A. Awaiss, P. Kestemont-1998
Aquaculture research, 29 : 731-741
Abstract :
The suitability of the freshwater rotifer Brachionus calyciflorus as starting food for the larviculture of African catfish, Clarias gariepinus Burchell, was investigated through studies of growth and fatty acid profiles in relation to different feeding sequences combining live food and dry diet in various proportions and during different mixed feeding periods. The best results for survival were observed when rotifers were supplied during the first week of feeding, i.e. sequences R2 (exclusive supply of rotifers, then dry diet from day 8, onwards) and R5 (50% rotifers + 50% dry diet until day 7, then dry diet 100%), reaching 99.2% and 96.3%, respectively. The specific growth rate of larvae was largely dependent on the duration of preliminary feeding with the rotifers. A feeding with rotifers as a unique food source did not produce satisfactory growth during the first week of feeding. A precocious weaning showed that the highest growth rate and protein efficiency ratio (PER) can be obtained by feeding the larvae rotifers in association with a dry diet. The best PER and protein productive value (PPV) were recorded with feeding sequences R 2 and R5 . On the other hand, the series of polyunsaturated fatty acids was characterized by a relatively constant concentration, and represented about 11.6% of the total fatty acids in sequence R2 because of the presence of the acids of the linoleic series, which apparently originated from the food. The R5 regime provided larvae with significant amounts of highly unsaturated fatty acids, such as linolenic acid C18:3n-3.
(Departement du Genie rural & des Eaux et Forets, Faculte d'Agronomie, BP. 10960, Universite Abdou Moumouni Dioffo, Niamey, Niger)