Dietary enrichments with the arachidonic acid (ARA)-rich
microalga, Parietochloris incisa, on the survival of guppy
(Poecilia reticulata) fry were examined. Diets were applied
via Artemia enrichment to fish from two commercial farms
for 34 and 36 days of experimental period (trials 1 and 2,
respectively). In trial 1, Artemia nauplii were enriched with
dry biomass of whole algal cells at 0 (control), 0.1, 0.2
and 0.4 mg mL)1. Fry fed with Artemia enriched with
0.4 mg mL)1 demonstrated the lowest mortality rates (24%
and 1% in farms 1 and 2, respectively) compared with controls
(36% and 13% in farms 1 and 2, respectively). In trial 2,
fry were fed with Artemia, enriched with whole algal cells
(0.4 mg ml)1), algal hexane extract (HE; containing primarily
ARA-rich triacylglycerols and b-carotene; 0.19 mg ml)1) or
the extraction residue (0.28 mg ml)1). Acute stress (5 min air
exposure) was applied after 18 days. The lowest mortality
was recorded in the whole alga-fed group (av. 26% and 2.6%
in farms 1 and 2, respectively), with a slightly, but not significantly
higher mortality in the HE-fed group (av. 29% and
6.2% in farms 1 and 2, respectively). Elevated lysozyme was
associated with the reduced mortality. Overall, the use of
P. incisa as a dietary supplement for guppy fry during their
first month of life enhanced their survival and stress resistance