OH-selenomethionine: an efficient source of Se in fattening pigs S. GREEN, K. COPPENS, P.-A. GERAERT Adisseo France SAS and Denkavit BV, Netherlands
What are our challenges at the animal level? Pork: Transform 1 kg piglet into 110 kg BW pig in 6 months With on average 2.6 kg feed per kg BW Free Radicals Oxidative Stress Stress High Metabolic Rate Rapid Growth Rate Excess Oxygen = Free Radicals Oxidative Stress Anti-Oxidant Capacity 2
Avery, 2011 High metabolic rate means production of ROS
3 major levels of antioxidant defence Free radicals First Level Breaking down Free Radicals (SOD, catalase, Se-GPx ) Second Level Capturing Free Radicals (glutathione, vitamin E, carotenoids ) Third Level Elimination of oxidized products Enzymes to breakdown oxidized lipids & proteins Surai, 2006 4
Selenium : key in the Anti-Oxidant System Vitamin E Lip Lip Vit E Vit C Vit E Vit C 2 GSH GSSG OH Lip Lip LOO GSH GSSG GCS Cys SeCys MetSO MsrB TRx Met SeMet SeMet or OH-SeMet LOOH Met or OH-Met 5
SeCys: the functional Se for antioxidation Se storage form Selenomethionine (SeMet) Selenium containing proteins Trace element Se as SeCys in enzyme catalytic site Selenocysteine: the 21 st amino acid (SeCys) Selenoproteins Schrauzer 2003, Flohé et al. 2011, Hondal et al. 2013 6
SeCys: key for functional Selenoproteins DIO1 DIO2 DIO3 GPx1 GPx2 GPx3 GPx4 GPx6 Known function Deiodinases Glutathione Peroxidases DIO GPx Thyroid hormone activation Peroxide detoxification TrxR1 TrxR2 TrxR3 MsrB Methionine Sulfoxide Reductase Thioredoxin Reductases TrxR MsrB1 Thioredoxin regeneration Methionine reduction SPS2 SelP SelH SelM SelT Sel15 SelK SelS Selenium metabolism Redoxine Protein folding Elusive function Major roles in Redox regulation SelW SelI SelN SelO 25 Selenoproteins in most animals SelV nknown function Lescure et al., 1999 ; Kryukov et al., 2003 7
Different sources of selenium for animal feed Mineral Se sources Selenate Selenite Intestinal barrier Organic Se sources SeMet OH-SeMet selenate Reduction selenite SeCys Transelenation Secystathionin Excretion of Seleno-derived products GS-Se-SG HSe - Selenide SPS2 Se-P SeCys β-lyase GA Serine Seryl-tRNA SeCys SeCys trna SeCys SeMet Containing proteins Selenoproteins Roman et al. 2014 8
OH-SeMet: more bioavailable Se source in pigs NC SS.1 SS.3 SY.1 SY.3 SO.1 SO.3 Selenite Se-yeasts OH-SeMet OH Se 9
Pure sources of organic Se are the most bioavailable Mineral Se sources Organic Se sources NC Selenite Glycinate Proteinate OH-SeMet SeMet Yeast Yeast Yeast Selisseo 74% SeMet 33% SeMet SeHLan - sing a 7d rapid bioavailability test in chicks (Poult. Sci. 2015, 94, 2708-2714) - Pure sources (OH-SeMet & SeMet) the most efficient Se sources - Se-Yeasts: an efficacy related to their SeMet level 10
Experimental protocol Practical swine trial One farm with 2 identical stables (Europe, Belgium 2015), pigs (PIC x Belgian Pietrain) Pre-study, animals were fed a standard commercial feed (0.20 mg Se/kg feed as Na selenite) up to # 65 kg BW During last 8 weeks before slaughtering (study phase), 2 treatments applied at the feedmill at 0.2 ppm on top of Na selenite in the premix SeMet (Excential Se 4000): 4 000 mg SeMet/kg i.e. 1 600 mg Se/kg OH-SeMet (Selisseo 2% Se): 50 000 mg OH-SeMet i.e. 20 000 mg Se/kg Dosage of total Se concentration in muscle and liver (after sampling at slaughter house on 10 pigs per treatment), speciation SeMet and SeCys done on male pigs Blood biomarkers: GPx and GSH (after blood sampling one week before slaughtering) 11
Experimental Feed Se analyses Se OH OH-Selenomethionine Selenomethionine Feed analyses Total Se (mgkg) Average Standard deviation Exp Diet SeMet 0,27 0,31 0,53 0,48 Exp Diet OH-SeMet 0,29 0,50 0,40 0,50 0,258 0,35 0,468 0,42 0,42 0,34 0,30 0,40 0,13 0,39 0,08
OH-SeMet an efficient source in fattening pigs a b 10 replicates of male & female pigs per treatment 13
Muscle Se speciation (SeMet & SeCys) in OH-SeMet or SeMet fed finishing pigs 1,400 Muscle Speciation (mg Se/kg) 1,200 1,000 0,800 A 0,600 0,400 0,200 0,000 a B A b B SO SO EX EX SeMet (mg eq. Se/kg DM) SeCys (mg eq. Se/kg DM) Total Se (mg Se/kg DM) 3 replicates of 2 male pigs per treatment 14
Liver Se speciation (SeMet & SeCys) in OH-SeMet or SeMet fed finishing pigs 2,500 Liver speciation (mg Se/kg) 2,000 1,500 1,000 a b 0,500 0,000 A SO SO EX EX SeMet (mg eq. Se/kg DM) SeCys (mg eq. Se/kg DM) B Total Se (mg Se/kg DM) 3 replicates of 2 male pigs per treatment 15
16 OH-SeMet an efficient source in fattening pigs
17 OH-SeMet: the source of functional Se as SeCys
Take home messages Within the range of Se sources on the market, the pure organic forms (SeMet & OH-SeMet) are the most efficient to enhance Se deposition Se is only deposited as SeMet in all tissues and as SeCys, the functional form of Se included in selenoproteins OH-SeMet is fully stable under feed processing conditions including premix storage (data not shown) OH-SeMet is also the only organic Se source enhancing the functional SeCys guaranteeing the most efficient antioxidant potential More research has to be performed to better understand the mechanism explaining the stimulation of SeCys synthesis 18