High-throughput sequencing of the 16S rRNA gene to analyze the gut microbiome in juvenile and adult tropical gar (Atractosteus tropicus)

Tropical gar (Atractosteus tropicus) is freshwater and estuarine fish, inhabiting the Earth since the Mesozoic era and undergoing limited physiological variation ever since. Besides its recognized cultural and scientific relevance, the species has seen remarkable growth in its economic impact due to pisciculture. In this study, we present the first report of the whole taxonomic composition of microbial communities in gut contents in juveniles and adults of A. tropicus, by sex and origin (wild and cultivated). For this study, 508 genera were identified, with the most and least abundant being Cetobacterium and Paludibacter, respectively. Fusobacteria, Proteobacteria, Firmicutes, and Bacteroidetes phyla are the core gut microbiome of A. tropicus juvenile and adult by sex and origin. Deinococcus-Thermus phylum sequence was only identified in wild-type males. In the phylogenetic trees reconstruction Lactococcus lactis strains CAU929 and CAU6600, Cp6 and CAU9951, Cetobacterium strain H69, Aeromonas hydrophila strain P5 and WR-5-3-2, Aeromonas sobria strain CP DC28 and Aeromonas hydrophila were identified, some of them with probiotic potential within the three dominant phyla in core gut microbiome in A. tropicus adults, especially in wild-type organisms. Myroides genus was recognized in microbiota gut of the cultivated juvenile A. tropicus. Nevertheless, Alpha diversity indicated that the highest gut microbiota abundance and richness is found in cultivated juvenile and wild-type adult A. tropicus female, rather than adult wild-type males and the least gut microbiota abundance and richness is found in a cultivated adult of A. tropicus for both sexes.The authors thank the Mexican National Council of Science and Technology for the postgraduate studies thesis scholarship and the mixed scholarship granted to carry out the research internship at the University of Valencia (Spain). This research received external funding from the Mexican National Council of Science and Technology "Strengthening of the Master's Degree in Environmental Sciences for its Permanence in the National Register of Quality Graduates of CONACYT" Reg. No. TAB-2014-C29-245836 and the Project "Estudio de la fisiología digestiva en larvas y juveniles de pejelagarto (Atractosteus tropicus) con base en técnicas histológicas, bioquímicas y moleculares" Reg. No. CB-2016-01-282765.Peer reviewe

Registro de larvas de Sebekia sp. (Pentastomida: Sebekidae) en peces de la cuenca media del río Usumacinta, Tabasco, México

Commercially important fish in Tabasco, Mexico have been naturally infested with pentastomid parasite. The present research the morphology show information about the ecological indexes of infection of the larvae in three species of fish of commercial importance. The fish under study are mojarra, which are of alimentary interest such as Parachromis managuensis, Petenia splendida and Gobiomorus dormitor. A total of 30 pentastomid larvae were registered. The highest prevalence in these fish was in G. dormitor 30% and 35%, during the year 2005 and 2015. The prevalence by pentastomid larvae has increased in the studied species, therefore, avoiding the consumption of raw fish in different dishes is recommended, and it is proposed to the health sector to establish caution measures in order to avoid infection to humans by this larvae.Peces de importancia comercial en Tabasco, México, están siendo infestados de manera natural con parásitos de pentastómidos. En la presente investigación se dan a conocer la morfología, los índices ecológicos de infección de la larva en tres especies de valor comercial. Los peces bajo estudio son mojarras de interés alimenticio como Parachromis managuensis, Petenia splendida y Gobiomorus dormitor. Se registró un total de 30 larvas de pentastómidos. La mayor prevalencia registrada en estos fue en G. dormitor de 30% y 35%, durante los años 2005 y 2015, respectivamente. La prevalencia por larvas de pentastómido ha incrementado en las especies estudiadas. Por tanto, se recomienda evitar el consumo de ejemplares crudos en diferentes platillos, y se propone al sector salud tomar las medidas precautorias ante la sociedad para evitar infección a humanos por esta larva