Comparison of bacterial diversity indexes of water samples from trout fed animal and plant protein diets.

<p>Comparison of bacterial diversity indexes of water samples from trout fed animal and plant protein diets.</p

Water system is a controlling variable modulating bacterial diversity of gastrointestinal tract and performance in rainbow trout

<div><p>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 16^th 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 <i>Proteobacteria</i>, <i>Firmicutes</i> and <i>Bacteroidetes</i>. 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 <i>Aeromonas</i> and <i>Acinetobacter</i> in the rainbow trout.</p></div

Bar chart of the relative abundance of bacterial community compositions at genus level at rearing water levels.

<p>Flow-through (FF), moved from flow-through to recirculating (FR), recirculating (RR) and moved from recirculating to flow-through (RF).</p

Chemical analysis (% dry weight) and apparent digestibility coefficients (ADCs) of nutrients in unbalanced or balanced APD and PPD.

<p>Chemical analysis (% dry weight) and apparent digestibility coefficients (ADCs) of nutrients in unbalanced or balanced APD and PPD.</p

Ingredients and chemical compositions of experimental diets.

<p>Ingredients and chemical compositions of experimental diets.</p

Bar chart of the relative abundance of bacterial community compositions at genus level at GIT locations.

<p>Bar chart of the relative abundance of bacterial community compositions at genus level at GIT locations.</p

Results of PEMANOVA analysis for the different diets, gut locations, and water samples.

<p>Results of PEMANOVA analysis for the different diets, gut locations, and water samples.</p

Bar chart of the relative abundance of bacterial community compositions at genus level at dietary treatments level with (BB) or without (UN) substitution with crystalline amino acids.

<p>Bar chart of the relative abundance of bacterial community compositions at genus level at dietary treatments level with (BB) or without (UN) substitution with crystalline amino acids.</p

Bacterial composition at phylum level of rainbow trout fed animal and plant protein diets.

<p>Digesta and water samples are grouped by dietary treatments. Dietary treatments: Balanced Animal protein diet (APD), Unbalanced animal protein diet (UnAPD), Plant protein diet (PPD),Unbalanced plant protein diet) (UnPPD), Luminal samples by Balanced APD diet (Lum_APD), Luminal samples by Balanced PPD diet (Lum_PPD), Mucosal samples by Balanced APD diet (Muc_APD), Mucosal samples by Balanced PPD diet Muc_PPD); and Water samples: Samples from APD diet (W_APD), Samples from PPD diet (W_PPD), Samples from Unbalanced APD diet (W_UnAPD), Samples from Unbalanced PPD diet (W_UnPPD).</p

Growth performance and whole-body (WB) composition of rainbow trout fed animal and plant protein diets¹.

<p>Growth performance and whole-body (WB) composition of rainbow trout fed animal and plant protein diets<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0195967#t003fn002" target="_blank">¹</a>.</p