Description of the unusual digestive tract of Platax orbicularis and the potential impact of Tenacibaculum maritimum infection

Type Article
Date 2020-09
Language English
Author(s) Alix Maud2, 6, Gasset EricORCID1, Bardon-Albaret Agnes3, Noel Jean4, 5, Pirot Nelly4, 5, Perez Valérie6, Coves Denis1, Saulnier Denis3, Lignot Jehan-Hervé6, Cucchi Patricia N.6
Affiliation(s) 1 : MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France
2 : Institute of Marine Research, Bergen, Norway
3 : Ifremer, UMR Ecosystèmes Insulaires Océaniens, UPF, ILM, IRD, Tahiti, French Polynesia
4 : BCM, Université de Montpellier, CNRS, INSERM, Montpellier, France
5 : IRCM, Université de Montpellier, ICM, INSERM, Montpellier, France
6 : MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France
Source Peerj (2167-8359) (PeerJ), 2020-09 , Vol. 8 , P. e9966 (29p.)
DOI 10.7717/peerj.9966
WOS© Times Cited 1
Keyword(s) Digestive system, Tenacibaculosis, Mucous, Osmoregulation, Absorption, Batfish, Teleost
Abstract

Background

Ephippidae fish are characterized by a discoid shape with a very small visceral cavity. Among them Platax orbicularis has a high economic potential due to its flesh quality and flesh to carcass ratio. Nonetheless, the development of its aquaculture is limited by high mortality rates, especially due to Tenacibaculum maritimum infection, occurring one to three weeks after the transfer of fishes from bio-secure land-based aquaculture system to the lagoon cages for growth. Among the lines of defense against this microbial infection, the gastrointestinal tract (GIT) is less studied. The knowledge about the morphofunctional anatomy of this organ in P. orbicularis is still scarce. Therefore, the aims of this study are to characterize the GIT in non-infected P. orbicularis juveniles to then investigate the impact of T. maritimum on this multifunctional organ.

Methods

In the first place, the morpho-anatomy of the GIT in non-infected individuals was characterized using various histological techniques. Then, infected individuals, experimentally challenged by T. maritimum were analysed and compared to the previously established GIT reference.

Results

The overlapped shape of the GIT of P. orbicularis is probably due to its constrained compaction in a narrow visceral cavity. Firstly, the GIT was divided into 10 sections, from the esophagus to the rectum. For each section, the structure of the walls was characterized, with a focus on mucus secretions and the presence of the Na+/K+ ATPase pump. An identification key allowing the characterization of the GIT sections using in toto histology is given. Secondly, individuals challenged with T. maritimum exhibited differences in mucus type and proportion and, modifications in the mucosal and muscle layers. These changes could induce an imbalance in the trade-off between the GIT functions which may be in favour of protection and immunity to the disadvantage of nutrition capacities.

Full Text
File Pages Size Access
Publisher's official version 29 29 MB Open access
Illustration of whitish patches caused by T. maritimum on the skin of P. orbicularis 5 MB Open access
Comparison of Na+/K+ ATPase labeling in different sections of P. orbicularis GIT in non-infected and infected fish using different settings for image correction 3 MB Open access
Measurements of the different muscles layers in the sections of the digestive tract in non-infected and infected Platax orbicularis 11 KB Open access
Measurements of the proportion of acidic mucocytes in different sections (3, 4 and 5) of the digestive tract in non-infected and infected Platax orbicularis 9 KB Open access
Measurements of the enterocyte length in different sections of the digestive tract in non-infected and infected Platax orbicularis 10 KB Open access
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How to cite 

Alix Maud, Gasset Eric, Bardon-Albaret Agnes, Noel Jean, Pirot Nelly, Perez Valérie, Coves Denis, Saulnier Denis, Lignot Jehan-Hervé, Cucchi Patricia N. (2020). Description of the unusual digestive tract of Platax orbicularis and the potential impact of Tenacibaculum maritimum infection. Peerj, 8, e9966 (29p.). Publisher's official version : https://doi.org/10.7717/peerj.9966 , Open Access version : https://archimer.ifremer.fr/doc/00652/76421/