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Publication - Professor Michael Lee

    The potential of silage lactic acid bacteria-derived nano-selenium as a dietary supplement in sheep


    Lee, MR & Whittington, FM, 2019, ‘The potential of silage lactic acid bacteria-derived nano-selenium as a dietary supplement in sheep’. Animal Production Science.


    Context. Selenium (Se) is a trace element essential for cellular function in animals as a component of the enzymes
    glutathione peroxidase and iodothyronine-5-deiodinase. In many parts of Europe, Se is often deficient in livestock diets due
    to the low Se status of soil. Supplementation of diets with selenised yeast (predominately as seleno-methionine) or inorganic
    sodium selenite is common practice in most livestock systems, including ruminants. Lactic acid bacteria have been shownto
    convert inorganic Se into predominantly elemental nano-Se, which has been used recently in human pro-biotics as a less
    toxic form of Se. Therefore, silage lactic acid bacteria may provide a supplementation route of bioavailable nano-Se for
    Aim.Here, we report onthe effect of feeding inoculated silage enriched with a supra-nutritionallevel of nano-Se (Selage)
    versus control inoculated silage (Silage) on the Se status of finishing lambs and their products, followed by a second study
    where blood parameters were investigated in ewes.
    Methods. In the first study, 40 Charollais · Suffolk lambs (42 1.7 kg) were paired according to weight and sex, then
    allocated to the two treatments for 8 or 10 weeks. Uptake of Se into wool was temporally assessed, as well as excretion of Se
    into faeces. Selenium concentrations in blood and muscle, carcass characteristics and meat quality are reported postmortem.
    In the second study, individually penned Suffolk · Mule ewes (n = 12; 76 4.5 kg) were offered the same diets as in the first
    study. Blood parameters were assessed at the start and after 6 weeks, with intake and excretion into faeces and urine assessed
    temporally throughout the study.
    Key results. In the first study, dry-matter (DM) intake was similar in both treatment groups, at 0.8 0.03 kg/day, but Se
    concentrations of the diets were significantly different, resulting in intakes of ~0.14 and 1.60 mg/day on the Silage and
    Selage diets, respectively. This was reflected in higher Se concentrations in faeces (0.4 vs 2.0 mg/kg DM; P < 0.001), wool
    (0.11 vs 0.25 mg/kg DM; P < 0.001), blood (0.19 vs 0.46 mg/L; P < 0.001) and muscle (0.31 vs 0.41 mg/kg: P < 0.01) on the
    Selagethan onthe Silage diet.Colour (chroma) shelflife ofthe meat was significantly higher onthe Selagetreatment (8.05 vs
    9.2 days; P < 0.05). In the second trial, for ewes fed Selage, blood seleno-methionine increased from 0.21 to 0.25 mg/L and
    seleno-cysteine from 0.25 to 0.35 mg/L after 6 weeks on the treatment, whereas there was no change in ewes fed Silage.
    Glutathione peroxidase increased, whereas haematocrit, haemoglobin and platelet count were decreased across time during
    the study, but there was no difference between the treatments.
    Conclusions. Nano-Se provided by the Selage treatment was shown to be available to sheep and improve shelf life, with
    no adverse haematological effects.
    Implications. There is potential to use silage inoculants to provide bioavailable Se to ruminants. Further research is
    required to determine the most appropriate dose for animal performance and product quality.

    Full details in the University publications repository