Supplementation of L-methionine has beneficial effects on intestinal morphology, redox status, and growth performance of broiler chicks compared with DL-methionine

Abstract Text: To evaluate the relative bioavailability (RBA) and functional differences of L-methionine (LM, 99%) to DL-methionine (DLM, 99%), a total of 888 (half male and half female) 1-d-old Ross 308 broiler chicks in 84 cages were weighed and randomly allotted to 7 dietary treatments in a randomized complete block design: basal diet (BD) with 0, 0.095, 0.190, or 0.285% LM or DLM (representing 60, 70, 80, or 90% of Ross nutrient recommendations, respectively). Chicks were reared in cages in 2 windowless air-conditioner controlled houses for 21 d. Body weight and feed disappearance were recorded on d 0, 7, 14, and 21 for computing growth performance. On d 0, 7, and 21, 1 bird representing the average weight of each cage from BD, BD + 0.285% LM, and BD + 0.285% DLM treatments were selected and killed to assess mucosal morphology, antioxidants, and oxidative stress in duodenum and liver. Data for each response were analyzed using MIXED model of SAS. A mutilinear regression analysis was used to evaluate the RBA of LM to DLM. Throughout experimental period, chicks fed diets supplemented with LM had greater (P < 0.05) ADG and gain:feed ratio than chicks fed diets supplemented with DLM.  The RBA of LM to DLM for ADG and gain:feed ratio was 138.2% and 140.7%, respectively. On d 7, chicks fed a diet supplemented with 0.285% LM had greater (P < 0.05) villus width compared with chicks fed a diet supplemented with 0.285% DLM.  Chicks fed a diet supplemented with 0.285% LM had lower (P < 0.05) crypt depth and greater (P < 0.05) villus height:crypt depth ratio as compared to chicks fed a diet supplemented with 0.285% DLM.  On d 21, chicks fed a diet supplemented with 0.285% LM had greater (P < 0.05) concentrations of GSH and TAC but less (P < 0.05) protein carbonyl content in duodenum mucosa as compared to chicks fed a diet supplemented with 0.285% DLM.  Overall, chicks fed diets supplemented with LM had better growth response than chicks fed diets with DLM. Dietary supplementation of LM resulted in better redox status and gut mucosal development of chicks than those supplemented with DLM.

Keywords: broiler chicken, DL-methionine, gut development, L-methionine, redox status