Fish Nutrition and Feed Technology (2+1)

Practical 3 - Determination of sinking rate and stability of formulated feeds

(a) Sinking rate of formulated feeds

The feed employed in the cultured system is preferably sink to the pond bottom and stable for long duration to enable maximum utilization by the cultured species. External mastication, explore of water currents and aeration system hasten pellet disintegration and result in loss of nutrients. Hence the sinking rate of the feed can be defined as the distance traveled by the pellets in water column at a particular time.

Materials and method
Pellets of known size, scale, stop watch, water, aquarium tank.

Procedure
Take an aquarium tank and fill it with clear fresh water. Note down the water level using a scale. Uniform size (1cm in length) pellet is then dropped gently into the water and note down the time taken by the pellets to travel the depth of water column with a stop watch. Repeat the experiment for atleast three times and find out average sinking rate and express it as cm/sec using the formulae,