Institute of Animal Nutrition, Key Laboratory for Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
Poult Sci. 2018 Dec 1;97(12):4315-4323. doi: 10.3382/ps/pey317.
The objective of the study was to investigate the effects of deficiency or high level addition of methionine (Met) in diet on homocysteine (Hcy) metabolism and hepatic lipid metabolism in broiler. A completely random design was used with 3 dietary treatments with the addition of Met from DL-methionine (DLM) at 0%, 0.22%, and 0.32% in a basal diet. The analyzed dietary Met was 0.271%, 0.485%, and 0.584% respectively for the Met-deficient, sufficient, and excessive diet. A total of 360 one-day-old male Ross 308 broiler chicks were randomly assigned to the treatments. The trial was last for 21 d. Compared to the Met-sufficient diet, the Met-deficient diet significantly resulted the decrease of 1 to 21 d growth performance and the increase of liver ether extract (EE). Compared to the Met-sufficient group, the expression of lipid transport gene apolipoprotein B (APOB) in both Met-deficient and Met-excessive group was decreased (P < 0.05). However, compared to the Met-sufficient group, a decreased of serum low-density lipoprotein cholesterol (LDLC) was only shown in birds fed a Met-deficient diet (P < 0.05). Although the plasma Hcy content was decreased, the expression of Cystathionine β-synthase (CβS) and hepatic inflammatory cytokines included interleukin-1 (IL-1) and interleukin-8 (IL-8) was significantly decreased in birds fed the Met-deficient diet when compared to those in Met-sufficient group (P < 0.05). When compared to the Met-sufficient group, the broilers in high dietary Met group had increased levels of catabolic enzyme genes expression especially acyl-coenzyme A oxidase 1 (ACOX1) and carbohydrate response element-binding protein (CHREBP) (P < 0.05), and a decreased content of liver EE. In conclusion, dietary Met deficiency decreased the hepatic lipid export and subsequently increased the hepatic lipid accumulation. High dietary Met addition increased the hepatic lipid catabolism and subsequently decreased the liver lipid accumulation.
本研究旨在探讨饲粮蛋氨酸（Met）缺乏或过量对肉鸡血液同型半胱氨酸（Hcy）代谢和肝脏脂代谢的影响。采用完全随机设计，设置 3 种饲粮处理，在基础饲粮中分别添加 0%、0.22%和 0.32%的 DL-蛋氨酸（DLM），相应饲粮 Met 分析值为 0.271%、0.485%和 0.584%，对应的饲粮 Met 分别为缺乏、适量和过量。选取 360 只 1 日龄雄性罗斯 308 肉鸡，随机分为 3 个处理组，每个处理 12 个重复，每个重复 10 只鸡。试验期 21 d。与饲粮 Met 适量组相比，饲粮 Met 缺乏显著降低了 1~21 d 肉鸡的生长性能，增加了肝脏乙醚提取物（EE）含量。与饲粮 Met 适量组相比，饲粮 Met 缺乏和过量组脂质转运基因载脂蛋白 B（APOB）的表达均降低（P＜0.05）。但与饲粮 Met 适量组相比，仅饲粮 Met 缺乏组肉鸡血清低密度脂蛋白胆固醇（LDLC）降低（P＜0.05）。虽然血液 Hcy 含量降低，但饲粮 Met 缺乏组肉鸡肝脏胱硫醚β合酶（CβS）和炎症因子白细胞介素-1（IL-1）、白细胞介素-8（IL-8）的表达显著低于饲粮 Met 适量组（P＜0.05）。与饲粮 Met 适量组相比，高饲粮 Met 组肉鸡的分解代谢酶基因表达增加，特别是酰基辅酶 A 氧化酶 1（ACOX1）和碳水化合物反应元件结合蛋白（CHREBP）（P＜0.05），肝脏 EE 含量降低。综上，饲粮 Met 缺乏降低了肝脏脂质输出，进而导致肝脏脂质蓄积增加；饲粮 Met 过量增加了肝脏脂质分解代谢，进而导致肝脏脂质蓄积减少。
