Stomach development in the sturgeon Acipenser naccarii: histoenzymatic and ultrastructural analysis

Abstract

This study describes the stomach development in the sturgeon Acipenser naccarii, focusing on its histoenzymatic and ultrastructural characteristics from hatching until the end of the juvenile phase, 1 month later. The study aims to assist the aquaculturist in identifying the best timing for the start of feeding and to select the appropriate food for each stage of A. naccarii development. At hatching, the anterior portion of the digestive system consists of a yolk sac with a large central yolk mass. The yolk mass is enclosed by differentiating endodermal epithelium. The most significant ultrastructural characteristics of the epithelium are the numerous supranuclear vacuoles containing protein and lipid yolk granules, dilated intercellular spaces, and filiform cytoplasmic projections related to the uptake of reserve material on the apical surface. Newly hatched eleutheroembryos show optimal enzymatic activities at a pH of 1.5 and 3, which is probably related to the presence of hatching glands and the digestion of yolk components. During the free-embryo phase, the yolk sac epithelium undergoes a series of histological, ultrastructural, and functional modifications to form a cecal stomach with anatomical characteristics similar to those of juvenile specimens. Gastric glands emerge between 6 and 7 days post-hatching (PH), although the absence of secretion granules in their oxyntic-peptic cells indicates that the stomach is not yet functional. During the following days (the exotrophic period), development of the tubular-vesicular network is observed, and secreting granules occur in the cytoplasm of oxyntic-peptic cells until around day 35 after fertilization (day 27 PH), when acid protease enzymatic activity is again detected. These histological and enzymatic changes and the greater number and size of oxyntic-peptic cell secretion granules appear to be related to the gastric compartment ontogeny reaching functionality at this developmental stage.

Morphological development in the first life phase of Adriatic sturgeon Acipenser naccarii under controlled conditions

“…In addition to these changes, the digestive system began to develop, the intestinal tract was partially differentiated, but did not open to the exterior (Ostos‐Garrido et al, ). The digestive system, which is already divided into two areas, yolk sac and spiral valve anlage (Camacho et al, ; Sanz et al, ), produces an increase in enzymatic activity at the time of hatching (Sanz et al, ). In the caudal section, the Wolff ducts join up to form a primitive cloaca (Boglione et al, ).…”

“…Whilst the development of the vital organs (Gómez et al, ; Icardo et al ., ; Ostos‐Garrido et al . ; Camacho et al, ; Sanz et al, ) allow for prey capture.…”

“…The increased swimming ability together with the differentiation of the sensory organs permit prelarvae to forage (Dettlaff et al, 1993). Whilst the development of the vital organs (Gómez et al, 2009;Icardo et al, 2009;Ostos-Garrido et al, 2009;Camacho et al, 2011;Sanz et al, 2011) allow for prey capture.…”

“…Although embryonic development of A. naccarii has recently been described (Cabrera et al, 2015), most of the available studies on this sturgeon species focus on morphological and physiological adjustments to changes in ambient salinity (Cataldi et al, 1995McKenzie et al, 1999McKenzie et al, , 2001aMcKenzie et al, , 2001bMartínez-Álvarez et al, 2002Martínez-Álvarez et al, , 2005Carmona et al, 2004), ontogenesis of various organs (Cataldi et al, 2002;Vázquez et al, 2002;Grandi & Chicca, 2004;Icardo et al, 2004;Gomez et al, 2009;Camacho et al, 2011), ampullary organs (Camacho et al, 2007), early ontogeny with special focus on the digestive tract and cutaneous receptors (Boglione et al, , 2006, some aspects related to feeding and nutrition (Agradi et al, 1993;Soriguer et al, 2002) and digestive (Furné et al, 2005(Furné et al, , 2008a and antioxidant (Trenzado et al, 2006;Furné et al, 2008b) capacities, however less is known about structural development at a macroscopic level.…”

Ultrastructural studies of Puntius shalynius an endemic and threatened hill stream fish

“…The overall gastrointestinal morphology is related to different feeding habits including the nature of the food and frequency of food intake, as well as taxonomy, body size and shape (Boglione et al, 1992;Domeneghini et al, 1999). The alimentary canal of teleostean fishes has been widely studied (MacDonald, 1987;Kuperman and Kuzmina, 1994;Domeneghini et al, 2002;Khojasteh et al, 2009;Camacho et al, 2011) and described morphologically to determine the function of many specialized anatomical structures (Cataldi et al, 1987). In many fish species, the anatomy of intestine has been studied which are important for aquaculture, recreation and aquarium (Caceci and Hrubec, 1990).…”