Week: 4

Growth and Metabolism

Dr. Ir. Happy Nursyam, MS

Growth and Metabolism

Im the1984 Model

So, this Is

2007

Length

Wei

ght

Growth

Growth – SignificancePopulation Estimators

Population EstimatorBiomass

Growth Recruitment

Mortality

Fishing

Growth (Continued)Descriptors

• Regression Models and Fit

• Condition Factor (K)

• RNA:DNA Ratios

• Hepato/Somatic Index

• Weight at Age

• Bioenergetics Model

Regression Models and Fit

Length

Wei

ght

Length

Wei

ght

r2 = .95

r2 = .75

Transition 1980s to 2000s

Condition Factor

K = W · L-3 · 100

K = Condition FactorW = WeightL = 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.

Increased ProteinSynthesis

Low ProteinSynthesis

Weight at Age

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 1 8

Age

1 2

3

4

5 6

7

8

9 1

0 1

1 1

2 1

3

Len

gth

Back River MD

Chester River MD

Growth Control

• Linear– G = Growth– a = Constant

(growth rate of a 1 gm fish)

– W = Fish Weight– b = weight

exponent (-0.35 - -0.45)

• Asymptotic – The real relationship

Age

Wei

ght

Age

Wei

ght

G = a x Wb

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 ManipulationPurpose

Aquaculture vs. Restoration

Fast Growth Not Important Except for Juvenile growth

Sterility Promotes No (An obvious)Diversion of Energy FromDevelopment of Eggs andSperm

Docility Promotes No Need Active Fish, Primarily Energy Conservation for ForagingGrowth

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 ExchangesGlucose - Glycogen

• 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

LiverAs

Glycogen

Blo

od

Glu

cose

Distribution to Organs

Metabolism – Products and ExchangesFats/Lipids

Liver – Conversions via Krebs from AAs, Glucose, FAs to FAs

Liver – Formation of Lipoproteins

Blood – Movement as FAs, Glycerol

Adipose – Release as Glycerol and FAs

Adipose – Conversion to Mobile FA Form

TAG Lipase at Adipose