Diets, Physiology, Biochemistry and Digestive Tract Development of Freshwater Fish Larvae

2008 ◽  
pp. 227-279 ◽  
Author(s):  
Maria Portella ◽  
Konrad Dabrowski
Keyword(s):  
Freshwater Fish ◽  
Digestive Tract ◽  
Fish Larvae

scholarly journals pH and Temperature Dependent Gut Enzyme Niche in a Stomachless Herbivorous Freshwater Fish Amblypharyngodon mola (Hamilton, 1822)

2020 ◽  
Vol 12 (4) ◽  
pp. 729-741
Author(s):  
S. Debnath ◽  
S. I. Maiti ◽  
S. K. Saikia
Keyword(s):  
Bile Salt ◽  
Freshwater Fish ◽  
Digestive Tract ◽  
Hierarchical Clustering ◽  
Standard Length ◽  
Active Regions ◽  
Temperature Dependent ◽  
Optimum Ph ◽  
Temperature Levels ◽  
Optimum Ph And Temperature

The activities of digestive α-amylase (E. C. 3.2.1.1), total proteases, and bile salt-activated lipase (E. C. 3.1.1.-) along the digestive tract (lengthwise divided into five equal parts) of a stomachless freshwater fish (n = 10, weight = 4.354±0.316 g, standard length = 21.641±2.271 cm) were measured at different pH and temperature levels. Different optimum pH and temperature for the activity of α-amylase (8-9, 35°C), proteases (7-8, 45°C), and lipase (8, 45°C) were observed. The first two regions of the digestive tract showed comparatively higher activity of all enzymes. The hierarchical clustering technique revealed three different enzymatically active regions, more inclined to pH in the digestive tract of the studied fish. The present study also supports that the stomachless gut of A. mola has substantial resemblances to the intestinal part of the digestive tract of fish.

scholarly journals The internal CO 2 threat to fish: high P CO 2 in the digestive tract

2019 ◽  
Vol 286 (1907) ◽  
pp. 20190832 ◽  
Author(s):  
Chris M. Wood ◽  
Junho Eom
Keyword(s):  
Climate Change ◽  
Rainbow Trout ◽  
Freshwater Fish ◽  
Digestive Tract ◽  
Venous Blood ◽  
External Environment ◽  
Current Concern ◽  
Anterior Intestine ◽  
The Mean

Our goal was to use novel fibreoptic sensors to make the first direct P CO 2 measurements in the digestive tracts of live freshwater fish (anaesthetized, artificially ventilated, 12°C). P CO 2 levels in gastrointestinal fluids were substantially higher than in blood, and were elevated after feeding. In the carnivorous, gastric rainbow trout, the mean P CO 2 in various parts of the tract increased from 7–13 torr (1 torr = 0.1333 kPa) during fasting to 20–41 torr after feeding, relative to arterial levels of 3.5–4 torr. In the agastric, omnivorous goldfish, the mean gut levels varied from 10–13 torr in fasted animals to 14–18 torr in fed animals, relative to arterial levels of 5–7 torr. These elevated P CO 2 values were associated with surprisingly high HC O 3 − concentrations (greater than 40 mmol l −1 ) in the intestinal chyme. Incubations of food pellets with acid or water revealed endogenous P CO 2 generation sufficient to explain gastric P CO 2 in fed trout and anterior intestine P CO 2 in fed goldfish. The impacts of possible equilibration with venous blood draining the tract are assessed. We conclude that fish are already coping with P CO 2 levels in the internal gastrointestinal environment many-fold greater than those of current concern in the external environment for climate change and aquacultural scenarios.

PARASITES OF FRESHWATER FISH: V. PARASITIC HELMINTHS OF THE MUSKALLUNGE, ESOX M. MASQUINONGY MITCHILL, IN THE ST. LAWRENCE WATERSHED

1951 ◽  
Vol 29 (4) ◽  
pp. 290-295 ◽  
Author(s):  
L. P. E. Choquette
Keyword(s):  
Freshwater Fish ◽  
Digestive Tract ◽  
Parasitic Helminths ◽  
Leptorhynchoides Thecatus ◽  
Triaenophorus Nodulosus

The incidence of the following species of helminths recovered from the digestive tract of 218 muskallunge, Esox m. masquinongy, from various localities in the St. Lawrence watershed is recorded: Azygia augusticauda, A. longa, Triaenophorus nodulosus, Proteocephalus pinguis, Neoechinorhynchus cylindratus, Leptorhynchoides thecatus, Metabronema salvelini, and Rhaphidascaris canadensis. One hundred and ninety-two, or 88% of the fish examined were found to harbor one or more species. The most commonly found species were T. nodulosus and A. longa. In all cases the number of worms recovered per host was small.

Growth, development and behaviour of artificially reared larval Pagrus auratus (Bloch & Schneider, 1801) (Sparidae)

1991 ◽  
Vol 42 (4) ◽  
pp. 391 ◽  
Author(s):  
PM Pankhurst ◽  
JC Montgomery ◽  
NW Pankhurst
Keyword(s):  
Digestive Tract ◽  
Brachionus Plicatilis ◽  
Fish Larvae ◽  
Yolk Sac ◽  
First Feeding ◽  
Pagrus Auratus ◽  
Swimming Mode ◽  
Growth Development ◽  
Marine Rotifers

Pagrus auratus eggs were obtained from wild broodstock with naturally and artificially ovulated fish. Larvae were cultured for periods of up to 1 month on a diet of marine rotifers, Brachionus plicatilis. Small yolk-sac larvae hatched without functional eyes, mouth or digestive tract and for 3 days spent long periods at rest. Growth was initially rapid but slowed by 3 days as yolk reserves were nearing depletion. By Days 4-5, the mouth had opened, eyes were pigmented, yolk was depleted, and a rudimentary gut had formed. Larvae were now able to maintain a horizontal swimming mode and were actively searching for and attacking prey. First-feeding was observed in some larvae. Growth was retarded during the transition from endogenous to exogenous nutrition and then increased, probably as feeding proficiency improved with experience. Larvae starved from hatching did not survive for longer than 8 days.

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