The effects of dietary organic or inorganic selenium in rainbow trout (Oncorhynchus mykiss) under crowding conditions

Abstract

In the present study, the effects of different sources of selenium (Se; sodium selenite or selenomethionine) supplementation on the growth and serum concentrations of oxidative stress markers [malondialdehyde (MDA), 8‐isoprostane, glutathione peroxidase (GSH‐Px) activity] and muscle Se, MDA and heat shock protein 70 (Hsp70) levels in rainbow trouts were evaluated. The fish (n = 360; 0 + years old) with initial average weight of 20 ± 0.8 g were randomly assigned to 12 treatment groups consisting of 3 replicates of 10 fish each in a 2 × 2 × 3 factorial arrangement of treatments (stocking densities, Se sources, Se levels). The fish were kept at low (25 kg m−3) or high (100 kg m−3) stocking densities and fed a basal (control) diet or the basal diet supplemented with either 0.15 or 0.30 mg of Se kg−1 of diet from two different forms: sodium selenite or selenomethionine. High stocking density decreased weight gain, feed intake and feed conversion ratio (FCR) when basal diet was fed (P = 0.001). A linear increase in feed intake and weight gain and improvement in FCR were found in sodium selenite (P = 0.01)‐ or selenomethionine (P = 0.001)‐supplemented fish reared under crowding conditions. Serum and muscle Se levels and serum GSH‐Px activity increased (P = 0.001) linearly, whereas serum and muscle MDA concentrations and serum 8‐isoprostane decreased linearly as dietary sodium selenite (P = 0.01) or selenomethionine (P = 0.001) supplementation increased. Selenomethionine and sodium selenite supplementation decreased Hsp70 in the muscle of fish reared under crowding conditions (P < 0.05). Supplementation with Se improved growth and antioxidant status of fish and the effects of selenomethionine were relatively greater than sodium selenite in the crowded groups. Results suggest that crowding conditions cause significant detrimental effects in rainbow trout indicated by increased oxidative stress, reduced feed intake and body weight gain. İt also indicates that dietary Se supplementation offers a feasible way of reducing the losses in performance of rainbow trout reared under crowding conditions. Selenomethionine seems to be more effective than sodium selenite and the higer dose in the present study also seems to be more effective than the lower dose.

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 effect of transportation of broilers during summer on the expression of heat shock protein 70, postmortem metabolism and meat quality1

“…The determination of Hsp70 was quantified according to the procedure of Küçükbay et al, (2009) and the analysis of phosphorylation of AMP-activated protein kinase (p-AMPK) was essentially as described by (Shen et al, 2008). A frozen muscle sample (0.5 g) was homogenized using a polytron homogenizer in 5 mL buffer [for Hsp70: 10mM Tris-HCl (pH 7.4), 0.1mM NaCl, 0.1mM phenylmethylsulphonyl fluoride (PMSF), 5μM soybean (soluble powder; Sigma, St. Louis, MO, USA) as trypsin inhibitor; for p-AMPK, 20mM Tris-HCl (pH 7.4 at 4°C), 2% SDS, 5mM EDTA, 5mM EGTA, 1mM DTT, 100mM NaF, 2mM sodium vanadate, 0.5mM PMSF, 10 μg/ml leupeptin, and 10 μg/ml pepstatin].…”

Influence of Dietary Selenium Species on Selenoamino Acid Levels in Rainbow Trout

“…14 Se supplementation of fish feeds has been already investigated in several studies, 15−17 but criteria taken into consideration to evaluate the effects of such supplementation on Se metabolism differ depending on studies. Schram et al 17 determined total Se and Se speciation in muscle, Kucukbay et al 15 measured total Se in both muscle and serum, as well as GPx activity in serum, and Rider et al 16 quantified total Se in whole body of fish and also determined hepatic GPx and TRx activities. The two latter studies concluded on a beneficial effect of Se supplementation and on the superiority of the organic form of Se supplementation over supplementation with selenite.…”