【作者】 高天增；

【导师】 李德发；

【作者基本信息】 中国农业大学 ， 动物营养与饲料科学， 2004， 博士

【摘要】 本文应用三个饲养试验和二个消化代谢试验，系统研究了日粮赖氨酸与粗蛋白质比例对不同阶段猪的生产性能及氮利用率的影响。 首先，选30头妊娠后期和60头分娩后的母猪，随机各均分为5个处理组。妊娠母猪五个处理日粮赖氨酸与粗蛋白质比例分别为(g/100 g)：3.5、4.0、4.5、5.0和5.5。结果表明：1、日粮赖氨酸与粗蛋白质比例从3.5提高到4.5时，母猪体增重、背膘厚和仔猪窝重呈线性增加(P＜0.05)；2、其比例从3.5提高到5.5，SUN的浓度呈线性或二次曲线下降(P＜0.05)，而血清游离赖氨酸的浓度呈线性或二次曲线上升(P＜0.01)；妊娠母猪适宜的赖氨酸与粗蛋白质比例(g/100 g)为4.0～4.5。哺乳母猪五个处理日粮赖氨酸与粗蛋白质比例分别为(g/100 g)：4.8、5.3、5.8、6.3和6.8。结果表明：1、随着哺乳母猪日粮赖氨酸与粗蛋白质比例的增加，母猪体重损失与背膘损失呈二次曲线下降(P＜0.05)，母猪体重损失先于背膘的损失；2、提高其比例，母猪的产奶量呈线性或二次曲线增加(P＜0.01)，但对第21 d天的乳成份无显著影响(P＞0.05)，哺乳期窝日增重呈线性或二次曲线增加(P＜0.05)；3、母猪产后14 d和21 d随着其比例增加，SUN的浓度呈现线性或二次曲线下降(P＜0.01)，而血清游离赖氨酸的浓度则呈现线性或二次曲线升高(P＜0.05)；对哺乳母猪适宜的赖氨酸与粗蛋白质比例为6.3g/100g。 其次，选90头体重为7.84±1.0 kg的仔猪，均分为五组，日粮赖氨酸与粗蛋白质比例分别是(g/100 g)5.1、5.6、6.1、6.6和7.1。结果表明：当日粮粗蛋白质水平为20％时，日粮赖氨酸与粗蛋白质比例不影响仔猪日增重和日采食量，但提高其比例，试验全期饲料转化效率得到改善(P＜0.05)；其比例为6.1(赖氨酸水平为1.2％)时，SUN的浓度最低(P＜0.05)；继续提高其比例至6.6和6.7(赖氨酸的水平至1.3％和1.4％)，则血清游离氨基酸的浓度显著升高(P＜0.05)；因此，8～20kg仔猪适宜的日粮赖氨酸与粗蛋白质比例为6.1g/100 g。 最后，分别选用5头体重为26±2.4kg和60.5±2.9kg三元杂交猪，采用5×5拉丁方设计，进行代谢试验，试验期35d。试验四中，生长猪日粮赖氨酸与粗蛋白质比例分别为(g／100g)4.7、5.2、5.7、6.2和6.7。结果表明，随着赖氨酸与粗蛋白质比例升高，生长猪氮的沉积显著下降(P＜0.01)，获得最大的氮沉积的比例为5.2；随着其比例从4.7升至6.7，总氮利用率线性提高，对20～60kg猪其适宜赖氨酸与粗蛋白质比例为5.2g/100g。试验五中，育肥猪五个处理组日粮赖氨酸与粗蛋白质比例(g/100g)分别为4.5、5.0、5.5、6.0和6.5，赖氨酸水平设为0.8％。结果表明：1、日粮赖氨酸与粗蛋白质比例对粪氮排泄量无显著影响(P＞0.05)；随着赖氨酸与粗蛋白质比例提高，尿氮排泄量显著降低(P＜0.05)；2、氮的沉积和氮的利用效率在比例为5.0g/100 g时最大(P＜0.05)，对60～90 kg猪适宜赖氨酸与粗蛋白质比例为5.2g/100 g。更多还原

【Abstract】 Three feeding trials and two metabolic trials were conducted to investigate the effects of lysine to protein ratio in practical swine diets on performance and the efficiency of nitrogen utilization in sow, piglet and growing-finishing pig.In trial 1 and 2, 30 later pregnant sows and 60 lactating sows were selected and allotted to five treatments, respectively, based on the parities and body weight. In pregnant sow trial, five lysine to protein rations was 3.5,4.0,4.5, 5.0 and 5.5 g/100 g, respectively. Each treatment had six replicates. The results showed that the body weight and the back-fat thickness of sows were increasing linearly with lysine to protein ratios increased from 3.5 to 4.5 (P < 0.05); with the ratios of lysine to protein increased from 3.5 to 5.5, the serum urea nitrogen significantly decreased linearly or quadraticly (P < 0.05), but serum free amino acid increased linearly or quadratic (P < 0.01); the optimum lysine to protein ration was 4.0-4.5 g/100 g for later pregnant sows. In lactating sow trial, five treatments of lysine to protein rations was 4.8, 5.3, 5.8, 6.3 and 6.8 g /100 g, respectively. Each treatment had twelve replicates (each sow as a replicate). The results showed that the body weight loss and back-fat thickness loss of lactating sows decreased quadraticly with the increasing of lysine to protein ratio (P < 0.05). The body weight loss occurred earlier than that of back-fat loss. The 20th day’s milk yield and litter body weigh gain increased linearly (P < 0.01) or quadraticly (P < 0.05) with the increased of lysine to protein ratios, but the 21th day milk compositions had no significant change (P > 0.05); with the ratios of lysine to protein increased, the serum urea nitrogen on 14th and 21th day decreased linearly or quadraticly (P < 0.01) while as the serum free amino acid has a linearly and quadraticly (P < 0.05), which showed to improve the efficiency of nitrogen utilization and decrease the nitrogen excretion.In trial 3, 90 piglets with 7.8 + 1.0 kg initial body weight were selected to study different lysine to protein ratios on performance and serum parameters of weaned pigs. Piglets were equally allotted to one of five treatments according to initial body weight, litters and sex. The protein concentration in the basal diets was 20% and the ratios used were 5.1, 5.6, 6.1, 6.6 and 7.1g/100 g CP, respectively. The results showed that feed efficiency was significantly improved (P < 0.05) by the increasing of dietary lysine to crude protein ratio. Serum urea nitrogen concentration decreased linearly (P < 0.01) and serum free lysine content increased linearly (P < 0.01) as the lysine to protein ratio in diets increased from 5.1 to 7.1 g/100g. The best of the ratio was 6.1 g lysine/100 g crude protein for piglets from 8 to 20 kg.In trial 4 and 5, two. metabolic trials were arranged to study the effect of the lysine to protein ratios on efficiency of nitrogen utilization in growing-finishing pigs. Five barrows with initial body weights of 26.0+2.4 kg and 60.5+2.9 kg. were use in each of the two trials, respectively. The pigs were allotted to five dietary treatments according to 5x5 Latin square design. In trial 4, the ratios of lysine to protein were 4.7, 5.2, 5.7, 6.2 and 6.7 and the ratios were 4.5, 5.0, 5.5, 6.0 and 6.5 g lysine/100 g CP in trial 5, respectively. The results showed that nitrogen retention in growing pigs decreased linearly (P < 0.01) with the dietary lysine to protein ratios increased inboth of the two trials. The maximum nitrogen retention was observed when the ratio of lysine to protein was 5.2 g/100 g and 5.0 g/100 g in trial 4 and 5. respectively. In trial 4, apparent biological value and gross nitrogen efficiency increased linearly (P < 0.01 and P < 0.05, respectively) with the lysine to protein ratios increased from 5.2 to 6.7 g lysine/100 g CP. In trial 5, the ratios of lysine to protein could significantly affect the urinary nitrogen concentration (P < 0.05); the ratio of 5.0 could decrease the urinary nitrogen concentration and increase更多还原