Morphometric parameters comparisons of the digestive tract of four teleosts with different feeding habits (original) (raw)
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FEEDING BEHAVIOUR OF ECONOMICALLY IMPORTANT TELEOST FISHES OF KERALA
Study of the food and feeding habits of fishes have always attracted the attention of fishery biologists. The structure of the alimentary canal in a given species of fish is related to its diet. The general documented trend is that herbivores fishes have longer thinner and narrower intestines than do carnivores due to the difficulty in digesting complex plant carbohydrates and to the quantity of indigestible material. Also the intestine of omnivores species have an intermediate length. Thus in the present study the intestinal quotient, hepatic somatic index and gastro somatic index of three different teleost fishes Rastrelliger kanagurta, Sardinella longiceps and Lethrinus lentijan were examined in order to understand the feeding habits of the fishes. The IQ of rastriliger kanagurta was a 1.69, Sardinella longiceps was 1.705 and Lethrinus lentijan was 0.226. R. Kanagurta and S.longiceps are omnivore feeding on phytoplanktons (diatoms) and small zooplankton (cladocerans, ostracods,larval polychaetes, etc.) L.lentijen is a carnivore and feeds primarily on crustaceans and mollusks but echinoderms, polychaetes and fishes are also consumed in considerable quantities. The highest GSI was observed in Sardinella longiceps with a value of 8.871 followed by Lethrinus lentijan (2.076) and Rastriliger kanagurta was 1.830. The results of GSI indicate 's stomach fullness.
Brazilian Journal of Biology, 2008
The present study is inspired by the great wealth of species exhibited by the ichthiofauna. Not only concepts and techniques of ecology deserve attention, but also knowledge in other biological areas, such as zoology and anatomy, are necessary. The intention of the present work is to discover the morphology of fish through the study of the digestive tract morphology, associating it to diet data, in order to better understand the biology of four fish species of the upper Paraná River floodplain. The samples were collected quarterly in the year 2000 with gillnets of different meshes. The stomach content was analyzed under a stereoscopic microscope and the frequencies of occurrence (FO) and volumetric (FV) and the alimentary index (IAi) were calculated. Various morphologic characteristics were analyzed and schematized using a light chamber. The species were grouped into two trophic guilds - insectivores (Astyanax altiparanae and Parauchenipterus galeatus) and piscivores (Serrasalmus marginatus and Hoplias aff. malabaricus). The first two, although consumers of insects, preyed on different alimentary groups, notably Hymenoptera in the case of A. altiparanae and Coleoptera in the case of P. galeatus. Serrasalmus marginatus and H. aff. malabaricus consumed mainly fishes. However, only pieces of prey were usually found in the stomach content of the first species, whereas whole fishes were found in the stomach content of the second. Astyanax altiparanae exhibited characteristics that allowed it to obtain food in several compartments of the water column. Similarly P. galeatus consumed food resources that were available in all aquatic compartments, although the abilities to capture, to manipulate and to absorb food differed, as shown by the importance of teeth plates and pharyngeal teeth. Serrasalmus marginatus and H. aff. malabaricus, although resembling each other in many aspects of the digestive tract morphology, differed in the strategies used to capture prey. The analysis showed that, according to the main food item of the diet, the species were grouped into two trophic guilds. However, those within the same category used different feeding methods, and similarity in items consumed does not imply the same group of morphological characteristics.
2017
Length weight relationship is an important tool for fishery management and which will able us to know about size, structure, age and also to assess the health of the host. It will provide various facts about seasonal cycle of the host, growth period of fishes and influential aspect of biotic and abiotic factor. The length-weight relationship of the same species may be different in the population because of feeding, reproduction activities and fishing. Likewise, relative gut length is the useful index used to know about the nature of food and feeding habit. It is therefore necessary to know the length and weight relationships of gutof fishes to understand depends on the nature of food they consume, the length increases with the increase in the vegetable matter in the diet. Most of the literatures show only the length and weight relationship of whole body but not the gut hence this study was conducted to establish the length and weight relationship of alimentary canal compared to the ...
The morphology of the post-gastric alimentary canal in teleost fishes: a brief review
The rapid expansion of aquaculture in many parts of the world has supported vigorous research programmers on nutrition and the feeding of cultivated aquatic organisms. Teleosts, as an important source of food supply for human, have successfully adapted themselves to every type of aquatic habitat. This versatility is reflected in their mode of feeding. The digestive tract of fishes shows a remarkable diversity of morphological and functional characteristics. This is related to different feeding habits and to taxonomy, as well as to body shape and weight, size and sex. The morphology of post-gastric alimentary canal has also been studied from many species of fish because knowledge of fish's alimentary canal morphology is becoming increasingly important in fish digestive physiology and improvement of nutrition protocols. Identification of digestive tract structure is essential for understanding the related histophysiological mechanisms and nutritional functions. This knowledge may help identify differences in microscopic anatomy of alimentary canal among various teleost species.
2003
Comparative anatomy and histology of the digestive tracts of two sympatric species of freshwater fish, Aphanius dispar (Cyprinodontidae) and Garra barreimiae (Cyprinidae) are studied. Morphometric measurements of alimentary canal such as length and the number and height of rugae in sections have been made for both species. Relationships between these morphometric characters and the total length of fish have been evaluated. The ratio between the length of alimentary canal and total length of fish in both species reflects their feeding habits. Histology of the 'stomach' and 'intestine' of these two species as shown by light microscopy has been described and compared. Results of this study are used to discuss the query whether these species have true stomachs.
Int. J. Morphol, 2009
The purpose of the present work was the anatomical, histological and histochemical description of Rhamdia quelen juvenile digestive system. Samples of gut were fixed, dehydrated and included in paraffin and then stained with haematoxylin and eosin. For the identification and differentiation of mucosubstances the preparations were treated with Periodic Acid Schiff, Alcian Blue pH 0,4 and 2,5 and PAS/AB pH 2,5. Anatomical details of the oesophagus were like a short tube with primary and secondary mucous folds. The stratified epithelium is composed of three cellular types: small cells, abundant goblet cells with acid and neutral mucosubstances (MS) and large acid cells. The stomach is J-shaped and its mucosa presents broad and deep folds in relaxing state. Histologically, the stomach shows three different regions: cardiac, fundic and pyloric region. The luminal surface of the epithelium consists of a layer of secretory columnar cells of neutral MS. Tubuloacinar glands were surrounded by connective and muscular smooth fibers bundle. The intestine extends from the stomach until the anus, and four different sections can be distinguished: ascending, descending, convoluta and terminal straight. It was identified a simple columnar epithelium mainly composed by two cellular types: absorptive cell and goblet cell neutral MS secretory. On the basis of the anatomical and histological study carried out, we conclude that R. quelen presents an alimentary canal compatible with species that possess omnivorous nutritious habits.
Biota Neotropica, 2020
Fish feeding habit associated to the morphology of their digestive tube can provide useful biological and ecological information. Between January and December 2012, we examined 16 fish species discarded by trawl in the Potiguar basin, northeastern Brazil, and classified them into four groups according to Alimentary Index-IAi. Our aims were to: (1) provide information on diet composition of one species represented by each group (Opisthonema oglinum, Conodon nobilis, Larimus breviceps and Sphoeroides testudineus), (2) examine the morphology of their digestive tube, and (3) associate ingested food items with the morphological features. Stomach contents were collected and classified according to IAi: main, accessory and secondary categories; fragments of esophagus, stomach, and small intestine were examined using paraffin section technique. Biometric data (total length-TL, standard length-SL and total weight-TW), stomach weight-SW, and gonadal weight-GW were recorded and applied in two indices: (1) the stomach Repletion Index-SRI (SRI = SW/TW × 100) and (2) the gonadosomatic index-GSI (GSI = GW/TW × 100) for the analyses of feeding and reproductive activities, respectively. The main food categories were (1) Teleostei for C. nobilis, (2) Crustacea for L. breviceps and O. oglinum, and (3) Mollusca for S. testudineus. The feeding activity was higher during the dry season, while the GSI was higher in the rainy season. The morphological analysis revealed a regular structure of the tissues analyzed. We highlight the presence of tubular gastric glands and strong muscular walls in the stomach (O. oglinum; L. breviceps); well-developed pyloric caecum in the intestine (O. oglinum; C. nobilis; L. breviceps); and presence of pseudo-stomach (S. testudineus). Our study confirms that the digestive tube of the examined species has morphological adequacy for carnivorous feeding habit, providing useful information on tissue structures associated to diet composition.
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2010
The gastrointestinal (GI) tract and associated organs are some of the most metabolically active tissues in an animal. Hence, when facing food shortages or poor food quality, an animal may reduce the size and function of their GI tract to conserve energy. We investigated the effects of prolonged starvation and varying food quality on the structure and function of the GI tract in a detritivorous catfish, Pterygoplichthys disjunctivus, native to the Amazonian basin, which experiences seasonal variation in food availability. After 150 days of starvation or consumption of a wood-diet too low in quality to meet their energetic needs, the fish reduced the surface area of their intestines by 70 and 78%, respectively, and reduced the microvilli surface area by 52 and 27%, respectively, in comparison to wild-caught fish consuming their natural diet and those raised in the laboratory on a high-quality algal diet. Intake and dietary quality did not affect the patterns of digestive enzyme activity along the guts of the fish, and the fish on the low-quality diet had similar mass-specific digestive enzyme activities to wild-caught fish, but lower summed activity when considering the mass of the gut. Overall, P. disjunctivus can endure prolonged starvation and low food quality by down-regulating the size of its GI tract.
A Mini Review on the Studies of Gastrointestinal Tract of Teleost Fishes in Indian Subcontinent
COJ Reviews and Research, 2018
A large body of information exists on the variety of teleost fishes which abound Indian subcontinent. The present review summarizes in chronological order of the research carried by various investigators on the teleost fishes of this important region. Efforts have also been made to identify the knowledge gaps and the strategy to fill such lacunae. Expectedly, this review will serve as a ready source of document to have an overview of the existing information of the GIT on the extant teleost fishes of Indian subcontinent.