Abstract:

Imported Artemia cysts (the Brine Shrimp) arc currently the readily available live starter feed to
locally grown rotifers (Brachionus calyciflorus) as an alternative starter live feed to Artemia in
the feeding of African catfish (Clarias gariepinus, Burchell, 1822) larvae was explored. African
tested on tlrree experimental live starter diets; freshly decapsulated Artemia cysts, rotifer B.
calyciflonis and a combination of the two on the third, fourth and fifth days to meet their
exclusive requirement for live starter feeds during the first three days. A short period (3 days) of
diet experimentation used in this study may have limited the lull understanding of growth
performance with diet in larval African catfish, but it was nonetheless based on the practice by
all commercial fish farmers in Uganda to provide a live starter diet for only two to tliree days
following commencement of exogenous feeding of the African catfish larvae. Change in Total
Length (TL) measurements of larvae was used as a measure of growth. Fatty acid profiles of sixday
old larvae were determined using Gas chromatography-mass spectrometry (GC-MS) method
and cost effectiveness of utilizing either Artemia or Rotifer starter diets computed. To explain
whether different Artemia strains used as live starter feeds for African catfish larvae may impart
different growth performance, three commonly used Artemia (USA - Artemia franciscana, Asia
- Artemia salina and China -Artemia strain) were tested on two days old African catfish larvae.
Feeding African catfish larvae on different Artemia strains yielded no significant differences in
growth (F= 0.875, P=0.42) and survival (F=1.485; P=0.299). However, overall growth of
Rotifer-fed African catfish larvae was significantly better than Artemia - fed larvae (F= 47.605,
P=0.000). Noteworthy, was tire 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 (Rotiferxii
catfish larvae were cultured in experimental tanks under ambient hatchery conditions and
African catfish breeders in Uganda but are highly priced. In this study, the potential use of 9.04±0.58 mm, Artemia -8.78±0.54 mm, P=0.147). Significantly higher composition of
Arachidonic acid (AA), Docosahcxacnoic acid (DIIA) and proportions of DHA/EPA and
P=0.016 and DHA, F=28.740, P=0.011, respectively).
significant role in the structural, physiological and functional development of larval fish and may
explain the better growth recorded in this study. The combination of rotifers with Artemia was
probably of an added advantage due to the large-sized Artemia that makes catchability easy. On
the other hand, partial or total replacement of Artemia with Rotifer was more cost effective than
using only Artemia. The results of this study recommend B. calyciflorus rotifers as alternative to
Artemia in hatchery in raising African catfish larvae because they compete favourably with
Artemia in fish larvae growth performance and are cost effective. However, utilization a
combined diet of rotifers and Artemia as live starter feeds in African catfish hatcheries would
provide added advantage in achieving better growth results of the fish.
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AA/EPA were recorded for Rotifer -fed larvae than for Artemia-fed larvae (AA, F=22.292,
These essential fatty acids play a