Fish Nutrition

Question 1

What is the most organic material for fish in diet?

Answer 1

Protein

Question 2

What are the limiting essential amino acids in fish?

Answer 2

Methionine & Lysine

• Limiting amino acids because if not supplied within required limits fish cannot absorb other amino acids

Question 3

Why do smaller fish require more protein than larger fish?

Answer 3

Need more protein during the growth period - organ and bone development

Question 4

What is the most expensive component of a fish’s diet?

Answer 4

Protein

Question 5

Plant sources of protein for fish

Answer 5

Soybean meal

Question 6

Animal sources of protein for fish

Answer 6

Fish meal - Very expensive (mix with plant sources)

Question 7

Effects of overfeeding fish:

Answer 7

Waste of money

Increases water pollution

Question 8

Why dont wont to overfeed protein to fish

Answer 8

It will then use protein as a source of energy which is expensive!!
Only want to use protein to meet growth and health requirements

Question 9

Not enough protein in fish diet:

Answer 9

Fish will draw protein from non essential tissues

Reduces growth rate

Question 10

Fish diet: Lipids

Answer 10

High energy nutrients

Supply essential fatty acids (EFAs)

Transporters of vitamins

Cellular membrane

Comprise 15% of fish diets

Question 11

Why do we want to maximise lipid use in fish diet?

Answer 11

Lipids reduce the amount of protein required for energy

Lowers the cost

Question 12

Plant sources of lipids for fish

Answer 12

Canola oil, sunflower oil, sesame oil

Question 13

Animal sources of lipids for fish

Answer 13

Fish oil (best source - more than 30% essential AAs)

Question 14

Fish diet: Carbohydrates

Answer 14

Most economical source of energy

Help make pellets float

Not essential

Not very efficient

Question 15

Carbohydrate sources for fish

Answer 15

Cereal grains

Question 16

Overfeeding lipids to fish

Answer 16

Fat accumulation on liver

Compromises health

Reduces fish shelf life

Question 17

Overfeeding carbohydrates to fish

Answer 17

Too much fibre in diet (over 8% of diet)

Causes to much fast moving traffic in intestines and fish cant absorb nutrients

Question 18

Why is the use of carbohydrates limited in cold water fish?

Answer 18

Cold water fish are usually carnivorous and not used to eating carbohydrates

Can feed short chain carbohydrates - easier to digest

Question 19

Fish energy to protein ration

Answer 19

85 to 110 mg of DP / kcal of DE

Fish energy requirement are a lot lower so the protein to energy ratio gets bigger

Fish don’t need energy to regulate body temp or to convert ammonia to urea

Question 20

Water soluble vitamins:

Answer 20

B vitamins
choline
inositol
folic acid (vit C)
pantothenic acid 
biotin
ascorbic acid

Question 21

Fat soluble vitamins

Answer 21

A, D, E and K vitamins

Question 22

Vitamin A

Answer 22

Important of vision

Question 23

Vitamin D

Answer 23

Important for bone integrity

Question 24

Vitamin C & E

Answer 24

Important antioxidants in fish

Work together to preserve cells from peroxidation

Question 25

Vitamin C

Answer 25

Transport of iron in the blood - not enough in diet can lead to anaemia

Antioxidant

Scar tissue formation

Question 26

Macrominerals

Answer 26

Important for osmoregulation process & bone formation and integrity

Calcium 
Magnesium 
Sodium 
Chloride 
Potassium 
Phosphorous

Question 27

Microminerals (trace minerals)

Answer 27

Important in VERY SMALL amounts for enzyme and hormone systems

Iron 
Copper 
Manganese 
Chromium 
Cobalt 
Iodine 
Zinc 
Selenium  

Fish can absorb many minerals from water

Question 28

What information must be available in a fish diet?

Answer 28

1. Nutrient requirements
2. Bioavailable nutrient and energy content
3. Minimum and maximum restrictions on concentrations of ingredients
4. Cost of ingredients

Question 29

Types of fish feed

Answer 29

Extruded (floating or buoyant feeds)
- Used to see fish are eating so you know they are healthy

Pressure pelleted (sinking) feeds

Want to feed fish the biggest size pellet that they can eat