The Development of the Digestive Tract in Larval European Catfish (Silurus glanis L.)
Department of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Zagreb, 10000 Zagreb, Croatia.Anantomia Histologia Embryologia (Impact Factor: 0.67). 05/2008; 37(2):141-6. DOI: 10.1111/j.1439-0264.2007.00812.x
The European catfish, Silurus glanis L., has become an important aqua cultural fish in Croatia, and it is cultivated extensively in ponds in polyculture with carps. The development of the digestive tract in S. glanis was studied with the aim of improving intensive fish production. Research was carried out on S. glanis larval stadium from 1- to 19-day post-hatching (DPH). The main histological methods used were: haematoxylin and eosin staining, periodic acid Schiff staining (PAS), Alcian blue (AB) and toluidin blue staining (TB). A yolk sac was present during the first 5 days (1-5-DPH). During the initial 3-DPH period, there was no trace PAS and AB activity in the digestive tract. Differentiation of the digestive tract began at 3- to 5-DPH. The oesophagus was positive for AB at 5-DPH, PAS and TB after 7-DPH. Differentiation of enterocytes began at 5-DPG and the intestines were complete at 11-DPH. Development of liver and pancreas was also studied. The analysis of data obtained in this study suggests that after 5-DPH catfish larvae have morphologically completed digestive tracts.
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- "The morphological differentiation of the digestive tract during larval ontogenesis is paralleled by functional changes which may be helpful in optimizing feeding protocols (Zambonino-Infante and Cahu, 2001; Suzer et al., 2007 a,b; Kozari c et al., 2008; De Amorim et al., 2009; Zambonino-Infante et al., 2009; Yang et al., 2010; Lazo et al., 2011). The secretion of digestive enzymes during early life stages reflects the functional development of the digestive tract and digestive capacities of the organism (Pradhan et al., 2013). "
ABSTRACT: Despite the growing importance of zebrafish (Danio rerio) as an experimental model in biomedical research, some aspect of physiological and related morphological age dependent changes in digestive system during larval development are still unknown. In this paper, a biochemical and morphological study of the digestive tract of zebrafish was undertaken to record the functional changes occurring in this species during its ontogenetic development, particularly from 24 hr to 47 days post fertilization (dpf). Endo- and exo-proteases, as well as a-amylase enzymes, were quantified in zebrafish larvae before first feeding (7 dpf). The most morphologically significant events during the ontogenesis of the gut occurred between 3 dpf (mouth opening) and 7 dpf (end of exocrine pancreas differentiation). The presence of a wide range of digestive enzymes, already active at earlier zebrafish larval stages, closely related with the omnivorous diet of this species. Increasing enzyme activities were found with increasing age, probably in relation with intestinal mucosa folding and consequent absorption surface increase.
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- "The appearance of gastric glands normally indicates the formation of a functional stomach (Stroband and Kroon, 1981), which is also a histological criterion to differentiate larvae from juveniles (Sarasquete et al., 1995). Similar results were reported for most part of Siluriformes described so far (Verreth et al., 1992; Kozarić et al., 2008; Yang et al., 2010; Saelee et al., 2011; Pradhan et al., 2012), although species-specific differences in terms of stomach morphogenesis and the putative transition from alkaline to acid digestion were observed among species (Table 2). These results indicated that P. punctifer might be weaned onto microdiets after 10 dpf, although further research on digestive system functionality (quantification of digestive enzyme activities) and weaning strategies are needed, as the physiology and morphogenesis of larval digestive tract might be stimulated or impaired, depending on how co-feeding is performed (Cahu and Zambonino-Infante, 2001; Pradhan et al., 2013). "
ABSTRACT: The organogenesis of the digestive system was described in the Amazonian pimelodid catfish species Pseudoplatystoma punctifer from hatching (3.5 mm total length, TL) to 41 days post-fertilization (dpf) (58.1 mm TL) reared at 28°C. Newly hatched larvae showed a simple digestive tract, which appeared as a straight undifferentiated and unfolded tube lined by a single layer of columnar epithelial cells (future enterocytes). During the endogenous feeding period, comprised between 20 and 96 h post-fertilization (3.5 to 6.1 mm TL), the larval digestive system experienced a fast transformation with the almost complete development and differentiation of most of digestive organs (buccopahrynx, oesophagus, intestine, liver and exocrine pancreas). Yolk reserves were not completely depleted at the onset of exogenous feeding (4 dpf, 6.1 mm TL), and a period of mixed nutrition was observed up to 6 to 7 dpf (6.8 to 7.3 mm TL) when yolk was definitively exhausted. The stomach was the organ that latest achieved its complete differentiation, characterized by the development of abundant gastric glands in the fundic stomach between 10 and 15 dpf (10.9 to 15.8 mm TL) and the formation of the pyloric sphincter at the junction of the pyloric stomach and the anterior intestine at 15 dpf (15.8 mm TL). The above-mentioned morphological and histological features observed suggested the achievement of a digestive system characteristic of P. punctifer juveniles and adults. The ontogeny of the digestive system in P. punctifer followed the same general pattern as in most Siluriform species so far, although some species-specific differences in the timing of differentiation of several digestive structures were noted, which might be related to different reproductive guilds, egg and larval size or even different larval rearing practices. According to present findings on the histological development of the digestive system in P. punctifer, some recommendations regarding the rearing practices of this species are also provided in order to improve the actual larval rearing techniques of this fast-growing Neotropical catfish species. Implications The aquaculture of Amazonian native species requires the mastering of their biological cycle, especially the improvement of current larval rearing procedures. In this context, the present study provides a detailed and comprehensive description of the development of the digestive tract and accessory glands in the pimelodid catfish Pseudoplatystoma punctifer. This information will provide insight in the digestive physiology of this Amazonian fish species in order to synchronize the stage of larval development with rearing procedures and overcome actual larval rearing bottlenecks (e.g. diet formulation, weaning and cannibalistic behaviour).
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- "e for a successful transition to exogenous feeding or delaying time of first feeding without affecting larval growth performance ( Gisbert and Williot , 1997 ) . These results contrast to most other freshwater species where this period is either non - exis - tent or lasts just a few days ( Kamler , 1992 ; Ostaszewska , 2005 ; Sysa et al . , 2006 ; Kozaric et al . , 2008 , among others ) ."
ABSTRACT: The ontogeny of the digestive tract in Cichlasoma urophthal-mus was studied by means of optical microscopy from hatch-ing to 30 days post-hatching (dph; 855 degree days, dd). The development of the digestive system in this precocial species was a very intense and asynchronous process, which pro-ceeded from both distal ends interiorly. At hatching, the digestive tract consisted of a straight tube with a smooth lumen dorsally attached to the yolk-sac. The digestive acces-sory glands were already differentiated and eosinophilic zymogen granules were visible in the exocrine pancreas. At the onset of exogenous feeding between 5 and 6 dph (142.5–171.0 cumulative thermal units, CTU), the buccophar-ynx, oesophagus, intestine, liver and pancreas were almost completely differentiated, with the exception of the gastric stomach that completed its differentiation between 11 and 14 dph (313.5–399.0 CTU). The development of gastric glands at 14 dph and the differentiation of the stomach in the fundic, cardiac and pyloric regions at 19 dph (541.5 CTU) were the last major events in digestive tract development and designated the onset of the juvenile period. Remnants of yolk were still detected until 16 dph (456.0 CTU), indicating a long period of mixed nutrition that lasted between 10 and 11 days (285.0–313.5 CTU). The results of the organogenesis of larvae complement previous data on the functionality of the digestive system and represent a useful tool for establish-ing the functional systemic capabilities and physiological requirements of larvae to ensure optimal welfare and growth under aquaculture conditions, which might be useful for improving current larval rearing practices for this cichlid species.
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