title: Effects of liquid DL-2-hydroxy-4-methylthio butanoic acid on growth performance and immune responses in broiler chickens.
abstract: 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.
authors.affiliation: The State Key Laboratory of Animal Nutrition, College of Animal Science & Technology, China Agricultural University, Beijing, PR China.
authors.forename: L B
authors.initials: LB
authors.lastname: Zhang
authors.forename: Y M
authors.initials: YM
authors.lastname: Guo
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000254:growth & development* / Q000276:immunology*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005916:Globulins / Q000378:metabolism; D008221:Lymphoid Tissue / Q000187:drug effects* / Q000254:growth & development; D008297:Male; D008715:Methionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D009751:Nutritional Requirements; D012709:Serum Albumin; D015430:Weight Gain / Q000187:drug effects*
chemical_list: D005916:Globulins; D012709:Serum Albumin; C008391:alpha-hydroxy-gamma-methylmercaptobutyric acid; D008715:Methionine