United States Fish and Wildlife Service, Bozeman Fish Technology Center, Bozeman, Montana, United States of America.
Department of Animal and Range Science, Montana State University, Bozeman, Montana, United States of America.
PLoS One. 2018 Apr 17;13(4):e0195967. doi: 10.1371/journal.pone.0195967. eCollection 2018.
A two-phase feeding study evaluating performance of rainbow trout and comparing luminal and mucosal gastrointestinal tract (GIT) bacterial community compositions when fed two alternative protein diets in two rearing systems was conducted. Alternative protein diets (animal protein and plant protein diets) balanced with crystalline amino acids: lysine, methionine and threonine or unbalanced, were fed to rainbow trout in two separate water systems (recirculating (RR) and flow-through (FF)) for a period of 16 weeks. The four diets, each contained 38% digestible protein and 20% fats, were fed to rainbow trout with an average weight of 12.02 ± 0.61 g, and sorted at 30 fish/tank and 12 tanks per dietary treatment. Phase 1 lasted for 8 weeks after which fish from each tank were randomly divided, with one-half moved to new tanks of the opposing system (i.e. from RR to FF and vice versa). The remaining halves were retained in their initial tank and system, and fed their original diets for another 8 weeks (phase 2). After the 16th week, 3 fish/tank were sampled for each of proximate analysis, body indexes and 16S rRNA analysis of GIT microbiota. Fish weight (P = 0.0008, P = 0.0030, P<0.0010) and body fat (P = 0.0008, P = 0.0041, P = 0.0177) were significantly affected by diet, diet quality (balanced or unbalanced) and system, respectively. Feed intake (P = 0.0008) and body energy (P<0.0010) were altered by system. Body indexes were not affected by dietary treatment and water systems. Compositional dissimilarities existed between samples from the rearing water and GIT locations (ANOSIM: (R = 0.29, P = 0.0010), PERMANOVA: R = 0.39, P = 0.0010), but not in dietary samples (ANOSIM: R = 0.004, P = 0.3140, PERMANOVA: R = 0.008, P = 0.4540). Bacteria were predominantly from the phyla Proteobacteria, Firmicutes and Bacteroidetes. Their abundance differed with more dissimilarity in the luminal samples (ANOSIM: R = 0.40, P = 0.0010, PERMANOVA: R = 0.56, P = 0.0010) than those from the mucosal intestine (ANOSIM: R = 0.37, P = 0.0010, PERMANOVA: R = 0.41, P = 0.0010). Bacteria generally associated with carbohydrate and certain amino acids metabolism were observed in the mucosal intestine while rearing water appeared to serve as the main route of colonization of Aeromonas and Acinetobacter in the rainbow trout.
进行了一项两阶段喂养研究，评估虹鳟鱼的性能，并比较当在两种养殖系统中以两种替代蛋白质饲料喂养时，肠道（GIT）腔内和黏膜表面的细菌群落组成。替代蛋白质饲料（动物蛋白和植物蛋白饲料）用结晶氨基酸（赖氨酸、蛋氨酸和苏氨酸）平衡或不平衡，以每 38%可消化蛋白和 20%脂肪的比例，喂给平均体重为 12.02 ± 0.61g 的虹鳟鱼，每 30 条鱼/缸，每 12 个缸进行一种饮食处理。四组饲料中，每组饲料都含有 38%可消化蛋白和 20%脂肪，喂养虹鳟鱼 16 周。第一阶段持续 8 周，此后，从每个缸中随机取出一半鱼，转移到相反系统（即从循环水系统到流水系统，反之亦然）的新缸中。另一半鱼保留在初始缸和系统中，并继续以初始饮食喂养 8 周（第二阶段）。第 16 周后，从每个缸中取出 3 条鱼进行常规分析、身体指标和 16S rRNA 分析。鱼的体重（P = 0.0008，P = 0.0030，P<0.0010）和体脂（P = 0.0008，P = 0.0041，P = 0.0177）显著受饮食、饮食质量（平衡或不平衡）和系统的影响。摄食率（P = 0.0008）和鱼体能量（P<0.0010）受系统影响。饮食处理和水系统对身体指数没有影响。养殖水和肠道位置的样本之间存在组成差异（ANOSIM：（R = 0.29，P = 0.0010），PERMANOVA：R = 0.39，P = 0.0010），但饮食样本中没有（ANOSIM：R = 0.004，P = 0.3140，PERMANOVA：R = 0.008，P = 0.4540）。细菌主要来自于变形菌门、厚壁菌门和拟杆菌门。它们的丰度因腔内样本的差异更大（ANOSIM：R = 0.40，P = 0.0010，PERMANOVA：R = 0.56，P = 0.0010）而与黏膜肠内样本不同（ANOSIM：R = 0.37，P = 0.0010，PERMANOVA：R = 0.41，P = 0.0010）。在黏膜肠内观察到与碳水化合物和某些氨基酸代谢相关的细菌，而养殖水似乎是虹鳟鱼中气单胞菌和不动杆菌定植的主要途径。
