Nutritional Biochemistry focuses on carbohydrates and proteins. Carbohydrates are composed of carbon, hydrogen, and oxygen and serve as short-term energy storage. Their digestion in fish involves breakdown by enzymes in the mouth, stomach, pancreas, and intestine. Factors like fish species and age affect carbohydrate digestibility. Proteins are composed of amino acids and are essential for growth, reproduction, and tissue repair. Good protein sources for fish include fish meal, soybean, and insects. Protein digestion occurs via enzymes in the mouth, stomach, pancreas, and bloodstream. The document provides information on nutrient requirements, sources, and digestion processes in fish.

1. Nutritional Biochemistry
(Carbohydrate and protein)
Presented by..
Karan Das
M.Sc. Zoology

2. Welcome….

3. Nutrition: Nutrition is the sum total of the processes
involved in the taking in and the utilization of food
substances in the body.
It involves ingestion, digestion,absorption and
assimilation.
 Feeds contain nutrients & the energy essential for :
(1) The growth,
(2) Reproduction &
(3) Repair and maintenance of the body.
 For Proper nutrition fish need feed, containing
proper nutrients.

4. • A nutrient is a chemical that
an organism needs to live and grow or a
substance used in an organism's
metabolism which must be taken in from
its environment.
• They are used to build and repair tissues,
regulate body processes and are converted
to and used as energy.
• A feed containing all nutrients in sufficient
amount is considered as good feed.

5. Types of Nutrients
• There are 6 types of nutrients. Such as-
i) Carbohydrate iv) Vitamin
ii) Protein v) Mineral
iii) Fat vi) Water
• Depending on the use in nutrition Nutrients are of 2
type. Such as-
a) Macro Nutrient
b) Micro Nutrient
• As the role of carbohydrate, protein, & Fat in
nutrition is more, these are considered as macro
nutrients.
• The role of vitamin, mineral, & water in nutrition is
quite less. So, they are considered as micro
nutrient. But these are essential for nutrition.

6. • A carbohydrate is an organic compound that is
composed of atoms of carbon, hydrogen and oxygen in a
ratio of 1 carbon atom, 2 hydrogen atoms, and 1 oxygen
atom.
• The common formula of carbohydrate is Cn(H2O)n
• The primary function of carbohydrates is for short-
term energy storage (sugars are for Energy). A
secondary function is intermediate-term energy
storage (as in starch for plants and glycogen for
animals). Other carbohydrates are involved as
structural components in cells, such as cellulose which is
found in the cell walls of plants.

8. The process of carbohydrates digestion in fish body are given below-
1. Mouth: It begins in the mouth. The salivary glands in the mouth
secrete saliva, which helps to moisten the food, which begins the
process of breaking down the polysaccharides in the carbohydrate
food.
2 . Stomach ( In Carnivorous fish ): After chewing into smaller pieces
and mixed with salivary amylase and other salivary juices, it is
swallowed and passed through the esophagus. The mixture enters the
stomach where it is known as chyme. The stomach produces acid
which destroys bacteria in the food and stops the action of the salivary
amylase.

9. 3. Pancreas and Intestine: In response to chyme
being in the duodenum, the pancreas releases the
enzyme pancreatic amylase, which breaks the
polysaccharide down into a disaccharide. The small
intestine then produces enzymes called lactase,
sucrose and maltase, which break down the
disaccharides into monosaccharaides. The
monosaccharaides are single sugars that are then
absorbed in the small intestine.

10. There are some factors that affect the
digestibility of carbohydrate. They are-
• Feeding Habits of fish.
• Age of fish.
• The availability of carbohydrate
enzymes.
• The anatomy of the digestive tract of
fish.
• The size of carbohydrate molecule.

11. Carbohydrates make up 20-30% of the common
commercial foods. 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 carbohydrate 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.

12. • The nutritional value of carbohydrates varies among fish.
• Tropical-water fish can use much greater amounts of
dietary carbohydrate than cold-water and marine fish.
• In general, carnivorous fish such as salmoids digest
carbohydrates less efficiently than omnivorous and
herbivorous fish .
• The poor ability to utilize carbohydrates applies also to
all the carnivorous fishes.
• Due to high enzyme activity certain carp species such as
common carp (Cyprinus carpio) & grass carp
(Ctenopharyngodon idella) utilize carbohydrates well.

13. • while fry respond negatively.
• Various catfish species use carbohydrates even at
levels of almost 50%.the african tilapia utilised
dietary carbohydrates satisfactorily.

14. • carbohydrate is the least expensive
source of dietary energy,
• concen

15. • In shrimp carbohydrate are important as energy
source for chitin synthesis and synthesis of non-
essential fatty acids. However, there are different in
utilization of the carbohydrate source.
Monosaccharaides such as glucose, galactose and
fructose inhibit the growth of brown shrimp(Penaeus
aztecus), kuruma shrimp(Penaeus japonicus).
• Chitin is a linear polysaccharide and the major
component of exoskeleton of shrimp. Due to molting
this has to be steadily replaced. It is synthesized
from glucose via glucomine, a precursor of chitin.

16. • In fish, carbohydrates are stored as glycogen that
can be mobilized to satisfy energy demands.
• The growth rate of channel catfish fingerlings was
greater when their diets contained some
carbohydrates rather than only lipids for all the non
protein energy (Garling and Wilson, 1977).
• The most likely symptom of oversupply of
carbohydrates in carp diets is excessive deposition of
fat in the liver, heart and carcass.

17. The most likely symptom of oversupply of
carbohydrates in carp diets is excessive
deposition of fat in the liver, heart and
carcass.
Fatty liver in fish

18. Carbohydrate percentage in some
fish feed (Sources)..
Fish Feed Carbohydrate(%)
Groundnut oilcake 6-7
Soybean Meal 4-5
Rice polish 7-10
Rice bran 8-12
Deoiled rice bran 10-15
Rapeseed cake 11-15
Salseed Cake 10-13

19. Cont….
Fish feed Carbohydrate(%)
Til oilcake 10-15
Mustard oilcake 10-16
Cotton seed cake 12-16
Sunflower oilcake 15-18
Copra cake 12-17
Maize flour 2-3
Barley grains 4-6

20. PROTEIN
-Greek word meaning, Primarily or
holding first place.
- Proteins are the main structural
components of the body.
- They are nitrogenous macromolecules
composed of many amino acids. In addition
to C,H,&O protein also contain N.

22. Factors Affecting Protein Requirement
- Size of fish: Small fish require more protein
than larger fish.
- Protein quality: Protein needs to be of good
quality(such as from grain amaranth or black
soldier flylarvae)
- Natural foods: Some fish use natural foods
effectively.
- Depends on stocking density

24. Protein Sources..
# Animal protein
* Fish meal
Balance of amino acids that approach requirements of most
fish
Palatable and digestible
Not sustainable
* Trash fish
By-catches
High water content, spoils
Anti-nutritional enzymes
Not sustainable
* Poultry
Plenty of product due to chicken farming
Nutrition depends on part of chicken
Warrants more experiments

25. * Insects
High in protein (e.g. Black soldier fly larvae)
High in water content
high Availability,
Diet supplement
* Crustaceans
High in protein
High in chitin
* Zooplankton
Fed in combination with commercial diet
Usually not sole source of feed because readily
take dry feed

26. Protein sources…
Plant Protein
Usually lacks in AA content
Must add additional AA
Many contain anti-nutritional factors and/or
toxins
Deactivated or destroyed by soaking or heat

27. Soybean (30-50%)
Farmed all over
Amino acid imbalance
High Palatability
Functions as Attractant
Trypsin inhibitor

29. The Process of protein digestion in fish are given below-
1 Mastication: Protein digestion begins in fish mouth, where
chewing combines saliva with food, also called mastication, and it
breaks down into smaller particles.
2 The Stomach (In Carnivorous fish): The stomach produces HCl,
which is needed to activate protein digestion.
3 Enzymes: The stomach secretes an enzyme called protease that
removes the bonds holding together the long chains of amino.
4 The Pancreas: The pancreas releases trypsin, another digestive
enzyme, into the small intestine. The protein molecules are reduced
in size until they can pass through the intestinal wall.
5 The Bloodstream: Once the protein molecules are reduced to
their smallest component parts, they are ready to enter the
bloodstream.

30.  Hand book of Fisheries and Aquaculture-
ICAR- S. AYYAPPAN.
 Hand book on Ingredients for Aquaculture
Feeds- Joachim W. Hertrampf and Felicitas
Piedad-Pascual
 An Introduction to fishes- S.S.Khanna
 www.fao.org
 www.wikipedia.org
 Pictures are collected from www.google.com

32. Any questions…????