Feed Nutrition and Feeding – SS2 Livestock Farming Lesson Note (First Term)

Fish nutrition is the supply of the food a fish needs to grow and stay healthy. A balanced fish diet contains proteins, carbohydrates, fats, vitamins and minerals. Fish in a pond depend on natural feed and on artificial feed from the farmer, which is mixed (formulated) and given by hand or machine.

Behavioural objectives

By the end of the lesson, students should be able to:

• state the nutrients a fish diet must contain and the use of each;
• distinguish between natural feed and artificial (supplementary) feed;
• name common ingredients used in fish feed in Nigeria;
• describe the four methods of feeding fish;
• state the golden rules of feeding fish.

Why do fish need to eat?

Just like you and I need food to grow, play and stay healthy, fish need balanced nutrition. In a pond, fish cannot go to a market. They depend on what the farmer gives them.

What must a good fish diet contain?

• Proteins: for building muscles and fast growth (the most important part).
• Carbohydrates and fats: for energy to swim and stay active.
• Vitamins and minerals: to prevent diseases and keep bones strong.

If you do not feed your fish well, they will be stunted (stay small), get sick easily, or even start eating each other.

What are the types of fish feed?

There are two main ways fish get their food: natural feed and artificial (supplementary) feed.

Natural feed

These are tiny organisms that grow naturally in the water.

• Phytoplankton: tiny green plants (this is why we fertilise ponds to make them green).
• Zooplankton: tiny water animals that eat the plants.
• Worms and insects: found at the bottom of earthen ponds.

Artificial (supplementary) feed

This is the food the farmer brings to the pond.

• Local materials: things like rice bran, maize offal or palm kernel cake.
• Pellets: “processed” balanced diets shaped into small balls. There are two kinds:
  • Floating pellets: these stay on top of the water. They are good because you can see the fish eating.
  • Sinking pellets: these drop to the bottom. They are cheaper but harder to monitor.

What is feed formulation?

Formulation means mixing different ingredients to make a balanced meal. A farmer wants the best growth for the lowest price.

Common ingredients used in Nigeria

1. Fish meal: made from dried, ground fish. It is the best source of protein but very expensive.
2. Soybean meal: a good plant-based protein.
3. Groundnut cake (GNC): also provides protein and fats.
4. Maize (corn): provides energy (carbohydrates).
5. Vitamin premix: a “medicine-like” powder added to make sure the fish do not get deficiency diseases.

The Pearson Square method

Farmers often use a simple mathematical tool called the Pearson Square. It helps them calculate how much maize and how much fish meal to mix to get, for example, a 35% protein diet.

How do you feed fish?

How you give the food is as important as what is in the food.

1. Broadcast feeding (hand feeding): the farmer stands by the pond and throws the feed across the surface.
   • Advantage: you can see which fish are not eating (maybe they are sick).
   • Disadvantage: it takes time and effort.
2. Spot feeding: you always throw the food in the same spot. The fish learn to gather there like a “dining room”.
3. Automatic feeders: machines that drop food at set times.
4. Demand feeders: a container with a trigger. When the fish are hungry, they touch the trigger and food falls out.

What are the golden rules of feeding?

To be a successful fish farmer, follow these three rules.

• Do not overfeed: this is the biggest mistake. If fish do not eat the food, it rots at the bottom, ruins the water quality and kills the fish. As the saying goes, “A hungry fish is a healthy fish; a stuffed pond is a dead pond.”
• The 5-minute rule: if the fish have not finished the food in 5 minutes, you have given them too much.
• Timing: feed them when they are most active, usually early morning (8:00 AM) and late evening (5:00 PM). Avoid feeding during the hottest part of the day, when oxygen in the water may be low.

Why does the cost of feed matter?

Feed usually takes up about 60-70% of all the money spent on a fish farm. If you learn to make your own quality feed locally, you can make more profit.

Evaluation

1. List the three groups of nutrients a good fish diet must contain and state one use of each.
2. Give two examples of natural fish feed.
3. State one advantage of floating pellets and one advantage of sinking pellets.
4. Name the tool farmers use to calculate how much of each ingredient to mix for a target protein level.
5. What is the 5-minute rule?

Assignment

1. If you noticed your fish are always staying at the bottom and not coming up to eat, what could be wrong?
2. Why is fish meal usually the most expensive part of a feed recipe?
3. Between floating and sinking pellets, which one would you recommend for a beginner farmer? Give reasons.