Fatty acid profiles and growth of African catfish (Clarias gariepinus, Burchell, 1822) larvae fed on freshwater rotifer (Brachionus calyciflorus) and Artemia as live starter feeds

The potential use of locally grown rotifers (Brachionus calyciflorus) as an alternative starter live feed to Artemia in the feeding of African catfish larvae was explored. Larvae cultured in experimental tanks under ambient hatchery conditions were fed on three experimental diets; freshly decapsulated Artemia cysts, rotifer, Brachionus calyciflorus and a combination of the two for three days following commencement of exogenous feeding. Change in Total Length (TL) measurements of larvae was used as a measure of growth and fatty acid profiles of six-day old larvae were determined using Gas chromatography-mass spectrometry (GC-MS) method. Overall, the growth of Rotifer-fed African catfish larvae was significantly better than Artemia – fed larvae (F= 47.605, P=0.000). Noteworthy, was the fact that catfish larvae fed on a mixture of rotifers and Artemia grew faster (10.04±0.45 mm, P=0.000) than those fed on either rotifers or Artemia (Rotifer-9.04±0.58 mm, Artemia -8.78±0.54 mm, P=0.147). Significantly higher composition of Arachidonic acid (AA) and Docosahexaenoic acid (DHA) were recorded for rotifer -fed larvae than for Artemia-fed larvae (AA: F=22.292 and P=0.016, DHA: F=28.740, P=0.011). These essential fatty acids play a significant role in the structural, physiological and functional development of larval fish and may explain the better growth recorded in this study. A combination of rotifers with Artemia was of an added advantage possibly due to the large-sized Artemia that makes catchability easy. The results demonstrated that partial or total replacement of Artemia with rotifers as a live starter feed for African catfish larvae is feasible because they compete favourably with Artemia in fish larvae growth performance.