FISH FEEDS AND FEEDING CULTURE
Feeding of fish during culture aims at producing the maximum weight of marketable fish within the shortest time at least cost. The fish feed should supply the energy for movement and all other activities the fish engages in. It should also provide nutrients for body maintenance, growth and reproduction.
Feeding increases fish growth and makes fish farming profitable. Feeds must be nutritious and economical in any farming system and must be properly managed to be effective.
The nutrients needed by fish include carbohydrates, fats, protein, vitamins and minerals. Other components of feed are fibre and moisture. Fish diet must contain all the nutrients in the right proportions to bring about growth.
TYPES OF FEED
Fish in culture can be maintained solely on natural foods in a pond, or on artificial (formulated) feedstuffs or a combination of the two.
The natural foods in a fish pond include mainly phytoplankton, and also zooplankton, detritus, insect larvae, etc.
The abundance of phytoplankton in a fish pond is shown by the extent of greenness of the pond water. The acceptable greenness of the water can be ascertained by the use of a Secchi disc.
The growth of phytoplankton in pond water can be enhanced by fertilization of the water, using inorganic or organic fertilizers. The most commonly used organic fertilizers are droppings of farm animals such as poultry, pigs and cattle, and compost. If the natural food in a pond is insufficient in quantity or lacks certain nutrients necessary for adequate growth, leaves of legumes, and agricultural by-products such as rice bran, wheat bran, groundnut peels, groundnut cake, etc can be used as supplementary feeds.
Formulated feeds can be used as supplementary feeds or as a sole source of nutrients for a fish in a pond.
PRESENTATION OF FEED
Formulated or compounded feeds may be given to fish in the dry, moist or wet form.
Dried compounded feeds can be presented to fish as powder, pellets, or crumbles. Pellets are most popular and their shape and size would depend on the age of the fish.
Floating Pellets are desirable for fish that feed from the surface layers of water (e.g. Tilapia), while sinking pellets are good for fish that feed from the bottom (e.g. Clarias sp).
Formulated feed for tilapia should contain between 27% and 40 % protein.
For fry and fingerlings, the feed should have small particles and a protein content of about 35%- 40%, while for adults the protein content could be between 27% and 30%.
FARM MADE FEEDS
Some farm-made feeds can have the following combinations.
Powdered Lucaena leaves 20%
Cooked maize……………………. 80%
Rice bran…………………………… 70%
Palm Kernel Cake……………… 15%
Maize meal/Cassava Dough… 15%
Wild Fish…………….. 20%
Several other agro-by products can be used in various combinations as feed for fish.
Crabs contain minerals and Calcium which could help improve fishes weigh and health.