Growth performance and fatty acid profile of nile tilapia oreochromis niloticus (Linnaeus, 1758) fed with different phytoplankton

Abstract

The effect of different phytoplankton species on growth, survival and fatty
acids composition of Nile tilapia (Oreochromis niloticus) was evaluated for 24
weeks. Treatment‐1 was fed with commercial feed as Control, treatment‐2 was
fed with Spirulina platensis, treatment‐3 was fed with Chlorella vulgaris and
treatment‐4 was fed with mixed phytoplankton (Chlorella vulgaris, Spirulina
platensis, Azolla pinnata and Pistia stratiotes). The condition factor of fish found in
treatment‐3 with Chlorella vulgaris (1.73 ± 0.02) was significantly higher than that
of treatment‐1 as control (1.56 ± 0.02) at 24 weeks culture period. The specific
growth rate of treatment‐4 with mixed phytoplankton diet (2.00 ± 0.10) was
significantly higher than treatment‐3 with Chlorella vulgaris (1.13 ± 0.05) after 24
weeks of rearing. There was no significant difference among the four treatments
in case of average daily gain, feed conversion ration and survival rate. The use of
different phytoplankton such as Spirulina platensis, Chlorella vulgaris and Azolla
pinnata influence the fatty acid profiles of Nile tilapia. Findings also showed that
the amount of eicosapentaenoic acid (EPA) in treatment‐3 fed with Chlorella
vulgaris (1.83 ± 0.22) was highly significant than the other treatments. The highest
amount of docosahexaenoic acid (DHA) was found in treatment‐1 fed with
commercial feed (2.70 ± 0.53%) and lowest in treatment‐2 with Spirulina platensis
(0.06 ± 0.02%). Among 19 unsaturated fatty acid, the highest concentration of
PUFAs were recorded in treatment‐3 (42.55 ± 3.46%) fed with Chlorella vulgaris.
The findings of this study suggest that raising Nile tilapia with Chlorella vulgaris
and Spirulina platensis in ponds may improve the growth and fatty acid profile of
the fish.