摘要
【目的】探讨mTOR信号通路对饲喂低蛋白饲料下中国花鲈生长性能、氨基酸代谢及肠道健康的影响。【方法】实验以粗蛋白含量为50%的饲料为对照组(CON组),设置48%蛋白含量的饲料为低蛋白饲料组(P48组),在低蛋白饲料基础上添加0.1%mTOR信号通路激活剂为P48S组。以初始体重为(21.20±0.20)g的中国花鲈为研究对象,在室内循环水养殖系统中开展为期8周的养殖实验。【结果】饲喂低蛋白饲料显著降低了中国花鲈增重率、特定生长率,提高了饲料系数。添加0.1%mTOR信号通路激活剂可有效激活中国花鲈mTOR信号通路,改善其生长性能与饲料利用,P48S组增重率、特定增长率较P48组分别提高25.12%、12.03%,饲料系数降低8.33%。相较于P48组,P48S组鱼体粗蛋白含量提高4.45%,血浆总胆固醇和甘油三酯含量分别降低12.57%、20.44%。P48S组血浆总游离氨基酸、总必需氨基酸及总非必需氨基酸水平均显著高于CON组和P48组,肌肉游离必需氨基酸含量也显著提高。P48S组肠绒毛高度较于P48组显著提高22.82%。进一步检测肠道消化酶及氨基酸转运载体,结果发现,P48S组肠道胰蛋白酶、脂肪酶活性显著提高,氨基酸及小肽转运载体基因pept1、lat1和asct2表达水平显著提高。【结论】降低饲料蛋白水平会抑制中国花鲈的生长性能,激活mTOR信号通路通过增强饲料蛋白质消化和促进氨基酸吸收与代谢,提高蛋白质合成,显著改善中国花鲈生长性能。
This study examined how activation of the mTOR pathway influences growth,amino-acid metabolism,and intest-inal health in juvenile spotted seabass(Lateolabrax maculatus)fed a low-protein diet.Triplicate groups received,for eight weeks,either a 50%crude-protein control diet(CON),a 48%crude-protein diet(P48),or the P48 diet supplemented with 0.1%of a specific mTOR activator(P48S).Fish[(21.20±0.20)g]were reared in a recirculating aquaculture system under controlled conditions.Relative to CON,P48 depressed weight gain rate(WGR)and specific growth rate(SGR)and increased feed-con-version ratio(FCR).Supplementation in P48S reversed these deficits:WGR rose 25.12%,SGR 12.03%,and FCR fell 8.33%compared with P48.Whole-body crude protein increased 4.45%,while plasma total cholesterol and triglycerides declined 12.57%and 20.44%,respectively.Blood analysis revealed that the P48S group had significantly higher plasma levels of total free amino acids(TAA),total essential amino acids(EAA),and total non-essential amino acids(NEAA)compared to both the CON and P48 groups,coupled with elevated muscle free EAA content.Morphologically,villus height was 22.82%greater in P48S than in P48.Complementing these findings,further biochemical analysis uncovered enhanced activity of key intestinal digestive enzymes,specifically trypsin and lipase,in the P48S group.Additionally,gene expression analysis indicated upregu-lated levels of crucial amino acid and small peptide transporters(pept1,lat1,and asct2)within the intestines of the P48S group.In conclusion,while reducing dietary protein levels clearly suppresses growth performance in L.maculatus,the activation of the mTOR signaling pathway presents a viable strategy to counteract these effects.This activation improves protein synthesis by enhancing feed protein digestion,promoting amino acid absorption and metabolism,and thereby significantly restoring and enhancing growth performance,even under suboptimal protein dietary conditions.
作者
孟迎冬
王旋
刘成栋
周慧慧
麦康森
何艮
MENG Yingdong;WANG Xuan;LIU Chengdong;ZHOU Huihui;MAI Kangsen;HE Gen(Key Laboratory of Mariculture,Ministry of Education,Key Laboratory of Aquaculture Nutrition and Feed,Ministry of Agriculture and Rural Affairs,Fisheries College,Ocean University of China,Qingdao 266003,China)
出处
《水产学报》
北大核心
2025年第10期1-12,共12页
Journal of Fisheries of China
基金
国家重点研发计划(2023YFD2400600)
国家现代农业产业技术体系(CARS-47-G10)。
关键词
中国花鲈
MTOR信号通路
生长性能
饲料利用率
氨基酸代谢
Lateolabrax maculatus
mTOR signalling pathway
growth
feed utilisation rate
amino acid metabolism
作者简介
第一作者:孟迎冬,从事水产动物营养与饲料研究,E-mail:3304328359@qq.com;通信作者:王旋,从事水产动物蛋白质代谢与营养调控研究,E-mail:xuanwang@ouc.edu.cn。
