不同理想蛋白水平对早期断奶仔猪生产性能及蛋白质利用的影响

Effect of Different Dietary Ideal Protein Level on Performance and Protein Utilization of Early-weaned Piglet

采用单因子试验设计,研究不同理想蛋白(IP)水平对早期断奶仔猪生产性能及蛋白质利用的影响。80头(6·5±0·5)kg,(21±1)d的DLY(Duroc×Landrace×Yorkshire)断奶仔猪随机分配到5个处理(4重复/处理,4头/重复),分别接受14%、17%、20%、23%、26%IP水平的饲粮处理,5种饲粮中TDLys∶TDSAA∶TDThr∶TDTrp相同,均为100∶57∶62∶18·5,其他真可消化必须氨基酸与真可消化赖氨酸分别达到或超过NRC(98)推荐数值。TDLys占粗蛋白比例均为5%。结果表明,日增重和饲料利用率与IP水平之间呈现出极显著的二次曲线关系(P<0·01),IP水平分别为20·2%和21·3%时可获得最大日增重和最大饲料利用率。氮表观消化率与IP水平呈二次曲线变化规律(P<0·05),IP水平为18·07%时氮表观消化率最高。氮表观代谢率及蛋白质表观生物学价值(ABV)IP水平增加而线性下降(P<0·01)。尿氮排泄与IP水平呈二次曲线关系,总氮排泄随IP水平线性增加(P<0·01)。综合考虑生产性能、蛋白质利用及氮排泄,早期断奶仔猪适宜IP水平为21·3%。

This single factorial designed experiment was conducted totein utilizationo investigate the effect of varying dietary ideal protein （IP） level on performance and pr of early-weaned piglets. Eighty （6.5 ± 0.5） kg, （21 ± 1 ） d DLY weaning piglets were randomly allocated into five treatments （4 replicates per treatment, 4 piglets per replicate） and fed with five graded levels of IP diets respectively （14%, 17%, 20%, 23%, 26%）. The ratios of TDLysT：DSAA：TDThr：TDTrp in five diets were kept the same （ 100 ： 57 ： 62 ： 18）, the ratios of other TDEAA to TDLys met or exceeded the recommended values in NRC（98）, the proportion of TDLys to CP was 5% in each diets. The experimental results demonstrate that quadratic curve relationships occur between ADG, feeding efficiency and dietary IP levels （P〈0.01）. ADG and feeding efficiency are the highest in 20.2% and 22.3% IP diets respectively. Apparent nitrogen digestibility exhibits quadratic curve relationship with dietary IP levels （P〈0.05） and the highest N digestibility occurs in 18.07% IP diet. Apparent nitrogen metabolism and ABV decrease linearly with the elevation of dietary IP levels （P 〈 0.01 ）. Urine N excretion changes with IP level quadratically, while total N excretion increases with dietary IP levels linearly （P 〈0.01）. Based on the comprehensive consideration of performance, protein utilization and nitrogen excretion, the optimal IP level for early-weaned piglets is 21.3%.