Irm Misbah, Mu Wei, Xiaoyi Wu, Geng Lina, Wang Xiao, Ye Bo, Ma Lei, Zhou Zhiyu
State Key Laboratory of Marine Resource Utilization in South China Sea, Haikou, Hainan, 570228, PR China.
Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, Haikou, Hainan, 570228, PR China.
Amino Acids. 2021 Jul;53(7):1065-1077. doi: 10.1007/s00726-021-03014-7. Epub 2021 Jun 3.
An 8-week feeding trial was conducted to evaluate optimum dietary methionine (Met) requirement of juvenile humpback grouper (Cromileptes altivelis) and the influence of dietary methionine (Met) supplementations on growth, gut micromorphology, protein and lipid metabolism. Seven isoproteic (48.91%) and isolipidic diets (10%) were made to contain 0.70, 0.88, 1.04, 1.27 1.46, 1.61 and 1.76% of dry matter Met levels. Results showed that lower survival, weight gain (WG%), protein efficiency ratio (PER), protein productive value (PPV) but higher daily feed intake (DFI) and feed conversion ratio (FCR) were observed in the Met deficient groups (0.70 and 0.88%). Optimum dietary Met requirement for humpback grouper was found to be 1.07% through the straight-broken line analysis of WG% against Met. Fish fed Met deficient diets (0.70, 0.88%) exhibited lower mRNA levels of growth hormone (GH), growth hormone receptor (GHR), insulin-like growth factor-I (IGF-1), target of rapamycin (TOR) as well as S6 kinase 1 (S6K1) than other dietary groups. Whereas, expression of genes related to general control nonderepressible (GCN2) kinase i.e., GCN2 and C/EBPβ enhancer-binding protein β was upregulated in fish fed low Met diets (P < 0.05). The mRNA expression of hepatic fatty acid synthase (FAS) and sterol regulatory element-binding protein-1 (SREBP-1) were higher in fish fed 0.70 and 0.88% dietary Met group and the lipolytic genes, hepatic peroxisome proliferator-activated receptor α (PPARα) and carnitine palmitoyl transferase-1 (CPT-1) showed an opposite variation tendency as FAS or SREBP1. Generally, the optimum Met requirement for humpback grouper was predicted to be 1.07% of dry matter.
进行了一项为期8周的饲养试验，以评估驼背鲈幼鱼的最佳日粮蛋氨酸（Met）需求量，以及日粮补充蛋氨酸（Met）对其生长、肠道微观形态、蛋白质和脂质代谢的影响。配制了七种等蛋白（48.91%）和等脂（10%）的日粮，使其干物质中蛋氨酸水平分别为0.70%、0.88%、1.04%、1.27%、1.46%、1.61%和1.76%。结果表明，在蛋氨酸缺乏组（0.70%和0.88%）中观察到存活率、增重率（WG%）、蛋白质效率比（PER）、蛋白质生产价值（PPV）较低，但日采食量（DFI）和饲料转化率（FCR）较高。通过对增重率（WG%）与蛋氨酸进行折线分析，发现驼背鲈的最佳日粮蛋氨酸需求量为1.07%。与其他日粮组相比，饲喂蛋氨酸缺乏日粮（0.70%、0.88%）的鱼生长激素（GH）、生长激素受体（GHR）、胰岛素样生长因子-I（IGF-1）、雷帕霉素靶蛋白（TOR）以及S6激酶1（S6K1）的mRNA水平较低。然而，在饲喂低蛋氨酸日粮的鱼中，与一般控制非抑制性（GCN2）激酶相关的基因，即GCN2和C/EBPβ增强子结合蛋白β的表达上调（P < 0.05）。在饲喂0.70%和0.88%日粮蛋氨酸组的鱼中，肝脏脂肪酸合酶（FAS）和固醇调节元件结合蛋白-1（SREBP-1）的mRNA表达较高，而脂解基因肝脏过氧化物酶体增殖物激活受体α（PPARα）和肉碱棕榈酰转移酶-1（CPT-1）的变化趋势与FAS或SREBP1相反。总体而言，预测驼背鲈的最佳蛋氨酸需求量为干物质的1.07%。
