Abstract
Diets incorporating different levels of corn gluten
meal replacement using biofuel algae or Spirulina
protein at 0%, 25%, 50%, 75% and 100% were
evaluated for larval/juvenile stage of Nile tilapia
(Oreochromis niloticus). Fish averaging 0.02 g were
divided into groups of 50. There were three replicates
per every dietary treatment that were fed
one of six diets for 11 weeks. Corn gluten protein
was replaced with algae on the protein basis. All
diets were supplemented with 1.5% lysine and
0.5% methionine. The experimental diets were
formulated to contain 37 ± 2.8% protein and
14 ± 4.3% lipid in the form of fish oil and soybean
lecithin (phospholipids source). The results indicated
that algae positively affected feed consumption
and fish growth up to the 50% replacement
and then performance was depressed. Significant
differences in concentration of individual minerals
(Al, Fe, Zn and Cu) in the whole fish body were
found. Mineral composition of algae might have
affected growth when diets which contained more
than 75% of plant protein were replaced with microalgae.
These findings suggest that up to 50% of
dietary corn gluten meal protein can be replaced
with microalgae which significantly enhance fish
growth.