Michele De Marco’s research while affiliated with Adisseo and other places

Seleno-Yeasts (SY) used as feed additives are known to contain different Selenium (Se) species. Seleno-Yeasts has been shown, on previous analytical methods, to contain selenomethionine (SeMet), selenocysteine (SeCys), selenate (SeIV) and selenite (SeVI), and various other organic and inorganic Se forms identified but rarely quantified. A new advanced method has allowed elemental Se (Se0), an inorganic Se species, to be quantified, thereby obtaining better insight into the proportion of inorganic Se in SY products. The study aimed to quantify the Se0 in SY products and assess the proportion of inorganic Se in SY. The Se speciation of 13 fresh commercials SY from different suppliers and batches, was assayed for the total Se, inorganic Se species (SeIV, SeVI and Se0), and organic Se species (SeMet and SeCys). Results on total Se were in line with the expected Se concentrations for all evaluated samples. The proportion of Se present as Se0 ranged from 3.6% to 51.8%. The quantity of Se0 in the SY products, added to SeIV and SeVI, indicated an average proportion of inorganic Se of 14.2% for the 13 analyzed SY products. The proportion of Se as SeMet ranged from 19.0% to 71.8%, (average of 55.8%), and a large variability in the SeMet content was observed. The SeCys content was also variable, with an average of 3.8%, relative to the total Se. In conclusion, advances in the analytical characterization have revealed that SY products can have a significantly high proportion of inorganic Se, which could affect the bioavailability of Se from SY supplements and explain their variable and lower bio-efficacy than pure SeMet supplements, such as hydroxy-selenomethionine.

The aim of this study has been to compare the effect of sodium selenite (SS) or hydroxy-selenometionine (OH-SeMet) on the performance of broiler breeders and their progeny. A total of 216 broiler breeders (AP95 Aviagen; 55-65 weeks old) were assigned to two treatments: a diet supplemented with 0.3 mg Se Se/kg as SS or a diet supplemented with 0.2 mg Se Se/kg as OH-SeMet. A total of 520 mixed progeny chicks were used for a growth trial (41 d), in a completely randomised 2 × 2 factoria design: 2 sources of Se for the breeder diets and two sources of Se for the progeny diets – SS at 0.3 mg Se Se/kg and OH-SeMet at 0.2 mg Se Se/kg. OH-SeMet increased the egg production, the Se content in the egg, eggshell strength and hatchability (p < .05), compared to SS. The high Se deposition in the hatching eggs benefitted the progeny, as reflected by the better feed conversion ratio (p < .05). No significant changes were observed in the feed intake or weight gain, or the interactions between the maternal diets and progeny diets. Overall, supplementation with OH-SeMet at 0.2 mg Se Se/kg has proved to be an effective approach to help maintain the productive and reproductive performances of ageing breeder flocks and to enhance the performance of their progeny. • Highlights • Replacement of dietary sodium selenite with hydroxy-selenomethionine in the broiler breeder diet increased Se accumulation in the eggs and improved egg production, the Se content in the eggs, eggshell strength and hatchability. • The increased Se deposition in the hatching eggs benefitted the progeny, as reflected by the better feed conversion ratio. • Supplementation with OH-SeMet at 0.2 mg Se/kg proved to be an effective approach to help maintain the productive and reproductive performances of ageing breeder flocks and to enhance the performance of their progeny.

This study has determined whether hydroxy-selenomethionine (OH-SeMet) exerts a better protective action on broilers against environmental stress than sodium selenite (SS) or seleno-yeast (SY). Day-old male Cobb 500 broilers (12 cages/diet, 9 broilers/cage) were fed a selenium (Se)-deficient diet (0.047 mg/kg) supplemented with SS, SY or OH-SeMet at 0.3 mg Se/kg under a high stocking density and heat stress condition for six weeks. OH-SeMet improved the FCR and Se concentration in the tissues than SS and SY. SY and OH-SeMet both reduced the serum cortisol, T3, IL-6, IgA, IgM and LPS, more than SS, while only OH-SeMet further increased IL-10 and IgG. SY and OH-SeMet improved the intestinal morphology and increased the T-AOC, TXRND, SELENON and OCCLUDIN activities but decreased CLAUDIN2 in the jejunum than SS, while OH-SeMet further improved these values than SY. SY and OH-SeMet both increased SELENOS and TXNRD2 in the muscles than SS, and OH-SeMet further raised T-AOC, GPX4, SELENOP, SELENOW and TXNRD1, and reduced malondialdehyde and protein carbonyl in the muscles than SS and SY. OH-SeMet showed a better ability to maintain the performance and the redox and immune status of broilers under a high stocking density and heat stress challenge than SS and SY.

The aim of the study was to compare the effects of sodium selenite (SS), selenium yeast (SY), and hydroxy-selenomethionine (OH-SeMet) on the meat quality and selenium (Se) deposition of finishing beef cattle. Sixty-three bulls were distributed over 3 treatments and fed SS, SY, or OH-SeMet at 0.2 mg kg−1 dry matter (DM) for 60 d. None of the Se sources affected the growth performance or carcass characteristics. OH-SeMet showed a higher Se transfer to the meat than SS or SY (p < 0.01). SY and OH-SeMet reduced the shear force of the meat (p < 0.0001), improved pH (p < 0.001), and reduced the drip losses (p < 0.001) and the lipid oxidation of the meat (p < 0.001). During 8 d of storage, OH-SeMet showed higher levels of meat lightness (L*) and yellowness (b*) than SS (p < 0.001), while the SY meat showed a higher L* than SS, albeit only on d 6. OH-SeMet improved b*, compared to SS, and also compared to SY on days 4, 7, and 8 (p < 0.001). Supplementing beef with SY and OH-SeMet improved several meat quality parameters. OH-SeMet appears to be the most effective strategy to improve the Se content and color stability of beef cattle meat.

The aim of the study was to compare the effects of sodium selenite (SS), selenium yeast (SY), and hydroxy-selenomethionine (OH-SeMet) on the meat quality and selenium (Se) deposition of fin-ishing beef cattle. Sixty-three bulls were distributed over 3 treatments and fed SS, SY, or OH-SeMet at 0.2 mg kg–1 dry matter (DM) for 60 d. None of the Se sources affected the growth performance or carcass characteristics. OH-SeMet showed a higher Se transfer to the meat than SS or SY (p < 01). SY and OH-SeMet reduced the shear force of the meat (p < 0001), improved pH (p < 001), and reduced the drip losses (p < 0.001) and the lipid oxidation of the meat (p < 0.001). During 8 d of storage, OH-SeMet showed higher levels of meat lightness (L*) and yellowness (b*) than SS (p < 0.001), while the SY meat showed a higher L* than SS, albeit only on d 6. OH-SeMet improved b*, compared to SS, and also compared to SY on days 4, 7, and 8 (p < 0.001). Supplementing beef with SY and OH-SeMet improved several meat quality parameters. OH-SeMet appears to be the most effective strategy to improve the Se content and color stability of beef cattle meat.

This study is aimed at comparing the bio-efficacy of different inorganic and organic Se compounds. Three broiler experiments (Exp1 = Ross PM3; Exp2 = Ross 308; and Exp3 = Ross 308) were performed, on the basis of Se tissue accretion, to define the bio-efficacy of Se sources. Birds were fed a control diet (negative control [NC]; no supplemental Se) and, depending on the study, the NC was supplemented with sodium selenite (SS), Se-yeast (35%, 56%, 65% or 72% of Se as selenomethionine (SeMet); SY35, SY56, SY65 and SY72), pure forms of selenocysteine (SeCys) (methylselenocysteine [MSeCys]; L-selenocystine [L-SeCys]), or pure form of organic Se (L-selenomethionine, L-SeMet or hydroxy-selenomethionine, OH-SeMet) at 0.3 mg Se/kg. In Exp 2, an additional treatment of SY65 + L-SeCys was also fed, with both sources added at 0.3 mg Se/kg. In Exp3, L-SeMet and OH-SeMet, were supplemented at 0.15, 0.30, 0.45 and 0.60 mg Se/kg. The results of Exp 1 (mg Se/kg muscle DM) were: NC, 0.56; SS, 0.73; MSeCys, 0.68; L-SeCys, 0.70; SY65, 1.52; OH-SeMet, 1.85 (p < .001); Exp 2 were: NC, 0.34; SS, 0.52; SY35, 0.84; SY65, 1.18; SY65 + L-SeCys, 1.22; OH-SeMet: 1.33 (p < .001); Exp 3 were: NC, 0.10; SS, 0.31; SY56, 0.88; SY72, 1.03; L-SeMet, 1.33; OH-SeMet, 1.33 (p < .01). The results of these three studies demonstrate that the bio-efficacy of organic Se supplements for chickens depends upon the proportion of SeMet, while dietary SeCys sources showed similar bio-efficacy as SS. Moreover, these data showed the high bio-efficacy of the pure form of organic Se and the bioequivalence between L-SeMet and OH-SeMet. • Highlights • Updated knowledge on the bioavailability of different Se compounds in broiler. • Direct L-selenomethionine and hydroxy-selenomethionine comparison.

The benefits of selenium (Se) supplementation during pregnancy and lactation in sows on piglet immunocompetence are not yet fully understood. This study aimed to assess piglet immune status when sows were fed Se-deficient or supplemented diets with sodium selenite (SS) or hydroxy-selenomethionine (OH-SeMet). Twelve pregnant sows were randomly assigned to 3 dietary treatments (4 sows each): no supplemental Se (NC), SS at 0.3 mg Se/kg (SS-0.3), OH-SeMet at 0.3 mg Se/kg (SO-0.3). The trial was carried out from gestation day (gd) 84 to weaning on postpartum day (ppd) 21, at which time all the piglets received the same diet having as Se source SS. On gd 98 and 105, sows were vaccinated with hen egg white lysozyme (HEWL). On ppd 0 and 21, 8 piglets/treatment were euthanized to obtain blood and muscle samples for total Se analyses. Serum samples were collected from 8 female piglets/treatment on ppd 0 and 2 to assess antigen-specific antibody titer for HEWL. On ppd 23, 6 weaned female piglets/treatment were intramuscular challenged with E. coli lipopolysaccharide (LPS) and serum IL-10 levels were measured at 24 h pre-challenge and at 2 and 48 h post challenge. At day 21, piglets from sows fed SO-0.3 showed the highest muscle Se deposition (P < 0.001). At ppd 0, no difference for HEWL-specific IgG was found while at ppd 2, SO-0.3 showed the highest HEWL-specific IgG concentration (P < 0.05). At 24 h pre-challenge and 2 h post LPS challenge, SO-0.3 showed a greater IL-10 level as compare to NC and SS-0.3, respectively (P < 0.05); no difference was found for the same parameter at 48 h post challenge. Piglets from SO supplemented sows exhibited stronger early immune response to LPS challenge. This study indicates the importance of sow Se supplementation with a pure organic form of Se such as OH-SeMet to enhance piglets Se and immune status.