Faecal bacterial communities from Mediterranean loggerhead sea turtles (Caretta caretta)

Abstract

The loggerhead sea turtle (Caretta caretta) is the most widespread sea turtle species in the Mediterranean Sea and a relevant pollution 'flagship species'. Here, we profiled the faecal microbiota from 29 C. caretta from a rescue centre, and explored the impact of several variables linked to both the animal itself and the environment (i.e., tank water ecosystem). We show that loggerhead turtles share more gut microbiota features with carnivorous marine mammals, than with phylogenetically close, but herbivorous, turtles, as a confirmation of the gut microbiota adaptive function to diet and environment. We also highlight a relation between the microbiota composition and the size (and consequently the age) of the turtles. Finally, we point out that the gut microbiota of sea turtles shows unexpectedly low exchange of microbes with the aquatic environment and is resilient to the stress induced by short-time captivity.

Antibiotic Resistance of Gram-Negative Bacteria from Wild Captured Loggerhead Sea Turtles

“…In this study, we report for the first time the isolation and the antibiotic resistance profile of Gram-negative bacteria, from wild free-living loggerhead sea turtles in the Mediterranean Sea. A few studies have previously described the microbiota associated with Caretta caretta turtles [30][31][32], but the analysis was carried out on fecal samples of animals which experienced from few to many days in specialized centers [30][31][32], or on the intestinal samples of dead animals [30]. These studies revealed the gut microbial composition of loggerhead sea turtles by using the metagenomics approach, but results could be biased by the health conditions of the animals, by conditions, treatments or therapies in the recovery centers.…”

“…The latter were the sea turtles with a problem (hook, plastic presence, gastrointestinal occlusion, collision with a boat) that needed a recovery period. A significant correlation was found among the different body measurements recorded To date, a few studies investigated the microbial community associated with Caretta caretta by using culture-dependent methods [9,10,[27][28][29] or metagenomic analysis [30][31][32], and even fewer studies were carried out on the antibiotic resistance of isolates [9,10,13,28]. All the latter studies collected samples from animals that needed to be recovered for several reasons (traumas, ingestion of fishing hooks, parasitosis, respiratory disorders) [9,10,13,28], or found dead along the seacoast [13].…”

Effects of rearing density on growth, digestive conditions, welfare indicators and gut bacterial community of gilthead sea bream (Sparus aurata, L. 1758) fed different fishmeal and fish oil dietary levels

“…Briefly, the thermal cycle consisted of an initial denaturation at 95 °C for 3 min, 30 cycles of denaturation at 95 °C for 30 s, annealing at 55 °C for 30 s and extension at 72°C for 30 s, and a final extension step at 72 °C for 5 min. PCR reactions were cleaned up for sequencing by using Agencourt AMPure XP magnetic beads as recommended in the Illumina protocol "16S Metagenomic Sequencing Library Preparation" for the MiSeq system, and as used in several other publications (Biagi et al, 2018;Soverini et al, 2016).…”

The effect of diet on the gastrointestinal microbiome of juvenile rehabilitating green turtles (Chelonia mydas)

“…Despite considerable advancements in the study of the GI microbiota and a seemingly exponential increase in the number of studies in various taxa of animals, the reptilian microbiome remains poorly understood [8]. Knowledge about the microbiome of sea turtles, all species of which are listed internationally as either Threatened or Endangered [9], is limited but expanding [10][11][12][13][14][15][16]. Understanding endangered sea turtle core microbiota and what influences its composition is likely to influence how we manage conservation efforts.…”