Key Laboratory of Aquatic Animal Diseases and Immune Technology of Heilongjiang Province, Heilongjiang Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin, 150070, PR China.
Key Laboratory of Aquatic Animal Diseases and Immune Technology of Heilongjiang Province, Heilongjiang Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin, 150070, PR China.
Fish Shellfish Immunol. 2022 Jan;120:271-279. doi: 10.1016/j.fsi.2021.11.040. Epub 2021 Dec 1.
Previous research has shown that dietary α-ketoglutarate (AKG) supplementation can promote growth performance, phosphorus metabolism, and skeletal development of juvenile mirror carp (Cyprinus carpio) fed low phosphorous diets. In the current study, we tested the hypothesis that 1% AKG dietary supplementation reduces the dietary phosphorus requirements of juvenile mirror carp. A total of 12 experimental isoproteic and isolipidic diets containing available phosphorus levels of 0.21%, 0.38%, 0.55%, 0.72%, 0.89%, and 1.07% dry matter with either 0 or 1% AKG supplementation were used in the study. A total of 1080 juvenile fish of similar initial weight (0.90 ± 0.03 g) were selected and randomly assigned to 36 tanks. There were three replicates for each experimental group, with a density of 30 fish per tank. Fish were fed to satiation for 8 weeks. The results indicated that fish fed the diet supplemented with 1% AKG showed a significant increase in final body weight (FBW), weight gain rate (WGR), feed intake (FI) and phosphorus intake (PI) compared to the diet without AKG (P < 0.05). FBW and WGR increased significantly with increasing available phosphorus levels from 0.21% to 0.89% (P < 0.05). The mRNA expression of ZO-1, claudin 11, and occludin was significantly increased by dietary AKG and phosphorus (P < 0.05). The mRNA expression of Nrf2, GPx1a, and CAT in the Nrf2 signaling pathway was significantly increased by dietary AKG and phosphorus (P < 0.05). The expression levels of IL-10 and TGF-β2 were significantly increased by dietary AKG and phosphorus, but the expression levels of IL-1β, IL-8, IL-10, TNF-a and NF-κB were significantly decreased with dietary AKG and phosphorus supplementation (P < 0.05). Based on second-order polynomial regression analysis of WGR against dietary phosphorus levels, the optimal dietary phosphorus level was found to be 0.79% of dry feed for juvenile mirror carp fed a diet with 1% AKG supplementation and 0.93% of dry feed without AKG supplementation. This study confirmed that AKG supplementation can reduce the phosphorus requirements of juvenile mirror carp by promoting growth performance, intestinal tight junctions, Nrf2 signaling pathways and immune response.
先前的研究表明，饮食中添加 α-酮戊二酸（AKG）可以促进磷代谢和骨骼发育，提高幼镜鲤（Cyprinus carpio）的生长性能。在本研究中，我们测试了以下假设，即 1%的 AKG 饮食补充可降低幼镜鲤对磷的饮食需求。研究共使用了 12 种实验等蛋白等脂饲料，其中有效磷水平分别为 0.21%、0.38%、0.55%、0.72%、0.89%和 1.07%干物质，同时添加或不添加 1%的 AKG。选择了 1080 条初始体重（0.90±0.03g）相似的幼鱼，并随机分配到 36 个鱼缸中。每个实验组有三个重复，每个鱼缸 30 条鱼。鱼被喂食至饱食 8 周。结果表明，与不添加 AKG 的饲料相比，添加 1%AKG 的饲料显著增加了终体重（FBW）、增重率（WGR）、采食量（FI）和磷采食量（PI）（P<0.05）。FBW 和 WGR 随着有效磷水平从 0.21%增加到 0.89%而显著增加（P<0.05）。ZO-1、claudin 11 和 occludin 的 mRNA 表达均显著增加，且添加 AKG 和磷后（P<0.05）。Nrf2 信号通路中的 Nrf2、GPx1a 和 CAT 的 mRNA 表达也显著增加，添加 AKG 和磷后（P<0.05）。IL-10 和 TGF-β2 的表达水平显著增加，但添加 AKG 和磷后，IL-1β、IL-8、IL-10、TNF-a 和 NF-κB 的表达水平显著降低（P<0.05）。根据 WGR 对饮食磷水平的二次多项式回归分析，发现添加 1%AKG 的饲料中幼镜鲤的最佳饮食磷水平为 0.79%干饲料，不添加 AKG 的饲料为 0.93%干饲料。本研究证实，AKG 补充剂可通过促进生长性能、肠道紧密连接、Nrf2 信号通路和免疫反应，降低幼镜鲤对磷的饮食需求。
