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SATURATED DIETARY LIPID SOURCES IN GROWOUT FEEDS FOR HYBRID STRIPED
BASS Morone chrysops ♀ x M. saxatilis ♂: ProDUction PerformAnce AnD fiLLet
FATTY ACID COMPOSITION
Jesse T. Trushenski*, John Boesenberg and Christopher C. Kohler
Fisheries and Illinois Aquaculture Center
Southern Illinois University Carbondale
Carbondale, IL 62901-6511 USA
saluski@siu.edu
Hybrid striped bass (HSB) generally tolerate
a wide range of alternative lipids in grow-out
feeds. However, grow-out feed fatty acid (FA)
composition influences long-chain polyunsaturated
FA (LC-PUFA) restoration during finishing.
Specifically, we have observed grow-out feeds
containing higher levels of saturated FA (SFA) to
yield fillets with greater LC-PUFA content after
finishing. To address whether different saturated
lipid sources are equivalent in this respect, we
fed juvenile (~25 g) HSB feeds (41/14% crude
protein/lipid) containing fish oil (100% FO),
coconut oil (100% CO), palm oil (100% PO), or
a 50:50 blend of FO and CO (50% CO) or PO
(50% PO). After 8 weeks of culture, production
performance was generally within acceptable
ranges for HSB; however, significantly reduced
feed intake and weight gain within the 100% CO
group suggest palatability and/or digestibility
of this feed may have been problematic (Table
1). Expectedly, fillet FA composition reflected
nutritional history (Figure 1): fillet levels of FOassociated
FA, particularly 20:5n-3 and 22:6n-3,
were reduced among fish fed the CO- and PObased
feeds. Increasing dietary inclusion of CO
and PO was associated with increased deposition
of SFA and MUFA, respectively, within the fillet.
Although fillet FA profile was significantly
altered in all CO- and PO-fed groups, LC-PUFA
content was better maintained among fish fed the
CO-based feeds. Although differences in fillet
LC-PUFA content between the CO- and PO-fed
fish were statistically significant, the magnitude
of these differences was relatively small.
Additional research is needed to determine
whether these differences in fillet profile would
affect overall finishing success. Assuming
issues of feed acceptance and/or utilization can
be rectified, CO and PO appear to be suitable
lipid sources for HSB grow-out feeds.