The study was conducted to investigate the effects of DL-Methionyl-DL-Methionine (Met-Met) (a dipeptide of two DL-methionine molecules) on growth performance, immune and antioxidative responses for Litopenaeus vannamei fed low fishmeal diet. Tested treatments consisted of positive control diet (PC) with 20 % fishmeal or 7 % fishmeal (basal diet) diets supplemented with different levels of Met-Met (0.00 %, 0.1 %, 0.15 %, 0.20 %, 0.25 % and 0.3 %). A total of 1680 shrimp (0.071 ± 0.001 g) were randomly distributed into 42 tanks (6 repetitions / each diet, 40 shrimp / tank) and fed for 91 days. Results showed that reduction of fishmeal from 20 % down to 7 % did not affect the survival rate of shrimp. Weight gain rate and feed efficiency were significantly decreased in the basal group compared to the PC group, while these were significantly increased with the increasing of Met-Met into the diets up to 0.15 % compared to the basal group. Malondialdehyde in 0.15 % Met-Met and PC groups were significantly lower than the basal group. Shrimp fed the diet with 0.15 % Met-Met had the highest phenol oxidase content and peroxidase and total antioxidant capacity. The highest values of intestinal wall thickness were observed in 0.15 % Met-Met and PC groups. The similar morphology of the hepatopancreas was observed between 0.15 % and PC groups. Overall, the present study indicated that Met-Met could improve adverse effects of Met deficiency on growth caused by low fishmeal. Low fishmeal diet with 0.15 % Met-Met (0.65 %–0.66 % Met and 1.14 % Met + Cys) is beneficial to the health of intestine and hepatopancreas, improves immunity and antioxidative capacity and promotes the growth of L. Vannamei.

本研究旨在研究 DL-Metionyl-DL-Methionine (Met-Met)（两个 DL-蛋氨酸分子的二肽）对南美白对虾的生长性能、免疫和抗氧化反应的影响喂低鱼粉饮食。测试处理包括阳性对照日粮 (PC) 和 20% 鱼粉或 7% 鱼粉（基础日粮）日粮，辅以不同水平的 Met-Met（0.00%、0.1%、0.15%、0.20%、0.25% 和 0.3%） . 总共 1680 只虾（0.071±0.001 g）被随机分配到 42 个鱼缸（6 次重复/每种饲料，40 只虾/鱼缸）并饲养 91 天。结果表明，将鱼粉从 20% 减少到 7% 不会影响虾的成活率。与 PC 组相比，基础组的增重率和饲料效率显着降低，而与基础组相比，随着 Met-Met 在日粮中添加量的增加，这些指标显着增加，最高可达 0.15%。0.15% Met-Met 和 PC 组的丙二醛显着低于基础组。虾用 0. 15% 的 Met-Met 具有最高的酚氧化酶含量、过氧化物酶和总抗氧化能力。在 0.15% Met-Met 和 PC 组中观察到肠壁厚度的最高值。在 0.15% 和 PC 组之间观察到类似的肝胰腺形态。总体而言，目前的研究表明，Met-Met 可以改善低鱼粉导致的 Met 缺乏对生长的不利影响。0.15 % Met-Met（0.65 %–0.66 % Met和1.14 % Met + Cys）的低鱼粉饲料有利于肠道和肝胰腺的健康，提高免疫力和抗氧化能力，促进生长 在 0.15% 和 PC 组之间观察到类似的肝胰腺形态。总体而言，目前的研究表明，Met-Met 可以改善低鱼粉导致的 Met 缺乏对生长的不利影响。0.15 % Met-Met（0.65 %–0.66 % Met和1.14 % Met + Cys）的低鱼粉饲料有利于肠道和肝胰腺的健康，提高免疫力和抗氧化能力，促进生长 在 0.15% 和 PC 组之间观察到类似的肝胰腺形态。总体而言，目前的研究表明，Met-Met 可以改善低鱼粉导致的 Met 缺乏对生长的不利影响。0.15 % Met-Met（0.65 %–0.66 % Met和1.14 % Met + Cys）的低鱼粉饲料有利于肠道和肝胰腺的健康，提高免疫力和抗氧化能力，促进生长南美白对虾。