Fatty Acid Profiles and Growth of African Catfish Larvae Fed on Freshwater Cyclopoid Copepods and <i>Artemia</i> as Live Starter Feed

Abstract

The possibility of utilizing freshwater crustaceans (Cyclopoid copepods) as an alternative live starter feed for African catfish ( Clarias gariepinus , Burchell, 1822) larvae was explored. Larvae cultured in experimental tanks under ambient hatchery conditions were tested on three experimental diets for three days following commencement of exogenous feeding: freshly decapsulated Artemia cysts, early stages of Cyclopoids-copepods and a combination of the two. Change in total length measurements of larvae was used as a measure of growth. Fatty acid profiles of four-day old larvae were determined using Gas chromatography-mass spectrometry (GC-MS) method. Overall, growth of catfish larvae was significantly different (F=25.94, P<0.05) across diets. Cyclopoid- Artemia -fed larvae grew faster (9.1±0.89) mm, followed by Cyclopoid-fed larvae (8.8±0.92) mm and Artemia -fed larvae (8.6±0.79) mm. Similarly, significantly high composition of α linolenic acid (LNA), Arachidonic acid (AA), and Docosahexaenoic acid (DHA) were recorded for Cyclopoid copepods-fed larvae than for Artemia -fed larvae (LNA, F=14.7, P=0.028; AA, F=12.1, P=0.037 and DHA, F=101.9, P=0.002, respectively) . These essential fatty acids play a significant role in the structural, physiological and functional development of larval fish thus promoting growth. A combination of Cyclopoid copepods with Artemia was of an added advantage possibly due to the large-sized Artemia that makes catchability easy. These results demonstrated that p artial or total replacement of Artemia with Cyclopoid copepods as a live starter feed for African catfish larvae is feasible but call for further investigations on cost benefit analysis.