The document discusses the alimentary canal and feeding adaptations in fishes. It describes the different parts of the alimentary canal including the mouth, teeth, buccal cavity, pharynx, esophagus, stomach, intestines, rectum, and digestive glands. It explains how the structure and components of the alimentary canal vary between different fish types, such as carnivorous, herbivorous, and omnivorous, to support their specific diets and feeding behaviors. For example, carnivorous fish tend to have shorter canals and sharper teeth for consuming meat, while herbivorous fish have longer intestines and specialized adaptations like molariform teeth for breaking down plant materials.
Digestive physiology of herbivorous fishMahendra Pal
The knowledge of food and feeding habits and the physiology of digestion of any organism is most essential for development of artificial feed in culture practices. Fish and shellfish belong to the poikilothermous animal. The digestion process is somewhat different than the terrestrial animals. Similarly the mechanism of digestion and absorption process is quite different in fishes and shellfishes. The basic function of digestive system is to dissolve foods by rendering them soluble so that they can be absorbed and utilized in the metabolic process. The system may also function to remove dangerous toxic properties of certain food substances.
Fish generally change their feeding habits depending upon availability of food. So according to their feeding fishes are classified into different categories viz., predators, grazers, strainers, suckers and parasites.
Digestive physiology of herbivorous fishMahendra Pal
The knowledge of food and feeding habits and the physiology of digestion of any organism is most essential for development of artificial feed in culture practices. Fish and shellfish belong to the poikilothermous animal. The digestion process is somewhat different than the terrestrial animals. Similarly the mechanism of digestion and absorption process is quite different in fishes and shellfishes. The basic function of digestive system is to dissolve foods by rendering them soluble so that they can be absorbed and utilized in the metabolic process. The system may also function to remove dangerous toxic properties of certain food substances.
Fish generally change their feeding habits depending upon availability of food. So according to their feeding fishes are classified into different categories viz., predators, grazers, strainers, suckers and parasites.
The cold water fisheries deal with fisheries activity in water where temperature of water ranges from 5 to 25 degrees centigrade. The water temperature under cold water fisheries should not be more than 25°C even in summer. Such conditions in India occur in Himalayan and peninsular regions.
9 Finest Coldwater Aquarium Fish
Orangethroat Darter.
Three-Spined Stickleback.
Orange-Spotted Sunfish.
Diamond Sturgeon.
Siberian Sturgeon.
Sterlet.
Fathead Minnow.
Southern redbelly dace.
Tench.
Rosy Barb. Hailing from Afghanistan and Bangladesh, this little fish is tolerant of temperatures in …
Gold Barb. The gold bard, or Chinese barb, is an extremely popular cold-water fish. Any aquarium …
Two Spot Barb. This fish hails from Nepal, India, and Pakistan. The omnivorous two spot barb …
Bloodfin Tetra. Natives to Southern Brazil and Paraguay, both the standard bloodfin .
Coldwater fish in terms of the aquarium trade refers to any fish species that prefer cooler water temperatures. The optimal temperatures for these fish hover around the 68-degree mark, although each species’ temperature range may vary from the norm.
Finfish breeding and hatchery management pdfKartik Mondal
Rivers were the major source of freshwater fish seed in India during 1950’s and 1960’s.
Over the years, the riverine contribution has declined and at present forms only a supplementary source, constituting less than 5% of the country’s total fish seed production.
The Ganga, the Brahmaputra and the Indus river systems in the North and the Peninsular East coast and the West coast river systems in the South are the important natural sources of fish seed.
The traditional fishery byproducts are fishmeal, fish body and liver oils, fish maw, isinglass etc. Fish protein concentrate, fish albumin, glue, gelatin, pearl essence, peptones, amino acids, protamines, fish skin leather etc. are some other byproducts generally processed out of fish and fish waste.
Oysters can change their gender. ...
Humans eat about two billion pounds of oysters every year.
Oysters are very healthy food source, they are loaded with vitamin C, D, and the B vitamins. ...
Clams can live up to 35 years. ...
Clams are high in protein and iron. ...
Lobsters sometimes eat their young.
This slide is about a pearl spot fish which includes about its habit, habitat ,morphology, food and feeding, breeding behaviour, hatching, larval rearing, embryonic development, nutritive values, farming practices, seed production and pond preparation...
Training manual on species identification 2017 vivekanand bharti_basic finfis...Ashish sahu
The ID tools reviewed are: Use of scientific experts (taxonomists) and folk local experts, taxonomic reference collections, image recognition systems, field guides based on dichotomous keys; interactive electronic keys (e.g. IPOFIS), morphometrics (e.g. IPez), scale and otolith morphology, genetic methods
The cold water fisheries deal with fisheries activity in water where temperature of water ranges from 5 to 25 degrees centigrade. The water temperature under cold water fisheries should not be more than 25°C even in summer. Such conditions in India occur in Himalayan and peninsular regions.
9 Finest Coldwater Aquarium Fish
Orangethroat Darter.
Three-Spined Stickleback.
Orange-Spotted Sunfish.
Diamond Sturgeon.
Siberian Sturgeon.
Sterlet.
Fathead Minnow.
Southern redbelly dace.
Tench.
Rosy Barb. Hailing from Afghanistan and Bangladesh, this little fish is tolerant of temperatures in …
Gold Barb. The gold bard, or Chinese barb, is an extremely popular cold-water fish. Any aquarium …
Two Spot Barb. This fish hails from Nepal, India, and Pakistan. The omnivorous two spot barb …
Bloodfin Tetra. Natives to Southern Brazil and Paraguay, both the standard bloodfin .
Coldwater fish in terms of the aquarium trade refers to any fish species that prefer cooler water temperatures. The optimal temperatures for these fish hover around the 68-degree mark, although each species’ temperature range may vary from the norm.
Finfish breeding and hatchery management pdfKartik Mondal
Rivers were the major source of freshwater fish seed in India during 1950’s and 1960’s.
Over the years, the riverine contribution has declined and at present forms only a supplementary source, constituting less than 5% of the country’s total fish seed production.
The Ganga, the Brahmaputra and the Indus river systems in the North and the Peninsular East coast and the West coast river systems in the South are the important natural sources of fish seed.
The traditional fishery byproducts are fishmeal, fish body and liver oils, fish maw, isinglass etc. Fish protein concentrate, fish albumin, glue, gelatin, pearl essence, peptones, amino acids, protamines, fish skin leather etc. are some other byproducts generally processed out of fish and fish waste.
Oysters can change their gender. ...
Humans eat about two billion pounds of oysters every year.
Oysters are very healthy food source, they are loaded with vitamin C, D, and the B vitamins. ...
Clams can live up to 35 years. ...
Clams are high in protein and iron. ...
Lobsters sometimes eat their young.
This slide is about a pearl spot fish which includes about its habit, habitat ,morphology, food and feeding, breeding behaviour, hatching, larval rearing, embryonic development, nutritive values, farming practices, seed production and pond preparation...
Training manual on species identification 2017 vivekanand bharti_basic finfis...Ashish sahu
The ID tools reviewed are: Use of scientific experts (taxonomists) and folk local experts, taxonomic reference collections, image recognition systems, field guides based on dichotomous keys; interactive electronic keys (e.g. IPOFIS), morphometrics (e.g. IPez), scale and otolith morphology, genetic methods
Identification of Indian Major Carps,Catla catla (catla), Labeo rohita (rohu) and Cirrhinus cirrhosus (mrigal),Chinese Major carps , Grass, silver, bighead, and black carp , OTHER COMMON SPECIES OF PAKISTAN, Trout, Salmon, Tilapia
Fish are the gill-bearing aquatic craniate animals that lack limbs with digits. They form a sister group to the tunicates, together forming the olfactores. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups.
Characteristics - Ariidae Medium to large sized fish.
Two pairs of nostrils closely on each side.
Paired maxillary and mental barbels present totally 4-6.
Dorsal fin short, with long more or less serrated spine preceded by a very short one.
Caudal fin deeply forked.
Adipose fin present.
Pectoral fin low set, with serrated spine.
Colour – Usually greyish blue, dark grey, yellow or brown sometimes with black patches or in some with silvery lateral stripe; pale to white below.
Delivering Micro-Credentials in Technical and Vocational Education and TrainingAG2 Design
Explore how micro-credentials are transforming Technical and Vocational Education and Training (TVET) with this comprehensive slide deck. Discover what micro-credentials are, their importance in TVET, the advantages they offer, and the insights from industry experts. Additionally, learn about the top software applications available for creating and managing micro-credentials. This presentation also includes valuable resources and a discussion on the future of these specialised certifications.
For more detailed information on delivering micro-credentials in TVET, visit this https://tvettrainer.com/delivering-micro-credentials-in-tvet/
How to Add Chatter in the odoo 17 ERP ModuleCeline George
In Odoo, the chatter is like a chat tool that helps you work together on records. You can leave notes and track things, making it easier to talk with your team and partners. Inside chatter, all communication history, activity, and changes will be displayed.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
Thinking of getting a dog? Be aware that breeds like Pit Bulls, Rottweilers, and German Shepherds can be loyal and dangerous. Proper training and socialization are crucial to preventing aggressive behaviors. Ensure safety by understanding their needs and always supervising interactions. Stay safe, and enjoy your furry friends!
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
2. Contents
Introduction
Alimentary canal in fishes
Mouth in different fishes
Teeth in Fishes
Buccal cavity, pharynx and gill rakers
Oesophagus
Stomach
Pyloric caecae
Intestine
Alimentary canal in Lamprey and Sharks
Alimentary canal in Bony fishes
Rectum
Digestive glands
Digestive enzymes
Conclusions
3. Introduction
Alimentary canal in fishes
As in other vertebrates, the alimentary tract can be divided into 1) The anterior part co
nsists of the mouth, buccal cavity, and pharynx.
2. The posterior part consists of the foregut (esophagus and stomach), midgut or intes
tine, and hindgut or rectum.
Voluntary striated muscle extends from the buccal cavity into the esophagus, involunt
ary smooth muscle from the posterior portion of the esophagus through the large inte
stine. Barrington (1957), Kapoor et al. (1975), and Fange and Grove (1979) provide det
ailed accounts of the alimentary tracts of fishes.
In hagfishes and lampreys, the absence of true jaws is correlated with the absence of
a stomach.
Presumably, the evolution of jaws permitted capture of larger prey, making a storage o
rgan, the stomach, highly advantageous. Both hagfishes and lampreys have a straight i
ntestine, but the surface area of the intestine is increased in the lampreys by the typhl
osole, a fold in the intestinal walls.
Chondrichthyes increase the surface area of the intestine by means of a spiral valve, a
sort of a spiral staircase inside the intestine
4.
5. .
Mouth is the anterior opening of alimentary canal .
Most fish mouth fall into first three general types:
1 . Superior mouth type: Some species with a superior mouth have an elongated
lower jaw that functions much like a scoop.
Archers, half-beaks, and hatchetfish and Catla are all examples of species of aquariu
m fish that have a superior mouth.
2. Terminal mouth type: Most fish that feed on other fish have terminal mouths,
which are often hinged to allow them to accommodate the action of snatching and sw
allowing another fish.
They may also possess specialized teeth, and in some cases an additional jaw.
Moray eels are one type of species that have a pharyngeal jaw placed well back in thei
r throat. Most barbs, cichlids, gouramis and tetras have terminal mouths
Mouth in Fishes
6. 3. Inferior or sub terminal mouth type:
Also called a sub-terminal or ventral mouth, the inferior mouth is turned downw
ard. The lower jaw is shorter than the upper jaw, and the jaw will often be pr
otrusible.
Fish with inferior mouths are usually bottom feeders and often possess barbels
that assist in locating food particles. Most members of the catfish family and
Mrigal have inferior jaws, and many of them also have a sucker mouth as w
ell.
The diet of fish with inferior mouths includes algae, invertebrates (such as snail
s), as well as detritus and any food that falls to the bottom.
The mouth of cartilaginous fishes is ventral.e.g. Sharks, Rays and Skates.
4. Protrusible Mouth
5. Sucker mouths are a common feature in fish with inferior mouths. Catfish, s
uch as the popular plecostomus (which literally translates to folded mouth),
7. 6. A greatly elongated snout is another kind of mouth adaptation. This ty
pe of mouth allows the fish to poke into small crevices and holes to find foo
d.
They may also use this mouth to dig through the substrate to reach buried f
ood treasures.
Some surface feeding fish also have an elongated mouth that allows them
to scoop insects and food particles from the surface.
Freshwater species with elongated mouths include the halfbeaks,
7. The beak mouth is an interesting, but less common, mouth variation; it'
s also known as a rostrum. In this design, the mouth consists of two very h
ard pieces that are hinged and come together in a scissor-like fashion. This
allows them to crush hard shells of invertebrates. Pufferfish, both freshwat
er and saltwater species, and Saltwater
8.
9. Outstanding among the obvious oral adaptation for feeding in fishes are the t
eeth.
They are thought to have arisen from scales covering the lips, as represented
in living sharks (squliformies) where the placoid scales of the skin visibly grade
into teeth on the jaws.
In bony fishes (Osteichthyes) Teeth are of three kinds, based on where they
are found Jaw, Mouth and Pharyngeal.
Jaw TeethJaw teeth are variously those on the maxillary and premaxillary bo
nes above and on the dentaries below.
In the roof of the oral cavity teeth are variously borne by the median vomer an
d by the palatine and ectopterygoid bones on each side. In the floor of the mout
h the tongue often has teeth on it.
Teeth
10. Pharyngeal teeth occur as pads on various gill arch eolements in many species. In
the carps (cyprinedae) and suckers (cjcatastromidae) the only teeth are those in deep
in the pharynx (gut, mouth and eoesophagous) that develoed modification of lower el
ements after last gill arch, in clarius and labeo the teeth are modified for grasping, te
aring, grinding and razor like cutting teeth have developed in predacious fishes.
Kinds of jaw teeth
Based on their form major kinds of Jaw teeth are
1) Cardiform 2) Villiform 3) Canine 4) Incisor and 5) Molariform.
1) Cardiform Teeth Cardiform teeth are numerous, shrotfine and pointed such de
ntition with variations is found in many fishes that have multiple rowed teeth. For ex
ample American catfish (Ictaluridae) perches (percidae) and many sea bases (serrani
dae)
11. 2) Villiform teeth Villiform teeth are more or less elongated cardiform teeth. For example : Nee
dlefishes (Belonidae) and Lion fishes as (Pterois).
3) Canine teeth Canines are dog tooth like or fange like (long pointed tooth) they are elongated a
nd subconical, straight or curved and are adapted for piercing and hodling for example walleyes (Al
ska pollock) (Stizostediosn). In certain fishes such as moreys (muraenidae) the canines are hinged (
the hook) yield ot backward pressure but lock when moved forward and adaptation to retain living
moving prey inside the mouth.
4) Incisors teeth
Incisors are sharp edged cutting teeth. In some fishes incisors fuse together in cutting beak as in pa
rrot fishes (scaridae).
5) Molariform teeth
Molariform teeth are for crushing and grinding thus flat with prodruding denticles on the surface.
These teeth are found in bottom dwelling fishes like skates and rays and some sciaenidae (drums).
12. Diversity in dentition in Bony fishes
With in a single group the diversity of dentition on identical bones may vary largely.
For example In carps and minnows (cyprinidae) the pharyngeal teeth range from sh
arp in carnivores such as in semotilus to molariform in the common carp (Cyprinus
carpio).
In general teeth are absent in plankton feeders and in some of the more generalize
d omnivore.
They are present in increasing numbers of bones in more and more relative to its pr
edatory behaviors.
The premaxillary bones are toothed when jaw bones have little or no teeth. This is t
rue for many soft rayed species such as bowfin (Amia) the gars (lepisosteus) the sal
mons and trouts (Salmonidae).
The maxillae are typically toothed in those soft rayed fishes as that carry premaxilla
ry teeth. However tooth less in otherwise tooth – bearing spiny rayed fishes.
14. Four types of shark teeth include:
Dense flattened: Nurse sharks and angel sharks use their dense flattened teeth to crush
crustaceans and mollusks.
Needle-like: Blue sharks and bulls sharks use their needle-sharp teeth to grab and eat s
mall- to medium-sized fish such as flounder, stingrays, and even smaller sharks.
Pointed lower with triangular upper: These razor-sharp teeth are a famous trait of the G
reat White shark, which feeds on large mammals and fish like dolphins, sea lions, other s
harks, and small whales.
Non-functional: Pretty much useless, these teeth belong to plankton feeders such as the
basking shark and whale shark that simply suck food into their mouths without chewing.
15. BUCCAL CAVITY, PHARYNX
& GILL RACKERS
The buccal cavity and pharynx are not clearly marked off from each oth
er.
A number of perforations of gill slits are located on each side of the ph
aryngeal wall.
Primary function of the gill rakers is to protect gill filaments from injury
and to assist the fishes in the process of ingestion .
16. OMNIVOROUS
In the omnivorous fishes
like Puntius sarana,gill ra
kers are short and
stumpy.
HERBIVOROUS:
Like Labeo rohita,Cirrhina marigala,
gill rakers form a broad sieve like st
ructure across the gill slits for filteri
ng the water in order to retain the f
ood in the bucco-pharynx
17. Carnivorous Fishes : Gill rakers are normally long, ha
rd and teeth like forming rasping organs as in Wallago attu, Mystu
s seenghala, Channa striatus.
18. Oesophagus
The pharynx opens behind into the oesophagus which have large nu
mber of mucus secreting cells which are scattered in the mucosa.
Taste buds are also present e.g. Labeo rohita, Cyprinus carpio, Catla
catla
Short & narrow tube in case of herbivorous and omnivorous fishes e.
g. Labeo rohita, Puntius sarana, Cyprinus carpio etc
Large & distensible tube in case of carnivores and predatory fishes (
e.g. Wallago attu, Heteropneustes fossilis etc.
19. Stomach
ANTERIOR – CARDIAC STOMACH
STOMACH
POSTERIOR – PYLORIC STOMACH
•Stomach acquire different shapes according to the availability
of space in the body cavities of different fishes.
A true stomach is present in the carnivorous and predatory fishes e.g
. Channa striatus, Mystus seenghala etc .
intestinal bulb (Stomachless Fishes ):
All the fishes do not possess a true stomach as it is almost absent in
various herbivorous fishes like Labeo rohita,Catla catla etc.
About 15% of teleosts, including cyprinids, have no stomach and no region of lo
w pH or pre-digestion. Anterior portion of intestine has some storage function, i
ntestine in these species is usually very long compared to, say, a trout (Rombo
ut, et al. 2011).
In such fishes, the anterior part of the intestine is swollen to form a s
ac like structure called intestinal bulb.
20. Carnivorous fishes:• Stomach is generally sac-like a
nd thick walled in Carnivorous an
d predatory fishes.
Omnivorous fishes:
Stomach of omnivorous fishes is also sac like .e.g. Puntius
sophore,Cyprinus carpio etc.
In some fishes like Hilsa hilsa,Gudusia chapra, stomach is red
uced in size but is greatly thickened to become gizzard like for
trituration of food
21. Pyloric caeca
•Anterior part of the intestine
give rise to a number of finger
-like outgrowths called
pyloric or intestinal caeca.
• Pyloric caeca serve as access
ory food reservoirs .
•Histologically, intestinal caeca
resembles the intestine and pr
obably serve to enhance the a
bsorptive area.
22. Intestine
• The part of alimentary canal that follows the stomach is called inte
stine and is divided into two parts:
1.Anterior part : small intestine
2.Posterior part : large intestine
The small intestine just behind the stomach receives ducts from th
e liver and pancreas is called as duodenum while rest part is called il
eum .
There is no clear cut demarcation between the small intestine and
large intestine .
The length of the intestine depends upon the feeding habit of the fi
sh.
23. Carnivorous fishes : It is shortened in carnivore
s such as in Wallogo attu, Mystus seenghala because flesh
can be digested more readily than the plant based food stu
ff.
24. Herbivorous fishes:
Intestine is often elongated and arranged in many folds in case of herb
ivorous fishes.
Longer intestines are of great advantage to herbivorous fishes as they r
etain food for long period of time to ensure digestion.
25. Omnivorous fishes:
Intermediate length of the gut is found in case
of omnivorous fishes e.g. Puntius sophore etc.
The intestinal bulb of Labeo rohita is about 25c
m,the small intestine about 8m and the large inte
stine about a meter in length.
28. Rectum
•It is not usually distinguishable externally but an ileo-r
ecta valve is present in few species of fish to demarcate
it from the intestine e.g. Tetradon
•Histologically ,the mucosal folds of the rectum differ fr
om the intestine in being shorter and broader, possess
a large number of mucus secreting cells produce copio
us mucus to lubricate waste food and aid in easy defec
ation
29. Digestive glands
The digestive system consists of alimentary canal and its associated glands. The diges
tive tube also contains numerous intramural glands which provide the tube by lubrica
ting mucus, enzymes, water, etc.
The extramural glands are liver, pancreas and gall bladder (Fig. 4.1a, b). The liver is pr
esent in all fishes.
The pancreas which is exocrine and endocrine organ, may be a discrete organ or it m
ay be diffused in the liver or in the alimentary canal.
In sharks and rays (Elasmobranchii) pancreas is relatively compact and usually well d
eveloped as a separate organ, often two lobed, but in teleosts, the pancreas is diffus
ed in the liver to form hepatopancreas.
It is also diffused in the alimentary canal in a few fishes. It is also present in the mese
nteric membranes surrounding the intestine and liver.
The gall bladder is vestigeal in deep sea fishes but it is prominent in other fishes.
While passing through the alimentary canal, the food is broken down physically and c
hemically and ultimately solubilized so that degraded products can be absorbed. The
absorption occurs chiefly through the wall of intestine.
30.
31. Two main digestive glands in Fish :
1 . Pancreas: pancreas is a diffuse gland, but is well developed around the
blood vessels between the lobes of the liver.
Pancreas has two digestive functions:
1.Source of exocrine secretion into the intestine.
2.Endocrine secretion of the hormones insulin and glucagon .
2.Liver:
• Liver is a bilobed gland usually yellowish brown in color.
• The liver in fish produces bile
which is stored in the gall bladder.
• Key storage of food energy
in the form of glycogen.
32. Conclusions
Various structures have been modified according to the natu
re of the food and feeding habits of the fish.
Position and shape of the mouth.
Dentition.
Lips may become cornified as in case of Labeo, granular
or papillated.
Taste buds and mucus secreting cells .
Structure of pharynx and gill rakers have also undergo m
odifications according to the feeding habit of the fish.
Relative length of the gut (RLG).
Continue….
33. Conclusions
The structure of the alimentary canal varies in d
ifferent species of fishes and is generally adapted
in relation to the food and feeding habit.
The variations are seen in the position of the mo
uth, architecture of the buccopharynx, relative len
gth of the gut, presence or absence of the stomac
h and pyloric caeca.
Thanks.
34. Textbook of fish biology and fisheries by S.S. Khanna & H.R. Si
ngh (2005)
Ichthyology by Lagler et al 1977
https://fr.slideshare.net/asimhaq1/alimentary-canal-and-feeding-a
daptations-in-fishes-by-nusrit