scholarly journals Feeding biology of carnivore and detritivore Mediterranean pycnogonids

Author(s):  
Anna Soler-Membrives ◽  
Claudia P. Arango ◽  
Montserrat Cuadrado ◽  
Tomás Munilla

The digestive system of sea spiders (Pycnogonida) presents peculiarities that have not been discussed in the context of their ecology or feeding behaviour. We investigated the digestive system of two Mediterranean species, a carnivorous speciesAmmothella longipesand a detritivorousEndeis spinosa, with special focus on its correlation with behavioural feeding habits. The midgut and hindgut sections did not present significant differences between the two species, but major differences were observed in the foregut, reflecting concordance to their diet and their feeding behaviour. Jaws, setose lips, the structure of the pharyngeal filter and musculature of the proboscis are the main differential elements when comparing feeding habits ofA. longipesandE. spinosa. These elements are responsible for the reduction of the food pulp down to subcellular size. The digestion process observed in the species studied agrees with that observed in other pycnogonid lineages, but differs from most marine arthropods mainly because of the absence of midgut gland cells and the presence of a unique multifunctional type of midgut epithelial cell. Epithelial digestive cells are present in a small ‘resting’ form during starvation periods. During digestion, secretion granules possibly containing zymogen move to their apical border to be secreted to the midgut lumen, secondary lysosomes are formed and intracellular digestion occurs within them. Residual bodies are formed within the epithelial cell and released to the midgut lumen to be transported towards the hindgut. The characteristics of the digestive process of the pycnogonids studied seem to reflect a plesiomorphic state in arthropods.

Author(s):  
M Rost-Roszkowska ◽  
K Janelt ◽  
I Poprawa

Abstract Three species of Macrobiotidae, Macrobiotus polonicus, Macrobiotus diversus and Macrobiotus pallarii, were selected for analysis of the fine structure of the midgut epithelium. They are gonochoric and carnivorous species that live in wet terrestrial and freshwater environments. The ultrastructure of the midgut epithelium of the investigated Macrobiotidae species was analysed in both males and females. Their digestive system is composed of fore- and hindguts that are covered by a cuticle, and the middle region, termed the midgut. It is lined with a simple epithelium that is formed by digestive cells that have a distinct brush border. Crescent-shaped cells that form an anterior ring in the border between the fore- and midgut were detected. The ultrastructure of the intestinal epithelium of the examined species differs slightly depending on sex. The digestive cells of the posterior segment of the intestine contain numerous lipid droplets, which are the reserve material. We concluded that the digestive cells of the Macrobiotidae midgut are responsible for its intracellular digestion owing to endocytosis. They also participate in the extracellular digestion owing to merocrine secretion (exocytosis). However, the midgut is not the main organ that accumulates reserve material. Additionally, the midgut epithelium does not participate in oogenesis.


2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Bhaskara Canan ◽  
Wallace Silva do Nascimento ◽  
Naisandra Bezerra da Silva ◽  
Sathyabama Chellappa

This study investigated the morphohistology of the digestive tract and the mean intestinal coefficient of the damsel fishStegastes fuscuscaptured from the tidal pools of Northeastern Brazil. The wall of the digestive tract ofS. fuscusis composed of the tunica mucosa, tunica muscularis, and tunica serosa. The esophagus is short with sphincter and thick distensible wall with longitudinally folded mucosa. Mucous glands are predominant, and the muscular layer of the esophagus presented striated fibers all along its extension. The transition region close to the stomach shows plain and striated muscular fibers. Between the stomach and intestine, there are three pyloric caeca. The intestine is long and thin with four folds around the stomach. The anterior intestine presents folds similar to those of pyloric caeca. The estimated mean intestinal coefficient and characteristics of the digestive system ofS. fuscuspresent morphological adequacy for both herbivorous and omnivorous feeding habits.


Author(s):  
Marcela Ribeiro Tosta ◽  
Mariane Leão Freitas ◽  
Rodrigo Diana Navarro

The initial development of carnivorous fish in farms requires intensive care regarding nutrition and management, in order to avoid the stress that can lead to cannibalistic behavior, a major cause of mortality in larvae and juveniles of cultivated carnivorous species. The objective of this article was to evaluate the initial development of carnivorous freshwater fish in South American territory, focusing on the development of the digestive tract and feeding, through a systematic literature review, resulting from research in scientific databases, with the strategy of searching for the key-words: fish and larvae and development and digestive and Brazil and "name of the different species found", besides manual searches made in the bibliographical references of the articles selected. At the end of the selection, 17 articles, published between 2007 and 2017, were included in the review. It was verified that the ontological evaluation of the digestive system of the larvae’s is of major importance to adapt the nutritional management to the needs of the young animals, reaching higher productivity of carnivorous fish.


1951 ◽  
Vol s3-92 (17) ◽  
pp. 1-25
Author(s):  
J. E. MORTON

The two neozelanic species Struthiolaria papulosa and Pelicaria vermis have been studied as regards ecology, feeding mechanism, and structure and function of the digestive system. They are dwellers on sand or sand-mud-flat, wit h a feeding position just below the surface, where they construct paired siphonal tubes with the rostrum. A ciliary mode of feeding has been acquired by the modification of the gill filaments and the pallial rejection system. The alimentary canal isadapted for deposit feeding and has developed a crystalline style. Food particles are conducted to the stomach by a functionally reduced mucus-secreting oesophagus, where they are subjected to the action of the rotating style, and a complex system of ciliary currents. Digestible par-ticles are passed into paired diverticula, where absorption and intracellular digestion, takes place, while faecal material is surrounded with mucus and formed into firm pellets by the ciliary and muscular action of the intestine. The relationships of the Struthiolariidae are discussed, and their origin from the Aporrhaidae is postulated.


1998 ◽  
Vol 41 (4) ◽  
pp. 423-428 ◽  
Author(s):  
Paulo de Tarso C. Chaves ◽  
Ana Lúcia Vendel

Feeding habits of Stellifer rastrifer (Perciformes, Sciaenidae) at Guaratuba mangrove, Parana, Brazil, were studied from February 1996 to February 1997. It was observed that its diet was based on invertebrates, mainly Decapoda non-Brachyura and Polychaeta. In a smaller proportion there were plants, Copepoda, Gammaridea and Mollusca. The level of contribution of each food item changed according to the season and the individual size. Such plasticity in feeding behaviour was similar to that described to some fish populations from other estuaries, and could be an indicator of the high level of instability presented by this kind of ecosystem.


1927 ◽  
Vol 55 (1) ◽  
pp. 219-253 ◽  
Author(s):  
H. Graham Cannon ◽  
S. M. Manton

The general biology of the Mysids has recently been studied at great length by Blegvad (1922) at Copenhagen. His paper, containing a very complete literature list, deals with Mysis inermis, Rathke, Mysis flexuosa, Müller, and Mysis neglecta, Sars. His comments on feeding are limited, and refer chiefly to the nature of the food that the animals ate in captivity. Gelderd's work (1909) on the digestive system of the Schizopoda describes the course taken by the food through the gastric mill, the masticatory functions of this apparatus, and the method by which the masticated food and digestive juices are brought together, but does not deal with the manner in which the food reaches the stomach. An account, then, of the method by which a mysid collects its food would fill a gap in our knowledge of these forms. The only description, as far as we are aware, of the feeding habits of a mysid is that of Depdolla (1923), who worked on Praunus [Mysis] flexuosus, but his account is superficial and in our opinion very inaccurate. The following paper deals with the feeding habits of a small mysid, Hemimysis lamornœ, about 8 mm. long, which has established itself in the larger fish-tanks at the M.B.A. laboratory at Plymouth. It breeds freely all the year round, and can be obtained from the tanks in abundance, although it is stated to be only a rare visitor in the Plymouth district.


1938 ◽  
Vol 59 (2) ◽  
pp. 267-307 ◽  
Author(s):  
Alastair Graham

During recent years there has been a very great advance in our knowledge of the minute structure and function of the various regions and glands of the alimentary canal of the prosobranch and pulmonate gastropods, without any corresponding increase in our understanding of the opisthobranch and, in particular, of the nudibranch gut. That the emphasis should be laid on the streptoneurous and the land-living forms is obviously due to their abundance and to the fact that they include almost all the familiar types of gastropod mollusc, but it is disappointing that, at the moment of writing, there exists only one account of the histology and function of the digestive system of either a dorid or an æolid—to confine attention to the two main types of nudibranch molluscs which occur in British waters—that of Millott (1937b). This is perhaps more noticeable when it is recalled that the nudibranchs have specialised along distinctly unusual lines, many of which are intimately associated with the food and feeding habits which the animals have adopted. The æolids, it is true, have attracted a lively interest in connexion with their possession of nematocysts, but the majority of investigators have apparently been content to trace these into the cnidosacs without concerning themselves over the other constituents of the animal's food.


Author(s):  
L. De Jong-Moreau ◽  
B. Casanova ◽  
J.-P. Casanova

Scanning microscope investigations were carried out on mandibles, labrum and paragnaths of several species of Mysidacea and Euphausiacea. Gut content analyses were in agreement with morphological observations. It appears that the morphology of the peri-oral structures and especially of the mandibles reflect the feeding habits, and that the well known relationships between the size of the molar process and the incisor one, i.e. a large molar process is associated with herbivorous feeding, is not always verified. Bacescomysis abyssalis and Bentheuphausia amblyops are believed to be mostly saprophagous, Boreomysis inermis and Meganyctiphanes norvegica are mostly phytophagous, Hemimysis speluncola is omnivorous, while Siriella armata and Thysanopoda orientalis are carnivorous species.


2014 ◽  
Vol 27 (1) ◽  
pp. 21-47 ◽  
Author(s):  
Stéphane Panserat ◽  
Nicole Rideau ◽  
Sergio Polakof

The glucokinase (GK) enzyme (EC 2.7.1.1.) is essential for the use of dietary glucose because it is the first enzyme to phosphorylate glucose in excess in different key tissues such as the pancreas and liver. The objective of the present review is not to fully describe the biochemical characteristics and the genetics of this enzyme but to detail its nutritional regulation in different vertebrates from fish to human. Indeed, the present review will describe the existence of the GK enzyme in different animal species that have naturally different levels of carbohydrate in their diets. Thus, some studies have been performed to analyse the nutritional regulation of the GK enzyme in humans and rodents (having high levels of dietary carbohydrates in their diets), in the chicken (moderate level of carbohydrates in its diet) and rainbow trout (no carbohydrate intake in its diet). All these data illustrate the nutritional importance of the GK enzyme irrespective of feeding habits, even in animals known to poorly use dietary carbohydrates (carnivorous species).


1987 ◽  
Vol 65 (7) ◽  
pp. 1812-1817 ◽  
Author(s):  
Gregory G. Barnes ◽  
Vernon G. Thomas

Discriminant function, cluster, and covariate analyses of gizzard, small intestine, and ceca weights were used to quantify the structure of feeding guilds and the effects of diet on gut morphology for 18 species of North American anatids. Guild structure based on gut measurements closely approximated that identified by generalized feeding habits. Herbivorous species such as Brant (Branta bernicla), Gadwall (Anas strepera), Redheads (Aythya americana), Canada Geese (Branta canadensis), and Mallards (Anas platyrhynchos) consistently had heavier gizzards and ceca than carnivorous species such as Common Goldeneye (Bucephala clangula), Bufflehead (Bucephala albeola), Oldsquaw (Clangula hyemalis), and Common Mergansers (Mergus merganser). Omnivorous species such as Lesser Scaup (Aythya afftnis), Greater Scaup (Aythya marila), and American Black Ducks (Anas rubripes) were characterized by heavy gizzards, intermediate ceca, and heavy intestines. The results provide further evidence that intestine size is primarily influenced by overall diet diversity and suggest that gut size may be used to indicate general food habits. The ability of waterfowl to adjust gut sizes and accommodate dietary changes is restricted to ranges dictated by the most frequently eaten foods. Thus, predictions of general food habits can be made without knowledge of the foods being consumed at a particular time and location.


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