【作者】 耿爱莲；

【导师】 呙于明；

【作者基本信息】 中国农业大学 ， 动物营养与饲料科学， 2005， 博士

【摘要】 本论文通过五个试验系统地研究了日粮中单独和同时添加L—肉碱与辅酶Q₁0（辅酶Q）对肉鸡腹水症敏感性的影响及有关作用机制。（1）研究日粮中L—肉碱与辅酶Q添加对肉鸡生产性能以及腹水症发生敏感性的影响。采用3×3因子安排。L—肉碱添加水平分别为0、75、150 mg/kg饲料,辅酶Q添加水平分别为0、20、40 mg/kg饲料。540只AA雄性肉仔鸡随机分为9组,每组6个重复,8日龄起开始添加。15-21日龄关闭水暖进行较低温处理（15.18℃）以诱发腹水症。结果表明日粮中单独添加辅酶Q和L—肉碱与辅酶Q同时添加对肉鸡的生产性能影响不显著,而150mg/kg L—肉碱可显著降低肉鸡的体增重。日粮中单独添加L—肉碱、辅酶Q以及L—肉碱与辅酶Q同时添加均可以降低肉鸡腹水症发生的敏感性和死亡率:（2）研究L—肉碱与辅酶Q添加对腹水症肉鸡脂质代谢和抗氧化能力的影响,结果表明L—肉碱与辅酶Q同时添加对TG、TC、HDL-C、LDL-C和VLDL-C均产生显著影响（P<0.05）,并且显著提高肝脏组织T-SOD并降低MDA含量（P<0.05）,说明能够起到改善腹水症肉鸡肝脏脂质代谢和降低过氧化损伤的作用:（3）研究在不同日龄添加L—肉碱与辅酶Q对腹水症敏感肉鸡生产性能、腹脂沉积以及免疫功能的影响。采用3×2×2因子安排,包括3个L—肉碱水平（0、75、100mg/kg）,2个辅酶Q水平（0、40 mg/kg）以及两种添加日龄（分别从1日龄和10日龄开始）。480只1日龄艾维茵公肉鸡随机分为12组,每组设5个重复,每重复8只鸡。结果表明日粮中同时添加L—肉碱与辅酶Q可显著降低腹水症敏感肉鸡0-3周的腹脂率（P<0.05）,提高肉鸡3-6周的胸腺指数和溶菌酶活性;单独添加L—肉碱对ConA以及LPS刺激丝裂原淋巴细胞增殖反应没有影响,而单独添加辅酶Q以及二者同时添加时ConA刺激丝裂原淋巴细胞增殖反应显著降低。（4）研究不同处理下L—肉碱与辅酶Q添加对腹水症敏感肉鸡肝脏线粒体功能及呼吸链有关酶活性的影响。采用3×2×2因子安排。1日龄艾维茵公肉鸡480只随机分为12组,每组设5个重复,每重复组8只。L—肉碱添加水平分别为0、75、100 mg/kg饲料,辅酶Q水平分别为0、40 mg/kg饲料,从1日龄开始添加。18日龄时按照1.0 mg/kg体重的剂量分别腹腔注射大肠杆菌内毒素（LPS）和等量的生理盐水,每周末注射一次,连续3周。10日龄开始关闭水暖进行低温处理以诱发腹水症。结果表明日粮单独添加L—肉碱或辅酶Q以及二者同时添加时都可降低肉鸡对腹水症发生的敏感性,可能是通过改善肉鸡肝脏线粒体功能、呼吸链有关酶的活性以及线粒体的抗氧化能力来实现的。（5）通过观察腹水症肉鸡是否存在心肌细胞凋亡的现象,来探讨L—肉碱与辅酶Q单独或同时添加时对其的作用。试验采用2×2×2因子安排,L—肉碱添加水平为0、100 mg/l(g饲料,辅酶Q添加水平为0、40mg/kg饲料,采用两种温度处理（一组采用常规温度控制,即缓慢降温,另一组从10日龄开始突然降低温度到15-18℃以诱发腹水症）。结果表明肉鸡发生腹水症与心肌细胞凋亡之间不存在必然联系。日粮添加L—肉碱与辅酶Q能够显著降低肉鸡腹水症死亡率,其机制仍与其能够提高心肌线粒体和血清中抗氧化能力有关,而对腹水症肉鸡心肌细胞凋亡酶Caspase-3的活性没有显著影响。更多还原

【Abstract】 Five experiments were conducted to study the effects of dietary L-carnitine and coenzyme Q10 (CoQ) supplementation alone and in combinationon on broiler’s ascites susceptibility, and the related mechanisms were discussed. 1) To determine the effects of L-carnitine and CoQ on growth performance and ascites susceptibility of broilers. A 3x3 factorial arrangement was employed with 3 levels of L-carnitine (0, 75 and 150 mg/kg) and 3 levels of CoQ (0, 20 and 40 mg/kg) supplementation during the experiment. Five hundred and forty one-day-old Arbor Acre (AA) male broiler chicks were randomly allocated into nine groups with six replicates each. From day 8, the diets were supplemented with L-carnitine and CoQ, respectively. From day 15 to day 21, all birds were exposed to low ambient temperature (15-18℃) to induce ascites. The results showed that growth performance of broilers were not significantly affected by CoQ or L-carnitine + CoQ supplementation, but body weight gain (BWG) of broilers was significantly reduced by 150 mg/kg L-carnitine. Ascites susceptibility and mortality of broilers were significantly decreased by L-carnitine, CoQ and L-carnitine + CoQ supplementation (P<0.05). 2) To study the effects of L-carnitine and CoQ supplementation on lipid metabolism and antioxidative capability of ascites broilers. The results showed that there were significant effects observed on TG, TC, HDL-C, LDL-C and VLDL-C in liver tissue by L-carnitine + CoQ supplementation together (P<0.05). T-SOD activity in liver tissue was significantly increased and MDA content was reduced by L-carnitine + CoQ supplementation together (P<0.05), which means L-carnitine and CoQ supplementation can improve lipid metabolism and antioxidative capability of ascites broilers. 3) To investigate the effects of L-carnitine and CoQ supplementation at different ages on performance, abdominal fat deposit and immune responses in ascites-susceptible broilers. 3×2×2 factorial arrangement were used, and the factors included 3 levels of L-carnitine (0, 75, 150 mg/kg), 2 levels of CoQ (0 and 40 mg/kg) and 2 supplementation ages (from day 1 and from day 10, respectively). Four hundred eighty 1 day-old Avain male broiler chicks were randomly allocated into 12 groups with 5 replicates each, 8 birds per replicate. The results showed that abdominal fat ratio at 0-3 wk was significantly reduced, and thymus index at 3-6 wk was increased by L-carnitine + CoQ supplementation together (P<0.05). Serum lysozyme activity was increased by L-carnitine + CoQ. The peripheral blood lymphocyte proliferations in response to ConA and LPS were not influenced by L-carnitine alone, but the proliferation in response to ConA was significantly decreased by CoQ and L-carnitine + CoQ (P<0.05). 4) To investigate the effects of L-carnitine and CoQ supplementation under different treatments on hepatic mitochondrial function, respiratory chain-related enzymes’ activities in ascites-susceptible broilers. Four hundred eighty 1-d-old Avain male broiler chicks were fed with corn-soybean based diets for 6 wks in a 3x2x2 factorial experiment, and the factors consisted of L-carnitine supplementation (0, 75 and 100 mg/kg), CoQ supplementation (0 and 40 mg/kg) and EschErichia coli lipopolysaccharide challenge (LPS and saline). L-carnitine and CoQ were supplemented from day 1. From day 18, the broilers received 3weekly i. p. injections of LPS (1.0 mg /kg BW) or an equivalent amount of sterile saline as the control. From day 10, all the birds were exposed to low ambient temperature (12-15℃) to induce ascites. The results showed that L-carnitine and CoQ supplementation alone and in combination reduces broilers’ susceptibility to ascites, which might be realized via improving hepatic mitochondrial function, some respiratory chain-related enzymes activities and mitochondrial antioxidative capability. 5) To observe if there exists cardiomycyte apoptosis in ascites broilers, and investigate the effects of L-carnitine and CoQ supplementation. 2×2×2 factorial arrangement were used, and the factors included 2 lev更多还原