White Feces Syndrome of Shrimp Arises from Transformation, Sloughing and Aggregation of Hepatopancreatic Microvilli into Vermiform Bodies Superficially Resembling Gregarines

Abstract

Accompanying acute hepatopancreatic necrosis disease (AHPND) in cultivated Asian shrimp has been an increasing prevalence of vermiform, gregarine-like bodies within the shrimp hepatopancreas (HP) and midgut. In high quantity they result in white fecal strings and a phenomenon called white feces syndrome (WFS). Light microscopy (LM) of squash mounts and stained smears from fresh HP tissue revealed that the vermiform bodies are almost transparent with widths and diameters proportional to the HP tubule lumens in which they occur. Despite vermiform appearance, they show no cellular structure. At high magnification (LM with 40-100x objectives), they appear to consist of a thin, outer membrane enclosing a complex of thicker, inter-folded membranes. Transmission electron microscopy (TEM) revealed that the outer non-laminar membrane of the vermiform bodies bore no resemblance to a plasma membrane or to the outer layer of any known gregarine, other protozoan or metazoan. Sub-cellular organelles such as mitochondria, nuclei, endoplasmic reticulum and ribosomes were absent. The internal membranes had a tubular sub-structure and occasionally enclosed whole B-cells, sloughed from the HP tubule epithelium. These internal membranes were shown to arise from transformed microvilli that peeled away from HP tubule epithelial cells and then aggregated in the tubule lumen. Stripped of microvilli, the originating cells underwent lysis. By contrast, B-cells remained intact or were sloughed independently and whole from the tubule epithelium. When sometimes engulfed by the aggregated, transformed microvilli (ATM) they could be misinterpreted as cyst-like structures by light microscopy, contributing to gregarine-like appearance. The cause of ATM is currently unknown, but formation by loss of microvilli and subsequent cell lysis indicate that their formation is a pathological process. If sufficiently severe, they may retard shrimp growth and may predispose shrimp to opportunistic pathogens. Thus, the cause of ATM and their relationship (if any) to AHPND should be determined.

Evaluation of medicinal plants and colloidal silver efficiency against Vibrio parahaemolyticus infection in Litopenaeus vannamei cultured at low salinity

“…Bacteria found in the detritus from the culture system orally colonized the digestive tract, produced toxins and caused HP cellular dysfunction, destroyed the E, R, F and B cells, sloughed the tubular epithelium cells from the proximal to the distal region and produced inflammation, hemocytic infiltration and necrosis. Sriurairatana et al (2014) reported that when AHPNS appears, similar vermiform structures (aggregated transformed microvilli, ATM) are found in the HP and intestine, as observed in our study. Multiple functions are attributed to the HP: it serves as temporary food storage, produces and synthesizes protein, is involved with secretion of digestive enzymes and absorption of nutrients and is capable of metabolizing lipids and carbohydrate; there fore, any injures to this important organ could cause mortalities (Ceccaldi 1997, Lehnert & Johnson 2002, McGaw & Curtis 2013.…”

“…Their organs and tissues were removed, dissected and squash-mounted with sterile seawater, then examined under the light microscope (Lightner 1996, Morales-Covarrubias & Gómez-Gil 2014, Sriurairatana et al 2014). …”

Necrosis aguda del hepatopáncreas: una revisión de la enfermedad en Penaeus vannamei

“…En los años siguientes y aún sin identificar la etiología, se propagó a países cercanos, afectando a Vietnam en el año 2010, Malasia en el 2011 y Tailandia durante el 2012 (NACA, 2012;FAO, 2013;Lightner et al, 2013;Sriurairatana et al, 2014). Recientemente, fue reportado en Filipinas (de-la- .…”

Acreditation Certificate Acreditation No. 21/E/KPT/2018 Article Tools Print this article Indexing metadata How to cite item Supplementary files Email this article Email the author About The Authors Heri Ariadi ORCID iD http://ub.edu/heri Fisheries and Marine Science Faculty, University of Brawijaya Indonesia Good luck to RJLS Publisher Mohammad Mahmudi Fisheries and Marine Science Faculty, University of Brawijaya Indonesia Mohamad Fadjar Fisheries and Marine Science Faculty, University of Brawijaya Ind

“…Vibrio bacteria that are sensitive to environmental conditions will be very opportunistic if their abundance is above the threshold (Heenatigala and Fernando, 2016). So that, it will cause various multiple diseases in cultivated shrimp such as white feces syndrome, Enterocytozoon hepatopenaei (EHP) infection, and mass death caused by physiological symptoms caused by Vibrio bacterial infections (Jayasree et al, 2006;Sriurairatana et al, 2014;Mastan, 2015;and Aranguren et al, 2017).…”