Host-Associated Bacterial Succession during the Early Embryonic Stages and First Feeding in Farmed Gilthead Sea Bream (Sparus aurata)

Abstract

One of the most widely reared fish in the Mediterranean Sea is Sparus aurata. The succession of S. aurata whole-body microbiota in fertilized eggs, five, 15, 21 and 71 days post hatch (dph) larvae and the contribution of the rearing water and the provided feed (rotifers, Artemia sp. and commercial diet) to the host’s microbiota was investigated by 454 pyrosequencing of the 16S rRNA gene diversity. In total, 1917 bacterial operational taxonomic units (OTUs) were found in all samples. On average, between 93 ± 2.1 and 366 ± 9.2 bacterial OTUs per sample were found, with most of them belonging to Proteobacteria and Bacteroidetes. Ten OTUs were shared between all S. aurata stages and were also detected in the rearing water or diet. The highest OTU richness occurred at the egg stage and the lowest at the yolk sac stage (5 dph). The rearing water and diet microbial communities contributed in S. aurata microbiota without overlaps in their microbial composition and structure. The commercial diet showed higher contribution to the S. aurata microbiota than the rearing water. After stage D71 the observed microbiota showed similarities with that of adult S. aurata as indicated by the increased number of OTUs associated with γ-Proteobacteria and Firmicutes.

Characterization of the skin and gill microbiomes in farmed seabass and seabream across different age groups

“…The water microbiome of shponds were signi cantly distinct and more diverse than the skin and gill microbiomes of both sh, regardless of their age. It is known that free-living microbial communities retain higher richness than host-associated communities [31], with many studies showing a higher bacterial diversity in water relative to sh skin [28,30,36,[58][59][60], gills [14,36], gut [7,15,18,21,61], stomach [36], hindgut [36] and whole larvae [22]. Although some studies in sh have shown that the microbial communities found in the water tend to be recovered in the larval gut microbiome [17,21], others have also shown that water microbiomes do not in uence directly the microbiomes of sh mucosa [7, 8, 13-15, 18, 19, 22, 28, 30, 34, 36, 58-60, 62, 63].…”

“…In piscine hosts, most of the microbiome studies related to the effects of age are focused on the gut microbiomes [12][13][14][15][16][17][18][19][20][21][22]. Some of these studies showed that microbial communities in the surrounding waters in uence the gut microbiome during early life stages, which becomes increasingly unique with age [17,21].…”

“…Importantly, most studies testing the role of age on sh microbiomes were cross-sectional and based on a single time point or short time window [e.g. 16,18,19,21,22]. Thus, given the high susceptibility of the sh microbiome to environmental changes and the high inter-individual microbiome variability [e.g.…”

Genetic selection for growth drives differences in intestinal microbiota composition and parasite disease resistance in gilthead sea bream

“…Due to its economic value, many studies on gilthead sea bream intestinal microbiota have been conducted. These studies were mainly focused on de ning baseline populations [35][36][37] or changes induced by diet [18,[38][39][40][41][42][43][44] or environmental conditions [45]. The microbiota is composed of very dynamic populations that are affected by different factors [18,36,[53][54][55]42,[46][47][48][49][50][51][52] such as diet, season, habitat, rearing density, age, sex and genetic background, the focus of the current study.…”

Genetic selection for growth drives differences in intestinal microbiota composition and parasite disease resistance in gilthead sea bream

“…Due to its economic value, many studies on gilthead sea bream intestinal microbiota have been conducted. These studies were mainly focused on de ning baseline populations [35][36][37] or changes induced by diet [18,[38][39][40][41][42][43][44] or environmental conditions [45]. The microbiota is composed of very dynamic populations that are affected by different factors [18,36,42,[46][47][48][49][50][51][52][53][54][55] such as diet, season, habitat, rearing density, age, sex and genetic background, the focus of the current study.…”