Hyperaccumulation of selenium in hybrid striped bass: a functional food for aquaculture?

Abstract

One method of increasing the value of aquacultured product is to produce fillets that are fortified with minerals that are beneficial to human health -that is enhance the functionality of an already healthy product. A good candidate mineral in this regard is selenium (Se) which is of vital importance to normal metabolism in humans. In order to evaluate the dose response and tissue accumulation of supplemental dietary Se, a study was undertaken with hybrid striped bass (HSB). Animals were fed diets supplemented with either organic (0-3.2 mg kg )1 as SelPlex Ò ) or inorganic (0.2 and 0.4 mg kg )1 as sodium selenite) Se for 6 weeks. Because basal fishmeal-based diets contained 1.22 mg Se kg )1 , doses of Se delivered equated to 1.22-4.42 mg kg )1 . At trial end, greatest weight gain was observed in fish receiving 0.2 mg Se kg )1 , irrespective of form (organic/inorganic). Se accumulation in HSB liver and fillet revealed a classical dose-response once a threshold level of 0.2 mg Se kg )1 was surpassed. Greatest tissue accumulation of Se was observed in fish fed the 3.2 mg Se kg )1 level (P > 0.0001). A 100 g portion of Se-enhanced HSB fillet would contain between 33 and 109 lg Se, amounting to a dietary intake of between 25 and 80 lg Se; a level that would satisfy present daily intake recommendations. Comparison of tissue Se levels indicated that the muscle provides a more conspicuous gauge of dietary Se dose-response than does liver. Dietary treatments of between 0.4 and 1.6 mg organic Se kg )1 reduced (P < 0.024) plasma glutathione peroxidase (GSH-Px) activity. No differences were observed in ceruloplasmin, lysozyme or GSH-Px activities between organic and inorganic Se when delivered at the 0.2 mg Se kg )1 level. Ceruloplasmin, lysozyme and GSH-Px levels were elevated (P ‡ 0.025) in fish fed the diet containing 0.4 mg inorganic Se kg )1 . KEY WORDS

The effects of dietary selenium on growth performances, oxidative stress and tissue selenium concentration of gibel carp (Carassius auratus gibelio)

“…This was supported by the studies in channel catfish (Gatlin & Wilson 1984) and hybrid striped bass (Cotter et al 2008). However, obvious linear relationships between tissue Se accumulation and dietary Se concentrations have been reported in rainbow trout (Hilton et al 1980;Ku¨c¸u¨kbay et al 2009), grouper (Lin & Shiau 2005), African catfish (AbdelTawwaba et al.…”

Modulation of selenium tissue distribution and selenoprotein expression in Atlantic salmon (Salmo salarL.) fed diets with graded levels of plant ingredients

“…Therefore, it would be interesting to study the possible restoration of Se content by returning fish to a 'finishing' diet containing higher levels of FM and FO for a period of time before harvest, as has been shown for n-3 LC-PUFA (50)(51)(52) . Alternatively, the supplementation of aquafeeds with organic sources of Se (Se-enriched yeast), less likely to cause toxicity than inorganic sources, could be used as a measure to maintain adequate Se levels in salmon flesh, as shown for several other fish species (53)(54)(55)(56) . In addition, the use of processed animal proteins such as poultry by-product meal with an average Se content of approximately 0·78 mg/kg (57) could supply Se of high digestibility for aquafeeds.…”

The immune system is limited by oxidative stress: Dietary selenium promotes optimal antioxidative status and greatest immune defense in pacu Piaractus mesopotamicus

“…This fish has ecological and commercial value besides it is the main farmed species in Brazilian aquaculture used primarily for human consumption [25]. In addition, little is known about the relationship between antioxidant status and immunity in fish in general [26,27,18,28,22]. To fill this gap, we investigated how supplementing the diet of pacu with selenium impacted their antioxidant and nonspecific immune systems.…”