Effects of dietary L-isoleucine on laying performance and immunomodulation of laying hens

摘要: Isoleucine may be a limiting amino acid for laying hens fed diets with lowered protein level. An experiment was conducted to examine performance and the immune function of provided varying in digestible isoleucine levels during peak production period. A total number 400 Lohmann Brown hens, 28 wk age, were allocated 5 dietary treatment groups, each which included replicates 16 per replicate (4 cages / replicate; 80 treatment). L-isoleucine added experimental diet (14% CP) containing synthetic (methionine, lysine, threonine, tryptophan, valine) by zero, 1.0, 2.0, 3.0, 4.0 g/kg, corresponding 0.54%, 0.64%, 0.74%, 0.84, 0.94% isoleucine, respectively. At end (wk 40), did not affect or egg quality. Serum albumin concentration increased quadratically (P 0.05) response excess level on serum IgG, IgA, IgM. In addition, concentrations secretory immunoglobulin (sIgA), tumor necrosis factor alpha (TNFα), interleukin (IL-2 IL-6) ileum. Also, expressions ileal MUC2 mRNA, sIgA IL-1β mRNA changed > Furthermore, change expression tight junction (claudin-1 occludin). No effect occurred when supplemented, suggesting that it is low crude intestinal mucosal immune.