【作者】 沈杰；

【导师】 吴德； 方正峰；

【作者基本信息】 四川农业大学 ， 动物营养与饲料科学， 2009， 硕士

【摘要】 苏氨酸和色氨酸作为生长猪日粮的限制性氨基酸,分别在促进免疫球蛋白合成和提高动物采食量方面发挥重要作用。免疫应激条件下动物采食量的降低和富含苏氨酸的免疫球蛋白的大量合成很容易引起日粮苏氨酸和色氨酸的缺乏和体蛋白的动员,进而降低动物的生产性能。因此,本研究以接种猪繁殖与呼吸综合征（PRRS）疫苗的生长猪为对象,以生产性能、体液免疫参数,血液生化指标为评价指标,探讨日粮补充苏氨酸和色氨酸对接种PRRS疫苗生长猪生产性能的影响及其可能的机制。试验选用26头日龄和体重相近的去势生长猪,按照2×2因子设计,设两个日粮组（对照组[CON]和添加苏、色氨酸组[TTR]）和两个接种处理组（PBS和PRRS疫苗）,当平均体重为29.0±2.9 kg时随机平均分到CON和TTR日粮组中,正式饲喂3周后,每组选择9头接种PRRS疫苗,余下的4头接种同剂量的PBS溶液,接种当日定义为接种0天;接种35天进行第二次相同的接种处理。分别在接种后0、7、14、21、28、35、48天采血;在-21、0、14、35、48天称重。试验结果如下:1、PRRS疫苗组在第一次免疫后,体温迅速升高,且在0-7天显著高于PBS组（P＞0.05）,直到14天时才恢复到免疫前水平;TTR组平均体温低于CON组,但差异不显著（P＞0.05）。二免后,免疫处理对各个处理组体温无影响。与PBS对照组比较,接种PRRS疫苗显著降低了0-13天的日采食量（P＜0.05）,日增重和饲料转化率差异不显著（P＞0.05）;在0-13天TTR日粮组的日采食量显著高于CON组（P＜0.05）,日增重和饲料转化率差异不显著（P＞0.05）。在14-34天和35-48天,PRRS疫苗处理组日增重、日采食量、饲料转化均较PBS处理组低,但差异不显著（P＞0.05）;从免疫全期来看,接种PRRS疫苗显著降低生长猪的ADG和ADFI（P＜0.05）,饲料转化率差异不显著（P＞0.05）,而饲喂TTR日粮生长猪的ADG和ADFI显著高于CON日粮组（P＜0.05）饲料转化率无显著差别（P＞0.05）。2、PRRS疫苗组大多数必需氨基酸和非必需氨基酸浓度在7天时的浓度显著高于PBS对照组（P＜0.05）;在PRRS疫苗组,TTR日粮组大多数必需氨基酸和非必需氨基酸浓度显著低于CON日粮组（P＜0.05）。接种疫苗后,PRRS疫苗组与PBS对照组在14天、35天和48天的总蛋白含量差异不显著（P＞0.05）,PRRS疫苗组内,CON日粮组与TTR日粮组在14天、35天和48天总蛋白含量差异也不显著。PRRS疫苗组在35天和48天总胆固醇浓度显著低于PBS对照组（P＜0.05）;PRRS疫苗组内TTR日粮组总胆固醇浓度在14天、35天和48天均高于CON日粮组,但差异不显著（P＞0.05）。PRRS疫苗组在35天甘油三酯浓度显著低于PBS对照组（P＜0.05）;PRRS疫苗组内TTR日粮组甘油三酯浓度在14天、35天和48天高于CON日粮组,但差异不显著（P＞0.05）。PRRS疫苗组血浆尿素氮在14天显著高于PBS对照组（P＜0.05）;PRRS疫苗组内,TTR日粮组血浆尿素氮浓度低于CON日粮组,但差异不显著（P＞0.05）。PRRS疫苗组在14天IGF-Ⅰ浓度显著低于PBS对照组（P＜0.05）;在PRRS疫苗组,TTR日粮组IGF-Ⅰ浓度均高于CON日粮组,但差异不显著（P＞0.05）。3、PRRS疫苗组的特异性抗体滴度在7天、14天、21天、28天、35天和48天极显著高于PBS对照组（P＜0.01）,14天抗体滴度达到最大值;在PRRS疫苗组,TTR日粮组PRRSv特异性抗体滴度在14天和48天显著高于CON日粮组（P＜0.05）,在7天、21天、28天、35天高于CON日粮组,但差异不显著（P＞0.05）。接种处理后,α₁-AGP在14天时达到最大值。PRRS疫苗组α₁-AGP浓度在14天、35天和48天显著低于PBS对照组（P＜0.05）;在PRRS疫苗组,饲喂TTR同粮生长猪α₁-AGP在14天和48天浓度显著高于CON日粮组（P＜0.05）。PRRS疫苗组在14天、35天和48天IgG浓度低于PBS对照组,但差异不显著（P＞0.05）;在PRRS疫苗组,饲喂TTR日粮生长猪IgG浓度在14天和35天显著高于CON日粮组（P＜0.05）。结论:生长猪的生产性能显著受第一次接种PRRS疫苗的影响,而饲喂添加苏、色氨酸日粮可缓解因接种疫苗而造成的生长抑制。可能是通过提高采食量、促进PRRSv特异性抗体、IgG和α₁-AGP的合成和IGF-Ⅰ的分泌,降低血清游离氨基酸的和血浆尿素氮的浓度来实现的。更多还原

【Abstract】 Thr and Trp are limited amino acids in diet of growing pigs and play important roles in promoting the synthesis of immunoglobulins and increasing feed intake of animal,respectively. Under the immune stress,it was easy to be short of Thr and Trp in diet and to mobilize the body protein caused by the decrease of feed intake and synthesis of immunoglobulins,and then decrease the growth performance.Therefore,this experiment is to investigate the effects of Thr and Trp supplementation on growing pigs vaccinated with PRRS and the probable mechanism through the evaluation of growth performance,parameters of humoral immunity and blood biochemical indicators.Twenty six castrated growing pigs（Landrance×Yorkshire） were used to investigate the effets of Thr and Trp supplementation on growth performance and blood parameters in pigs immunological challenge（IC） with PRRS vaccine.The experiment designed as 2×2 factorial and was constituted of two dietary groups（conventional diet[CON] vs Thr and Trp-rich diet[TTR]） and two challenge treatments（PRRS vaccine vs PBS）.Pigs were averagely divided into the two diet groups until body weight was 29.0±2.9 kg.After pigs received their experimental diet for 3 weeks,9 pigs per diet group were intramuscularly vaccinated with PRRS and the rest 4 pigs per diet group were intramuscularly injected with equal volume of PBS.The first IC day was defined as d 0 and the second same treatment was conducted again on d 35.Blood samples were obtained on d 0,7,14,21,28,35 and 48.Body weight was examined on d-21,0,14,35 and 48.The results were as follows:1.The daily rectal temperature of pigs vaccinated with PRRS increased sharply after 1^st IC and was significantly higher than PBS group on d 0 to 7（P＜0.05）.Until on d 14,the temperature depressed to the prechallenge level.However,there is no influence on daily rectal temperature in four groups caused by the 2^nd IC.Compared with PBS treatments,PRRS-vaccinated pigs had lower ADFI（P＜0.05）,ADG（P＞0.05） and F:G（P＞0.05） on d 0 to 13.However,pigs fed TTR diet had higher ADFI than those fed CON diet（P＜0.05）.During d 14 to 35 and d 35 to 48,there was no significant difference between PRRS vaccine treatment and PBS treatment on ADG, ADFI and F:G（P＞0.05）.During the whole challenged period,ADG and ADFI were significantly decreased by PRRS vaccine（P＜0.05） and no significant difference on F:G（P＞0.05）.Otherwise, pigs fed TTR diet had higher ADG and ADFI（P＜0.05） than those fed CON diet.No significant difference between the two diet groups on F:G（P＞0.05）.2.Except Glycine,concentrations of most EAA and NEAA of PRRS-vaccinated pigs were significantly higher than those of PBS-injected pigs（P＜0.05）.In PRRS vaccination groups,pigs fed TTR diet had lower concentration of EAA and NEAA than those fed CON diet （P＜0.05）.After vaccination with PRRS,no significant difference in total protein concentrations between PRRS vaccine treatment and PBS treatment and between TTR diet and CON diet in PRRS vaccine treatment on d 14,35 and 48（P＞0.05）.Pigs in PRRS vaccination treatment had lower concentration of total cholesterol than those in PBS treatment on d 35 and 48（P＜0.05）. Pigs fed TTR diet had a higher concentration of total cholesterol than those fed CON diet on d 14,35 and 48 in FRRS vaccination treatment（P＞0.05）.Triglyceride concentrations of PRRS-vaccinated pigs were significant lower than that of PBS-injected pigs on d 35（P＜0.05）. Pigs fed TTR diet had higher triglyceride concentrations than those fed CON diet on d 14,35 and 48 in PRRS vaccination treatment（P＞0.05）.Plasma urea nitrogen concentrations of PRRS-vaccinated pigs were significantly higher than those of PBS-injected pigs on d 14 （P＜0.05）.Pigs fed TTR diet had a lower plasma urea nitrogen than those fed CON diet on d 14, 35 and 48（P＞0.05）.IGF-I concentrations of PRRS-vaccinated pigs were significantly lower than those of PBS-injected pigs on 14（P＜0.05）.Pigs fed TTR diet had higher IGF-I concentrations than those fed CON diet on d 14,35 and 48（P＞0.05）.3.PRRSv-specific antibody titers of pigs in PRRS vaccine treatment were extremely significantly higher than those of pigs in PBS treatment on d 7,14,21,28,35,48（P＜0.01） and peaked at the maxmium value on d 14.In PRRS vaccine groups,pigs fed TTR diet had higher PRRSv-specific antibody titers than those fed CON diet on d 14 and 48（P＜0.05）.After IC,α₁-AGP concentrations of PRRS-vaccinated pigs were significantly lower than those of PBS-injected on d 14,35 and 48（P＜0.05） and peaked at the maxmium value on d 14.Pigs fed TTR diet had higherα₁-AGP concentrations than those fed CON diet on d 14 and 48（P＜0.05）. IgG concentrations of PRRS-vaccinated pigs were lower than those of PBS-injected pigs on 14 （P＞0.05）.Pigs fed TTR diet had higher IGF-I concentrations than those fed CON diet on d 14 and 35（P＜0.05）.Conclusions:During 1^st IC period,growth performance of growing pigs was significantly influenced by PRRS vaccination.The diet supplementation with Thr and Trp could mitigate the growth inhibition caused by PRRS vaccination probable via promoting the synthesis of PRRS-specific antibody,IgG andα₁-AGP and secretion of IGF-I,or decreasing concentration of serum free amino acids and plasma urea nitrogen.更多还原