February 15-18, 2009 Washington State Convention Center Seattle ...

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SUNSHINE BASS EMBRYONIC AND LARVAL SURVIVAL DIFFER IN RESPONSE TO
REMOVAL OF MARINE OIL FROM MATERNAL BROODSTOCK DIETS
Heidi A. Lewis, Jesse T. Trushenski, Ryan L. Lane and Christopher C. Kohler
Fisheries and Illinois Aquaculture Center
Southern Illinois University
Carbondale, IL 62901-6511 USA
hal7e7@siu.edu
Development of suitable broodstock feeds while reducing dependence on marine oil resources is limited by not knowing fatty
acid requirements for many taxa. Quantification of fatty acid utilization by larvae during the endogenous feeding period will
provide information on essentiality of specific fatty acids for larval development. Accordingly, we monitored sunshine bass
larval survival and fatty acid profile change throughout the endogenous feeding period after altering oocyte fatty acid composition
by feeding female white bass broodstock different dietary lipid sources.
Female white bass (790 ± 19.7 g; mean ± standard error) were stocked into a recirculation system, 7 fish per tank. Triplicate
tanks were fed diets (45% protein and 14% crude lipid) containing graded levels (0, 33, 67, or 100%) of flax to menhaden fish
oil as the primary dietary lipid source. All fish were fed daily to apparent satiation for 6 months. Oocytes were collected by
manual stripping and fertilized using striped bass semen. Egg viability and fertilization were assessed, and larval survival and
fatty acid profile were monitored through 5 days post hatch (DPH).
The fatty acid composition of the oocyte largely reflected maternal dietary intake. However, at the end of the endogenous
feeding period, larval composition deviated from initial oocyte composition (Table 1). Embryonic survival of 100% fish oilfed
broodstock (20.7 ± 3.5%) was significantly greater than 100% flax oil-fed broodstock (6.6 ± 3.8%). Alternatively, larval
survival was significantly reduced in progeny of the 100% fish oil-fed broodstock (51.6 ± 4.7%) compared to those fed the
100% flax oil diet (72.0 ± 5.1%). Differential responses in embryonic and larval survival resulted in comparable total larval
yields at 5 DPH among all maternal dietary treatments (11,000 ± 4,200 female -1 ).
These data support the use of flax oil as a suitable lipid source for marine oil replacement in white bass broodstock diets.
Although n-3 HUFA from fish oil is essential for embryonic survival, sunshine bass appear to have lower n-3 HUFA requirements
after hatch. Larval survival was highly dependent on the presence of 18-carbon polyunsaturated fatty acids (18-C PUFA)
which were present due to flax oil inclusion in maternal diets. Further research is needed to maximize both embryonic and
larval survival of sunshine bass through provision of both dietary 18-C PUFA and n-3 HUFA to maternal white bass broodstock.