Nutrition: A series of processes by which

1
Nutrition A series of processes by which an
organism takes in and assimilates food for
promoting growth and replacing worn or injured
tissues
An interdisciplinary science
Research on coldwater fish began in
1940s Warmwater fish 1950s Intensification of
research 1970s
2
Nutrition affects growth, health and
product quality while accounting for gt 50 of
variable operating costs
3
The aquatic medium provides a potential source of
nutrients
Poikilothermy dont maintain body temperature
Less energy in maintaining position in water
column
Fish require less energy for protein synthesis as
they are better able to assimilate high protein
diets
Trout 1.1 g wt gain g-1 diet
chickens 0.5 g wt gain g-1 diet
4
Body composition useful in understanding
nutritional requirements and responses to diets
Protein
16 by weight
Comprises muscle, enzymes and hormones
Remains fairly constant during growth
Measured as crude protein (N x 6.25)
5
Protein Digestion and Assimilation
6
Lipid
20 by weight
Components of cell membranes and energy reserves
Increases during growth
Quantified by extraction with chloroform/methanol
7
Ash
4 by weight
Components of bones, teeth, scales etc.
Remains quite constant during growth
Combustion at 500 C for 6-8 hours
8
Carbohydrates
lt1 by weight
Present as glucose and glycogen in the liver and
muscle
Moisture
60 by weight
Universal solvent for digestion, absorption,
excretion, translocation, heat exchange etc.
Content decreases with age and fattiness
Heating at 100-125 C for 24 h
9
Essential amino acids
Ten, comprising
Arginine, histidine, isoleucine, leucine, lysine,
methionine, phenylalanine, threonine, tryptophan,
valine
Lack of essential amino acids (EAA) can cause
depressed growth, body malformation, death.
Protein requirements of shrimp and fish vary with
Species, size, protein quality, water
temperature, feeding rates, natural food
presence, non-protein energy
Protein requirements tilapia 35 shrimp 38
trout 40
10
Dietary lipids
Source of essential fatty acids n-3 CC, RBT,
n-6 carp, tilapia and HUFAs marine fish and
shrimp
Concentrated source of digestible energy high
fat diets
Important for transport of vitamins (A,D,E, K)
and pigments
Serve as a source for essential sterols, which
form precursors to synthesis of certain hormones
and vitamins
Essential fatty acid requirements trout 1
183n3 yellowtail 2 n3 HUFA tilapia 0.5
182n6
11
Vitamins
Required for normal health, reproduction and
growth
Generally not synthesized
15 vitamins identified as being required in trace
amounts
Two groups fat soluble and water soluble
Essential vitamin requirements trout 30-50
mg/kg diet vit. E antioxidant 10 mg/kg vit. K,
coagulation folic acid, 0.02 mg/kg carbon
metabolism 3-30 mg/kg diet riboflavin hydrogen
transfer
12
Minerals
20 minerals required by shrimp and fish for good
growth and health
Two groups micro-, and macro minerals depends
on presence
Marine shrimp and fish may acquire some minerals
from water
Mineral mix is more important to freshwater diet
formulation
Minerals are important to bone growth (Ca, P),
enzyme activation (Mg, Cu, Zn), osmotic balance
(Na, K), CH2O metabolism (Cr), etc.
13
Energy flow
DE values are widely applied in feed formulation
14
You are what you eat
Most aquafeeds contain fishmeal as their protein
component
Protein is the most expensive ingredient in
aquafeeds gt50 of cost
Alternate proteins have been examined feather
meal, meat by-products, plant proteins, etc.
Carnivorous species however, really like
fishmeals
One strategy is to supply energy as lipid
15
Diet impacts shape
High energy (lipid) diets
Spare protein
Decrease fecal waste and P output
Enhance feed conversion efficiencies
But also
Produce a fatty fish
Decrease dressout percentage
Increase trimming loss
Diet increases visceral and muscle fat
16
(No Transcript)
17
Feeding Methods
Numerous methods available for delivering feed
Method employed will depend on several factors
Labor costs Farm size Species cultured Type of
holding system (cage, tank, raceway, pond etc.)
Whether farm is hatchery or grow-out operation or
both
18
Feeding Methods
Various features of feeding protocol should be
assessed
Spread or distribution of feed in holding system
Feeding intensity or volume of food equipment is
capable of delivering during a feeding event
Storage capacity
Cost and reliability
19
Feeding Methods