The Design of Prototype Recirculating Aquaculture System and its Use to Examine the Histology of Hybrid Catfish Fed Practical Diets

Abstract

The study designed and constructed a prototype recirculating aquaculture system (RAS) which was used to examine the liver and kidney histology of hybrid catfish (Heterobranchus bidorsalis (♂) X Clarias gariepinus (♀)) fed six practical diets after 12 weeks. Fingerlings of the test fish, mean weight and length of 1.01±0.02g and 4.63±0.34cm were used for the study. In the formulated diets fishmeal was replaced with 100% Fluted Pumpkin Leaf (FPL) as D1, 60% FPL and 40% Parboiled Fermented African Locust Bean (PFALB) as D2, 40% FPL and 60% PFALB as D3, 100% PFALB as D4 and 0% FPL and PFALB as D5 where Diet D6 was Coppens (commercial fish fed). At the end of the experimental period eight fish were sacrificed per tank for the histological examination of the liver and kidney. The designed RAS was efficient for the culture of catfish, however, the significant different in the constructed system and previously reported systems were the systematic operation mechanism, use of one pumping machine and the oxygenation method. The examined liver and kidney histology were normal with the slight difference observed in fish fedrndiet D2. This study revealed that the designed system can be used to culture hybrid catfish. Similarly, the formulated diets do not show an effect on the liver and kidney histology of the test fish.