PDF(Pubmed)
Abstract：
An 8-week feeding trial was conducted to evaluate the effects of L-methionine and methionine hydroxy analogue calcium (MHA-Ca) supplements in low-fishmeal diet on growth performance, hepatopancreas morphology, protein metabolism, anti-oxidative capacity, and immunity of Pacific white shrimp (Litopena eus vannamei). Four isonitrogenous and isoenergetic diets were designed: PC (203.3 g/kg fishmeal), NC (100 g/kg fishmeal), MET (100 g/kg fishmeal +3 g/kg L-methionine) and MHA-Ca (100 g/kg fishmeal +3 g/kg MHA-Ca). White shrimp (initial body weight 0.23 ± 0.00 g, 50 shrimp per tank) were allocated to 12 tanks and divided among 4 treatments in triplicates. In response to L-methionine and MHA-Ca supplementations, the shrimp exhibited higher weight gain rate (WGR), specific growth rate (SGR), condition factor (CF), and lower hepatosomatic index (HSI) compared to those fed the NC diet (p < 0.05). The WGR and SGR of shrimp fed L-methionine and MHA-Ca showed no difference with those in the PC diet (p > 0.05). Both of L-methionine and MHA-Ca supplementary diets significantly decreased the malondialdehyde (MDA) levels of shrimp when compared with the NC diet (p < 0.05). L-methionine supplementation improved the lysozyme (LZM) activity and total antioxidant capacity (T-AOC) of shrimp, while the MHA-Ca addition elevated the reduced glutathione (GSH) levels in comparison with those fed the NC diet (p < 0.05). Hypertrophied blister cells in hepatocytes were observed in shrimp fed the NC diet, and alleviated with L-methionine and MHA-Ca supplementations. Shrimp fed the MET and MHA-Ca diets had higher mRNA expression levels of target of rapamycin (tor) than those fed the NC diet (p < 0.05). Compared to the NC group, dietary MHA-Ca supplementation upregulated the expression level of cysteine dioxygenase (cdo) (p < 0.05), while L-methionine supplementation had no significant impact (p > 0.05). The expression levels of superoxide dismutase (sod) and glutathione peroxidase (gpx) were significantly upregulated by L-methionine supplemented diet in comparison with those in the NC group (p < 0.05). Overall, the addition of both L-methionine and MHA-Ca elevated the growth performance, facilitated protein synthesis, and ameliorated hepatopancreatic damage induced by plant-protein enriched diet in L. vannamei. L-methionine and MHA-Ca supplements enhanced anti-oxidants differently.
摘要：
进行了为期8周的喂养试验，以评估低鱼粉饮食中L-蛋氨酸和蛋氨酸羟基类似物钙（MHA-Ca）补充剂对生长性能的影响，肝胰腺形态学，蛋白质代谢，抗氧化能力，和太平洋白虾（凡纳滨对虾）的免疫力。设计了四种同氮和等能量饮食：PC（203.3g/kg鱼粉），NC（100克/公斤鱼粉），MET（100g/kg鱼粉3g/kgL-蛋氨酸）和MHA-Ca（100g/kg鱼粉3g/kgMHA-Ca）。白虾(初始体重0.23±0.00g,每个罐50只虾）被分配到12个罐中，并在4个处理中重复三次。为了响应L-蛋氨酸和MHA-Ca的补充，虾表现出更高的增重率(WGR)，比增长率(SGR)，条件因子(CF)，与饲喂NC饮食的人相比，肝细胞指数（HSI）较低（p<0.05）。饲喂L-蛋氨酸和MHA-Ca的虾的WGR和SGR与PC饲粮无差异（p>0.05）。与NC日粮相比，L-蛋氨酸和MHA-Ca补充日粮均显着降低了虾的丙二醛（MDA）水平（p<0.05）。补充L-蛋氨酸提高了虾的溶菌酶(LZM)活性和总抗氧化能力(T-AOC),与饲喂NC饮食的那些相比，添加MHA-Ca提高了还原型谷胱甘肽（GSH）水平（p<0.05）。在饲喂NC饮食的虾中观察到肝细胞中肥大的水泡细胞，并通过补充L-蛋氨酸和MHA-Ca来缓解。饲喂MET和MHA-Ca饮食的虾比饲喂NC饮食的虾具有更高的雷帕霉素（tor）靶mRNA表达水平（p<0.05）。与NC组相比，饲粮MHA-Ca上调半胱氨酸双加氧酶(cdo)的表达水平(p<0.05),而补充L-蛋氨酸没有显著影响(p>0.05)。与NC组相比，添加L-蛋氨酸的饮食显著上调了超氧化物歧化酶（sod）和谷胱甘肽过氧化物酶（gpx）的表达水平（p<0.05）。总的来说,L-蛋氨酸和MHA-Ca的添加提高了生长性能，促进蛋白质合成，并改善了富含植物蛋白的饮食引起的凡纳滨对虾肝胰腺损伤。L-蛋氨酸和MHA-Ca补充剂不同地增强抗氧化剂。
