Zhang L B, Guo Y M
The State Key Laboratory of Animal Nutrition, College of Animal Science & Technology, China Agricultural University, Beijing, PR China.
Poult Sci. 2008 Jul;87(7):1370-6. doi: 10.3382/ps.2007-00366.
An experiment was conducted to determine the effects of different doses of liquid dl-2-hydroxy-4-methylthio butanoic acid (LMA) on growth performance and immune response in broiler chickens. In an arrangement with 4 graded levels of LMA to meet 80, 100, 120, and 140% of methionine requirements of broilers recommended by Chinese feeding standards for chickens, 256 one-day-old Arbor Acres male broiler chickens were randomly divided into 4 treatments with 8 replicates of 8 birds each. Growth performance, cellular immunity, and humoral immunity were determined. Results from increasing LMA levels were as follows. There were no significant differences (P > 0.05) in body weight gain and feed intake among the treatments, but the ratio of feed to gain was linearly decreased and significantly greatest (P < 0.05) in the group fed at 80% of methionine requirement. Serum globulin levels on d 21 and 42 were linearly increased significantly (P < 0.05); phagocytosis of neutral red of peripheral blood lymphocyte was quadratic and was lowest in the deficient group (P < 0.05). The proliferation of peripheral blood lymphocytes in response to lipopolysaccharide was quadratically influenced, and that of the 120% group on d 21 and the 100% group on d 42 was significantly greater than in the other groups (P < 0.05). Antibody titers to Newcastle disease virus on d 4 after the first inoculation of the vaccine were quadratically increased, anti-bovine serum albumin antibody production on d 13 after the second immunization was quadratic, and antibody titers were greatest in the groups fed at 100 or 120% of methionine requirement. In conclusion, methionine deficiency resulted in decreased feed utilization and decreased humoral and nonspecific immuno-competence of broiler chickens. The use of LMA to correct a methionine deficiency corrected these problems.
进行了一项实验，以确定不同剂量的液态dl-2-羟基-4-甲硫基丁酸（LMA）对肉鸡生长性能和免疫反应的影响。按照LMA的4个分级水平进行安排，以满足中国鸡饲养标准推荐的肉鸡蛋氨酸需求量的80%、100%、120%和140%，将256只1日龄的艾维茵雄性肉鸡随机分为4个处理组，每组8个重复，每个重复8只鸡。测定了生长性能、细胞免疫和体液免疫。提高LMA水平的结果如下。各处理组之间的体重增加和采食量没有显著差异（P>0.05），但料重比呈线性下降，在蛋氨酸需求量80%的饲喂组中显著最高（P<0.05）。第21天和第42天的血清球蛋白水平呈线性显著升高（P<0.05）；外周血淋巴细胞的中性红吞噬作用呈二次曲线变化，在缺乏组中最低（P<0.05）。外周血淋巴细胞对脂多糖的增殖反应受到二次影响，第21天120%组和第42天100%组的增殖反应显著高于其他组（P<0.05）。首次接种疫苗后第4天对新城疫病毒的抗体效价呈二次升高，第二次免疫后第13天抗牛血清白蛋白抗体产生呈二次变化，在蛋氨酸需求量100%或120%的饲喂组中抗体效价最高。总之，蛋氨酸缺乏导致肉鸡饲料利用率降低以及体液和非特异性免疫能力下降。使用LMA纠正蛋氨酸缺乏可纠正这些问题。
