |
| 原料Ingredients | 含量Content | 营养水平Nutrient levels | 含量Content | |
|---|---|---|---|---|
| 玉米Corn | 63.65 | 粗蛋白质Crude protein3) | 18.67 | |
| 麸皮Wheat bran | 0.60 | 代谢能Metabolizable energy/(MJ/kg)4) | 11.76 | |
| 豆粕Soybean meal | 30.95 | 蛋氨酸Methionine4) | 0.36 | |
| 贝壳粉Oyster shell powder | 0.82 | 赖氨酸Lysine4) | 0.98 | |
| 磷酸氢钙CaHPO4 | 1.62 | 钙Calcium3) | 0.75 | |
| 食盐NaCl | 0.30 | 总磷Total phosphorus3) | 0.66 | |
| DL-蛋氨酸DL-Met | 0.06 | 非植酸磷Non-phytate phosphorous4) | 0.40 | |
| 预混料Premix1) | 0.50 | |||
| 沸石粉Zeolite powder2) | 1.50 | |||
| 合计Total | 100.00 |
1)预混料为每千克饲粮提供 Premix supplied the following for per kilogram of the diet: VA 8 000 IU,VD3 1 250 IU,VE 10 IU,VK3 0.55 mg,VB1 2.25 mg,VB2 3.75 mg,VB6 2.25 mg,VB12 0.015 mg,D-泛酸 D-pantothenic acid calcium 10 mg,烟酸niacin 35 mg,叶酸folic acid 0.60 mg,生物素biotin 0.15 mg,钴维素, 0.015 mg,胆碱choline 1 000 mg; I (from potassium iodide) 0.35 mg,Se (from sodium selenite) 0.15 mg,Fe (from ferrous sulfate) 80 mg,Zn (from zinc sulfate) 60 mg,Cu (from copper sulfate) 8 mg,Mn (from manganese sulfate) 80 mg。 2)通过改变沸石粉及贝壳粉的用量调整饲粮钙水平。Dietary Ca level was adjusted by changing the quantities of zeolite powder and oyster shell powder. 3)实际测定值。Actual measured value. 4)根据《鸡饲养标准》(NY/T 33—2004)[2]计算得出。Calculated based on Feeding Standard of Chicken (NY/T 33—2004)[2]. |
1.3 饲养管理
1.4 血液采样与指标测定
1.5 骨骼采样与指标测定
1.6 胫骨碱性磷酸酶基因表达测定
表2 PCR引物信息Table 2 Information of primers for PCR |
| 基因 Genes | 登录号 Accession number | 引物序列 Primer sequences (5'—3') | 产物长度 Product length/bp |
|---|---|---|---|
| 碱性磷酸酶ALP | NM-205360.1 | F:GGAGAAGGACCCCGAATACTG R:TTGACGCCGCAGAGGTAAG | 300 |
| β-肌动蛋白 β-actin | NM-205518.1 | F:ACCTGAGCGCAAGTACTCTGTCT R:CATCGTACTCCTGCTTGCTGAT | 95 |
1.7 养分表观代谢率
1.8 统计分析
2 结果与分析
2.1 生长性能
表3 饲喂不同钙水平饲粮怀乡鸡的生长性能Table 3 Growth performance of Huaixiang chickens fed diets with different Ca levels |
| 项目 Items | 饲粮钙水平Dietary Ca level/% | P值 P-value | ||||
|---|---|---|---|---|---|---|
| 0.75 | 0.85 | 0.95 | 1.05 | 1.15 | ||
| 始重Initial weight/g | 378.91±4.82 | 381.25±4.25 | 385.22±8.02 | 382.00±5.43 | 381.93±8.26 | 0.735 |
| 末重Final weight/g | 904.88±25.71 | 904.25±20.34 | 910.25±21.74 | 893.63±22.17 | 896.13±48.99 | 0.642 |
| 平均日增重ADG/g | 20.36±0.51 | 20.90±0.16 | 20.77±0.18 | 20.01±0.21 | 20.00±0.27 | 0.311 |
| 平均日采食量ADFI/g | 66.37±0.49 | 65.91±0.47 | 66.34±0.51 | 67.70±0.24 | 67.61±0.27 | 0.823 |
| 耗料增重比F/G | 3.26±0.26 | 3.15±0.41 | 3.20±0.52 | 3.38±0.27 | 3.38±0.47 | 0.602 |
同行数据肩标不同字母表示差异显著(P<0.05),无字母或相同字母表示差异不显著(P>0.05)。下表同。 | |
Values in the same row with different letter superscripts mean significant difference (P<0.05), while with no letter or the same letter superscripts mean no significant difference (P>0.05). The same as below. |
2.2 胫骨特性
表4 饲喂不同钙水平饲粮怀乡鸡的胫骨特性Table 4 Tibia characteristics of Huaixiang chickens fed diets with different Ca levels |
| 项目 Items | 饲粮钙水平Dietary Ca level/% | P值P-value | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 0.75 | 0.85 | 0.95 | 1.05 | 1.15 | 钙水平 Ca level | 线性 Linear | 二次曲线 Quadratic | ||
| 胫骨折断力 Tibia broken strength/N | 81.25±9.60 | 77.25±2.81 | 79.26±13.80 | 86.75±17.96 | 86.75±11.42 | 0.971 | — | — | |
| 胫骨灰分含量 Tibia ash content/% | 40.46±2.40 | 40.56±2.49 | 42.63±2.56 | 41.20±0.85 | 44.42±1.25 | 0.621 | — | — | |
| 胫骨灰分钙含量 Ca content in tibia ash/% | 34.59±0.66b | 36.08±0.53b | 36.13±1.85b | 40.09±0.66a | 35.76±0.59b | 0.015 | 0.062 | 0.049 | |
| 胫骨灰分磷含量 P content in tibia ash/% | 14.35±1.66 | 14.74±0.76 | 14.93±0.74 | 15.97±0.99 | 13.80±1.13 | 0.720 | — | — | |
| 胫骨灰分钙磷比 Ratio of Ca∶P in tibia ash | 2.49±0.23 | 2.47±0.14 | 2.42±0.04 | 2.54±0.15 | 2.66±0.27 | 0.915 | — | — | |
2.3 趾骨特性
表5 饲喂不同钙水平饲粮怀乡鸡的趾骨特性Table 5 Toe characteristics of Huaixiang chickens fed diets with different Ca levels |
| 项目 Items | 饲粮钙水平Dietary Ca level/% | P值P-value | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 0.75 | 0.85 | 0.95 | 1.05 | 1.15 | 钙水平 Ca level | 线性 Linear | 二次曲线 Quadratic | ||
| 趾骨灰分含量 Toe ash content/% | 0.39±0.01 | 0.38±0.02 | 0.40±0.02 | 0.43±0.05 | 0.42±0.01 | 0.810 | — | — | |
| 趾骨灰分钙含量 Ca content in toe ash/% | 37.95±0.27a | 38.52±0.21a | 37.98±0.26a | 37.09±0.35ab | 36.53±0.21b | 0.001 | 0.035 | 0.079 | |
| 趾骨灰分磷含量 P content in toe ash/% | 15.55±1.35 | 16.85±1.33 | 18.38±1.83 | 19.80±2.47 | 17.32±0.77 | 0.602 | — | — | |
| 趾骨灰分钙磷比 Ratio of Ca∶P in toe ash | 2.51±0.20 | 2.34±0.21 | 2.21±0.61 | 1.99±0.44 | 2.18±0.20 | 0.791 | — | — | |
2.4 血清钙磷代谢指标及胫骨碱性磷酸酶mRNA相对表达量
表6 饲喂不同钙水平饲粮怀乡鸡的血清钙磷代谢指标及胫骨碱性磷酸酶mRNA相对表达量Table 6 Serum Ca and P metabolic indices and tibia ALP mRNA relative expression level of Huaixiang chickens fed diets with different Ca levels |
| 项目 Items | 饲粮钙水平Dietary Ca level/% | P值P-value | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.75 | 0.85 | 0.95 | 1.05 | 1.15 | 钙水平 Ca level | 线性 Linear | 二次曲线 Quadratic | ||||||||||||
| 血清钙含量 Serum Ca content/(mg/dL) | 12.55±0.37b | 13.10±0.44a | 13.31±0.35a | 12.90±0.20ab | 12.87±0.21ab | 0.049 | 0.405 | 0.011 | |||||||||||
| 血清磷含量 Serum P content/ (mg/dL) | 4.11±0.11 | 4.19±0.26 | 4.20±0.40 | 4.10±0.12 | 4.22±0.20 | 0.932 | — | — | |||||||||||
| 血清钙磷比 Serum ratio of Ca∶P | 3.06±0.12 | 3.13±0.16 | 3.19±0.22 | 3.15±0.47 | 3.06±0.17 | 0.698 | — | — | |||||||||||
| 血清碱性磷 酸酶活性 Serum ALP activity/(U/L) | 24.24±0.33 | 24.28±0.50 | 24.17±0.88 | 24.35±0.87 | 23.62±0.45 | 0.526 | — | — | |||||||||||
| 项目 Items | 饲粮钙水平Dietary Ca level/% | P值P-value | |||||||||||||||||
| 0.75 | 0.85 | 0.95 | 1.05 | 1.15 | 钙水平 Ca level | 线性 Linear | 二次曲线 Quadratic | ||||||||||||
| 胫骨碱性磷酸 酶mRNA相 对表达量 Tibia ALP mRNA relative expression level | 1.32±0.05a | 1.21±0.04ab | 1.16±0.03b | 1.15±0.03b | 1.16±0.03b | 0.015 | 0.071 | 0.008 | |||||||||||
2.5 养分表观代谢率
表7 饲喂不同钙水平饲粮怀乡鸡的养分表观代谢率Table 7 Apparent metabolic rates of nutrients of Huaixiang chickens fed diets with different Ca levels% |
| 项目 Items | 饲粮钙水平Dietary Ca level/% | P值P-value | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 0.75 | 0.85 | 0.95 | 1.05 | 1.15 | 钙水平 Ca level | 线性 Linear | 二次曲线 Quadratic | ||
| 干物质DM | 72.92±1.47 | 74.58±0.90 | 76.01±2.48 | 75.64±0.81 | 75.42±1.59 | 0.675 | — | — | |
| 粗灰分Ash | 12.98±0.92d | 16.48±0.61c | 21.26±0.64a | 18.38±0.95abc | 16.77±1.52bc | 0.001 | 0.394 | <0.001 | |
| 钙Ca | 35.18±0.29c | 36.57±0.47bc | 39.07±0.71a | 37.25±0.55b | 35.73±0.63bc | 0.001 | 0.765 | <0.001 | |
| 磷P | 53.93±6.17 | 61.26±1.38 | 63.62±3.69 | 62.88±1.23 | 62.69±2.42 | 0.315 | — | — | |
2.6 敏感指标拟合方程确定钙需要量
表8 敏感指标拟合方程确定钙需要量Table 8 Fitted equations of sensitive indices to acquire Ca requirement for Huaixiang chickens |
| 项目 Items | 模型 Modal | 拟合方程 Fitted equation | 拟合度 R2 | 钙需要量 Ca requirement/% |
|---|---|---|---|---|
| 胫骨灰分钙含量Ca content in tibia ash | 二次曲线 | y=-56.12x2+109.80x-18.10 | 0.48 | 0.98 |
| 趾骨灰分钙含量Ca content in toe ash | 二次曲线 | y=-18.64x2+ 31.15x+ 25.22 | 0.92 | 0.84 |
| 血清钙含量Serum Ca content | 二次曲线 | y=-12.71x2+24.60x+13.31 | 0.77 | 0.97 |
| 胫骨碱性磷酸酶mRNA相对表达量 Tibia ALP mRNA relative expression level | 线性折线 | y=1.15-1.16×(0.90-x) | 0.99 | 0.90 |
| 粗灰分表观代谢率 Apparent metabolic rate of ash | 二次曲线 | y=-128.17x2+251.00x-104.93 | 0.87 | 0.98 |
| 钙表观代谢率 Apparent metabolic rate of Ca | 二次曲线 | y=-72.00x2+139.71x-28.99 | 0.84 | 0.97 |
