Suitability of cyclopoids as starter live feed for the African Catfish (Clarias Gariepinus, Burchell 1822) larvae culture in Uganda

Abstract

Imported Artemia cysts (the Brine Shrimp) are the only readily available live feed for purchase to catfish seed aquaculturists in Uganda. The current study explored the possibility of using cyclopoid copepods as alternative starter live food for African catfish larvae. Cyclopoid copepods were found to be widely distributed in all the three habitats, fish pond, Lagoon and Murchison Bay of Lake Victoria. Although they were numerically dominate at Murchison bay. On the other hand rotifers were predominant in the fish pond and lagoon. Competition, predation and physico-chemical tolerance are thought to shape the relative abundance of this zooplankton population.

Body measurement revealed that the size of cyclopoid copepods (nauplii and early copepodite C1 and C2) are suitable for catfish larvae than the first instar of Artemia nauplii, as the former were much smaller than the later. Fatty acid profiling of larvae fed on cyclopoid copepods, Artemia cysts and a combination of the two, revealed that larvae fed of the combination of Artemia and cyclopoids had significantly high composition of essential fatty acids, Linoleic acid (LA), α linolenic acid (LNA) and eicosapentaenoic acid (EPA) (F=24.1, P<0.05, F=14.7, P<0.05 and F=96.3, P<0.05, respectively). On the other hand, Docosahexaenoic acid (DHA) and Arachidonic acid (AA) were significantly high (F=101.9, P<0.05and F=12.1 P<0.05, respectively) in cyclopoid-fed larvae. In addition overall, growth of catfish larvae was significantly different (F=25.94, P<0.05) among diets with cyclopoid & Artemia fed larvae revealing best growth performance (9.1 ± 0.89) mm followed by larvae fed on cyclopoids (8.8 ± 0.92) mm and lastly Artemia (8.6 ± 0.79) mm.Findings suggest that essential fatty acids; LA, LNA, AA, EPA and DHA are critical dietary requirements of catfish larvae.

Availability of cyclopoids, small nauplii sizes, higher composition of essential fatty acids and correspondingly improved growth performance of catfish larvae fed on cyclopoid copepods as compared to the case where Artemia is used, indicates the suitability of cyclopoid copepods as an alternative starter fed to Artemia for African catfish larvae.