Digestive System in Fishes (With Diagram)

The digestive system

Feeding and Digestive Functions in Fishes
Bones, teeth and scale tissues require lots of minerals. In the oceans In conservation: Learn More about VitalSource Bookshelf. We provide a free online form to document your learning and a certificate for your records. Applect Learning Systems Pvt. The intestine is primarily an organ for absorbing nutrients into the bloodstream. If thawed, these feeds should not be refrozen.

Protein and fish

IX. Metabolism

The liver does not have the typical lobular architecture that is present in mammals. In many species of fish the re are areas of exocrine pancreas hepatopancreas that are present near the small veins of f the hepatic portal vein. The pancreas is scattered in the mesentery, primarily near the pylorus. Irrespective of their main dietary requirements, the digestive systems of fish are very similar. All have a mouth, oesophagus throat , and areas for the absorption of food components fore and midgut and compaction of indigestible waste material hindgut.

In adaptation to diet, the major differences are seen in the structure of the mouth and the teeth, the gill rakers, the pharynx, the stomach if present and in the length of the intestine. In carnivorous fish or those with a meat-orientated omnivorous diet there is a definite stomach foregut whilst herbivorous or plant-orientated omnivores have no stomach but rely on a much extended midgut area. These two situations are shown below.

Digestive system of a Carnivorous Fish. Digestive system of a Omnivorous Fish. Additionally carnivorous fish have extensions to the upper part of the midgut known as pyloric caecae. Two other internal organs are associated with digestion, namely the liver and the gall bladder, located anteriorly to the stomach or anterior section of the midgut.

Before being digested, the fish food, whether live or in the form of a pellet, has to be caught and positioned before being 'swallowed' - this is the function of the mouth. In carnivorous or predatory fish teeth may be present on the jaws, tongue and inner mouth buccal cavity - these teeth do not bite or crush food but simply hold it and prevent escape.

Herbivorous fish or those which feed on hard-shelled prey may have pharyngeal teeth to aid in crushing the food before it enters the stomach. For those fish species with a stomach, two areas can be identified - a cardiac area anteriorly i.

Combined Worm Culture - Grindal worms and red worms can be cultured in one container together, thus providing live food for different sizes fish Tropical fish food - An introduction to fish food for beginners.

Types of fish food - A guide to the basic types of fish food available. Feeding your fish vegetables - Fresh cooked high fibre vegetables benefit the digestive systems of many fish. Protein and fish Protein is the single most important nutrient that the fish needs to grow. On a dry-weight basis, this makes up the maximum weight in their body structure. Amino acids are derived from proteins and the fish uses them to make new body tissues as well as enzymes. Fish are very adept at converting food to body tissues.

That is why fish need lesser amounts of food than do most other animals. Carbohydrates are almost non-existent in the food intake for many fish species, since energy is also derived from proteins. The quantity of protein required for the fish to be healthy depends on a number of variables like the species of fish, amount of natural food available, growth rate etc.

Fry and larvae require a more protein rich diet to maximize their adaptability and chances of survival. As the fish grow larger, their dependency on protein reduces. The temperature of the water also affects protein requirements. Fatty acids and fish Fatty acids are a storehouse of energy for most fish. Carbohydrates can also do this job. It is also seen that some of the predatory fish species require some source of fish oil in their diet too. Fish that live within the confines of an aquarium are naturally prone to obesity.

They do not use up their excess energy in swimming long distances or looking for food. In most cases, excess fat can be damaging to the general health of the fish.

Some fish lose their reproductive capabilities if there is too much body fat. Fat-soluble carotenoid and fish Fat-soluble carotenoid is responsible for the bright hues in some fish. Krill and brine fish are some of the foods that are rich in pigments. While they are alternate sources of energy, they are not very necessary for fish growth. Though most fish will handle some amount of carbohydrates, they develop signs of ill health if there is a high concentration of carbs in their diet.

For instance, if young fish ingest too much of carbs, other nutrients will not be absorbed appropriately by their bodies. That is why cereal grains, which have very high levels of raw starch, are not ingested fully by fish.

Vitamins and minerals and fish Vitamins are vital to fish health. These are organic substances that act as catalysts for many of the biochemical reactions within the fish. Almost all vitamin deficiency will increase the fish's susceptibility to diseases and stress. The best way to get a rich supply of vitamins to your fish is to buy small quantities of diverse food for them. As in all vertebrates, the pancreas has two digestive functions. It is the source of: The liver in fish produces bile which is stored in the gall bladder until a bolus passes the stomach, at which time the bile is expelled into the intestine.

Bile contains waste products of liver activity which pass out of the fish in the feces. Bile has a digestive function in that it emulsifies lipids, greatly increasing their absorbtion in the intestine. The liver is key in the anabolism and catabolism of amino acids absorbed during digestion and is also the site of storage of food energy in the form of glycogen.

Most absorbtion of nutrients occurs in the intestine. The large protein, fat, and starch molecules in food that have been broken into smaller molecules by gastric acid and digestive enzymes move by diffusion or active transport ATPase pumps into the network of capillaries surrounding the gut.

MSD and the MSD Veterinary Manual