Transcript Fish Physiology

Week: 4
Growth and Metabolism
Dr. Ir. Happy Nursyam, MS
Growth and Metabolism
So, this
Is
2007
Weight
Im the
1984
Model
Length
Growth
Growth – Significance
Population Estimators
Fishing
Growth
Population Estimator
Biomass
Mortality
Recruitment
Growth (Continued)
Descriptors
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Regression Models and Fit
Condition Factor (K)
RNA:DNA Ratios
Hepato/Somatic Index
Weight at Age
Bioenergetics Model
Regression Models and Fit
Length
Weight
Weight
r2 = .95
r2 = .75
Length
Condition Factor
K = W · L-3 · 100
K=
W=
L=
Condition Factor
Weight
Length
Used to describe growth as
a function of weight length
relationships. Is a linear
model.
RNA:DNA Ratios
• Assumption –
Growth is protein
based, therefore an
indirect measure of
growth is the ratio
of RNA to DNA, the
greater the ratio the
less the production
of protein, hence
growth. IE lower
RNA indicates a
lack of protein
production
Hepato-Somatic Index
• Assumption –
Protein biosynthesis
is largely mediated
through the liver,
hence increased
demand for protein
will be matched with
and increase in liver
volume.
Low Protein
Synthesis
Increased Protein
Synthesis
1 2 3 4 5 6 7 8 9 10 11 12 13
Length
Weight at Age
Chester River MD
Back River MD
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 1 8
Age
Growth Control
• Asymptotic
G = a x Wb
Age
Weight
– G = Growth
– a = Constant
(growth rate of a 1
gm fish)
– W = Fish Weight
– b = weight
exponent (-0.35 - 0.45)
Weight
• Linear
– The real relationship
Age
Growth Manipulation
Treatment
Response
High Protein Diet
Protein based growth increases
Arginine enrichment
Enhanced juvenile growth
Growth hormone
Early smolt, hypoglycemia,
decreased muscle protein
IGF-1 (osmotic
minipump)
Mixed results, hypoglycemia
Androgens
Reduced condition factor
Estrogens
Mixed results
Growth Manipulation
Purpose
Aquaculture
vs.
Restoration
Fast Growth
Not Important Except for
Juvenile growth
Sterility Promotes
Diversion of Energy From
Development of Eggs and
Sperm
No (An obvious)
Docility Promotes
Energy Conservation for
Growth
No Need Active Fish, Primarily
Foraging
Growth – Issue of Markers
• Growth – Juvenile Oyster
Disease (JOD) Selection
resulted in fast growth,
allowing for spat to grow
beyond the effects of
infection, interpreted as
increased resistance.
• Immune Response –
Rainbow trout selected for
resistance to Enteric
Redmouth, result was
increased non-specific
resistance, but not cell
mediated resistance
Metabolism – Storage Sites
• Glycogen
– Liver, Brain
• Lipid/Fats
– Brain, Adipose Tissue, Liver, Red Muscle
(Some Species)
• Proteins
– All Cells, Muscle
Metabolism – Products and Exchanges
Glucose - Glycogen
Liver
As
Glycogen
Blood Glucose
• Products – Glycogen,
branched complex
carbohydrate, mobilized to
blood as glucose a
monosaccharide
• Glycogen – Low storage
amounts, short term solution
to energy needs, rapidly
depleted
• Dysfunctions – Carbohydrate
rich diets (>20%) result in
glycogen liver syndrome,
excess stimulation of
gluconeogenic pathways
results in same condition
Distribution to Organs
Metabolism – Products and Exchanges
Fats/Lipids
Liver – Conversions via Krebs from AAs,
Glucose, FAs to FAs
Liver – Formation of
Lipoproteins
Blood – Movement as FAs,
Glycerol
TAG Lipase at Adipose
Adipose – Conversion to
Mobile FA Form
Adipose – Release as
Glycerol and FAs